Biology I Honors Study Guide Midterm 2024 PDF

Bio 4 Little shorter version of study guide(still a little long) - Chapter 1 Identify: What are the important themes in biology? There were 4 important ones? note several at the end of chapter 1 Themes of life: - Cell - Homeostasis/ regulation - Adaptation/ evolution - Respon...

Bio 4 Little shorter version of study guide(still a little long) - Chapter 1 Identify: What are the important themes in biology? There were 4 important ones? note several at the end of chapter 1 Themes of life: - Cell - Homeostasis/ regulation - Adaptation/ evolution - Response to the Environment/ stimuli - Growth and Development - Energy Processing - Reproduction - Organization and Hierarchy (Order) Remember CHARGERO 4 main themes of Biology: - Evolution - emerging properties related to natural selection (which was discovered by Darwin). Gene Expression - Structure and function are related - Energy Transfer (Cell Respiration, Metabolism, etc.), - and Systems Biology (interactions between organisms and their environment.) - A(n) cell is the smallest unit capable of life but an atom is the smallest unit of matter. Define Biology, Science, Species, family, biological community, reproduction a. Biology: Biology is the scientific study of life. It encompasses various properties of life, including order, reproduction, growth and development, energy processing, regulation, response to the environment, and evolutionary adaptation. The cell is considered the structural and functional unit of life. b. Science: Science is a systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the universe. c. Species: A species is defined as a group of populations whose members have the potential to interbreed in nature and produce fertile offspring. This definition is known as the biological species concept. Other concepts include the morphological species concept, which is based on physical traits, and the ecological species concept, which focuses on ecological niches. d. Family: In biological classification, a family is a higher taxonomic category than genus and species. It groups together related genera.  e. Biological community: A biological community consists of all the populations of different species that live in the same area and interact with each other. f. Reproduction: Reproduction is a fundamental property of life, involving the production of new individuals. It can occur sexually, with the combination of genetic material from two parents, or asexually, with offspring arising from a single organism. Name the eight properties of life Understand the differences in the following: 1. Response vs. stimulus: Stimulus(cause) triggers a response(reaction/effect) 2. Homeostasis vs. Adaptation: Homeostasis is the maintenance of stable internal conditions, while Adaptation is the long-term change in response to environmental pressures. 3. Science vs. Pseudoscience: Science relies on empirical evidence and the scientific method, while Pseudoscience lacks rigorous testing and often does not follow scientific principles. 4. Growth vs. Development: Growth refers to an increase in size and in mass, while Development refers to changes in form and function over time. 5. Adaptation vs. Evolution: which one is long term change and which one is the result of the biological environment in the community? Adaptation is short term adaptation for a specific time. Evolution is long term change over a long period of time. 6. How does organization relate to the atom all the way through the biosphere? It starts with the first level of organization (the atom), which fits into the next level of organization (the molecule), which fits into the next level of organization (organelles), and so on and so forth until we reach the highest level of organization possible (the biosphere). Scientific Method Most scientific investigations begin with observations or problems that lead to questions. Understand all the components of the scientific method and their order in experimental design. Problem statement, observation, research, hypothesis, design, experiment, Data, analysis, control variables, conclude, publish, etc.: 1. Problem Statement: Identify the question or issue to be solved. 2. Observation: Gather information using your senses. 3. Research: Look for existing information to help answer the question. 4. Hypothesis: Make an educated guess about the answer. 5. Design: Plan the experiment, including variables and methods. 6. Experiment: Conduct the test and collect data. 7. Data: Record the results from the experiment. 8. Analysis: Interpret the data to see if it supports the hypothesis. 9. Control Variables: Keep all variables constant except the one you're testing. 10. Conclude: Summarize the findings and determine if the hypothesis is supported. 11. Publish: Share the results with others to advance knowledge. Hypothesize, identify the independent and dependent variables, and identify any constants for the experiment. Differentiate Constants from controls.  THEORY is a general explanation for a broad range of data; while a hypothesis is a testable explanation of an observation. How does this differ from a hypothesis? Hypothesis is a testable prediction you make based off observations ○ a theory is a broad, well-supported explanation for many observations, while a hypothesis is a focused, testable prediction that can be tested to confirm or deny a specific aspect of the theory. Explain the difference between independent and dependent variables in a controlled experiment. There are two types of samples or groups: the test sample and the control sample: control indicates whether or not the experiment worked. If the control fails you cannot use your date. The test samples would test each variable. Would the results of the known response be found in a control sample (groups) data or the experimental sample (group)? experimental bc that's where the iv. manipulates d.v to acc see results Independent Variable: The factor you change or manipulate in an experiment to see how it affects something. (e.g., amount of sunlight for plant growth) Dependent Variable: The factor you measure or observe, which is affected by the independent variable. (e.g., plant height) Control Sample: The group that does not receive the experimental treatment or variable. It helps to show whether the treatment has an effect. If the control fails, the experiment’s validity is questioned, and you cannot trust the results. Test Sample: The group that receives the experimental treatment or variable. This is where you measure the dependent variable in response to changes in the independent variable. When do you repeat vs. refine/revise an experiment in relation to a hypothesis. Repeat: Do the experiment again if the results were unclear or if there were errors, to verify consistency. Refine/Revise: Adjust the experiment or hypothesis if the results don’t support the hypothesis, improving the setup or prediction for better accuracy next time. define Clinical trial results: blind vs double-blind, control vs test, placebo clinical trial: a controlled experiment involving humans to test new meds/treatments blind: Participants don’t know which group (control or test) they are in. double- blind Neither participants nor researchers know who is in which group (control or test). control: The group that does not receive the treatment, used for comparison. test: The group that receives the treatment being tested. placebo: A "fake" treatment given to the control group to mimic the test treatment, without the active ingredient.  How many times is an experiment repeated to ensure there is enough data? FIVE Understand Quantitative vs. Qualitative data: one is objective measured numerical data, one is, observations only, and therefore considered subjective, which is which? Quantitative Data: Objective, measured numerical data (e.g., height, weight, temperature). Qualitative Data: Subjective observations, usually descriptive (e.g., color, texture, behavior). ○ Quantitative = numbers, Qualitative = descriptions. SI units and what they are used for. SI Units (International System of Units) are a standardized system of measurement used globally in science, industry, and everyday life. - provides consistency and allow easy comparison in results What are examples of each system American (Imperial) Units: SI (Metric) Units: Inch (in) – used to measure length. Centimeter (cm) – used to measure Yard (yd) – used to measure length. length. Pound (lb) – used to measure Meter (m) – used to measure length. weight/mass. Kilogram (kg) – used to measure Fahrenheit (°F) – used to measure mass. temperature. Celsius (°C) – used to measure temperature. What is the SI unit system based on mathematically? The SI unit system (International System of Units) is based on powers of 10. How does a clinical trial differ from routine lab experiments? blind study, double blind, placebo =control group Clinical Trial: Tests treatments on humans, often using blind or double-blind designs to prevent bias. The control group gets a placebo to compare effects. Routine Lab Experiment: Tests ideas in controlled settings, often with non-human subjects (like cells or animals), to explore scientific questions. Data, know the difference between constants and controls. Constants are factors you keep the same to make the experiment fair. ○ These are the factors in an experiment that stay the same across all groups (both test and control) to ensure that any changes observed are due to the independent  variable alone. For example, the type of soil used in a plant growth experiment might be constant. Controls are groups used for comparison to see if the experiment's treatment has an effect. ○ These are the baseline or reference group(s) in an experiment, which do not receive the experimental treatment or variable. The control group helps to compare the effect of the independent variable. For example, in a drug test, the control group might receive a placebo instead of the actual drug. Ethics in relationship to science, when and who does a Peer review, what does a scientist do with new information once his hypothesis is tested? when does he refine vs just move forward with clinical data Ethics in Science: Ensures research is conducted honestly, with integrity, and with respect for participants and the environment. Peer Review: Other scientists in the field review research before it's published to ensure accuracy and quality. What a Scientist Does with New Information: If the hypothesis is supported, they move forward; if not, they may refine the hypothesis and test again. Refine vs. Move Forward with Clinical Data: Refine when results are unclear or unexpected; move forward if the data supports the hypothesis or shows a clear conclusion. Hierarchy and Organization as a theme in biology helps biologists understand how organisms are related to other living organisms and to organisms that have lived in the past. Any physical or behavioral traits that help an organism to survive and reproduce better than the last generation are called adaptations. Evolution is long term change over many generation The scientific naming of animals was created by Linnaeus and is called Binomial Nomenclature.. What are the two parts in an organism’s scientific name and how are they written? ○ Genus: The first part, capitalized (e.g., Homo). ○ Species: The second part, lowercase (e.g., sapiens). ○ The full name is written in italics (or underlined when handwritten): Homo sapiens. The current naming system by Linnaeus is binomial nomenclature and consists of genus and species, know which is which Define species, vs species, population, a. species: A group of populations whose members have the potential to interbreed and produce viable, fertile offspring b. vs species: Different species can’t typically reproduce with each other (chat gpt idk fs) c. population: A group of individuals belonging to one species that live in the same geographic area and can potentially interbreed.  The current classification system is known as Phylogenetic Systematics and is the science that groups and classifies organisms. Cladistics as a theme in biology helps biologists understand how organisms are related to other living organisms and to organisms that have lived in the past. What is the Tree of Life, gene expression, a. tree of life: portrays the evolutionary relationships among groups of plants, animals and all other forms of life. b. gene expression: how genes get their function from information Why does life depend on the flow of information? How does information flow from DNA to protein production? ○ Life depends on the flow of information because organisms need instructions to grow, function, and reproduce. Information is passed down and used to create the molecules that carry out life’s processes. Information Flow (DNA to Protein): 1. DNA: Holds the genetic code (instructions). 2. Transcription: DNA is copied into messenger RNA (mRNA). 3. Translation: mRNA is read by ribosomes to assemble amino acids into a protein. Systems biology definition ○ Systems biology is the study of how different parts of a biological system interact and work together to understand the whole system's behavior. How are structure and function related? Terms for same function different structure and different structure same function ○ Structure: The way something is built or organized. ○ Function: What it does or how it works. ○ Relation: how something is shaped or arranged allows it to do its job well. ○ analogous structures: same function diff structure ○ homologous structures: same structure diff function: How are biology Technology and Sociology connected? Section 1.8 ○ The goal of Science is to understand natural phenomenon ○ The goal of Technology is to apply scientific knowledge for a purpose ○ The goal of sociology is to use Science and Technology to improve life Chapter 2 There is a direct relationship between structure and function of living organisms and their components. for example, the carbon molecule bonds strongly with 4 valence electrons, this allows for different Shape, function and diversely in organic molecules (macromolecules) The process by which cells are programmed into their specific functions is called cellular differentiation What are the subatomic particles? *their location? *their charge? *atomic # *mass # *valence electrons *types of ions *parts of a chemical equation *activation energy *catalyst vs enzyme and how it affects activation energy? by bonding substrates to the enzyme which lowers the activation energy to speed up the reaction time but does not make more product.  Subatomic Particles ○ Particles smaller than atoms including neutrons, electrons, and protons Charge ○ Negative, positive, or neutral - depend on particles (electron, proton, neutron) effect particle Atomic number ○ The number of protons in each form of a particular element Mass number ○ The number of protons and neutrons in an atom’s nucleus Valence electrons ○ electrons in outermost shell of element Types of Ion If anyone knows the answer to this please type below the different types of ions ○ Atom with electrical charge Cations:Positively charged ions. Anions: Negatively charged ions. Parts of a chemical equation ○ Reactants - what are put in the equation to make ○ Products - the outcomes Ex: ATP in cell respiration Activation energy ○ Energy needed for a chemical reaction to happen catalyst vs enzyme ○ Catalyst Something that speeds up the process of a chemical reaction ○ Enzyme A biological catalyst ○ Both reduce the activation energy needed for a chemical reaction, hence quickening it Metabolic pathways vs Cellular metabolism, Metabolic pathways → a series of reactions in a cell that converts substrates into products Cellular metabolism → sum of all chemical reactions within a cell Metabolic pathways vs. Cellular Metabolism → cellular metabolism is the broad concept of all chemical processes in a cell while metabolic pathways are the individual routes taken by specific reactions inside that process. Solutions, compounds, mixtures, etc. Solution → a homogeneous mixture of two or more substances ○ Solvent → the dissolving substance of a solution (water) ○ Solute → Substance that will dissolve due to a solvent ○ Aqueous solution →solution where water is solvent Compounds → a substance containing two or more elements in a fixed ratio Mixtures →a combination of two or more things  ○ Homogeneous mixture → Mixture where all substances are perfectly mixed together, can’t see different elements ○ Heterogeneous mixture → Mixture where substances are easily seen and are not perfectly mixed elements, compounds, molecules vs salts (molecules have covalent bonds, salts have ionic bonds. Element ○ A substance that cannot be broken down to another substance by chemical means Molecules ○ The smallest particle of a substance that has all the properties of that substance - made up of one or more atoms Salt ○ A compound resulting from the formation of an ionic bond trace elements are the essential components available in only small quantities but necessary for life such as iodine and iron? yuh What is the difference between hydrogen, ionic and covalent bonds? how are they formed with electrons? which is strongest to weakest , why is that important? What is the difference between Molecules, electronegativity, nonpolar bonds and polar covalent bonds? Covalent Bond (strongest): A covalent bond forms when two atoms share electrons. The shared electrons help both atoms "feel" stable. How it forms: In a covalent bond, two atoms share electrons. Each atom needs electrons to be stable, so they share electrons to fill their outer shells. Why it's strong: The atoms are "stuck" together because they both rely on the shared electrons to feel stable. This sharing makes the bond hard to break. Ionic Bond (middle strength): An ionic bond forms when one atom gives up an electron to another atom. This creates positively and negatively charged ions that attract each other. It's a stronger bond than a hydrogen bond How it forms: In an ionic bond, one atom gives away electrons, and another takes them. This creates oppositely charged ions (positive and negative) that attract each other. Why it's strongish: The attraction between the oppositely charged ions is strong, but the bond can be weaker than covalent bonds, especially in liquids or when surrounded by other charged particles..Hydrogen Bond (weakest): A hydrogen bond is a weak attraction between a hydrogen atom (which is bonded to an electronegative atom like oxygen or nitrogen) and another electronegative atom. It's not a full bond, more like a connection.  How it forms: A hydrogen bond is not a full bond. It happens when a hydrogen atom that is already bonded to a very electronegative atom (like oxygen or nitrogen) is attracted to another electronegative atom nearby. Why it's weak: It’s just an attraction between molecules, not a true bond where electrons are shared or transferred. This is why it’s weaker than ionic or covalent bonds. Why does it matter? Stronger bonds (like covalent) are harder to break, so they help hold molecules together more tightly, which is important for keeping biological systems stable. Weaker bonds (like hydrogen bonds) allow for flexibility and easier changes, which is important for things like the structure of water and DNA, where molecules need to interact but also separate and rejoin. In short: Covalent bonds are the strongest because atoms share electrons tightly. Ionic bonds are strong but can break easier than covalent bonds because of their dependence on charge attraction. Hydrogen bonds are the weakest because they are just attractions between molecules, not real bonds. Key Differences b/w Covalent, Ionic, and Hydrogen Bonds Covalent Bonds: Involve sharing of electrons. Ionic Bonds: Involve transfer of electrons and attraction between ions. Hydrogen Bonds: Weak attractions between a hydrogen atom and an electronegative atom. Molecules are groups of atoms bonded together. - Two or more atoms held together by covalent bonds. Electronegativity is how strongly an atom attracts electrons. - The attraction of a given atom for the electrons of a covalent bond. Nonpolar bonds occur when atoms share electrons equally, with no charge difference. - A type of covalent bond in which electrons are shared equally between two atoms of similar electronegativity. Polar covalent bonds occur when atoms share electrons unevenly, creating partial charges (positive and negative). - A covalent bond between atoms that differ in electronegativity. The shared electrons are pulled closer to the more electronegative atom, making it slightly negative and the other atom slightly positive. The sum of all chemical reactions carried out in an organism is metabolism What is the pH scale that measures the potential of H+ IONS IN acids and bases: what are the ions found in ACID VS BASES AND THEIR pH ranges, how buffers affect solutions. 1. pH Scale Definition: The pH scale measures how acidic or basic (alkaline) a solution is ranges from 0 to 14. ○ pH < 7 = Acidic higher H+ concentration lower OH- concentration ○ pH = 7 = Neutral (like pure water) ○ OH- and H+ concentrations are evenly distributed ○ pH > 7 = Basic (Alkaline) lower H+ concentration higher OH- concentration 2. Ions in Acids vs. Bases Acids: ○ Ions found in acids: Acids release hydrogen ions (H⁺) when dissolved in water. ○ 0-7 Bases: ○ Ions found in bases: Bases release hydroxide ions (OH⁻) when dissolved in water. ○ 7-14 3. How Buffers Affect Solutions Buffers are special solutions that resist changes in pH. How buffers work: Buffers usually contain a weak acid and its corresponding base absorb excess H⁺ ions (if the solution becomes too acidic) or OH⁻ ions (if the solution becomes too basic), maintaining the pH within a narrow range. Importance of buffers: Buffers are crucial in biological systems because many reactions in the body require a stable pH. Chapter 37 Ecology natural selection is the most important force in evolution. Define these terms: biogeochemical cycle, - Any of the various chemical circuits that involve both biotic and abiotic components of an ecosystem. energy. -The capacity to cause change, especially to perform work. coevolution - Evolutionary change in which adaptations in one species act as a selective force on a second species, inducing adaptations that in turn act as a selective force on the first species; a series of reciprocal evolutionary adaptations in two interacting species. keystone species, - A species whose impact on the community is much larger than its biomass or abundance would indicate. invasive species, - A non-native species that spreads beyond its original point of introduction and causes environmental or economic damage. biological diversity - The variety of living things; includes genetic diversity, species diversity, and ecosystem diversity. Types of ecological succession, how they return to mature climax community ecological succession - The process of biological community change resulting from disturbance; transition in the species composition of a biological community. See also primary succession; secondary succession. 1. primary succession - A type of ecological succession in which a biological community arises in an area without soil. See also secondary succession. 2. secondary succession - A type of ecological succession that occurs where a disturbance has destroyed an existing biological community but left the soil intact. See also primary succession. Symbiosis relationships and their types symbiosis - A physically close association between organisms of two or more species. 1. Mutualism:This is a mutually beneficial relationship between one organism and another. This is a +/+ relationship 2. Commensalism: There are organisms that grow on other organisms. They do not harm the host but benefit by gaining access to things. This is a +/0 relationship 3. Parasitism: One organism siphons nutrients from their host, often harming them in the process. Parasite benefits, host gets hurt. This is +/- relationship  Interspecific vs. Intraspecific interactions, herbivory Intraspecific vs. Interspecific Interactions 1. Intraspecific Interactions: a. Definition: These interactions occur within a single species. b. Impact: Intraspecific competition is often more severe because members of the same species have exactly the same niche and compete for the same resources. 2. Interspecific Interactions: a. Definition: These interactions occur between different species. b. Impact: Interspecific competition generally lowers the carrying capacity for competing populations because the resources used by one population are not available to the other. 3. Key Differences: a. Scope: Intraspecific interactions occur within a species, while interspecific interactions occur between different species. b. Competition Severity: Intraspecific competition is often more intense due to identical resource needs. These interactions are fundamental to understanding community structure and dynamics in ecology. herbivory - Consumption of plant parts or algae by an animal. carnivory - Competition of meat parts by an animal Ecological terms like habitat, niche ecosystem habitat - A place where an organism lives; the environment in which an organism lives. niche/ecological niche - The role of a species in its community; the sum total of a species’ use of the biotic and abiotic resources of its environment. ecosystem - All the organisms in a given area, along with the nonliving (abiotic) factors with which they interact; a biological community and its physical environment. Species Richness vs. abundance know the difference and how it affects population 1. Species Richness: a. Definition: The number of different species present in a community. b. Example: If you walk through two different woodlots (A and B) and both have four different species of trees, the species richness is the same for both woodlots. 2. Relative Abundance: a. Definition: The proportional representation of each species in a community.  b. Example: In woodlot A, one species might dominate, making up most of the trees, while the other three species are less common. In woodlot B, all four species are equally represented. 3. Impact on Population: a. Community Diversity: A community with high species richness and even relative abundance (like woodlot B) is considered more diverse. b. Animal Populations: Diverse plant communities provide a variety of habitats and food sources, supporting a greater diversity of animal species. c. Pathogen Spread: In communities with high relative abundance of a single species (like woodlot A), pathogens can spread more easily among the dense population of that species. In more evenly distributed communities (like woodlot B), pathogens have a harder time spreading. By understanding these concepts, we can see how both species richness and relative abundance contribute to the overall health and stability of ecosystems. the hierarchy from atom all the way to biosphere 1. Atom:The smallest unit of matter that retains the properties of an element. 2. Molecule: A group of atoms bonded together. 3. Organelle: Specialized structures within a cell that perform specific functions. 4. Cell: The basic unit of life. 5. Tissue:A group of similar cells that perform a specific function. 6. Organ: A structure composed of different tissues working together. 7. Organ System:A group of organs that work together to perform a complex function. 8. Organism:An individual living entity. 9. Population:A group of organisms of the same species living in a specific area. 10. Community:All the populations of different species living and interacting in an area. 11. Ecosystem:A community plus the non-living (abiotic) environment. 12. Biosphere:The global ecosystem; the sum of all the planet’s ecosystems. coevolution, adaptation, camouflage, coevolution - Evolutionary change in which adaptations in one species act as a selective force on a second species, inducing adaptations that in turn act as a selective force on the first species; a series of reciprocal evolutionary adaptations in two interacting species. adaptation - An inherited character that enhances an organism’s ability to survive and reproduce in a particular environment. camouflage - the disguising of an organism by painting or covering themselves to make them blend in with their surroundings.  Food webs, pyramids vs chains (not what eats what): trophic levels, consumer types, nutrient transfer Trophic Structure: Trophic Levels: These are the different levels in a food chain or web, representing the position an organism occupies in the sequence of energy transfer. Producers: Autotrophs like plants and phytoplankton that synthesize their own food using light or chemical energy. Consumers: Heterotrophs that depend on producers or other consumers for energy. They are classified into: Primary Consumers: Herbivores that eat producers (e.g., grasshoppers, zooplankton). Secondary Consumers: Carnivores that eat primary consumers (e.g., small mammals, small fishes). Tertiary Consumers: Carnivores that eat secondary consumers (e.g., snakes). Quaternary Consumers: Top-level carnivores that eat tertiary consumers (e.g., hawks, killer whales). Food Chains: A linear sequence showing the direct transfer of energy and nutrients from one organism to another. Food Webs: A complex network of interconnected food chains, providing a more realistic representation of how organisms feed on multiple types of food and occupy multiple trophic levels. Energy Pyramids: Illustrate the energy flow through trophic levels, showing a stepwise decline in energy from producers to top-level consumers. Only a small fraction of energy (about 1/1,000) produced by photosynthesis reaches top-level consumers, explaining why these consumers need large territories and why food chains are limited to three to five levels. Comparison: Food Chains are simple and linear, while Food Webs are complex and interconnected. Energy Pyramids help visualize the energy loss at each trophic level, emphasizing the inefficiency of energy transfer in ecosystems. Understanding these concepts helps explain the dynamics of ecosystems and the importance of energy flow in maintaining ecological balance.  Return of matter: decomposers, detritus, detritivores, scavengers Decomposers: Role: Decomposers, mainly bacteria and fungi, break down dead organic material into simpler inorganic compounds. Process: They secrete enzymes that digest organic molecules, converting them into forms that can be reused by producers. Importance: This decomposition process recycles nutrients back into the ecosystem, making them available for plants and other producers. Detritus: Definition: Detritus consists of dead organic matter, including animal wastes, plant litter, and the remains of dead organisms. Stages of Decay: Different organisms consume detritus at various stages of decay. Detritivores: Diet: These organisms feed primarily on decaying organic material. Examples: Earthworms and millipedes are common detritivores that help break down detritus into smaller particles. Scavengers: Role: Scavengers are large animals that consume carcasses left behind by predators or accidents. Examples: Crows and vultures are typical scavengers that help clean up dead animal remains. Nutrient Cycling: Process: Decomposers and detritivores play a crucial role in nutrient cycling by breaking down complex organic materials into inorganic compounds. Outcome: These inorganic compounds, such as nitrates and phosphates, replenish the abiotic reservoirs and are used by producers to create new organic matter. Understanding these roles highlights the importance of decomposers, detritivores, and scavengers in maintaining the balance and health of ecosystems by ensuring the continuous recycling of matter. What are the four cycles of matter: Carbon, water, nitrogen and phosphorus and why they are important. Carbon Cycle:  Role: Carbon is the major ingredient of all organic molecules. Cycle: It cycles globally through processes like photosynthesis and respiration. Plants absorb CO2 from the atmosphere, which is then passed through the food chain and returned to the atmosphere by respiration and decomposition. Impact: This cycle is essential for maintaining the balance of carbon in the atmosphere and supporting life on Earth. Water Cycle: Role: Water is crucial for all living organisms, acting as a solvent and medium for chemical reactions. Cycle: It involves evaporation, condensation, precipitation, and runoff, distributing water across the planet. Impact: The water cycle ensures the availability of water in various ecosystems, supporting life and regulating climate. Nitrogen Cycle: Role: Nitrogen is a key component of amino acids, proteins, and nucleic acids. Cycle: Nitrogen gas from the atmosphere is converted into usable forms like ammonium and nitrate by bacteria, which plants absorb. It then moves through the food chain and is returned to the soil by decomposers. Impact: This cycle is vital for the synthesis of essential biological molecules. Phosphorus Cycle: Role: Phosphorus is needed for nucleic acids, phospholipids, ATP, and bones and teeth in vertebrates. Cycle: It depends on the weathering of rocks to release phosphate ions into the soil, which plants absorb. Phosphorus moves through the food chain and is returned to the soil by decomposers. Impact: Unlike other cycles, phosphorus does not have an atmospheric component and cycles locally within ecosystems. These cycles are crucial for maintaining the balance of essential nutrients in ecosystems, supporting life, and regulating environmental processes. How is energy stored and flow in a biological system? (in and out of living things) Energy Flow in Ecosystems: 1. Sunlight as the Primary Energy Source: Energy enters ecosystems as sunlight. Plants (producers) convert sunlight into chemical energy through photosynthesis. 2. Energy Transfer Through Trophic Levels: Producers: Plants store chemical energy in organic compounds. Consumers: Animals eat plants, transferring chemical energy to themselves.  Decomposers: Bacteria and fungi break down dead plants and animals, releasing energy. 3. Energy Loss as Heat: Every energy transfer results in some energy being lost as heat. This heat loss means ecosystems need a continuous energy input from the sun. Chemical Cycling in Ecosystems: 1. Matter Recycling: Unlike energy, matter cycles within ecosystems. Chemical elements like carbon and nitrogen move between the air, soil, plants, animals, and decomposers. 2. Role of Decomposers: Decomposers break down dead organisms, returning nutrients to the soil and air. These nutrients are then reused by plants, continuing the cycle. Thermodynamics in Biological Systems: 1. First Law of Thermodynamics: Energy cannot be created or destroyed, only transformed. Example: Plants convert light energy to chemical energy. 2. Second Law of Thermodynamics: Every energy transfer increases the universe's entropy (disorder). Example: Energy transformations in cells release heat, increasing entropy. Summary: Energy Flow: Energy flows in one direction—entering as sunlight, moving through trophic levels, and exiting as heat. Matter Cycling: Matter cycles within ecosystems, being reused and recycled by different organisms. Most of our freshwater on the earth is found in ice/glaciers/the polar ice caps. life depends on the interactions between and within organisms Biogeochemical cycles include Biotic/abiotic factors: what are they? 1. Biotic Factors: Producers: Plants and other photosynthetic organisms that incorporate chemicals from abiotic reservoirs into organic compounds. Consumers: Animals that feed on producers, incorporating chemicals into their bodies. Decomposers: Organisms like bacteria and fungi that break down dead matter, returning chemicals to the environment. 2. Abiotic Factors: Atmosphere: A reservoir for elements like carbon and nitrogen. Soil: A reservoir for elements like phosphorus and nitrogen. Water: A medium where many chemical reactions and exchanges occur.  Climax community, Primary vs. Secondary succession, Heterotroph ,Autotroph, Producers consumers Climax Community: A climax community is a stable and mature ecosystem that has reached the final stage of ecological succession. It remains relatively unchanged until a disturbance occurs. Primary vs. Secondary Succession: Primary Succession: This occurs in lifeless areas where there is no soil, such as on a lava flow. The process begins with the colonization of pioneer species that can survive in harsh conditions. Secondary Succession: This happens in areas where a disturbance has destroyed an existing community but left the soil intact, such as after a fire or flood. The ecosystem recovers more quickly because the soil already contains the necessary nutrients. Heterotroph: Heterotrophs are organisms that cannot produce their own food and must consume other organisms for energy. Examples include animals, fungi, and many bacteria. Autotroph: Autotrophs are organisms that can produce their own food from inorganic substances. They are primary producers in ecosystems. Examples include plants and algae. Producers and Consumers: Producers (Autotrophs): These organisms, like plants, convert sunlight into energy through photosynthesis. Consumers (Heterotrophs): These organisms, such as herbivores, carnivores, and omnivores, rely on consuming other organisms for energy. Omnivore, Herbivore, Carnivore Detritivore, scavenger, decomposers, keystone species Omnivore - eats both plants and animals/meat Herbivore, - only eats plants Carnivore - only eats other animals/meat Detritivore, - An organism that consumes decaying organic material scavenger, - An animal that feeds on the carcasses of dead animals. decomposers, - A prokaryote or fungus that secretes enzymes that digest molecules in organic material and convert them to inorganic forms. keystone species - A species whose impact on the community is much larger than its biomass or abundance would indicate. Interspecies competition vs. Intra species competition Interspecies Competition vs. Intraspecies Competition Interspecies Competition:  Definition: Occurs when populations of two different species compete for the same limited resource. Example: Desert plants competing for water or plants in a tropical rainforest competing for light. Animals like squirrels and black bears competing for acorns in a temperate forest. Effects: Generally negative for both populations involved. For instance, the introduction of non-native house sparrows and European starlings led to a decline in eastern bluebird populations due to competition for nesting sites. Intraspecies Competition: Definition: Occurs when members of the same species compete for the same resources. Example: Members of a population competing for food or space. Effects: More severe than interspecies competition because members of the same species have exactly the same niche and thus compete for exactly the same resources. Key Points: Carrying Capacity: Both types of competition can lower the carrying capacity of the environment for the populations involved. Reproductive Fitness: Interspecies competition can directly affect reproductive success, as seen in the study of warblers in Arizona. A(n) ecosystem includes all the biotic and abiotic factors within a given area. Name the three types of symbiosis and recognize them: mutualism, commensalism and parasitism as well as the general definition for symbiosis and recognize who benefits from each? - Already listed in previous answer to a question Why does matter cycle? How does it flow? Water cycle: know the vocabulary from the water cycle Why Does Matter Cycle? Interconnected Systems: Matter cycles because ecological subdivisions, such as biomes, are interconnected. Events in one biome can affect the entire biosphere. Sustainability: Cycling ensures that essential elements like water, carbon, and nitrogen are reused and made available for different organisms, maintaining ecosystem balance. How Does Matter Flow? Solar Energy: Drives the movement of water and air in global patterns. Processes: Precipitation, evaporation, and transpiration continuously move water between land, oceans, and the atmosphere. Biogeochemical cycles Water Cycle Vocabulary:  1. Transpiration: The process by which plants move water from the ground to the atmosphere through evaporative water loss. 2. Precipitation: Water released from clouds in the form of rain, snow, sleet, or hail. 3. Evaporation: The process by which water changes from a liquid to a gas or vapor. 4. Aquatic and Terrestrial Biomes: Ecosystems in water and on land that are connected by the water cycle. - not sure if this is all of them Understanding these concepts helps in grasping how the water cycle supports life by connecting different ecosystems and ensuring the continuous movement of water. Carbon cycle: what is the opposite of cellular respiration in this cycle, i.e. how does carbon get released in the atmosphere and return to the carbon cycle Photosynthesis vs. Cellular Respiration: Photosynthesis: This process is the opposite of cellular respiration in the carbon cycle. During photosynthesis, plants remove CO2 from the atmosphere and convert it into organic molecules like glucose. Cellular Respiration: Both producers (plants) and consumers (animals) perform cellular respiration, which releases CO2 back into the atmosphere. How Carbon Gets Released and Returns: 1. Photosynthesis: Plants absorb CO2 from the atmosphere and use sunlight to convert it into glucose and oxygen. 2. Food Chain: These organic molecules are passed along the food chain to consumers. 3. Cellular Respiration: Consumers and producers break down these organic molecules, releasing CO2 back into the atmosphere. 4. Decomposition: Decomposers break down dead organic material, releasing CO2 as a byproduct. 5. Burning Fossil Fuels: Human activities like burning wood and fossil fuels also release significant amounts of CO2 into the atmosphere. Key Points: Balance: The carbon cycle maintains a balance between CO2 removal by photosynthesis and its release by cellular respiration. Human Impact: Increased burning of fossil fuels disrupts this balance, leading to higher atmospheric CO2 levels and contributing to global warming. Chapter 3 dehydration reactions vs. hydrolysis reactions, what is the function of each and how does water play a role? which builds molecules and which one is used to break down molecules (absorbs water or releases water?) Dehydration Reactions: Function: Build molecules. Role of Water: Removes a molecule of water. Process: During a dehydration reaction, two monomers are linked together by removing a water molecule. One monomer loses a hydroxyl group (–OH), and the other loses a hydrogen atom (–H), forming H2O. This process creates a new covalent bond between the monomers, forming a polymer. Example: Linking glucose molecules to form starch. Hydrolysis Reactions: Function: Break down molecules. Role of Water: Adds a molecule of water. Process: Hydrolysis is the reverse of a dehydration reaction. It breaks the bond between monomers by adding a water molecule. The hydroxyl group from the water attaches to one monomer, and the hydrogen attaches to the adjacent monomer, effectively splitting the polymer into monomers. Example: Digesting proteins into amino acids. Both reactions are essential for cellular functions and require enzymes to facilitate the making and breaking of bonds. Periodic table families and periods mean? Families (Groups): Definition: Vertical columns in the periodic table. Characteristics: Elements in the same family have similar chemical properties because they have the same number of valence electrons. 2 Examples: Alkali Metals (Group 1): Highly reactive, especially with water. Noble Gases (Group 18): Inert and non-reactive due to having a full valence shell. Periods: Definition: Horizontal rows in the periodic table. Characteristics: Elements in the same period have the same number of electron shells. Trend: As you move from left to right across a period, the atomic number increases, and elements become less metallic and more non-metallic. Role of Water in Reactions: Dehydration Reactions: Build molecules by removing water. Hydrolysis Reactions: Break down molecules by adding water. What is a valence shell, electron and how do they affect shape? Valence Shell: Definition: The outermost electron shell of an atom. Importance: Determines the chemical properties and reactivity of the atom. Atoms with incomplete valence shells tend to interact with other atoms to achieve a full valence shell. Valence Electrons: Definition: Electrons located in the valence shell. Role: Involved in forming chemical bonds. The number of valence electrons influences how atoms bond with each other. Chemical Bonds: Ionic Bonds: Formed when electrons are transferred from one atom to another, resulting in attraction between oppositely charged ions. Covalent Bonds: Formed when atoms share pairs of electrons to fill their valence shells. The number of covalent bonds an atom can form is called its valence or bonding capacity. Effect on Shape: Molecular Shape: The arrangement of atoms in a molecule is influenced by the number of bonds and the distribution of electrons. For example, carbon can form four covalent bonds, leading to various shapes like chains or rings. Understanding these concepts helps explain why atoms interact and how molecules form specific shapes, which is crucial in fields like chemistry and biology. Enzymes, catalysts, proteins, activation energy, polar electronegativity, polar molecules and nonpolar covalent/polar covalent pods. Types of chemical bonds and their strengths 1. Enzymes and Catalysts: Enzymes: Proteins that act as biological catalysts, speeding up chemical reactions in cells without being consumed. Catalysts: Substances that increase the rate of chemical reactions without undergoing permanent changes themselves. 2. Proteins: Definition: Large, complex molecules made up of amino acids. They perform various functions in the body, including acting as enzymes. 3. Activation Energy: Definition: The minimum amount of energy required to start a chemical reaction. Enzymes lower the activation energy needed, making reactions occur more easily. 4. Polar Electronegativity and Molecules: Electronegativity: A measure of an atom's ability to attract and hold electrons. Polar Molecules: Molecules with an unequal distribution of charges due to differences in electronegativity between bonded atoms. Example: Water (H₂O). 5. Nonpolar Covalent and Polar Covalent Bonds: Nonpolar Covalent Bonds: Electrons are shared equally between atoms. Example: O₂ (oxygen gas). Polar Covalent Bonds: Electrons are shared unequally, leading to partial charges. Example: H₂O (water). 6. Types of Chemical Bonds and Their Strengths: Covalent Bonds: Strong bonds formed by sharing electrons. Can be polar or nonpolar. Ionic Bonds: Formed by the attraction between oppositely charged ions. Generally strong but weaker than covalent bonds in water. Hydrogen Bonds: Weak bonds important in the chemistry of life, formed between a slightly positive hydrogen atom and a slightly negative atom (often oxygen or nitrogen). Chemical Bonds and Their Importance: Covalent Bonds: Join atoms into molecules through electron sharing. Ionic Bonds: Result from the attraction between ions of opposite charge. Hydrogen Bonds: Crucial for the structure and function of biological molecules like DNA and proteins. Understanding these concepts helps explain how molecules interact and form the structures necessary for life. Cohesion, adhesion, surface tension, density of water vs. ice (ice is less dense) due to molecular structure, why? 1. Cohesion: Definition: The tendency of molecules of the same kind to stick together. Example: Water molecules exhibit strong cohesion due to hydrogen bonding, which is crucial for processes like water transport in plants. 2. Adhesion: Definition: The clinging of one substance to another. Example: Water molecules adhere to the walls of plant veins, helping counteract gravity and assist in water transport. 3. Surface Tension: Definition: A measure of how difficult it is to stretch or break the surface of a liquid. Example: Water has high surface tension due to hydrogen bonds, allowing insects like water striders to walk on its surface. 4. Density of Water vs. Ice: Explanation: Ice is less dense than liquid water because of the hydrogen bonds that form a stable, spacious crystal structure in ice. This structure holds water molecules at a distance, making ice less dense and allowing it to float. Importance: Floating ice insulates the water below, protecting aquatic life during cold periods. Summary Water's unique properties, such as cohesion, adhesion, surface tension, and the lower density of ice, are all due to hydrogen bonding. These properties are essential for life, aiding in processes like nutrient transport in plants and providing insulation in aquatic environments. Describe molecules: what are All the components found in water? H2O molecules, H+ ions (hydrogen(, OH- (hydroxide) ions and Hydronium H30 ions structure and function of : nucleic acids, Lipids, Carbohydrates, Proteins types, functions, elements, monomer of four macromolecules *polymer. *Organic *dehydration reactions *hydrolysis reactions *substrate *active site *four levels of organization of proteins *parts of ATP *where is the energy stored in an ATP molecule 1. Water Molecules (H2O): Structure: Each water molecule consists of two hydrogen atoms covalently bonded to one oxygen atom. Function: Water is essential for life, acting as a solvent, temperature buffer, and participant in chemical reactions. 2. Hydrogen Ions (H+): Structure: A hydrogen ion is simply a proton. Function: H+ ions play a crucial role in determining the pH of a solution, affecting enzyme activity and biochemical reactions. 3. Hydroxide Ions (OH-): Structure: A hydroxide ion consists of one oxygen atom bonded to one hydrogen atom, carrying a negative charge. Function: OH- ions also influence pH and are involved in various chemical reactions, including those in biological systems. 4. Hydronium Ions (H3O+): Structure: A hydronium ion forms when a water molecule gains an extra hydrogen ion (H+), resulting in H3O+. Function: Hydronium ions are central to acid-base chemistry, affecting the acidity of solutions. Structure and Function of Macromolecules 1. Nucleic Acids: Structure: Made of nucleotides, which include a phosphate group, a nitrogenous base, and a sugar (ribose or deoxyribose). Function: Store, transmit, and help express hereditary information. 2. Lipids: Structure: Composed mainly of carbon and hydrogen atoms, forming fats, phospholipids, and steroids. Function: Energy storage, cell membrane structure, and signaling. 3. Carbohydrates: Structure: Consist of sugar molecules (monosaccharides) and their polymers (polysaccharides). Function: Provide energy, structural support, and cell recognition. 4. Proteins: Structure: Made of amino acids linked by peptide bonds, forming primary, secondary, tertiary, and quaternary structures. Function: Catalyze reactions (enzymes), provide structure, transport molecules, and defend against pathogens. Key Concepts Dehydration Reactions: Link monomers to form polymers by removing water. Hydrolysis Reactions: Break down polymers into monomers by adding water. Substrate: The reactant an enzyme acts on. Active Site: The region on an enzyme where the substrate binds. Four Levels of Protein Structure: Primary: Sequence of amino acids. Secondary: Coiling or folding (alpha helices and beta sheets). Tertiary: Overall 3D shape. Quaternary: Arrangement of multiple polypeptides. ATP: Consists of adenine, ribose, and three phosphate groups. Energy is stored in the bonds between phosphate groups. What is an exergonic reaction and endergonic and how does that relate to exothermic and endothermic reactions? Exergonic Reactions: Definition: Reactions that release energy. The term "exergonic" means "energy outward." Characteristics: These reactions start with reactants that have more potential energy than the products. The energy difference is released to the surroundings. Example: Cellular respiration, where glucose is broken down to release energy, which is stored in ATP and some is released as heat. Endergonic Reactions: Definition: Reactions that require a net input of energy. The term "endergonic" means "energy inward." Characteristics: These reactions start with reactants that have less potential energy than the products. Energy is absorbed from the surroundings. Example: Photosynthesis, where energy from sunlight is used to convert carbon dioxide and water into glucose. Relation to Exothermic and Endothermic Reactions Exothermic Reactions: Definition: Reactions that release heat. Relation to Exergonic: All exothermic reactions are exergonic because they release energy, but not all exergonic reactions are exothermic (some may release energy in forms other than heat). Endothermic Reactions: Definition: Reactions that absorb heat. Relation to Endergonic: All endothermic reactions are endergonic because they absorb energy, but not all endergonic reactions are endothermic (some may absorb energy in forms other than heat). Energy Coupling in Cells Energy Coupling: The use of energy released from exergonic reactions to drive endergonic reactions. Role of ATP: ATP transfers energy from exergonic to endergonic processes by phosphorylating other molecules. By understanding these concepts, you can see how cells manage energy to perform various functions essential for life. Chapter 3 Name the four macromolecule groups and know how they are used in biological systems. Label all the parts of the molecules above 1. Carbohydrates Function: Carbohydrates are the body's primary source of energy. They can also be used for structural support in cells. Used in Biological Systems: ○ Energy: Glucose, a simple sugar, is used for energy in cells. ○ Storage: Starch (plants) and glycogen (animals) store energy. ○ Structure: Cellulose is a key structural component of plant cell walls. Example: Glucose (C₆H₁₂O₆), a simple sugar. Parts of a Carbohydrate Molecule: ○ Monosaccharides: Single sugar molecules (like glucose). ○ Disaccharides: Two monosaccharides joined together (like sucrose). ○ Polysaccharides: Long chains of monosaccharides (like starch or cellulose). 2. Proteins Function: Proteins are involved in nearly every function of the body, including enzymatic reactions, immune response, transporting molecules, and providing structure to cells. Used in Biological Systems: ○ Enzymes: Catalyze (speed up) biochemical reactions. ○ Structural Proteins: Like collagen in connective tissues or keratin in hair and skin. ○ Transport Proteins: Like hemoglobin, which carries oxygen in the blood. Example: Hemoglobin (transports oxygen), enzymes (like amylase, which breaks down starch). Parts of a Protein Molecule: ○ Amino acids: The building blocks of proteins. There are 20 different amino acids. ○ Peptide bonds: Chemical bonds that link amino acids together to form a protein. ○ Primary structure: The sequence of amino acids in the protein. ○ Secondary structure: Local folding into structures like alpha helices or beta sheets. ○ Tertiary structure: The overall 3D shape of the protein. ○ Quaternary structure: Multiple protein subunits coming together. 3. Lipids Function: Lipids are used for energy storage, insulation, and cell membrane structure. They also play roles in hormone production. Used in Biological Systems: ○ Energy storage: Fat (triglycerides) stores large amounts of energy. ○ Cell membranes: Phospholipids form the lipid bilayer of cell membranes. ○ Signaling: Steroid hormones, like estrogen and testosterone, are made from lipids. Example: Triglycerides (fats), phospholipids (cell membranes), cholesterol. Parts of a Lipid Molecule: ○ Fatty acids: Long chains of carbon and hydrogen atoms. ○ Glycerol: A three-carbon molecule that bonds with fatty acids. ○ Phosphate group: In phospholipids, a phosphate group is attached to a glycerol backbone. 4. Nucleic Acids Function: Nucleic acids store and transmit genetic information. They are responsible for the production of proteins and the inheritance of traits. Used in Biological Systems: ○ DNA: Contains the genetic blueprint for organisms. ○ RNA: Helps in protein synthesis by carrying messages from DNA. Example: DNA (deoxyribonucleic acid), RNA (ribonucleic acid). Parts of a Nucleic Acid Molecule: ○ Nucleotides: The building blocks of nucleic acids. Each nucleotide consists of: A phosphate group. A sugar (deoxyribose in DNA or ribose in RNA). A nitrogenous base (adenine [A], thymine [T], cytosine [C], guanine [G] for DNA; in RNA, uracil [U] replaces thymine). ○ Double helix: The shape of DNA, formed by two strands of nucleotides twisted around each other. Summary of the Four Macromolecule Groups: 1. Carbohydrates: Provide energy and structure (sugars, starches). 2. Proteins: Perform a wide range of functions (enzymes, transport, structure). 3. Lipids: Store energy, form membranes, and act as hormones. 4. Nucleic Acids: Store and transmit genetic information (DNA, RNA). The Four Macromolecule Groups and Their Roles in Biological Systems 1. Carbohydrates Structure: Made up of sugar molecules (monosaccharides) that can form larger polysaccharides. Function: Provide energy and structural support. For example, glucose is a primary energy source, and cellulose provides structural support in plant cell walls. 2. Lipids Structure: Composed mainly of carbon and hydrogen atoms, forming fats, oils, and phospholipids. Function: Store energy, form cell membranes, and act as signaling molecules. For instance, triglycerides store energy, and phospholipids are key components of cell membranes. 3. Proteins Structure: Built from 20 different amino acids linked by peptide bonds into polypeptide chains. Function: Perform a wide range of functions including catalyzing reactions (enzymes), providing structural support, and regulating processes. Hemoglobin, for example, transports oxygen in the blood. 4. Nucleic Acids Structure: Made of nucleotide monomers, which include a sugar, a phosphate group, and a nitrogenous base. Function: Store and transmit genetic information. DNA holds the instructions for building proteins, while RNA translates these instructions to synthesize proteins. Summary Cells construct these macromolecules from smaller units (monomers) through polymerization. The diversity and function of these macromolecules are crucial for the unique characteristics and functions of different organisms. Many molecules are repeating subunits which are called polymers and are different from Hydrocarbons. What makes a phospholipid different from a lipid and where are they found. Phospholipids: Structure: Phospholipids are similar to fats but have a distinct structure. They consist of two fatty acids and a negatively charged phosphate group attached to glycerol. Hydrophilic and Hydrophobic Regions: The phosphate group forms the hydrophilic (water-attracting) head, while the fatty acid chains form the hydrophobic (water-repelling) tails. Function: Phospholipids are crucial for forming cell membranes. They arrange themselves into a double-layered sheet in water, with hydrophobic tails facing inward and hydrophilic heads facing outward, creating a barrier that protects the cell. Lipids: Structure: Lipids are a diverse group of hydrophobic molecules, including fats, phospholipids, and steroids. Fats, specifically, are composed of three fatty acids attached to a glycerol molecule. Function: Fats primarily serve as energy-storage molecules. They are not involved in forming cell membranes like phospholipids. Location: Phospholipids: Found in cell membranes, providing structure and regulating the movement of substances in and out of cells. Lipids: Found throughout the body, serving various roles such as energy storage, insulation, and hormone production. Summary Phospholipids: Two fatty acids + phosphate group, hydrophilic head, hydrophobic tails, form cell membranes. Lipids: Diverse group, hydrophobic, includes fats (three fatty acids + glycerol), primarily for energy storage. How are carbohydrates stored as glycogen (short term energy), fats as saturated triglycerides (richest energy and long-term storage), immediate energy in ATP in mitochondria. Energy Storage in the Body 1. Carbohydrates Stored as Glycogen: Storage Form: Glycogen is a polymer of glucose molecules. Location: Stored in the liver and muscles. Function: Provides short-term energy. Glycogen can be quickly broken down into glucose to supply energy during activities like exercise. Example: Athletes often "carbo load" before events to ensure their glycogen stores are full. 2. Fats Stored as Saturated Triglycerides: Storage Form: Triglycerides consist of glycerol and three fatty acids. Location: Stored in adipose (fat) cells. Function: Long-term energy storage. Fats are energy-dense, providing more than twice the energy per gram compared to carbohydrates. Example: Fat reserves can sustain the body through periods of starvation. 3. Immediate Energy in ATP: Production: ATP is produced in the mitochondria through cellular respiration. Function: Provides immediate energy for cellular processes. Pathways: Aerobic Respiration: Uses glucose and oxygen, producing a large amount of ATP. Anaerobic Respiration (Lactic Acid Fermentation): Uses glucose without oxygen, producing ATP quickly but in smaller amounts. Summary Glycogen: Short-term energy, stored in liver and muscles. Fats: Long-term energy, stored in adipose cells. ATP: Immediate energy, produced in mitochondria How do functional groups play a role in hydrophilic and hydrophobic functions of molecules? Role of Functional Groups in Hydrophilic and Hydrophobic Functions of Molecules Functional Groups and Their Properties: Hydrophilic Groups: Hydroxyl Group (-OH): Polar, makes molecules soluble in water. Carbonyl Group (C=O): Polar, found in sugars, increases solubility. Carboxyl Group (-COOH): Acts as an acid, ionizes in water, making molecules hydrophilic. Amino Group (-NH2): Acts as a base, ionizes in water, increasing solubility.  Phosphate Group (-PO4): Usually ionized, highly polar, involved in energy transfers. Hydrophobic Groups: Methyl Group (-CH3): Nonpolar, does not interact with water, making molecules hydrophobic. Hydrophilic vs. Hydrophobic Amino Acids: Hydrophilic Amino Acids: Have polar or charged R groups, making them soluble in water. Hydrophobic Amino Acids: Have nonpolar R groups, such as those with C-H bonds, making them insoluble in water. Examples: Leucine (Leu): A hydrophobic amino acid with nonpolar R groups. Amino Acids with Acidic or Basic R Groups: These are hydrophilic due to their charged nature at cellular pH. Summary Functional groups determine whether a molecule is hydrophilic (water-loving) or hydrophobic (water-fearing) based on their polarity and ability to ionize in water. Hydrophilic groups are polar and soluble in water, while hydrophobic groups are nonpolar and insoluble. Structure of phospholipid bilayer is different than fluid mosaic model. How? Structure of Phospholipid Bilayer vs. Fluid Mosaic Model Phospholipid Bilayer: Composed of two layers of phospholipids. Each phospholipid has a hydrophilic (water-attracting) head and two hydrophobic (water-repelling) tails. The hydrophilic heads face outward towards the water, while the hydrophobic tails face inward, away from the water. Fluid Mosaic Model: Describes the structure of cell membranes. Suggests that the membrane is a fluid combination of phospholipids, cholesterol, and proteins. Proteins float in or on the fluid lipid bilayer like boats on a pond. Carbon based molecules are considered organic Carbon-Based Molecules as Organic Carbon's ability to form four covalent bonds makes it the backbone of organic molecules.  Organic molecules include carbohydrates, lipids, proteins, and nucleic acids. Anabolic steroids vs. steroids. Not all anabolic steroids are bad they can be used to treat disease Anabolic Steroids vs. Steroids Anabolic Steroids: Synthetic variants of the male hormone testosterone. Used medically to treat conditions like delayed puberty and diseases that cause muscle loss. Steroids: A broader category that includes hormones like cortisol and cholesterol. Not all steroids are anabolic; some are used for reducing inflammation or other functions. Carbohydrates are used for more than energy, review the use of polysaccharides. (cellulose glycogen, starches and chitin. Uses of Polysaccharides Cellulose: Provides structural support in plant cell walls. Glycogen: Stores energy in animal cells, especially in liver and muscle cells. Starch: Stores energy in plant cells. Chitin: Provides structural support in the exoskeletons of arthropods and cell walls of fungi. Trans fats, saturated and unsaturated fats Fats: Trans, Saturated, and Unsaturated Trans Fats: Created by hydrogenating unsaturated fats, associated with health risks. Saturated Fats: Have no double bonds between carbon atoms, solid at room temperature. Unsaturated Fats: Have one or more double bonds, liquid at room temperature. Protein, enzyme/substrate use and the importance of shape and function, denaturization Proteins: Enzyme/Substrate Use and Importance of Shape Enzymes: Proteins that act as catalysts to speed up chemical reactions. Substrate: The specific reactant that an enzyme acts on. Shape and Function: The specific shape of a protein determines its function. Denaturation (loss of shape) can lead to loss of function. Amino acids are the monomer to protein and they make up a polypeptide chain in the rough ER by ribosomes. They are folded into proteins in the ER. Amino Acids and Protein Formation  Amino Acids: The monomers that make up proteins. Polypeptide Chain: Formed in the rough ER by ribosomes. Protein Folding: Polypeptides are folded into functional proteins in the ER. Summary Understanding these concepts helps in grasping the complexity and functionality of biological molecules and their roles in living organisms. Chapter 4 *Hooke *van Leeuwenhoek *organelle and their functions *function of cytoskeleton *compare and contrast animal to plant cell *cellular hierarchy *what factors limit cell size? Cytoskeleton and Its Functions The cytoskeleton is a network of fibers within the cell that helps maintain its shape and organize its activities. It consists of three main components: 1. Microfilaments: These are thin fibers that support the cell's shape and are involved in muscle contraction and cell movement. 2. Intermediate Filaments: These provide mechanical support for the cell and help anchor organelles. 3. Microtubules: These are thick, hollow tubes that guide the movement of organelles and are essential for cell division and the movement of cilia and flagella. Functions of the Cytoskeleton Maintenance of Cell Shape: The cytoskeleton provides structural support to the cell. Anchorage and Movement of Organelles: It helps position and transport organelles within the cell. Amoeboid Movement: Microfilaments enable cells to move by changing shape. Muscle Contraction: Microfilaments interact with myosin to contract muscle cells. Factors Limiting Cell Size Cells are small to maximize their surface area-to-volume ratio, which is crucial for efficient nutrient uptake and waste removal. A larger surface area relative to volume allows for better exchange of materials across the plasma membrane. Comparing Animal and Plant Cells Animal Cells: Lack cell walls, have smaller vacuoles, and contain centrioles. Plant Cells: Have cell walls made of cellulose, large central vacuoles, and chloroplasts for photosynthesis. Cellular Hierarchy Cells are organized into a hierarchy:  1. Cells: Basic unit of life. 2. Tissues: Groups of similar cells performing a specific function. 3. Organs: Structures made of different tissues working together. 4. Organ Systems: Groups of organs that perform related functions. Hooke and van Leeuwenhoek Robert Hooke: Discovered cells in 1665 using a light microscope. Antonie van Leeuwenhoek: Improved the microscope and observed microorganisms. Organelles and Their Functions Nucleus: Contains genetic material and controls cell activities. Mitochondria: Produce energy through cellular respiration. Ribosomes: Synthesize proteins. Endoplasmic Reticulum (ER): Rough ER has ribosomes for protein synthesis; Smooth ER synthesizes lipids. Golgi Apparatus: Modifies, sorts, and packages proteins and lipids. Lysosomes: Contain enzymes for digestion. Chloroplasts: Conduct photosynthesis in plant cells. Function of the Cytoskeleton The cytoskeleton is crucial for maintaining cell shape, enabling movement, and facilitating intracellular transport. It is composed of microfilaments, intermediate filaments, and microtubules, each with specific roles in the cell's structure and function. *cell theory what are the principles, how is cell size limited? Principles of Cell Theory Cell theory is a fundamental concept in biology that states: 1. All living things are composed of cells: Every organism, from the smallest bacterium to the largest whale, is made up of cells. 2. All cells come from pre-existing cells: New cells are produced by the division of existing cells. Factors Limiting Cell Size The size of a cell is limited by its need to efficiently exchange materials with its environment. Here are the key factors: 1. Surface Area-to-Volume Ratio: As a cell grows, its volume increases faster than its surface area. A larger surface area relative to volume is crucial for the efficient exchange of oxygen, nutrients, and waste products across the cell membrane. 2. Logistics of Cellular Functions: A cell must be large enough to house essential components like DNA, proteins, and organelles. However, if a cell becomes too large, it cannot efficiently transport materials within itself. For example, a chicken egg is a single large cell, but it is not very active. Once the embryo starts developing, the egg divides into many smaller cells, each with a membrane that facilitates the necessary exchange of materials. Know all the organelles, there structure and functions, Differentiate plant cells from animal cells Organelles: Structure and Functions, and Differences Between Plant and Animal Cells Organelles and Their Functions Eukaryotic cells contain various organelles, each with specific functions: 1. Nucleus: Contains the cell's DNA and controls its activities. 2. Ribosomes: Synthesize proteins. 3. Endoplasmic Reticulum (ER): Rough ER: Studded with ribosomes; synthesizes proteins. Smooth ER: Synthesizes lipids and detoxifies toxins. 4. Golgi Apparatus: Modifies, sorts, and packages proteins and lipids. 5. Lysosomes: Contain enzymes to digest cellular waste. 6. Vacuoles: Store substances; large central vacuole in plant cells maintains turgor pressure. 7. Peroxisomes: Break down fatty acids and detoxify harmful substances. 8. Mitochondria: Produce energy (ATP) through cellular respiration. 9. Chloroplasts (in plant cells): Conduct photosynthesis. Differences Between Plant and Animal Cells Plant Cells: Cell Wall: Provides structure and protection; made of cellulose. Chloroplasts: Sites of photosynthesis. Large Central Vacuole: Stores water and maintains cell firmness. Plasmodesmata: Channels between cell walls for communication. Animal Cells: Lysosomes: More prominent in animal cells. Centrosomes: Involved in cell division. Flagella/Cilia: Present in some animal cells for movement. Plant cells have unique structures like chloroplasts, a central vacuole, and a cell wall, which are not found in animal cells. Conversely, animal cells have lysosomes and centrosomes, which are typically absent in plant cells. Differentiate eukaryotic cells from prokaryotic cells Differentiating Eukaryotic Cells from Prokaryotic Cells Key Differences 1. Nucleus: Eukaryotic Cells: Have a membrane-enclosed nucleus that houses most of their DNA.  Prokaryotic Cells: Lack a nucleus; their DNA is coiled into a region called the nucleoid, which is not enclosed by a membrane. 2. Organelles: Eukaryotic Cells: Contain many membrane-enclosed organelles (e.g., mitochondria, endoplasmic reticulum, Golgi apparatus). Prokaryotic Cells: Do not have membrane-enclosed organelles. 3. Size: Eukaryotic Cells: Generally larger, typically 10-100 μm in diameter. Prokaryotic Cells: Smaller, typically 1-5 μm in diameter. 4. Complexity: Eukaryotic Cells: More complex in structure. Prokaryotic Cells: Simpler in structure. Common Features Plasma Membrane: Both types of cells are bounded by a plasma membrane. Cytoplasm: Both have cytoplasm, though in eukaryotic cells, it refers to the region between the nucleus and the plasma membrane. Ribosomes: Both contain ribosomes, though prokaryotic ribosomes are smaller and differ somewhat from those of eukaryotes. DNA: Both have chromosomes containing DNA. Unique Features of Prokaryotic Cells Cell Wall: Most prokaryotes have a rigid, chemically complex cell wall. Capsule: Some prokaryotes have a sticky outer coat called a capsule. Surface Projections: Prokaryotes may have short projections for attachment or longer flagella for movement. Evolutionary Context Prokaryotic Cells: First to evolve and were Earth's sole inhabitants for more than 1.5 billion years. Eukaryotic Cells: Evolved from ancestral prokaryotic cells about 1.8 billion years ago. Understanding these differences helps in comprehending the diversity and complexity of life forms on Earth. Know the structure of the prokaryote and its layers, pathogenicity Structure of Prokaryotic Cells 1. Cell Wall: Most prokaryotes have a rigid, chemically complex cell wall that protects the cell and maintains its shape. 2. Capsule: Some prokaryotes have a sticky outer coat called a capsule that helps them adhere to surfaces or other cells in a colony. 3. Plasma Membrane: The plasma membrane encloses the cell, controlling the movement of substances in and out.  4. Nucleoid: The DNA is coiled into a region called the nucleoid, which is not enclosed by a membrane. 5. Ribosomes: Prokaryotic cells contain ribosomes, which are smaller and differ somewhat from those in eukaryotic cells. 6. Surface Projections: Short projections called fimbriae help in attachment, while longer projections called flagella aid in movement. Pathogenicity Exotoxins and Endotoxins: Pathogenic bacteria often cause disease by producing exotoxins (proteins secreted by bacteria) or endotoxins (components of the outer membrane of gram-negative bacteria). Biofilms: Prokaryotes can form biofilms, which are complex associations of microbes that are difficult to eradicate and can cause medical and environmental problems. Rapid Adaptation: Prokaryotes can adapt rapidly to environmental changes, increasing their survival and pathogenic potential. What is the difference in nucleus, nucleoid, nucleolus and whether they make ribosomes or contain DNA. Nucleus: Contains DNA: The nucleus is the command center of a eukaryotic cell, housing the cell’s genetic material in the form of DNA. Ribosome Production: It directs protein synthesis via messenger RNA (mRNA) and contains the nucleolus, where ribosomal RNA (rRNA) is synthesized and ribosomal subunits are assembled. Structure: Enclosed by a double membrane called the nuclear envelope, which controls the flow of materials in and out of the nucleus. Nucleoid: Contains DNA: Found in prokaryotic cells, the nucleoid is a non-membrane-bound region where the cell’s DNA is concentrated. No Ribosome Production: Unlike the nucleus, the nucleoid does not have a nucleolus and does not directly participate in ribosome production. Nucleolus: Ribosome Production: Located within the nucleus, the nucleolus is the site where rRNA is synthesized and combined with proteins to form ribosomal subunits.  No DNA Storage: It does not contain DNA but plays a crucial role in assembling the components needed for protein synthesis. Differentiated the forms of DNA: double helix, chromatin, chromosomes, single chromosome (in prokaryotes) What are the two forms of RNA that we studies 1. Double Helix: Structure: DNA in its most common form is a double helix, consisting of two polynucleotide strands coiled around each other. Function: This structure allows for the storage of genetic information and its replication. 2. Chromatin: Structure: DNA wrapped around histone proteins, forming a complex that looks like beads on a string. Function: Chromatin condenses to form chromosomes during cell division and helps regulate gene expression. 3. Chromosomes: Structure: Highly condensed chromatin, visible during cell division. Function: Ensures accurate distribution of DNA during cell division. 4. Single Chromosome (in Prokaryotes): Structure: A single, circular DNA molecule. Function: Contains all the genetic information necessary for the cell's functions. Forms of RNA 1. Messenger RNA (mRNA): Function: Carries genetic information from DNA to the ribosome, where proteins are synthesized. 2. Ribosomal RNA (rRNA): Function: Combines with proteins to form ribosomes, which are the sites of protein synthesis. Key Points DNA Forms: Double helix, chromatin, chromosomes, single chromosome (prokaryotes). RNA Types: mRNA and rRNA. DNA vs. RNA: DNA contains deoxyribose and thymine (T), while RNA contains ribose and uracil (U). Plants have a central vacuole, vesicles, chloroplasts and peroxisomes What is a contractile vacuole vs. central vacuole and where do you find them. How are animal vacuoles different in multicellular organism? Contractile Vacuole: Location: Found in unicellular eukaryotes like the protist Paramecium. Function: Helps expel excess water from the cell. It collects water through "spokes" and expels it through a central "hub" to prevent the cell from bursting due to osmotic pressure. Central Vacuole: Location: Found in plant cells. Function: Growth: Absorbs water and enlarges, helping the cell grow. Storage: Stockpiles vital chemicals and stores toxic waste products. Protection: Stores compounds that deter herbivores, such as nicotine and caffeine. Pigmentation: Contains pigments in flower petals to attract pollinators. Animal Vacuoles in Multicellular Organisms Function: In multicellular organisms, vacuoles are generally smaller and have more specialized functions compared to the large central vacuole in plant cells. They can be involved in storage, waste disposal, and maintaining hydrostatic pressure. Key Differences Contractile Vacuole: Found in unicellular organisms, primarily for expelling water. Central Vacuole: Found in plant cells, primarily for storage, growth, and protection. Animal Vacuoles: Smaller and specialized, found in multicellular organisms.  1. Nucleolus 2. Nuclear envelope 3. Ribosomes 4. Peroxisome/Transport Vesicle 5. rough endoplasmic reticulum 6. golgi apparatus 7. Plasma Membrane 8. smooth endoplasmic reticulum 9. mitochondria 10. Vacuole 11. cytoplasm 12. lysosome 13. centrosome ALL of these organelles and their functions. Difference in lysosome and a vacuole is that lysosomes have liquid enzymes in them to break down molecules and old organelles while vacuoles store. What are the advantages and disadvantages of electron microscopes vs. light microscopes Electron Microscopes: smaller structures like viruses. Advantages: ○ Can magnify up to 2 million ○ Higher resolution (much times. greater detail) – can see Disadvantages: ○ Expensive and large.  ○ Specimens must be dead ○ Can observe living ○ Complex specimens. ○ Less expensive. Light Microscopes: Disadvantages: ○ Lower resolution (can't see Advantages: very small details). ○ Easier to use. ○ Limited magnification (up to about 1,000 times). What is found inside the nucleus of a cell and their functions 1. DNA: Function: Contains the genetic blueprint for the cell. DNA is organized into structures called chromosomes, which are made up of DNA and proteins. When the cell is not dividing, this complex is called chromatin. 2. Chromosomes: Function: Carry genetic information. Before cell division, chromatin fibers coil up to form visible chromosomes, ensuring each daughter cell receives an identical set of genetic instructions. 3. Nuclear Envelope: Function: A double membrane that encloses the nucleus, controlling the flow of materials in and out of the nucleus through its protein-lined pores. It also connects with the endoplasmic reticulum. 4. Nucleolus: Function: The site where ribosomal RNA (rRNA) is synthesized. Proteins from the cytoplasm are assembled with rRNA to form ribosomal subunits, which then exit to the cytoplasm to become functional ribosomes. 5. Messenger RNA (mRNA): Function: Transcribes protein-synthesizing instructions from DNA and moves to the cytoplasm, where ribosomes translate it into proteins. Processes in the Nucleus: DNA Replication: DNA is copied before cell division. rRNA Synthesis: Ribosomal subunits are assembled. mRNA Transcription: Protein-making instructions in DNA are transcribed into mRNA. differentiate between vacuoles, vesicles, and lysosomes. Vacuoles: Function: Vacuoles are large vesicles with various functions. In protists, contractile vacuoles expel excess water to prevent bursting. In plants, vacuoles store nutrients, pigments, and toxic substances, and help in cell growth by absorbing water. Vesicles:  Function: Vesicles are small membrane-bound sacs that transport materials within the cell. They can carry proteins and lipids from the ER to the Golgi apparatus and then to other destinations, including the plasma membrane. Lysosomes: Function: Lysosomes are membrane-enclosed sacs containing digestive enzymes. They break down food particles, bacteria, and damaged organelles, recycling the cell’s organic materials. What is the endomembrane system and its different to the components of the Cytoskeleton system, and their purpose. Cytoplasm vs, Cytosol vs cytoskeleton. Functions of the filaments Endomembrane System: Components: Includes the nuclear envelope, endoplasmic reticulum (ER), Golgi apparatus, lysosomes, various vesicles and vacuoles, and the plasma membrane. Functions: These organelles work together in the synthesis, distribution, storage, and export of molecules. For example, the ER is involved in protein and lipid synthesis, while the Golgi apparatus modifies and ships these products. Lysosomes digest ingested substances and damaged organelles. Example: Vesicles transport proteins from the ER to the Golgi apparatus. Cytoskeleton System: Components: Made up of three types of fibers: microtubules, intermediate filaments, and microfilaments. Functions: Provides structural support, aids in cell movement, and organizes cell activities. Microtubules shape the cell and guide organelle movement, intermediate filaments reinforce cell shape and anchor organelles, and microfilaments support cell shape and are involved in cell movements. Example: Microtubules guide the movement of chromosomes during cell division. Cytoplasm vs. Cytosol vs. Cytoskeleton: Cytoplasm: The entire contents within the cell membrane, excluding the nucleus, including the cytosol and organelles. Cytosol: The fluid part of the cytoplasm where organelles are suspended. Cytoskeleton: The network of fibers within the cytoplasm that provides structural support and aids in movement. Functions of the Filaments: Microtubules: Shape and support the cell, guide organelle movement, and are involved in cell division. Intermediate Filaments: Reinforce cell shape and anchor organelles. Microfilaments: Support cell shape and are involved in muscle contraction and cell movement. Endosymbiont theory; related to eukaryotes and photosynthetic organisms. Endosymbiont Theory Overview: The endosymbiont theory explains the origin of mitochondria and chloroplasts in eukaryotic cells. It suggests that these organelles were once free-living prokaryotes that began living inside larger host cells. Key Points: 1. Mitochondria Origin: Hypothesis: In an increasingly aerobic world, a host cell would benefit from an endosymbiont capable of using oxygen to release energy from organic molecules. Evolution: Over time, the host cell and the endosymbiont merged into a single organism, forming a eukaryotic cell with mitochondria. 2. Chloroplasts Origin: Hypothesis: A eukaryotic cell with mitochondria might have later acquired a photosynthetic prokaryote, which could provide nourishment through photosynthesis. Evolution: This led to the development of eukaryotic cells containing both mitochondria and chloroplasts. 3. Evidence: DNA and Ribosomes: Mitochondria and chloroplasts contain circular DNA and ribosomes similar to those of prokaryotes. Reproduction: Both organelles reproduce in a manner similar to prokaryotes. 4. Photosynthetic Organisms: Cyanobacteria: The chloroplasts of eukaryotes likely originated from endosymbiotic cyanobacteria, which are the only prokaryotes with plant-like, oxygen-generating photosynthesis. Evolutionary Explanation: All eukaryotes have mitochondria because the first endosymbiotic event involved a prokaryote that could use oxygen. Not all eukaryotes have chloroplasts because the acquisition of photosynthetic prokaryotes occurred in a second endosymbiotic event. Functions: Mitochondria: Release energy from organic molecules using oxygen. Chloroplasts: Perform photosynthesis, converting light energy into chemical energy. Chapter 5. Passive Transport vs. Active Passive transport: the diffusion of a substance with NO energy use  - O2 and CO2 diffuse easily - facilitated diffusion - assisted transport of a substance through a specific transport protein (driving force is concentration gradient) Active transport: this is when energy is used to push a solute AGAINST concentration gradient to side with more concentrated solute - atp supplies energy here - allows cells to maintain internal concentrations of small molecules Define each: *diffusion *osmosis *passive transport *active transport *dynamic equilibrium *Na+/K+ pump *types of solutions * protein channels *plasmolysis *cytolysis *energy *energy transformation *ATP *Enzymes, endocytosis, exocytosis, metabolic pathways, enzymes 1. Diffusion The movement of particles from an area of higher concentration to an area of lower concentration, without the need for energy investment. This process continues until dynamic equilibrium is reached. 2. Osmosis A specific type of diffusion that involves the movement of water across a selectively permeable membrane. Water moves from an area of lower solute concentration to an area of higher solute concentration until equilibrium is achieved. 3. Passive Transport The movement of substances across a cell membrane without the use of energy by the cell. This includes diffusion and facilitated diffusion, where transport proteins help move substances down their concentration gradient. 4. Active Transport The movement of substances against their concentration gradient, requiring energy expenditure by the cell. This process often involves transport proteins. 5. Dynamic Equilibrium A state where the concentrations of solutes are equal across a membrane, and there is no net movement of particles, although individual particles continue to move. 6. Na+/K+ Pump A type of active transport where sodium ions are pumped out of the cell and potassium ions are pumped into the cell, against their concentration gradients, using energy from ATP. 7. Types of Solutions Hypertonic: Solution with a higher solute concentration than the cell, causing the cell to shrink. Hypotonic: Solution with a lower solute concentration than the cell, causing the cell to swell. Isotonic: Solution with equal solute concentration as the cell, resulting in no net water movement. 8. Protein Channels  Proteins embedded in the cell membrane that facilitate the movement of substances across the membrane. 9. Plasmolysis The process where plant cells lose water in a hypertonic solution, causing the cell membrane to pull away from the cell wall. 10. Cytolysis The bursting of a cell due to excessive water intake in a hypotonic solution. 11. Energy The capacity to do work. In biological systems, energy is often stored in chemical bonds and can be transformed from one form to another. 12. Energy Transformation The process of converting energy from one form to another, such as the transformation of chemical energy in food to kinetic energy for movement. 13. ATP (Adenosine Triphosphate) The primary energy carrier in cells. ATP releases energy when its phosphate bonds are hydrolyzed. 14. Enzymes Proteins that act as biological catalysts, speeding up chemical reactions without being consumed in the process. 15. Endocytosis The process by which cells take in large molecules by engulfing them in a vesicle formed from the cell membrane. 16. Exocytosis The process by which cells expel large molecules by fusing a vesicle with the cell membrane and releasing its contents outside the cell. 17. Metabolic Pathways Series of chemical reactions within a cell, facilitated by enzymes, that lead to the synthesis or breakdown of substances. Turgor or turgidity in plants is water based: how? Turgor Pressure Explained: Turgor pressure, or turgidity, is a crucial aspect of plant cell health and structure. It is the pressure exerted by the cell membrane against the cell wall due to water intake. This pressure is essential for maintaining the rigidity and structural integrity of plant cells. How It Works: 1. Hypotonic Environment: When a plant cell is in a hypotonic environment (where the surrounding solution has a lower solute concentration than the cell's interior), water enters the cell by osmosis. As water enters, the cell swells, but the rigid cell wall prevents it from bursting. This creates turgor pressure, making the cell turgid (very firm), which is the healthy state for most plant cells. 2. Role of Turgor Pressure:  Turgor pressure provides mechanical support to non-woody plants, helping them maintain their shape and stand upright. It also plays a role in the opening and closing of stomata, which are essential for gas exchange and transpiration. 3. Isotonic and Hypertonic Environments: In an isotonic solution (equal solute