Biology Chapter 2: Cellular Processes and Reactions

UNIT 1: MACROMOLECULES - CH 2

• Atoms: Basic units of matter
• Protons: Positively charged particles found in the atomic nucleus
• Neutrons: Neutral particles found in the atomic nucleus
• Electrons: Negatively charged particles orbiting the nucleus
• Nucleus of an atom: Contains protons and neutrons
• Element: A substance composed of only one type of atom
• Atomic number: The number of protons in an atom's nucleus
• Valence electrons: Electrons in the outermost shell of an atom, involved in chemical bonding
• Compound: A substance formed by the chemical combination of two or more different elements
• Covalent bonds: Bonds formed by the sharing of electrons between atoms. Example: Water (H₂O)
• Ionic bonds: Bonds formed by the transfer of electrons between atoms.
• Lizard walking on water: A specialized adaptation using surface tension and water cohesion.

2.2 Properties of Water

• Hydrogen bond: A weak attraction between a slightly positive hydrogen atom and a slightly negative atom (often oxygen or nitrogen) in another molecule.
• Cohesion: Attraction between like molecules. Example- water molecules sticking together.
• Adhesion: Attraction between unlike molecules. Example - water molecules sticking to a glass surface.
• Water in the human body: Approximately 60-70%
• Solution: A homogeneous mixture of two or more substances
• Solute: The substance dissolved in a solution
• Solvent: The substance that dissolves the solute
• pH range for acids: 0-7
• pH range for bases: 7-14
• Neutral pH: 7
• Buffer: A substance that resists changes in pH.

2.3 Carbon Compounds

• Monomer: A single repeating unit of a polymer
• Polymer: A large molecule formed by the repeating units of monomers

2.4 Chemical Reactions and Enzymes

• Chemical reaction: Process where substances change into different substances.
• Reactants: Substances that undergo change in a chemical reaction
• Products: Substances produced by a chemical reaction
• Equation O₂ + 2H₂ → 2H₂O - Balanced (Reactants: Oxygen and Hydrogen; Products: Water)
• Activation energy: Energy needed to start a reaction
• Catalyst: A substance that speeds up a chemical reaction without being consumed
• Effect of catalyst on activation energy: Lowers activation energy; increases the speed of the reaction.
• Enzymes: Biological catalysts, typically proteins
• Are enzymes, catalysts?: Yes
• Effect of enzyme on activation energy: Reduces activation energy (as shown in the graph)
• Active sites: Specific regions on an enzyme where substrate molecules bind
• Substrate: Reactant molecule that binds to an enzyme
• One enzyme to many substrates?: No
• Enzyme-substrate complex (illustration): Enzyme (A) binds to substrate (B) forming a complex (C & D); Products are released.
• Factors affecting enzyme activity: Temperature, pH, and substrate concentration.

UNIT 2: ECOLOGY - CH 3 & 4

• Ecology: Study of the interactions of organisms with one another and with their environment
• Organism: Living thing (e.g., a tree)
• Population: Group of organisms of the same species living in the same area (e.g., all the trees of a species)
• Community: All the populations of different species living in the same area (e.g., all living organisms in a forest)
• Ecosystem: A community of organisms and their physical environment (e.g., the entire forest, including soil & climate)
• Biome: A large region characterized by specific climate and plant communities (e.g., tundra)
• Biosphere: The part of Earth where life exists
• Biotic factors: Living components of an ecosystem (e.g., plants, animals, bacteria)
• Abiotic factors: Non-living components of an ecosystem (e.g., sunlight, water, temperature)
• Earth's four global systems: Interact constantly in cycles of matter and energy.
• Ecosystem energy source: The sun
• Producer: Organism that creates its own food through photosynthesis (e.g., plants)
• Producer synonym: Autotroph
• Photosynthesis: Process where plants use sunlight to make food
• Consumers: Organisms that get energy by consuming other organisms (e.g., animals)
• Herbivore: Consumer that eats plants only
• Carnivore: Consumer that eats animals only
• Omnivore: Consumer that eats both plants and animals
• Decomposer: Consumer that breaks down dead organic matter (e.g., fungi, bacteria)
• Specialist: Consumer that eats only one type of organism. Example - panda eats bamboo only
• Generalist: Consumer that eats a variety of organisms. Example - raccoon eats various food sources.
• Food chain: Linear sequence of organisms showing energy transfer
• Food web: Network of interconnected food chains
• Ecological pyramids: Models that show the distribution of energy and biomass at different trophic levels in an ecosystem
• Biomass: Total mass of organisms in a given area or trophic level
• Energy pyramid: Shows the amount of energy at each trophic level in an ecosystem; energy is lost as heat
• Biomass pyramid: Shows the total biomass at each trophic level in an ecosystem.
• Pyramid of numbers: Illustrates the number of organisms at each trophic level
• Biogeochemical cycles: Processes that cycle matter through the living and non-living parts of an ecosystem
• Water cycle: Process involving evaporation, condensation, precipitation, and collection of water.
• Carbon cycle: Process involving carbon fixation, respiration, and combustion.
• Carbon reservoir: Atmosphere (carbon dioxide) , fossil fuels
• Nitrogen cycle: Process of converting nitrogen into usable forms for organisms.
• Nitrogen fixation: Process converting nitrogen gas into ammonia.
• Denitrification: Process converting nitrates back into nitrogen gas.
• Phosphorus cycle: Process involving phosphate's movement in different parts of the biosphere.
• Phosphate release: From weathering of rocks
• Phosphorus cycle location: Earth's crust and oceans.
• Nutrient limitation: Inability of an organism to grow or reproduce because of a lack of a specific nutrient
• Species affected by nutrient limitation: Survival of plants and animals

UNIT 2: ECOLOGY - CH 6 AND 5

• Habitat: Physical place where an organism lives
• Microhabitat: Small part of a habitat with specific conditions
• Microbiome: Community of microorganisms inhabiting a specific habitat
• Tolerance: An organism's ability to survive variations in its environment
• Niche: An organism's role in its ecosystem, including its interactions, food sources, and interactions with other organisms. Example- role a lion plays in the savanna ecosystem
• Competition: Interaction where organisms struggle for limited resources
• Herbivore: Organisms that feed on plants
• Herbivore impact: Affects plant populations, influencing plant diversity.
• Keystone species: A species that has a disproportionately large effect on its ecosystem. Example - sea otters
• Commensalism: One organism benefits, and the other is neither harmed nor benefited. Example - birds nesting in trees
• Mutualism: Both organisms benefit. Example - bacteria living in the gut
• Parasitism: One benefits, one is harmed. Example- tick on a dog
• Ecological succession: Gradual changes in an ecosystem over time
• Pioneer species: First species to establish in an area. Example - Lichens, grasses
• Primary succession: Succession starting on bare rock
• Secondary succession: Succession starting on disturbed land
• Climax community: Stable, mature community at the end of succession
• Biodiversity: Variety of life in an ecosystem and includes genetic, species, and ecosystem diversity
• Resilience: Ability of an ecosystem to recover after disturbance
• Conservation biology: Study of the conservation of species and ecosystems
• Geographic range: Distribution area of a population
• Density distribution: Even, clumped, or random organization of organism density in an area
• Population growth rate =1: Population size stays constant
• Population growth rate > 0: Population is growing
• Population growth rate < 0: Population is shrinking
• Factors increasing population size: Birth, immigration, resource availability
• Factors decreasing population size: Death, emigration, resource scarcity
• Exponential growth: Population growth accelerating without limitations.
• Logistic growth: Population growth that levels off at the carrying capacity.
• Carrying capacity: Maximum population size that an environment can sustain
• Limiting factors: Factors that restrict population growth
• Density-dependent limiting factors: Factors where effect is related to population density (e.g., competition, disease, predation)
• Density-independent limiting factors: Factors where effect is not related to population density (e.g., natural disasters)
• Demography: Study of human populations
• Age structure diagrams: show the distribution of different age groups within a population, indicating potential growth patterns. More quickly populations will grow when it has a larger number of individuals in younger age groups.
• Events shaped by resource availability: Species distribution; migration patterns; population fluctuations; extinction events

UNIT 3: HUMAN IMPACT - CH 7

• Ecological footprint: Amount of Earth's resources a human population uses
• Resources in ecological footprints: Land, water, energy, and materials
• Great Acceleration: Period of rapid human population and resource consumption growth (supported by text graphs)
• Anthromes: Anthropogenic biomes, regions modified by humans
• Climate change: Long-term variations in Earth's climate
• Global warming: Increase in Earth's average temperature
• Ocean acidification: Decrease in pH of the ocean due to absorption of CO₂ from the atmosphere
• Steps of ocean acidification:

1. CO₂ dissolves in seawater
2. CO₂ reacts with water to form carbonic acid (H₂CO₃)
3. Carbonic acid releases hydrogen ions (H⁺)
4. This lowers the pH of the water, impacts marine life by affecting shells and skeletons

• Algal blooms cause: Excessive nutrient input (eutrophication)
• Algal bloom effects: Ecosystem disruption from excess nutrients
• Monoculture: Large-scale planting of a single crop
• Monoculture purpose: Increased efficiency in production, but decreased biodiversity
• Deforestation: Cutting down of trees
• Succession: Gradual changes in an ecosystem over time (already mentioned)
• Reforestation: Planting of trees in deforested areas
• Urbanization: Growth of cities and urban areas
• Habitat loss: Reduction of natural habitats due to human activities
• Habitat fragmentation: Breaking of large habitats into smaller, isolated pieces
• Habitat restoration: Repairing and restoring damaged environments
• Invasive species: Non-native species that outcompete native species and disrupt ecosystems
• CFCs: Chlorofluorocarbons, banned for their ozone depletion effect.
• Smog effect on ozone: Smog does not directly harm the ozone layer, but it can contain chemicals that contribute to air pollution.
• Biological magnification: Increase in concentration of a pollutant as it moves up trophic levels
• Pollutant concentration: Increases as pollutants move up trophic levels for example through food chains
• Lead dangers: Neurological damage, developmental problems, and other health problems
• IPCC data on climate change: Shows increasing temperatures, rising sea levels, etc.
• Climate change ecological impacts: Altered habitats, species migration, and ecosystem instability
• Sustainable development: Meeting the needs of the present without compromising the ability of future generations to meet their own needs
• Renewable resources: Resources that can be replenished (e.g., solar energy, wind energy)
• Nonrenewable resources: Resources that cannot be replenished (e.g., fossil fuels)
• Complex ecosystems: Interconnected systems, like the Amazon rainforest
• Humans in complex ecosystems: Often damage biodiversity and stability through human activity
• Resilience and sustainable development: Related but distinct; resilience is about adapting to change, while sustainable development focuses on avoiding harm to future generations.
• Scientific research impact: Drives solutions and promotes environmental awareness.

UNIT 4: CELLS - CH 9 & 10

• Prokaryotic vs. Eukaryotic Cells (Summary): Prokaryotes are simpler, lacking membrane-bound organelles, while eukaryotes have a nucleus and other organelles.

• Prokaryotic Cell Description (Textbook Page 258):

• Describes the simpler structure with few organelles

• Eukaryotic Cell Description (Textbook Page 259):

• Describes the more complex structure with various membrane-bound organelles.

Photosynthesis And Cellular Respiration

• Photosynthesis:

• Organelle: Chloroplast

• Cell type: Plant cell

• Equation: 6CO₂ + 6H₂O + light energy → C₆H₁₂O₆ + 6O₂ (Reactants: carbon dioxide, water, and light energy) (Products: glucose and oxygen)

• Reactants: carbon dioxide, water, light energy

• Goal: Produce glucose

• Waste product: Oxygen

• Light-dependent reaction location: Thylakoid membranes

• Light-dependent reaction power source: Light

• Light-independent reaction location: Stroma

• Light-independent reaction power source: ATP and NADPH

• Inorganic carbon molecule into dark reaction: CO₂

• Organic carbon molecule made: Glucose

• Cellular Respiration

• Organelle: Mitochondria

• Cell type: Plant and animal cell

• Equation: C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + 36 ATP (Reactants: glucose and oxygen) (Products: carbon dioxide, water, and 36 ATP)

• Reactants: Glucose, oxygen

• Goal: Produce energy (ATP)

• Waste products: Carbon dioxide, water

• Carbon source in CO₂: Glucose

• Waste product used in photosynthesis: Carbon dioxide

• Glycolysis - Location: Cytosol - Starting ATP: 2 - Glycolysis product: Pyruvate. - ATP produced: 2

• Respiration (Krebs Cycle/Electron Transport Chain) - Location: Mitochondrial matrix - Krebs Cycle ingredients: Pyruvate - Krebs Cycle products: ATP, NADH, FADH₂ and CO₂ - Electron Transport Chain final electron acceptor :Oxygen - Water made: Electron Transport Chain - ATP produced in Krebs cycle: 2 ATP - ATP produced in Electron Transport Chain: 32 ATP

• Fermentation - Two types: Alcohol fermentation and Lactic acid fermentation - Aerobic or anaerobic: Anaerobic - NADH during fermentation: Oxidized to NAD⁺ - Muscle soreness cause: Lactic acid fermentation - Additional ATP in fermentation: Zero ATP Produced in fermentation

UNIT 4: CELLS - CH 11

• Cell growth limitations: Surface area-to-volume ratio; DNA overload
• Cell division key points: Copies DNA, divides cytoplasm, maintains genetic integrity
• Asexual reproduction: Offspring are genetically identical to the parent
• Sexual reproduction: Offspring inherit genetic material from two parents
• Asexual vs. sexual reproduction comparison: Genetically identical offspring in asexual, while genetically diverse in sexual. Variability in sexual reproduction.
• Chromosomes: Threadlike structures containing genetic information
• Chromosome packaging in prokaryotes: Circular DNA
• Chromosome packaging in eukaryotes: Linear DNA associated with proteins, packaged tightly
• Binary fission: Prokaryotic cell division, a form of asexual reproduction; DNA replicates, the cell grows, the cell divides into two new identical cells.
• Mitosis: Eukaryotic cell division, produces genetically identical daughter cells, part of cell cycle
• Cyclins: Proteins that regulate the cell cycle
• Internal vs. external regulators: Internal regulate conditions inside the cell; external from outside the cell; both regulate growth, division
• Apoptosis: Programmed cell death; necessary for development and homeostasis
• Cancer: Uncontrolled cell division due to malfunctioning regulatory genes
• Cancer treatments: Surgery, radiation, chemotherapy
• Cell differentiation: Process where cells become specialized for specific functions
• Differentiation process: Cells express specific genes to perform unique roles in tissues & organs
• Stem cells: Undifferentiated cells; can give rise to specialized cell types
• Stem cell sources: Embryos, umbilical cord blood, and adult tissues
• Stem cell abilities: Self-renewal and differentiation
• Stem cell types: Embryonic, adult, induced pluripotent
• Stem cell research pros: Potential to treat diseases, regenerate damaged tissues; improve understanding of development processes
• Stem cell research cons: Ethical considerations surrounding embryonic stem cells; potential for misuse; ensuring safety and efficacy in treatments.