BIOL 105 Lec 04 (Unit I Review) PDF

Dates and Fates! Qui Discussi zze on Date Chapter Material/Exam s Boards 1/21/202 5 0 Course Introduction 1 1/23/202 5 1 Process of Science 2 1/28/202...

Dates and Fates! Qui Discussi zze on Date Chapter Material/Exam s Boards 1/21/202 5 0 Course Introduction 1 1/23/202 5 1 Process of Science 2 1/28/202 5 2 Chemistry of Life 3 1 1/30/202 Cell Structure and 5 3 Function 4 2/4/2025 Review Review 2 2/6/2025 Exam I Exam I  Remember!!!! Exam I is next class! DO NOT BE LATE!!! I can only allow make ups with an excuse! If you are anticipating using the access center, be sure those requests have been submitted! I will provide The answer key The Exam You will provide Big, beautiful brains Pencil(s) Review Time!  Chapter 1 Process of Science  Types of Evidence Anecdotal evidence: Scientific evidence: Derived from personal Derived from systematic observation and experience observation and experimentation Geaux Colonels!  Anecdotal Evidence (1 of 3) Inspired by evidence, but not systemically tested One or a few points of data considered Data analyzed from the perspective of personal experience Geaux Colonels!  Anecdotal Evidence (2 of 3) Conclusions informally vetted, based on personal experiences Conclusions published on social media Conclusions not verified Geaux Colonels!  Anecdotal Evidence (3 of 3) Anecdotal evidence may feel correct and seem very persuasive. Anecdotal evidence is not very reliable. It may inspire questions for scientific studies. Geaux Colonels!  Scientific Evidence (1 of 2) Hypotheses that are testable and falsifiable are examined. Hundreds to thousands of data points are considered. Data are subjected to statistical analysis. Geaux Colonels!  Scientific Evidence (2 of 2) Conclusions are: formally vetted in a peer-review process by other scientists who have expertise in the area. published in scientific journals. supported or disproved through further scientific experimentation. Geaux Colonels!  Science Is a Process: Studying Previous Research (2 of 2) Peer review: is a review of an article by experts before publication. ensures that the authors have appropriately designed and interpreted their study. weeds out sloppy research. Geaux Colonels!  Science Is a Process: Forming Scientific Hypotheses (1 of 4) Use information to formulate a scientific hypothesis. A testable and falsifiable explanation for a scientific observation or question “Exposure to cell phone radiation increases the incidence of cancer.” Geaux Colonels!  Science Is a Process: Forming Scientific Hypotheses (2 of 4) Testable: supported or rejected by carefully designed experiments or nonexperimental studies Falsifiable: can be ruled out by data Geaux Colonels!  Science Is a Process: Forming Scientific Hypotheses (4 of 4) A hypothesis is never proven. If found false, it is rejected and no longer considered a possible answer to the original question. If the data support the hypothesis, it will be accepted until further testing and data show otherwise. Geaux Colonels!  Science Is a Process: Experimentation (3 of 8) experimental group: experiences the experimental intervention or manipulation control group: experiences no experimental intervention or manipulation Basis for comparison Geaux Colonels!  Science Is a Process: Experimentation (5 of 8) The experimental group experiences the independent variable. This is the factor being deliberately changed in the experimental group. Geaux Colonels!  Science Is a Process: Experimentation (6 of 8) The control group receives a placebo. A placebo is a fake treatment that mimics the experience of the experimental groups. Geaux Colonels!  Science Is a Process: Experimentation (7 of 8) The dependent variable is the measured result of an experiment. It is analyzed in both the experimental and control groups. Geaux Colonels!  Science Is a Process: Drawing Conclusions (4 of 4) A hypothesis that continues to hold up after many years of rigorous testing may eventually be considered a scientific theory. Geaux Colonels!  Science Is a Process: Finding Patterns (2 of 4) Observing patterns can show a consistent relationship between variables. Correlation: a consistent relationship between two variables Correlation between two variables does not prove that one variable causes the other. Geaux Colonels!  Evaluating Scientific Information (2 of 3) Media reports greatly simplify the results for the public, often leading to misleading or sensationalized information. Geaux Colonels!  Summary (1 of 4) How is the scientific method used to test hypotheses? Science is a process—a way of seeking answers to questions using observations and experiments. A potential answer to a scientific question is called a hypothesis. Hypotheses are tested and improved or rejected by the results of controlled experiments or in observational studies.  Summary (2 of 4) What factors influence the strength of the conclusions of scientific studies and their relevance to humans? Peer review helps ensure that the scientific results are valid as well as accurately and fairly presented. Experimental controls help distinguish what is being tested from other factors. The strength of the conclusions of a scientific study depends on the type of study, the sample size, and other factors.  Summary (3 of 4) How can you evaluate the evidence presented in media reports of scientific studies? Scientific theories have undergone extensive testing and are supported by a large body of evidence. Most people rely on media reports for scientific information, but these are not always completely accurate in how they portray scientific studies. To understand a study properly, it is often necessary to look at how the study was designed and to evaluate the strength of the study conclusions for yourself.  Summary (4 of 4) How does the scientific process help us make important decisions about human health? Case control studies are observational studies in which people without a disease are compared to controls to identify the cause of the disease. When independent variables (such as cell phone use) and dependent variables (such as cancer) correlate, it does not necessarily mean one caused the other.  Chapter 2 Chemistry of Life All living organisms share five properties that define them as “alive.” Geaux Colonels!  All living organisms share five properties that define them as “alive”... except A mule (the offspring of a female horse and a male donkey) is alive, but cannot reproduce (sterile). Fire grows, reproduces, and uses energy, but it is not alive. If scientists found an alien specimen with only a few of these traits, would it be considered alive? Geaux Colonels!  All life is composed of the same chemical building blocks. Matter is anything that takes up space and has mass. All matter is made of elements—substances that cannot be chemically broken down. Geaux Colonels!  Atoms Atom: the smallest unit of an element that still retains the property of that element The nucleus is the dense core of an atom. Geaux Colonels! Subatomic particles determine the properties of the atom. Geaux Colonels!  Carbon is a key component of life’s molecules. (2 of 4) Carbon is a key component of the molecules of living organisms. Carbon can form multiple covalent bonds, the sharing of a pair of electrons between two atoms. Carbon atoms can bond up to four atoms. Geaux Colonels!  Carbon is a key component of life’s molecules. (3 of 4) Organic molecules have carbon-based backbones and at least one C–H bond. Geaux Colonels!  Molecules of Life (2 of 6) Four types of complex macromolecules make up living things: Carbohydrates Proteins Lipids Nucleic acids Geaux Colonels!  Molecules of Life (3 of 6) Carbohydrates Made of repeating subunits of simple sugars Simple sugars are monomers. Geaux Colonels!  Molecules of Life (4 of 6) Proteins: Folded polymers made of repeating units of amino acids Always the same atoms in the main chain Different groups of atoms in a side chain Geaux Colonels!  Molecules of Life (5 of 6) Lipids: Not made of repeating monomers Lipids are hydrophobic—they do not mix with water Geaux Colonels!  Molecules of Life (6 of 6) Nucleic acids: Polymers made of repeating nucleotide subunits DNA and a similar molecule, RNA, are nucleic acids. Geaux Colonels!  Cells are bounded by a cell membrane. Cell membranes: Have a double layer (bilayer) Separate the contents of a cell from its environment Geaux Colonels!  Water is essential for life on Earth. All of life’s chemical reactions take place in water. Water is composed of oxygen and hydrogen atoms. Many of its functions are due to its shape. Geaux Colonels!  Water is a polar molecule. (1 of 2) Polar molecule: Electrons in bonds not shared equally between atoms Partial negative charge at one end and a partial positive charge at the other Geaux Colonels!  Properties of Water Water molecules cling to each other (cohesion) and to other surfaces (adhesion). Large liquid range (freezing at 0oC; boiling at 100oC) Solid water is less dense than liquid water, so ice floats. Geaux Colonels!  Water is a good solvent. (1 of 2) Solvent: a substance in which another substance dissolves Solute: a dissolved substance Solution: the mixture of solute and solvent Geaux Colonels!  Water is a good solvent. (2 of 2) Water dissolves other polar molecules and substances that contain ionic bonds. Ionic bonds: strong bonds formed between oppositely charged ions Ion: a charged atom due to loss or gain of electron Geaux Colonels!  Acids and Bases Water molecules (H2O) sometimes split into separate hydrogen (H+) and hydroxide (OH−) ions. pH is a measure of the concentration of hydrogen ions (H+) in a solution. pH ranges from 0 to 14. Geaux Colonels!  Summary (1 of 4) How do we define life? Living organisms grow, reproduce, maintain homeostasis, sense and respond to their environment, and rely on energy to carry out their functions.  Summary (2 of 4) How is matter organized into the molecules of living organisms? All matter is composed of elements, each with a particular number of protons, neutrons, and electrons in their atoms. When atoms share pairs of electrons, they form covalent bonds, building molecules. Living organisms are made up of organic molecules, which are centered around carbon atoms. Four types of carbon-based organic molecules make up living things: carbohydrates, proteins, nucleic acids, and lipids.  Summary (3 of 4) What is the basic structural unit of life, and what are its properties? Cells are the smallest unit of life on Earth. Cells contain water and are bounded by a cell membrane. Cell membranes are made of a bilayer of phospholipids, which have a hydrophilic (water-loving) head group and a hydrophobic (water-fearing) tail.  Summary (4 of 4) Why is water so important for life and living organisms? Water molecules are polar, with partial positive and negative parts. Water molecules can form weak attractions (hydrogen bonds) with other polar molecules. Water is crucial for life on Earth: it is “sticky,” it regulates heat well, it floats when frozen, and it is a good solvent. Atoms that lose or gain electrons are ions, which can form strong electrical attractions (ionic bonds). The concentration of hydrogen ions (H+) ions in a solution determines its pH.  Chapter 3 Cell Structure and Function  How do antibiotics work? Antibiotics: Preferentially kill bacteria without harming human or animal host Target what is unique about bacterial cells Geaux Colonels!  Cells Cell theory All living things are made of cells. Every new cell comes from the division of a pre-existing cell. Geaux Colonels!  Types of Cells Prokaryotic cells: lack internal Eukaryotic cells: membrane- membrane-bound organelles bound organelles, including a nucleus Geaux Colonels! Differences of Prokaryotic and Eukaryotic Cells Only eukaryotic cells: Only prokaryotic cells: A nucleus: an organelle that DNA floating freely in contains the DNA cytoplasm Many organelles No organelles Cell wall made of peptidoglycan, a rigid structure enclosing the cell membrane Geaux Colonels!  Antibiotics Target Prokaryotic Cells (3 of 7) Osmosis is the diffusion of water across a semipermeable membrane. When concentrations are equal inside and outside the cell, it is isotonic. Water flows in and out of the membrane at the same rate. Geaux Colonels!  The Cell Membrane (2 of 7) Phospholipids Primary component of cell membranes Structure is hydrophobic and partly hydrophilic Form a bilayer in an aqueous environment Hydrophilic heads point toward the water Hydrophobic tails point away from water Geaux Colonels!  The Cell Membrane (4 of 7) Simple diffusion Natural tendency of dissolved substances to move from an area of higher concentration to one of lower concentration No energy required Geaux Colonels!  The Cell Membrane (7 of 7) Active transport Like facilitated diffusion, uses the help of transport proteins Unlike facilitated diffusion, active transport: Requires energy input Pumps solutes to the side of the membrane with higher solute concentration Geaux Colonels!  Eukaryotic Organelles (1 of 8) Nucleus Encloses the cell’s DNA Reactions for interpreting the genetic instructions take place here. Surrounded by the nuclear envelope Geaux Colonels!  Eukaryotic Organelles (2 of 8) Endoplasmic reticulum (ER) Network of membrane- covered “pipes” Proteins and lipids synthesized here Rough ER Smooth ER Geaux Colonels!  Eukaryotic Organelles (3 of 8) Golgi apparatus Stacked membranous discs Receives proteins from ER via vesicles Packages and transports proteins Geaux Colonels!  Eukaryotic Organelles (4 of 8) Nucleus, ER, and Golgi apparatus work together to produce and transport proteins. Geaux Colonels!  Eukaryotic Organelles (5 of 8) Mitochondria Extract energy from food Convert energy into a useful form Geaux Colonels!  Eukaryotic Organelles (6 of 8) Chloroplasts Plants and algae have them. Sites of photosynthesis – capture and conversion of sunlight energy into a usable form Geaux Colonels!  Eukaryotic Organelles (7 of 8) Lysosomes Full of digestive enzymes Break down worn-out cell parts and food molecules Geaux Colonels!  Eukaryotic Organelles (8 of 8) Cytoskeleton Network of protein fibers Functions include cell support, cell movement, and movement of structures within cells Geaux Colonels!  Evolution of Eukaryotic Cells Endosymbiosis theory: Free-living prokaryotic cells engulfed other free-living prokaryotic cells billions of years ago, forming mitochondria and chloroplasts. Geaux Colonels!  Summary (1 of 2) Antibiotics are chemicals, originally produced by living organisms, that selectively target and kill bacteria. All living organisms are made of cells, and new cells arise from existing cells. Two types of cells exist, which are distinguished by their structure: prokaryotic and eukaryotic. All cells are enclosed by a cell membrane, which controls the passage of molecules between the exterior of the cell and the cytoplasm.  Summary (2 of 2) Substances cross cell membranes by simple or facilitated diffusion or by active transport. Water crosses cell membranes by osmosis. All cells have ribosomes: complexes of RNA and proteins that synthesize new proteins. Eukaryotic cells contain many specialized organelles.