Biology Finals Review PDF

CHAPTER 1: Introduction to Biology 1. Define Biology. Biology is the scientific study of life and living organisms, including their structure, function, growth, origin, evolution, and distribution. 2. Identify all the characteristics that define life. Order: Organisms are comp...

CHAPTER 1: Introduction to Biology 1. Define Biology. Biology is the scientific study of life and living organisms, including their structure, function, growth, origin, evolution, and distribution. 2. Identify all the characteristics that define life. Order: Organisms are complex and highly organized. Reproduction: Organisms reproduce their own kind. Growth and Development: Organisms grow and develop following specific instructions coded in their DNA. Energy Utilization: Organisms take in energy and use it to perform activities. Response to Stimuli: Organisms respond to environmental stimuli. Regulation: Organisms regulate their internal environment to maintain a stable condition (homeostasis). Adaptation: Organisms evolve over generations through natural selection. 3. Discuss Biological Organization. What are emergent properties? Biological organization refers to the hierarchy of biological systems, from atoms to the biosphere. At each level, new properties emerge that were not present at the simpler levels. ○ Emergent Properties: Characteristics of a system that emerge as a result of interactions among its components (e.g., consciousness from neural networks in the brain). 4. What are feedback mechanisms? Feedback mechanisms regulate biological processes, maintaining homeostasis by responding to changes. ○ Positive Feedback: Amplifies a change (e.g., blood clotting). ○ Negative Feedback: Reduces or counteracts a change (e.g., temperature regulation). 5. Name the different Kingdoms and Domains. Domains: Bacteria, Archaea, Eukarya. Kingdoms (under Eukarya): Animalia, Plantae, Fungi, Protista. 6. Explain Discovery Science and the Scientific Method. Discovery Science: Involves making observations and drawing conclusions without experimentation. Scientific Method: A systematic approach to solving problems involving observation, hypothesis, experimentation, analysis, and conclusion. CHAPTER 2-6: The Chemistry of Life 1. Define “element” and “compound.” Which are the four elements that make up 96% of substances in life? Element: A substance that cannot be broken down into simpler substances by chemical means. Compound: A substance formed by the chemical combination of two or more elements. ○ The four elements that make up 96% of substances in life are Carbon (C), Hydrogen (H), Oxygen (O), and Nitrogen (N). 2. What are the constituents/subatomic particles of an atom? What charge (if any) do they have? Protons: Positive charge (+), 1 AMU. Neutrons: No charge (0), 1 AMU. Electrons: Negative charge (-), 0 AMU. 3. Describe the difference between atomic number and atomic mass. Atomic Number: The number of protons in the nucleus of an atom, determines the element. Atomic Mass: The total mass of an atom, approximately equal to the sum of protons and neutrons. 4. What is a valence shell and when is it most stable? Why? The valence shell is the outermost electron shell of an atom. It is most stable when it contains 8 electrons (octet rule), as this configuration is energetically favorable. 5. How many electrons are in the outer shell of an atom that has 25 protons?  The element with 25 protons is Manganese (Mn), and its electron configuration is 2, 8, 13, 2, meaning it has 2 electrons in the outermost shell. 6. Briefly describe the following types of bonds: covalent (polar and non-polar), ionic, hydrogen. Covalent Bond: Electrons are shared between atoms. ○ Non-polar: Electrons are shared equally (e.g., O2). ○ Polar: Electrons are shared unequally, creating partial charges (e.g., H2O). Ionic Bond: One atom donates an electron to another atom, creating charged ions (e.g., NaCl). Hydrogen Bond: A weak bond formed between a hydrogen atom covalently bonded to one electronegative atom and another electronegative atom (e.g., between water molecules). 7. What are van der Waals interactions, and why do they occur? Van der Waals interactions are weak, non-covalent interactions due to transient partial charges between molecules. They occur because of the constant motion of electrons. 8. What does it mean when a reaction is at “equilibrium”? What is happening to the reactants and products? Equilibrium occurs when the forward and reverse rates of a reaction are equal, so concentrations of reactants and products remain constant. 9. What is an Isotope? An isotope is an atom of the same element that has a different number of neutrons, resulting in a different atomic mass. 1. Why does ice float? Ice floats because it is less dense than liquid water. In solid form, water molecules form a crystalline structure held together by hydrogen bonds, which creates more space between the molecules compared to liquid water, making ice less dense. 2. Define the different properties of water:  Adhesion: The attraction between water molecules and different substances (e.g., water clinging to a glass surface). Cohesion: The attraction between water molecules themselves, which leads to surface tension (e.g., water droplets sticking together). High Specific Heat: Water can absorb a lot of heat without changing its temperature much, helping stabilize temperatures in organisms and environments. High Heat of Vaporization: It requires a lot of energy to change water from liquid to gas. Universal Solvent: Water dissolves many substances due to its polarity, allowing it to dissolve salts, sugars, acids, gases, and other polar molecules. 3. Define the terms: Solution: A homogeneous mixture of two or more substances. Solvent: The substance that dissolves the solute in a solution (usually water). Solute: The substance that is dissolved in a solution. Aqueous: A solution in which water is the solvent. Hydrophobic: Substances that repel water (non-polar molecules). Hydrophilic: Substances that are attracted to water (polar molecules or ions). 4. Describe how the pH of a solution relates to the hydrogen ion concentration: pH is a measure of the concentration of hydrogen ions (H⁺) in a solution. A lower pH indicates a higher concentration of H⁺, while a higher pH indicates a lower concentration of H⁺. A pH 1 solution has more hydrogen ions than a pH 4 solution. 5. How does a buffer work? A buffer maintains a stable pH in a solution by neutralizing excess acids or bases. It contains a weak acid and its conjugate base (or a weak base and its conjugate acid), which can absorb or release H⁺ ions as needed to resist changes in pH. 1. What is the valence of Carbon, Nitrogen, Oxygen, and Hydrogen? Why? Carbon (C): Valence of 4, because it needs 4 electrons to fill its outer shell. Nitrogen (N): Valence of 3, because it needs 3 electrons to fill its outer shell. Oxygen (O): Valence of 2, because it needs 2 electrons to fill its outer shell.  Hydrogen (H): Valence of 1, because it needs 1 electron to fill its outer shell. 2. Distinguish between structural and geometric isomers and enantiomers. Structural isomers: Compounds with the same molecular formula but different arrangements of atoms (e.g., butane vs isobutane). Geometric isomers: Compounds with the same molecular formula but differ in the spatial arrangement of atoms (cis-trans isomers). Enantiomers: Stereoisomers that are non-superimposable mirror images of each other, often referred to as "left-handed" and "right-handed" molecules. 3. What are the functional groups of an amino acid? The functional groups of an amino acid include: ○ Amino group (-NH₂) ○ Carboxyl group (-COOH) ○ Hydrogen atom (-H) ○ R group (side chain, varies for each amino acid). 4. What is the difference between an aldehyde and a ketone? What is the name of the structural group that characterizes these types of molecules? Aldehydes have a carbonyl group (C=O) attached to a terminal carbon (e.g., formaldehyde). Ketones have a carbonyl group attached to two other carbon atoms (e.g., acetone). The characteristic structural group is the carbonyl group (C=O). 5. How is an alcohol able to dissolve in water? Alcohols can dissolve in water due to the presence of a hydroxyl group (-OH) that can form hydrogen bonds with water molecules, making alcohols polar and soluble in water. 6. Identify the structure and properties of all the functional groups discussed in class: Hydroxyl group (-OH): Found in alcohols, makes molecules polar. Carbonyl group (C=O): Found in aldehydes and ketones. Carboxyl group (-COOH): Found in carboxylic acids, makes the molecule acidic. Amino group (-NH₂): Found in amines and amino acids, acts as a base. Sulfhydryl group (-SH): Found in thiols, forms disulfide bonds in proteins.  Phosphate group (-PO₄²⁻): Found in DNA, RNA, and ATP, makes molecules negatively charged. Methyl group (-CH₃): Non-polar, affects the expression of genes. 1. Describe how polymers are synthesized and broken down. Polymers are synthesized through dehydration synthesis, where water is removed to form a bond between monomers. Polymers are broken down by hydrolysis, where water is added to break the bond between monomers. 2. What is the general formula for a carbohydrate? For glucose? The general formula for a carbohydrate is C₆H₁₂O₆ (CH₂O)n. The formula for glucose is C₆H₁₂O₆. 3. What is the name of the bond formed between the monomers of a carbohydrate? The bond is called a glycosidic linkage. 4. What are the plant and animal storage polysaccharides? How are they similar? How do they differ? Plant storage polysaccharide: Starch. Animal storage polysaccharide: Glycogen. Similarity: Both are polysaccharides used for energy storage. Difference: Starch is made of amylose and amylopectin, while glycogen is more highly branched. 5. Why is cellulose a good structural polysaccharide? Cellulose has a linear, rigid structure with hydrogen bonding between parallel strands, making it an effective structural component in plant cell walls. 6. What is the structure of a triglyceride? How is it different from the structure of a phospholipid? Triglycerides consist of a glycerol backbone and three fatty acids.  Phospholipids have a glycerol backbone, two fatty acids, and a phosphate group, which makes them amphipathic (hydrophilic head and hydrophobic tail). 7. How do saturated and unsaturated fatty acids differ in structure and appearance? Saturated fatty acids have no double bonds between carbon atoms, making them straight and solid at room temperature. Unsaturated fatty acids have one or more double bonds, causing kinks in the chain, and they are liquid at room temperature. 8. Describe the structure and components of a cell membrane in terms of the type of fat it comprises. What is the reason for the molecular arrangement of these molecules? The cell membrane is made up of a phospholipid bilayer, with hydrophilic heads facing outward and hydrophobic tails facing inward. This arrangement forms a semi-permeable membrane, with the hydrophobic interior preventing the passage of certain molecules. 9. What does a cholesterol molecule look like? What are some of its functions? Cholesterol has a four-ring structure and is amphipathic. It helps maintain membrane fluidity by preventing phospholipid tails from packing too tightly and is also a precursor for steroid hormones. 10. Draw the general structural formula of an amino acid. Label the Amino terminus/end and the carboxyl terminus/end. The general structure consists of an amino group (-NH₂), a carboxyl group (-COOH), a hydrogen atom (-H), and an R group (side chain). ○ The Amino terminus is the -NH₂ group. ○ The Carboxyl terminus is the -COOH group. 11. How are peptide bonds formed? Peptide bonds are formed by dehydration synthesis, where the carboxyl group of one amino acid bonds to the amino group of another amino acid, releasing a water molecule. 12. What are the four levels of protein structure? What types of bonding are involved at each level?  Primary structure: Sequence of amino acids (peptide bonds). Secondary structure: Folding into alpha-helices or beta-pleated sheets (hydrogen bonds). Tertiary structure: Overall 3D shape (hydrogen bonds, ionic bonds, hydrophobic interactions, disulfide bridges). Quaternary structure: Multiple polypeptides come together (same bonds as tertiary). 13. What does it mean when a protein is denatured? How can this occur? A protein is denatured when its 3D structure is disrupted, often losing its function. This can occur due to changes in temperature, pH, or chemical exposure. 14. What are some of the functions of proteins in our bodies? Proteins serve as enzymes, hormones, structural components, transporters, antibodies, and more. 15. Name the basic components of a nucleotide. What are the nucleotides in DNA? A nucleotide consists of a phosphate group, a sugar (deoxyribose in DNA), and a nitrogenous base. ○ In DNA, the nucleotides are adenine (A), thymine (T), cytosine (C), and guanine (G). 16. How does the general structure of a DNA macromolecule differ from that of an RNA macromolecule? DNA: Double-stranded, deoxyribose sugar, thymine as a base. RNA: Single-stranded, ribose sugar, uracil replaces thymine. 17. Write the complementary sequence for the following DNA strand: ACCGTTACTC. The complementary strand is: TGGCAATGAG. 18. Describe the Alpha-helix of DNA and what it means to be antiparallel. The alpha-helix is a right-handed spiral shape in DNA. The strands are antiparallel, meaning one strand runs 5' to 3' and the other runs 3' to 5'. Chapter 7: Cell Structure and Function 1. Describe the general components of a cell membrane. The cell membrane is composed of a phospholipid bilayer, proteins (integral and peripheral), cholesterol, and carbohydrates. 2. Describe the differences between Prokaryotic and Eukaryotic cells. Prokaryotic cells: Lack a nucleus, smaller, no membrane-bound organelles (e.g., bacteria). Eukaryotic cells: Have a nucleus, larger, contain membrane-bound organelles (e.g., plants, animals). 3. Name and describe all the organelles and their functions in Plant and Animal cells. Nucleus: Stores genetic information. Mitochondria: Powerhouse of the cell, produces ATP. Ribosomes: Protein synthesis. Endoplasmic Reticulum (ER): Rough ER (protein synthesis), Smooth ER (lipid synthesis). Golgi apparatus: Modifies and packages proteins. Lysosomes: Digestive enzymes for waste. Vacuoles: Storage, waste disposal, and protection. Chloroplasts (in plants): Photosynthesis. 4. How do plant and animal cells differ from each other just by looking at them? Plant cells: Have a cell wall, chloroplasts, and large central vacuoles. Animal cells: No cell wall, smaller vacuoles, no chloroplasts. 5. Name and describe the function of all the parts of the nucleus of a cell. Nuclear membrane: Separates the nucleus from the cytoplasm. Nucleolus: Produces ribosomal RNA. Chromatin: Contains DNA. 6. How are ribosomes made? Where can they be found, and what is their function in the cell?  Ribosomes are made in the nucleolus. They can be found either floating in the cytoplasm or attached to the rough ER. They are responsible for protein synthesis. 7. Describe the rough ER and the smooth ER. What are some of the functions they each perform? Rough ER: Has ribosomes, involved in protein synthesis and modification. Smooth ER: Lacks ribosomes, involved in lipid synthesis and detoxification. 8. What does the Golgi apparatus of a cell look like? What is its function? The Golgi apparatus is a series of flattened sacs. It modifies, sorts, and packages proteins and lipids for transport or secretion. 9. What is the function of lysosomes in a cell? Lysosomes contain enzymes that digest excess or worn-out organelles, food particles, and bacteria. 10. Describe some of the functions of the central vacuole of a mature plant cell. The central vacuole stores water, nutrients, and waste, and maintains turgor pressure for structural support. 11. Describe the path a secretory protein takes in a cell, from its creation to its eventual secretion from the cell. The protein is synthesized by ribosomes on the rough ER, modified in the Golgi apparatus, and transported in vesicles to the cell membrane, where it is secreted. 12. Describe the structure and function of a mitochondrion, a chloroplast, and a peroxisome. Mitochondrion: Powerhouse of the cell, produces ATP through cellular respiration. Chloroplast: Site of photosynthesis in plant cells. Peroxisome: Breaks down fatty acids and detoxifies harmful substances. 13. Write about the structure and functions of the three components of the cytoskeleton. Microtubules: Hollow tubes that provide structural support and assist with intracellular transport.  Microfilaments: Thin filaments that help with cell movement and shape. Intermediate filaments: Provide mechanical strength and support the cell structure. Extracellular Matrix (ECM) and Junctions 1. What is the Extracellular Matrix (ECM)? What is it made of? More abundant in plant or animal cells? ○ The Extracellular Matrix (ECM) is a complex network of proteins and carbohydrates outside the cell that provides structural and biochemical support. It is made of collagen, elastin, fibronectin, and glycosaminoglycans. The ECM is more abundant in animal cells than in plant cells. 2. What does Anchorage dependence mean? ○ Anchorage dependence is the requirement of a cell to be attached to a surface or ECM to divide and grow. 3. What are the roles of ECM? ○ The ECM provides structural support, influences cell behavior, aids in cell signaling, and regulates molecular transport. It also plays a role in tissue development, repair, and differentiation. 4. What are the different junctions in animal cells? Plant cells? ○ Animal cells: Tight junctions, gap junctions, desmosomes. ○ Plant cells: Plasmodesmata. 5. Which junctions in plant and animal cells are similar? ○ Gap junctions (animal cells) and plasmodesmata (plant cells) are functionally similar in that they both allow for communication between adjacent cells. 6. Explain how different junctions function. ○ Tight junctions: Seal cells together, preventing leakage of substances between them. ○ Desmosomes: Anchor cells to each other, providing mechanical strength. ○ Gap junctions: Form channels between cells for direct communication. ○ Plasmodesmata: Channels between plant cells that allow for the passage of molecules and communication. 7. Describe what plant cell walls are made of. What are some functional differences that we see in plants because of their cell walls? ○ Plant cell walls are made of cellulose, hemicellulose, and pectin. The cell wall provides structural support, protection, and regulation of cell growth.  Plants are able to maintain turgor pressure and resist external stress due to the rigidity of their cell walls. Chapter 8: Metabolism and Enzymes 1. What is meant by catabolic and anabolic reactions? Give an example of each. ○ Catabolic reactions break down molecules and release energy (e.g., cellular respiration). ○ Anabolic reactions build molecules and consume energy (e.g., protein synthesis). 2. Is the ΔG for an exergonic reaction more than or less than zero? What about an endergonic reaction? In which type of reaction do the products have more energy than the reactants? Why? ○ Exergonic reactions have ΔG less than zero (release energy). ○ Endergonic reactions have ΔG greater than zero (consume energy). ○ In endergonic reactions, products have more energy because energy is required to form them. 3. How do metabolic pathways keep from reaching equilibrium? ○ Metabolic pathways are regulated by enzymes, which ensure that reactions proceed in a specific direction and do not reach equilibrium. 4. Describe the components of ATP. What is the purpose of ATP in the cell? How is it recycled? ○ ATP consists of adenine, a ribose sugar, and three phosphate groups. ATP provides energy for cellular processes. It is recycled by removing one phosphate group to form ADP and then re-phosphorylating ADP to form ATP again. 5. What is meant by the EA of a reaction? How do enzymes affect the EA and the ΔG of a reaction? ○ EA (Activation Energy) is the energy required to start a reaction. Enzymes lower the EA without changing the ΔG (free energy change) of the reaction. 6. Describe the cycle of an enzyme as it catalyzes a reaction. ○ The enzyme binds to its substrate to form an enzyme-substrate complex, catalyzes the conversion to products, and then releases the products, regenerating the active site. 7. How does an enzyme lower the EA of a reaction?  ○ Enzymes lower the EA by stabilizing the transition state, providing an environment conducive to the reaction, and orienting substrates properly. 8. What is the difference between a competitive and a non-competitive inhibitor of an enzyme? Which type of inhibition can be overcome by increasing the substrate concentration? Why? ○ Competitive inhibitors bind to the enzyme's active site, competing with the substrate. Non-competitive inhibitors bind to a different site, changing the enzyme's shape. Competitive inhibition can be overcome by increasing substrate concentration because it increases the likelihood of the substrate binding to the active site. 9. Describe how an allosteric enzyme works. ○ Allosteric enzymes have regulatory sites where molecules bind, causing a change in the enzyme's shape and activity. 10. Why is feedback inhibition important in metabolic pathways? Feedback inhibition regulates metabolic pathways by preventing the overproduction of end products. When the end product accumulates, it inhibits an earlier enzyme in the pathway. 11. Define Energy. What are the different types of Energy? Energy is the capacity to do work. Types of energy include kinetic, potential, thermal, chemical, and lightenergy. 12. What are the laws of Thermodynamics? 1st Law: Energy cannot be created or destroyed, only transferred or converted. 2nd Law: Entropy (disorder) of the universe tends to increase over time. 13. Explain redox reactions. Redox reactions involve the transfer of electrons: oxidation (loss of electrons) and reduction (gain of electrons). Chapter 6: Membranes and Transport 1. Describe the factors affecting the fluidity of a cell membrane. How do these factors affect fluidity as the temperature decreases? ○ Factors: Fatty acid composition (unsaturated fats increase fluidity), cholesterol (stabilizes membrane fluidity), temperature (lower temperatures reduce fluidity). 2. Describe the functions of different types of proteins that are associated with a cell membrane.  ○ Integral proteins: Transport, signal transduction, cell recognition. ○ Peripheral proteins: Support and signaling, often associated with the cytoskeleton. 3. Define the terms hypertonic, hypotonic, and isotonic. Use these terms to describe the process of osmoregulation in a cell. ○ Hypertonic: Solution has more solute, causing the cell to shrink. ○ Hypotonic: Solution has less solute, causing the cell to swell. ○ Isotonic: Equal solute concentration, cell remains stable. ○ Osmoregulation: The process by which cells maintain balance of water and solute. 4. What are the ideal states (hypertonic, hypotonic, or isotonic) of a plant cell? An animal cell? Why? ○ Plant cells: Ideally hypotonic (to maintain turgor pressure). ○ Animal cells: Ideally isotonic (to prevent bursting or shriveling). 5. Which kinds of molecules pass through the phospholipid bilayer of a cell? Why? ○ Non-polar molecules (e.g., oxygen, carbon dioxide) pass easily because they are hydrophobic and can dissolve in the lipid layer. 6. Which type of molecules need to pass through the cell membrane via a protein? Why? ○ Polar molecules (e.g., glucose) and ions need transport proteins because they cannot pass through the hydrophobic lipid bilayer. 7. How does facilitated diffusion work? ○ Facilitated diffusion uses transport proteins (channels or carriers) to move molecules down their concentration gradient. 8. Define and describe active transport. ○ Active transport requires energy (usually ATP) to move molecules against their concentration gradient via pumps or transport proteins. 9. Define the following: endocytosis, exocytosis, phagocytosis, pinocytosis, receptor-mediated endocytosis. ○ Endocytosis: Cell engulfs materials. ○ Exocytosis: Cell expels materials. ○ Phagocytosis: Engulfment of large particles. ○ Pinocytosis: Engulfment of liquids. ○ Receptor-mediated endocytosis: Specific molecules are taken up after binding to receptors. 10. Describe the Fluid Mosaic.  The Fluid Mosaic Model describes the cell membrane as a dynamic structure with proteins floating in a fluid lipid bilayer. 11. Explain the phospholipid bilayer. The phospholipid bilayer consists of hydrophobic tails and hydrophilic heads, forming a semi-permeable membrane. Chapter 10: Photosynthesis 1. Which pigment is directly involved in the conversion of light energy to chemical energy during photosynthesis? ○ Chlorophyll is the main pigment involved in light absorption and energy conversion during photosynthesis. 2. Describe, in general terms, the two stages of photosynthesis. ○ Light reactions (occur in the thylakoid membranes, convert light energy into chemical energy as ATP and NADPH). ○ Calvin cycle (occurs in the stroma, uses ATP and NADPH to fix CO2 and produce sugar). 3. What is the actual product of the Calvin Cycle? ○ The product is glyceraldehyde-3-phosphate (G3P), which can be used to make glucose and other carbohydrates. Three molecules of CO2 are required to produce one G3P molecule. 4. Describe how light energy is converted to chemical energy in the first stage of photosynthesis. ○ Photons excite electrons in chlorophyll, which are transferred through photosystems to generate ATP and NADPH via photophosphorylation. 5. What is the mechanism for ATP production during photosynthesis? ○ ATP is produced through phosphorylation using the proton gradient generated by the electron transport chain in the light reactions. 6. What are the three stages of the Calvin cycle? ○ Carbon fixation, reduction, and regeneration of RuBP. 7. How and when is NADPH produced during photosynthesis? ○ NADPH is produced in the light reactions when electrons are passed through the electron transport chain. 8. At which stage of photosynthesis is water split? ○ Water is split during the light reactions, releasing oxygen. 9. Describe Non-cyclic and Cyclic electron flow in the light reactions.  ○ Non-cyclic flow involves both photosystems and produces ATP and NADPH. ○ Cyclic flow only involves Photosystem I and produces ATP but not NADPH. 10. How do pigments capture light energy? Pigments absorb specific wavelengths of light and transfer the energy to reaction centers in photosystems. 11. What are the differences between Photosystem II and I? Photosystem II splits water to produce oxygen and ATP. Photosystem I produces NADPH and completes the electron transport chain. 12. What are the alternatives to carbon fixation: C4 and CAM plants? C4 plants perform carbon fixation in a different compartment to minimize photorespiration. CAM plants fix CO2 at night to conserve water. Chapter 9: Cellular Respiration 1. What is the name of the enzyme involved in controlling the rate of cellular respiration? ○ Phosphofructokinase (PFK) is a key regulatory enzyme in glycolysis. 2. When is ATP consumed during respiration? ○ ATP is consumed during the energy investment phase of glycolysis. 3. What is the end product of glycolysis? ○ The end product of glycolysis is pyruvate. 4. In what molecule is most of the energy in glucose stored before it is used to make ATP? ○ Most of the energy in glucose is stored in its electrons, carried by NADH. 5. Describe how ATP is produced during oxidative phosphorylation. ○ ATP is produced by the electron transport chain and chemiosmosis. 6. How is the H+ gradient achieved by the electron transport chain? ○ H+ ions are pumped across the membrane as electrons move through the chain. 7. How are electrons passed through the Electron transport chain? ○ Electrons are transferred between proteins, with the final electron acceptor being oxygen, forming water. 8. At which stages are CO2 released during respiration? ○ CO2 is released during the transition step and Krebs cycle. 9. How are fats broken down for energy?  ○ Fats are broken down into glycerol and fatty acids, and the fatty acids enter the Krebs cycle. 10. What happens to proteins before they are used in cellular respiration? Amino acids are deaminated and their carbon skeletons enter the Krebs cycle. 11. Where does each stage of cellular respiration take place? Glycolysis occurs in the cytoplasm; Krebs cycle in the mitochondrial matrix; Electron transport chain in the inner mitochondrial membrane. 12. Describe what happens in a muscle cell when there is a lack of oxygen. In anaerobic conditions, lactic acid fermentation occurs, regenerating NAD+ but producing lactic acid. 13. What are the 5 Energy investment steps in Glycolysis? Steps that consume ATP to prepare glucose for cleavage into pyruvate. 14. What are the 5 Energy yielding steps in Glycolysis? Steps where ATP and NADH are produced during the breakdown of glucose. 15. What happens in the Bridge step between Glycolysis and the Krebs cycle? Pyruvate is converted to Acetyl-CoA, releasing CO2 and producing NADH. 16. What is a redox reaction? A redox reaction involves the transfer of electrons between molecules. 17. What role do NADH and FADH2 play in cell respiration? NADH and FADH2 shuttle electrons to the electron transport chain. 18. How much ATP is generated from theoretical maximum yield? The theoretical maximum is 38 ATP per molecule of glucose. 19. What happens in Fermentation pathways? regenerates NAD+ for glycolysis without oxygen, producing 2 ATP and either lactic acid or ethanol. Chapter 12: Mitosis and the Cell Cycle 1. How many chromosomes are present in a human somatic cell? In a gamete? ○ A human somatic cell has 46 chromosomes (23 pairs). A gamete (sperm or egg) has 23 chromosomes(haploid). 2. What are: chromatin, sister chromatids, centromeres, centrosomes, centrioles, kinetochore, mitotic spindle? ○ Chromatin: A complex of DNA and proteins found in the nucleus; it condenses to form chromosomes during cell division. ○ Sister chromatids: Two identical copies of a chromosome formed by DNA replication, joined by a centromere.  ○ Centromeres: The region of the chromosome where the sister chromatids are joined. ○ Centrosomes: Regions of the cell that organize microtubules and help form the mitotic spindle. ○ Centrioles: Cylinder-shaped structures in the centrosomes that help organize the microtubules during cell division (present in animal cells). ○ Kinetochore: A protein structure on the centromere where spindle fibers attach to pull chromatids apart. ○ Mitotic spindle: A structure made of microtubules that helps segregate chromosomes during mitosis. 3. Name any “phase” of mitosis and describe what is happening (Do this for all phases). ○ Prophase: Chromatin condenses into visible chromosomes; the mitotic spindle forms; the nuclear envelope begins to break down. ○ Metaphase: Chromosomes align at the cell's equatorial plate, and spindle fibers attach to their kinetochores. ○ Anaphase: Sister chromatids are pulled apart toward opposite poles of the cell. ○ Telophase: Chromatids arrive at opposite poles, and new nuclear envelopes form around the separated sets of chromosomes. ○ Cytokinesis: The cytoplasm divides, resulting in two daughter cells. 4. Draw the cell cycle. Name each stage and describe what goes on in each part. ○ Interphase (G1, S, G2): The cell grows (G1), DNA is replicated (S), and the cell prepares for division (G2). ○ Mitosis (prophase, metaphase, anaphase, telophase): The cell divides its nucleus and chromosomes. ○ Cytokinesis: The cell divides its cytoplasm, forming two daughter cells. 5. What happens at G2 of Interphase in preparation for mitosis? ○ The cell continues to grow and synthesizes proteins required for mitosis, including microtubules for the spindle apparatus. 6. At what stage of mitosis do the chromosomes line up in the middle of the cell? What is happening at this stage in mitosis? ○ Metaphase: Chromosomes align along the metaphase plate (center of the cell), and spindle fibers attach to the kinetochores of each chromosome. 7. What are the purposes of mitosis? ○ Mitosis ensures cell growth, repair, and asexual reproduction by producing two genetically identical daughter cells. Chapter 13: Meiosis and Sexual Reproduction 1. Define the following: homologous chromosomes, autosomes, chiasmata, synapsis, haploid, diploid, tetrad, recombinant chromosomes, n, 2n. ○ Homologous chromosomes: Chromosomes that have the same genes but may have different alleles. ○ Autosomes: Non-sex chromosomes (22 pairs in humans). ○ Chiasmata: Points where homologous chromosomes exchange genetic material during meiosis (crossing over). ○ Synapsis: The pairing of homologous chromosomes during meiosis I. ○ Haploid (n): A cell with half the number of chromosomes (e.g., gametes). ○ Diploid (2n): A cell with a full set of chromosomes (e.g., somatic cells). ○ Tetrad: A group of four chromatids formed by the pairing of homologous chromosomes during meiosis I. ○ Recombinant chromosomes: Chromosomes with new combinations of alleles due to crossing over. ○ n: Number of distinct chromosomes in a gamete (haploid). ○ 2n: Number of chromosomes in a somatic cell (diploid). 2. Describe what happens to the chromosomes of a cell during each stage of meiosis. ○ Meiosis I: Prophase I: Homologous chromosomes pair up and cross over. Metaphase I: Homologous chromosomes align at the metaphase plate. Anaphase I: Homologous chromosomes are pulled to opposite poles. Telophase I: Chromosomes reach poles, and the cell divides into two haploid cells. ○ Meiosis II: Similar to mitosis but no DNA replication. Prophase II: Chromosomes condense. Metaphase II: Chromosomes align at the metaphase plate. Anaphase II: Sister chromatids separate. Telophase II: Four haploid cells are formed. 3. When do haploid cells first form during the process of meiosis? ○ Haploid cells first form at the end of Meiosis I, when homologous chromosomes are separated into two cells.  4. Draw the sexual life cycle of a human, indicating the haploid and diploid stages of the cycle. ○ Diploid: Zygote → Somatic cells (2n) ○ Haploid: Gametes (n) → Fertilization → Zygote (2n) 5. What is a gamete? A zygote? How many chromosomes do they have (n or 2n)? Are they haploid or diploid cells? ○ Gamete: A sex cell (sperm or egg) with n chromosomes (haploid). ○ Zygote: The fertilized egg with 2n chromosomes (diploid). 6. Describe the three points at which meiosis contributes to genetic variation between individuals. ○ Independent assortment of chromosomes during meiosis I. ○ Crossing over during prophase I. ○ Random fertilization of gametes. Chapter 14: Mendelian Genetics 1. Define the following terms: allele, incomplete dominance, codominance, pleiotropy, epistasis. Give examples of each. ○ Allele: A variant of a gene (e.g., A or a for a gene controlling flower color). ○ Incomplete dominance: When the phenotype is a blend of the two alleles (e.g., red + white = pink flowers). ○ Codominance: When both alleles are expressed equally (e.g., AB blood type). ○ Pleiotropy: When one gene influences multiple traits (e.g., sickle cell disease). ○ Epistasis: When one gene affects the expression of another gene (e.g., coat color in mice). 2. What is meant by polygenic inheritance? Quantitative characters? Give examples. ○ Polygenic inheritance: When multiple genes contribute to a single phenotype (e.g., skin color). ○ Quantitative characters: Traits that vary along a continuum (e.g., height, weight). 3. What roles can the environment play in the phenotypic expression of a genotype?  ○ Environmental factors (e.g., temperature, nutrition) can influence how genes are expressed. Example: PKU is influenced by diet (affected by both genetics and environment). 4. Describe how a pedigree can be used to determine trait inheritance. How would recessively inherited traits be shown on a pedigree? What about dominantly inherited traits? ○ A pedigree maps family relationships and trait inheritance. Recessive traits show up when both parents carry the allele (often skip generations). Dominant traits appear in every generation if the individual has at least one dominant allele. 5. Work through the questions on your Mendelian inheritance worksheet. ○ This depends on the specific questions in the worksheet. 6. Describe how sex-linked inheritance works. ○ Sex-linked traits are carried on the X chromosome. Males (XY) are more likely to express X-linked recessive traits because they only have one X chromosome, whereas females (XX) need two copies of the recessive allele to express the trait. 7. How do disease genes found on the X chromosome affect males differently from females? ○ Males are more likely to express X-linked recessive diseases because they only have one X chromosome. Females need two copies of the recessive allele to express the disease. Chapter 15: DNA Replication 1. Name the three components of a DNA nucleotide and draw how they come together to form a DNA double helix structure. Label all components, including the 3’ and 5’ ends of the molecule. ○ Components: A phosphate group, a deoxyribose sugar, and a nitrogenous base (A, T, C, or G). ○ The double helix is formed by hydrogen bonds between complementary bases (A-T, C-G) and phosphodiester bonds between nucleotides. 2. Where does the energy required for DNA synthesis (adding bases to the new daughter strand) come from?  ○ Energy comes from the nucleotides themselves, which have high-energy bonds between their phosphate groups. 3. How many bonds, and of what type, are found between G and C nucleotides? Between A and T nucleotides? Which bases are purine? Which are pyrimidine? ○ G-C: 3 hydrogen bonds. ○ A-T: 2 hydrogen bonds. ○ Purines: A and G. ○ Pyrimidines: C and T. 4. Describe the roles of the following enzymes in DNA replication: DNA polymerase, Helicase, Ligase, Primase, another DNA polymerase. ○ Helicase: Unwinds the DNA double helix. ○ Primase: Synthesizes RNA primers to start DNA replication. ○ DNA polymerase: Adds nucleotides to the growing DNA strand. ○ DNA ligase: Joins Okazaki fragments on the lagging strand. ○ Another DNA polymerase: Replaces RNA primers with DNA nucleotides. 5. Why is there a leading and lagging strand in DNA replication? ○ The leading strand is synthesized continuously in the direction of the replication fork, while the lagging strand is synthesized in fragments (Okazaki fragments) because it runs in the opposite direction. 6. Name all the components that are involved in synthesis of the lagging strand of DNA. What are their purposes? ○ Primase: Adds RNA primers to the lagging strand. ○ DNA polymerase: Extends the DNA strand from the primers. ○ Ligase: Joins the Okazaki fragments together. Chapters 16, 17: Transcription and Translation 1. What is a codon? ○ A codon is a sequence of three nucleotides in mRNA that codes for a specific amino acid. 2. What is the difference between a primary transcript and an mRNA molecule that is about to leave the nucleus? Name and describe the process that forms an mRNA from a primary transcript.  ○ Primary transcript is the initial RNA sequence made from DNA. It undergoes RNA processing (capping, splicing, and polyadenylation) to become mature mRNA. 3. Which amino acid is the first to be coded when synthesizing a protein? ○ The first amino acid is methionine, encoded by the start codon (AUG). 4. Describe what happens at each stage of transcription (initiation, elongation, termination). ○ Initiation: RNA polymerase binds to the promoter region of DNA. ○ Elongation: RNA polymerase adds nucleotides to form an RNA strand. ○ Termination: RNA polymerase reaches a terminator sequence and detaches from the DNA. 5. What is the promoter region? Where is it found? What is its role? ○ The promoter region is a DNA sequence near the start of a gene where RNA polymerase binds to begin transcription. 6. What is the function of tRNA? Draw the molecule and label its components. ○ tRNA (transfer RNA) brings amino acids to the ribosome during translation. It has an anticodon that matches the mRNA codon and an amino acid attachment site. 7. What are the purposes of the E-site, P-site, and A-site of a ribosome? ○ A-site: Where tRNA binds to the mRNA codon. ○ P-site: Where the tRNA adds its amino acid to the growing polypeptide chain. ○ E-site: Where the tRNA exits the ribosome after its amino acid is added. 8. Describe translation i) initiation, ii) elongation, iii) termination ○ Initiation: mRNA binds to the ribosome, and the first tRNA binds to the start codon. ○ Elongation: The ribosome moves along the mRNA, adding amino acids to the polypeptide chain. ○ Termination: The ribosome reaches a stop codon, and the polypeptide is released. 9. At which stages of translation is energy consumed? ○ Energy is consumed during initiation (loading tRNA and ribosome assembly), elongation (adding amino acids), and termination (release of the polypeptide).