Biology Chapter on Proteins and Enzymes

Practice Exam Questions and Answers

• High boiling point of water: The presence of hydrogen bonds is responsible for water's high boiling point.
• DNA base stacking stabilization: Hydrogen bonding stabilizes DNA base stacking.
• Van der Waals interaction cause: Temporary dipoles from electron movement cause van der Waals interactions.
• Interaction between charged species/ions/dipoles: Ionic (Coulombic) interactions occur between charged species or between ions and dipoles.
• Law of thermodynamics: The first law of thermodynamics states that energy cannot be created or destroyed, only transformed.
• Spontaneous reaction: A reaction is considered spontaneous when ΔG < 0.
• Catalyst function: A catalyst decreases activation energy in a chemical reaction.
• Exergonic reaction: A reaction that releases energy.
• Endergonic reaction: A reaction that absorbs energy.
• Reaction rate factors: Temperature, enzyme presence, and concentration of reactants all influence reaction rate.
• Activation energy: The amount of energy required for a reaction to proceed.
• Protein monomers: Amino acids are the monomers that make up proteins.
• Amino acids in protein synthesis: 20 standard amino acids are used in protein synthesis.
• Bond linking amino acids: Peptide bonds link amino acids together.
• Protein structure level describing amino acid sequence: Primary structure.
• Stabilization of alpha-helices and beta-sheets: Hydrogen bonds stabilize alpha-helices and beta-sheets in proteins.
• Protein structure determined by R-group interactions: Tertiary structure.
• Protein structural example: Hemoglobin is an example of a protein with quaternary structure.
• Protein denaturation disruption: Denaturation of a protein disrupts secondary, tertiary, and quaternary structures.
• Chaperone protein role: Chaperone proteins assist in protein folding.

Additional Biochemistry Topics

• Net ATP production in glycolysis: Two ATP molecules are produced per glucose molecule in glycolysis.
• Rate-limiting step in glycolysis: Phosphofructokinase-1 (PFK-1) is the rate-limiting enzyme of glycolysis.
• Pyruvate fate under anaerobic conditions: Pyruvate is converted to lactate under anaerobic conditions in muscle cells.
• Citric Acid Cycle Location: The citric acid cycle occurs in the mitochondrial matrix.
• Citric Acid Cycle Function: The primary function of the citric acid cycle is to generate ATP.
• ATP generation process: Oxidative phosphorylation generates the most ATP.
• Final electron acceptor in electron transport chain: Oxygen is the final electron acceptor in the electron transport chain.
• Monomer of nucleic acids: Nucleotides are the monomers of nucleic acids.
• Enzyme unwinding DNA: Helicase unwinds the DNA double helix during replication.
• DNA polymerase role: DNA polymerase synthesizes new DNA strands.
• Removal of RNA primers: DNA polymerase I removes RNA primers.
• Enzyme joining Okazaki fragments: DNA ligase joins Okazaki fragments together.
• Central dogma of molecular biology: DNA → RNA → Protein
• RNA to protein conversion: Transcription and Translation
• Phospholipid type: Phospholipids are the primary component of cell membranes.
• Plasma membrane description: Described by the fluid mosaic model.
• Cholesterol function: Cholesterol in cell membranes affects fluidity and permeability.
• Transport requiring ATP: Active transport requires ATP.
• Process for large particle engulfing: Phagocytosis engulfs large particles into cells.
• Signaling involving hormones: Endocrine signaling involves hormones traveling through the bloodstream.
• Hormone receptor type: Intracellular receptors bind to hydrophobic ligands, such as steroid hormones.
• Second messenger role: Relaying and amplifying signals inside the cell.
• Oncogene definition: A gene that promotes cancer growth.
• Apoptosis definition: Programmed cell death.
• Determining protein function: Its three-dimensional structure determines a protein's function.
• Native fold: The stable 3D structure a protein naturally assumes to function.
• Non-covalent interaction stabilizing protein structure: Hydrophobic effect, hydrogen bonds, and van der Waals forces are stabilizing interactions for proteins.
• Primary driving force for protein folding: The hydrophobic effect is a primary force driving protein folding.
• Hydrogen bonds in proteins: Between N-H and C=O groups of the peptide bond, primarily, and other parts of the molecule.
• Non-covalent stabilization of alpha-helices/beta-sheets: Hydrogen bonds.
• Amino acid disrupting alpha-helix: Proline, for example, disrupts alpha-helix formation.
• Beta-sheet arrangement: Parallel and antiparallel.
• Beta-turn length: A beta-turn consists of 4 amino acids.
• Amino acid in beta-turns: Proline, for example, is common.
• Peptide bond rigidity: The partially double bond character and little rotation around the peptide bonds.

Additional Enzyme-Related Concepts & Other Topics

• Rate limiting step: The first committed step of a metabolic pathway.
• Allosteric regulation: Enzyme activity is altered by small molecules binding to allosteric sites (not the active site).
• Michaelian constant: represents the substrate concentration when the reaction is at half Vmax. This shows the affinity between an enzyme and its substrate.
• Different types of inhibitors: Competitive and Non-competitive inhibitors affect enzymes in different ways.