BIOD 171 Module 2 Complete Questions and Correct Answers Exam 2026

What is cellular metabolism? - Correct Answer-Metabolism is a controlled set of biochemical reactions that occur in living organisms in order to maintain life What is the primary function of enzymes, and how are they regulated? - Correct Answer-Enzymes speed up chemical reactions. Most notably, the enzyme is not consumed during the reaction and can be used repeatedly by the cell. Enzymes can also be regulated by a cofactor such that in the absence of the proper cofactor, enzymes are inactive while in its presence enzymes are active. What is the difference between catabolism and anabolism? - Correct Answer Catabolism is the process of breaking down larger molecules into useful energy sources whereas anabolism is the building up or biosynthesis od macromolecules from smaller molecular units into larger complexes, most often associated with cellular growth and repair ATP has the energy to ______, while ADP has the capacity to ______ energy. - Correct Answer-Donate, accept Chemotrophs can be subdivided into what two additional subgroups? - Correct Answer Chemotrophs, which acquire energy from preformed chemicals found in the environment, can be divided into either organotrophs (removing electrons from organic molecules such as glucose) or lithotrophs, which remove electrons from inorganic molecules Chemotrophs utilize which form of phosphorylation? - Correct Answer-Chemotrophs use oxidative phosphorylation (may also accept substrate level phosphorylation). Oxidative phosphorylation utilizes the energy released by the chemical oxidation of nutrients to reform ATP What are the three distinct stages in the catabolism of glucose? - Correct Answer Glycolysis is the first step of this process and yields 2 molecules of ATP. Next, by either fermentation (or respiration) 2 additional molecules of ATP can be produces. Last, the electron transport chain (ETC) produces 34 ATP via an oxidative phosphorylation event at the plasma membrane. BIOD 171 BIOD 171 What are the reactants of glycolysis? - Correct Answer-Reactants are defined as any molecules present and involved at the beginning of a specific chemical reaction (ie) glycolysis. In terms of writing out a chemical reaction, the reactants are everything located to the left of the arrow. The reactants of glycolysis are glucose, the co-enzyme NAD+ and ATP. How are the TCA and ETC related? - Correct Answer-The end products of the Kreb's (TCA) cycle are used to fuel the electron transport chain. In other words, as the Kreb's cycle (TCA) produces an abundance of reduced electron carriers (NADH and FADH2), it fuels the ETC. As the electrons are transferred from NADH/FADH2 to terminal electron acceptors a proton motor force is generated, ATP synthase is activated and up to 34 molecules of ATP can be produced. In the absence of sugars, are entirely different metabolic pathways used to process alternative sugar sources (fructose or lactose)? - Correct Answer-No. Additional enzymatic steps are simply required at the beginning of catabolism to convert complex sugars into usable forms of either glucose or a glucose intermediate (glucose-6 phosphate) Proteases are used to catabolize what? - Correct Answer-Proteases are used to breakdown proteins (whereas lipases are used to breakdown lipids) Excluding sugars, what are the other sources of energy? Which is highest in energy? - Correct Answer-Carbohydrates, proteins, and lipids can all serve as potential energy sources in the absence of sugar. Lipids are rich in energy, often having several reduced carbon molecules (high in hydrogen content) that can be used in both the TCA and ETC cycles In what organelle does photosynthesis take place? - Correct Answer-Photosynthesis, the process of capturing sunlight and converting it into a usable energy source, occurs in the chloroplasts. Chloroplasts are double-membrane enclosed organelles. Each chloroplast contains the green photosynthetic pigment chlorophyll. What are the two main strategies for replenishing cellular concentrations of NAD+, and when are these strategies utilized? - Correct Answer-Fermentation and respiration are the two strategies used by the cell to convert NADH (end product of glycolysis) back to NAD+. Fermentation occurs in the absence of oxygen (anaerobic conditions) while respiration occurs under aerobic (presence of oxygen) conditions. Notably, respiration is more efficient than fermentation. In phosphorylation, the light reactions always occur where? - Correct Answer-The process of converting light energy into chemical energy (photophosphorylation) always occurs in the membrane. Similar to the electron transport chain, one of its main functions is to generate a proton concentration gradient to generate ATP. BIOD 171 BIOD 171 What are the byproducts of light reactions used for in dark reactions? - Correct Answer The ATP and NADPH produced via light reactions are used in dark reactions to convert carbon dioxide and water into organic carbon compounds as well as useful carbohydrates (a process called carbon fixation) What is the chemical reaction for the Calvin cycle? - Correct Answer-6 CO2 + 18 ATP + 12 NADPH + 12 H2O -- C6H12O6 + 18 ADP + 12 NADP+ What determines the specificity of an enzyme? - Correct Answer-The specificity of an enzyme is heavily influenced by its active site - a unique chemical structure bound only by select target molecules. The structure is influenced by the amino acid composition of the protein as this in turn influences the fold, shape, and 'appearance' of the enzyme. The active site (and its target protein) can be thought of as a lock-and-key relationship. The active site provides specificity (like a lock) that only specific target proteins can bind - much like how only a specific key will fit into, unlock, and 'activate' a lock Do catabolic reactions release or consume energy? - Correct Answer-Release Do anabolic pathways release or consume energy? - Correct Answer-Consume Do catabolic pathways rely on oxidized cofactors (like NAD+) to oxidize intermediates, or do they rely on reduced cofactors (like NADPH) to reduce intermediates? - Correct Answer-They rely on oxidized cofactors (like NAD+) to oxidize intermediates Do anabolic pathways rely on oxidized cofactors (like NAD+) to oxidize intermediates, or do they rely on reduced cofactors (like NADPH) to reduce intermediates? - Correct Answer-They rely on reduced cofactors (like NADPH) to reduce intermediates Is cellular respiration catabolic or anabolic? - Correct Answer-Catabolic Is lipid biosynthesis catabolic or anabolic? - Correct Answer-Anabolic Cofactors - Correct Answer--Metal ions that activate or enhance enzyme activity (like Ca2+ or Zn2+) -Regulate enzymes Substrate - Correct Answer-Target of enzyme action Specificity - Correct Answer-Selectiveness of an enzyme for a specific substrate What affects the rare of reaction and degree of reactivity? - Correct Answer-Enzyme concentration, substrate concentration, temperature, pH Protease - Correct Answer-Enzyme that breaks down proteins Lipase - Correct Answer-Enzyme that breaks down lipids BIOD 171 BIOD 171 Amylase - Correct Answer-Enzyme that breaks down starch Catalase - Correct Answer-Enzyme that breaks down H2O2 into water and oxygen Hydrolases - Correct Answer--Catalyze hydrolysis (breaking) of chemical bonds with the addition of water -A-B + H2O -- A-OH + B-H Isomerases - Correct Answer--Catalyze rearrangement of bonds within a molecule to produce an isomer -A-B -- B-A Ligases - Correct Answer--Covalent bonds join two molecules together -A + B -- A-B Lyases - Correct Answer--Cleave (break) bonds other than using hydrolysis or oxidation -A-B -- A + B Oxioreductases - Correct Answer--Transfer electrons from reductant (electron donor) to the oxidant (electron acceptor) -Redox -A- + B -- A + B- Transferases - Correct Answer--Transfer a functional group -A-b + C -- A + C-b What do metabolic reactions involve? - Correct Answer-The transfer of electrons (redox reactions) Electron acceptor - Correct Answer--Reduced -Oxidizing agent Electron donor - Correct Answer--Oxidized -Reducing agent What is the most widely used form of energy in the cell? - Correct Answer-ATP Is ATP an activated carrier? - Correct Answer-Yes Activated carrier molecules - Correct Answer-ATP, NADH, NADPH, FADH2, Acetyl CoA Is ATP high energy or low energy? - Correct Answer-High energy Is ADP high energy or low energy? - Correct Answer-Low energy BIOD 171 BIOD 171 Phosphorylation - Correct Answer-The metabolic process of introducing a phosphate group into ADP to form ATP (or to any other organic molecule) Which types of phosphorylation do chemotrophs and phototrophs utilize? - Correct Answer-Oxidative phosphorylation and substrate-level phosphorylation Which type of phosphorylation do only phototrophs utilize? - Correct Answer Photophosphorylation Phototroph - Correct Answer-An organism that utilizes light as its primary energy source Organotroph - Correct Answer-A chemotroph that utilizes organic compounds as its primary source of energy Lithotroph - Correct Answer-A chemotroph that utilizes inorganic compounds as its primary source of energy Photophosphorylation - Correct Answer-Light energy is used to power the formation of ATP from ADP Substrate-level phosphorylation - Correct Answer-Phosphoryl (PO3) group of a chemical compound is transferred and donated directly to ADP The chemical compound losing the phosphate group is referred to as the phosphorylated reactive intermediate Oxidative phosphorylation - Correct Answer-The energy released by the chemical oxidation of nutrients is used to reform ATP. This process occurs in the mitochondria of eukaryotic cells and is highly efficient What is the formula for glycolysis? - Correct Answer-Glucose + 2 NAD+ + [2 ADP + Pi] -- 2 pyruvate + NADH + 2 ATP + H+ Is glycolysis aerobic or anaerobic? - Correct Answer-Anaerobic (does not require oxygen) Where does glycolysis occur? - Correct Answer-Cytoplasm What are the two phases of glycolysis? - Correct Answer-Energy investment