Cellular Metabolism: Key Concepts and Quiz Insights

M2: Module 2 Review Due No due date Points 5 Questions 20 Time Limit None Attempt History Attempt Time Score LATEST Attempt 1 169 minutes 5outof5 Score for this quiz: 9 out of 5 Submitted Sep 10 at 11:15am This attempt took 169 minutes. Question 1 0/0 pts What is cellular metabolism? Your Answer: a controlled set of biochemical reactions that occur in living organisms to maintain life Metabolism is a controlled set of biochemical reactions that occur in living organisms in order to maintain life. Question 2 0/0 pts What is the primary function of enzymes, and how are they regulated? Your 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. 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. Question 3 0/0 pts What is the difference between catabolism and anabolism? Your Answer: catabolism is breaking down complex molecules into smaller ones to make energy, anabolism is building molecules and using energy Catabolism is the process of breaking down larger molecules into useful energy sources whereas anabolism is the building up or biosynthesis of macromolecules from smaller molecular units into larger complexes, most often associated with cellular growth and repair. Question 4 0/0 pts

Correct! Correct! ATP has the energy to donate , while ADP has the capacity to accept energy_ Answer 1: Donate Answer 2: Accept Question 5 0/0 pts Chemotrophs can be subdivided into what two additional subgroups? Your Answer: Organotrophs, which remove electrons from organic molecules (such as glucose). Lithotrophs, which remove electrons from inorganic molecules (such as elemental sulfur). 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. Question 6 0/0 pts Chemotrophs utilize which form of phosphorylation?

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Your Answer: Oxidative phosphorylation 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. Question 7 0/0 pts What are the three distinct stages in the catabolism of glucose? Your 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 produced. Last, the electron transport chain (ETC) produces 34 ATP via an oxidative phosphorylation event at the plasma membrane. 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 produced. Last, the electron transport chain (ETC) produces 34 ATP via an oxidative phosphorylation event at the mitochondrial membrane. Question 8 0/0 pts What are the reactants of glycolysis? Your Answer:

Glucose and 2 ATP 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. Question 9 0/0 pts What are the two main strategies for replenishing cellular concentrations of NAD+, and when these strategies be utilized? Your 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 that fermentation. 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 that fermentation. Question 10 0/0pts

How are the TCA and ETC related? Your Answer: The end product of the TCA cycle are used to fuel the ETC. The 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. 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. Question 11 0/0pts In the absence of sugars, are entirely different metabolic pathways used to process alternative sugar sources (fructose or lactose)? Your Answer: No. Additional enzymatic steps are simply required at the beginning of catabolism to convert complex sugars into the usable forms of either glucose or a glucose intermediate (glucose-6-phosphate).

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- No. Additional enzymatic steps are simply required at the ~ beginning of catabolism to convert complex sugars into the usable forms of either glucose or a glucose intermediate (glucose-6- phosphate). Question 12 0/0 pts Proteases are used to catabolize what? Your Answer: Proteases are used to breakdown proteins (whereas lipases are used to breakdown lipids). Proteases are used to breakdown proteins (whereas lipases are used to breakdown lipids). Question 13 0/0pts Excluding sugars, what are the other sources of energy? Which is highest in energy? Your Answer: Proteins, lipids, polysaccharides. Lipids are highest in energy, can generate 48 ATP to glucose's 38.

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. Question 14 0/0 pts In what organelle does photosynthesis take place? Your Answer: Chloroplast Photosynthesis, the process of capturing sunlight and converting it into usable energy source, occurs in the chloroplasts. Chloroplasts are double-membrane enclosed organelles. Each chloroplast contains the green photosynthetic pigment chlorophyll. Question 15 0/0pts In phosphorylation, the light reactions always occur where? Your Answer: The membrane

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. Question 16 0/0 pts What are the byproducts of light reactions used for in dark reactions? Your 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). 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). Question 17 0/0 pts Complete the following chemical reaction by placing the appropriate number in the blanks: 6 co2 + 18 ATP + 12 NADPH + 12 H20 -C6H1206 + 18

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Correct! Correct! Correctl! Correct! Correctl! Correctl! Correct! ADP + 12 Answer 1: 6 Answer 2: 18 Answer 3: 12 Answer 4: 12 Answer 5: 18 Answer 6: 12 NADP+ Question 18 0/0 pts |dentify the enzyme associated with the following enzymatic reactions: A-B — B-A Isomerases Ab + C > A+ Cbh Transferases Answer 1: Isomerases Answer 2:

Correct! Transferases Question 19 0/0 pts What determines the specificity of an enzyme? Your Answer: Active Site 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 it’s target protein) can be thought of as a lock-and-key relationship. The ~ active site provides a 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. Question 20 5/ pts As a reminder, the questions in this review quiz are a requirement of the course and the best way to prepare for the module exam. Did you complete all questions in their entirety? Your Answer: Yes Quiz Score: 5 out of 5

M2 Module Review

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