Connect Chapter 6

Consider the following linear metabolic pathway of a bacterial cell: Starting compound → Intermediate-a → Intermediate-b → End Product. The first two reactions are catalyzed by enzymes A and B, respectively. If a mutant cell arose that was unable to produce enzyme B, what would be the impact on the other components of the pathway? Multiple choice question. The cell could still produce intermediate-a but would be unable to produce intermediate-b or the end product. The metabolic pathway would be forced to run at a higher rate to make up for the absence of enzyme B. The cell would be unable to produce any of the intermediates shown. The metabolic pathway would proceed forward at the normal rate, resulting in production of the end product.

The cell could still produce intermediate-a but would be unable to produce intermediate-b or the end product.

Which of the following is an example of activation energy? Multiple choice question. The energy present in the carbon bonds of glucose. The energy present in the battery of your cell phone. The energy in photons of sunlight. The energy of a small flame used to light the natural gas of a Bunsen burner. The energy present in the water stored behind a dam.

The energy of a small flame used to light the natural gas of a Bunsen burner

The ________ energy is the energy it takes to start a reaction.

activation

The critical site of an enzyme to which a substrate binds by weak forces is called the ________ ________.

active site

Cells use ATP as the ready and immediate donor of free energy. ATP stands for ________ ________.

adenosine triphosphate

Metabolic pathways can be linear, ________ , or ________.

branched/ cyclical

The energy released by ______ is captured by cells to make ATP; this ATP can then be used for biosynthesis, or ______.

catabolism; anabolism

Some enzymes act with the assistance of a non-protein component. This component is called a ________; if that component is an organic molecule it can be called a ________.

cofactor; coenzyme

Proteins that function as biological catalysts are called

enzymes

All of the following accurately describe enzymes EXCEPT ______. Multiple choice question. the name of an enzyme typically reflects its function and ends in -ase enzymes are not used up in the process of catalyzing reactions enzymes are biological catalysts enzymes are very specific, usually acting on only one or a few substrates enzymes provide energy to help reactions proceed more rapidly

enzymes provide energy to help reactions proceed more rapidly

Use the following four words to correctly complete the sentence: endergonic, exergonic, anabolism, catabolism. "Cells constantly produce ATP during ________ reactions of ________ and then use it to power ________ reactions of ________."

exergonic, catabolism, endergonic, anabolism

The primary pathway used by many organisms to convert glucose to pyruvate is ________.

glycolysis

The series of sequential chemical reactions in a cell that converts a starting compound to an end product is called a ________ pathway.

metabolic

The sum total of all chemical reactions in a cell is called ________.

metabolism

The enzymes of the tricarboxylic acid cycle are found in the ________ matrix in eukaryotes and in the ________ in prokaryotes.

mitochondrial; cytosol

The TCA cycle completes the ______ of glucose. Multiple choice question. oxidation hydrolysis synthesis reduction

oxidation

The mechanism by which cellular respiration uses reducing power generated in glycolysis, the transition step, and the TCA cycle to synthesize ATP is ________ phosphorylation.

oxidative

What are the two main forms of energy?

potential and kinetic

Energy is the ability to do work and can exist as ________ energy (stored energy) and ________ energy (energy of motion).

potential/ kinetic

Consider the three key central metabolic pathways (glycolysis, pentose phosphate pathway, and the TCA cycle). What three beneficial products of these pathways? Multiple select question. CO2 precursor metabolites water oxidized electron carriers large carbon polymers ATP reducing power

precursor metabolites, ATP, reducing power

The form of energy that results from the electrochemical gradient established by the electron transport chain is the ______. Multiple choice question. oxidative phosphorylation proton motive force substrate-level phosphorylation photophosphorylation chemiosmosis

proton motive force

Which of the following are reasons an organism might use fermentation? Multiple select question. The energy yield is greater from fermentation than from respiration. They lack an electron transport chain. A suitable inorganic terminal electron acceptor is not available. They lack the ability to perform glycolysis.

- A suitable inorganic terminal electron acceptor is not available - They lack an electron transport chain

Enzymes are biological ______ that are typically _______. Multiple choice question. catabolites; protein catabolites; lipid reducters; protein catalysts; lipid catalysts; protein

catalysts; protein

Identify each of the following by the most precise descriptive term as either a cofactor or coenzyme: magnesium: ________; NADP+: ________; zinc: ________.

cofactor; coenzyme; cofactor

Enzymes function as biological catalysts, accelerating the conversion of one substance, the ________, into another, the ________.

substrate; product

As part of cellular respiration, a membrane-bound enzyme called ATP ________ uses energy from a proton-motive force to add a phosphate group to ADP.

synthase

If the theoretical maximum ATP yield in prokaryotes from oxidative phosphorylation is 34 ATP for a single glucose molecule, what is the total ATP gain when substrate-level phosphorylation is included? Multiple choice question. 34 ATP 38 ATP 68 ATP 76 ATP 4 ATP

38 ATP

In prokaryotes, the electron transport chain is located in the ________ membrane, whereas in eukaryotic cells it is in the ________ membrane of mitochondria.

cytoplasmic/ plasma/ cell; inner/ internal

The electron transport chain consists of large protein-complexes embedded in a membrane. These pass electrons from one to the next, while simultaneously pumping ________ across the membrane, generating a proton motive force.

protons

During the transition step of central metabolism, all of the following occur EXCEPT ______. Multiple choice question. 2 ATP are generated. The 2-carbon acetyl group is joined to coenzyme A to form acetyl-CoA. Electrons are transferred to NAD+, reducing it to NADH + H+. CO2 is removed from pyruvate.

2 ATP are generated

All of the following are essential for an electron transport chain to function EXCEPT ______. Multiple choice question. a terminal electron acceptor ATP electron carriers such as quinones, cytochromes, and flavoproteins electrons a membrane protein complexes that function as proton pumps

ATP

The main energy currency of cells is the molecule called _________.

ATP

In respiring bacteria, how does ATP synthase generate ATP? Multiple choice question. It takes energy from NADH and FADH2 and uses it to add a phosphate group to ADP. It uses the energy released from allowing protons to flow back into the cell to add a phosphate group to ADP. It uses high energy phosphate bonds to transfer a phosphate group to ADP. It uses reducing power generated by the central metabolic pathways to add a phosphate group to ADP.

It uses the energy released from allowing protons to flow back into the cell to add a phosphate group to ADP.

The electron transport chain is a cluster of membrane-embedded electron carriers that accept electrons from the coenzymes ________ and ________ and then pass these electrons along the chain.

NADH; FADH2

What is the active site of an enzyme? Multiple choice question. The critical site to which a substrate binds by weak forces. The site of allosteric regulation of the enzyme. The site at which ATP is generated. The site characterized by constant motion of molecules. The site that breaks off the enzyme as it catalyzes a reaction.

the critical site to which a substrate binds by weak forces

The step that links glycolysis to the TCA cycle is called the ________ step.

transition

For each six-carbon molecule of glucose that enters glycolysis, how many molecules of pyruvate are made, and how many carbon atoms does each pyruvate have? Multiple choice question. Two molecules of pyruvate, each with two carbon atoms. Two molecules of pyruvate, each with three carbon atoms. Six molecules of pyruvate, each with one carbon atom. One molecule of pyruvate with six carbon atoms. Three molecules of pyruvate, each with two carbon atoms.

two molecules of pyruvate, each with three carbon atoms

Consider the theoretical maximum ATP yield from the complete oxidation of glucose via aerobic respiration in prokaryotes. Match the relative contribution in terms of ATP (substrate-level phosphorylation plus oxidative phosphorylation) with the correct metabolic component.

8 ATP: Glycolysis6 ATP: Transition step24 ATP: TCA Cycle38 ATP: Total yield of aerobic respiration

Oxidative phosphorylation, the mechanism by which cellular respiration uses the NADH and FADH2 generated in glycolysis, the transition step, and the TCA cycle to synthesize ATP, involves what two steps? Multiple select question. Electrons flow through ATP synthase to drive the synthesis of ATP. ATP synthase uses the energy of the proton motive force to drive the synthesis of ATP. The electron transport chain is oxidized by the donation of electrons from NADH and FADH2. A phosphate group is removed from each NADH and FADH2. The electron transport chain generates a proton motive force. The electron transport chain uses the energy in protons to transfer electrons across the membrane.

- ATP synthase uses the energy of the proton motive force to drive the synthesis of ATP. - The electron transport chain generates a proton motive force.

Which of the following are true statements about what happens to glucose inside a cell? Multiple select question. Glucose can be used in catabolism to yield energy, or the precursor metabolites generated from its breakdown can be used in anabolism. All the glucose molecules are oxidized to CO2, generating ATP and reducing power in the process. Some glucose might be oxidized to CO2, generating the maximum amount of ATP. Some glucose might enter glycolysis, only to be siphoned off as a precursor metabolite for biosynthesis.

- some glucose might enter glycolysis, only to be siphoned off as a precursor metabolite for biosynthesis - glucose can be used in catabolism to yield energy, or the precursor metabolites generated from its breakdown can be used in anabolism - some glucose might be oxidized to CO2, generating the maximum amount of ATP

When a cell processes glucose or other organic molecules through its central metabolic pathways, it does so to generate what three critical things? Multiple choice question. ADP, NADH, glucose ATP, reducing power, precursor metabolites ATP, reducing power, ethanol ADP, reducing power, lactic acid ATP, NAD+, pyruvate

ATP, reducing power, precursor metabolites

Proton motive force is ______. Multiple choice question. the positive charge that repels protons from the electrons orbiting around them in atoms the attractive force that makes up hydrogen bonds, for example, those holding together water molecules the form of energy that results from the electrochemical gradient established by the electron transport chain

the form of energy that results from the electrochemical gradient established by the electron transport chain

True or false: With respect to the location of the electron transport chain, the inner membrane of mitochondria is analogous to the cytoplasmic membrane of bacterial cells. True false question. True False

true

Glucose catabolism encompasses two key processes: (1) oxidizing glucose molecules to generate ATP, reducing power, and precursor metabolites; and (2) transferring the electrons carried by NADH and FADH2 to the terminal electron acceptor. The second process, transfer of electrons, is accomplished as part of which of the following? Multiple select question. the TCA cycle fermentation cellular respiration glycolysis the pentose phosphate pathway

-Fermentation-Cellular respiration

Although the actual procedure is much more involved, the basic metabolism of wine-making involves inoculating grape juice with a special strain of the yeast Saccharomyces cerevisiae. S. cerevisiae will preferentially perform aerobic respiration on sugars in the juice but can also ferment those sugars to yield CO2 and alcohol, an important component of wine. Assume you inoculate a completely full container of juice and then close the lid. What will the yeast do? Multiple choice question. They will grow aerobically on the sugars, producing O2 in the process. They will grow aerobically, consume the O2 dissolved in the juice, and then switch to fermenting sugars to yield alcohol. They will grow aerobically, then switch to anaerobic respiration as the O2 level drops. They will grow aerobically until all the O2 is gone and then stop, because aerobic respiration yields the greatest energy. They will only ferment the sugars to yield alcohol.

They will grow aerobically, consume the O2 dissolved in the juice, and then switch to fermenting sugars to yield alcohol.