BSC1010 chapter 9- Cellular respiration

Glycolysis results in the net production of which of the following sets of molecules per glucose molecule?

2 NADH, 2 pyruvate, and 2 ATP

Which of the following combinations of products would result from three acetyl CoA molecules entering the citric acid cycle?

3 ATP, 6 CO2, 9 NADH, and 3 FADH2

Approximately how many molecules of ATP are produced from the complete oxidation of one molecule of glucose (C6H12O6) in aerobic cellular respiration?

30-32

Drugs known as uncouplers facilitate diffusion of protons across the membrane. With an uncoupler, what will happen to ATP synthesis and oxygen consumption if the rates of glycolysis and the citric acid cycle stay the same?

ATP synthesis will decrease; oxygen consumption will stay roughly the same

Which of the following is one of the molecules formed by the removal of a carboxyl group (as CO2) from a molecule of pyruvate?

Acetyl CoA

If your cells needed ATP, what could help you?

All of the above

Which of the following molecules is the lowest-energy donor of electrons to the electron transport chain?

FADH2

Which of the following statements best describes the electron transport chain?

It consists of a series of redox reactions

Which of the following statements best describes how a reducing agent in is chemically altered in a biological redox reaction?

It loses a hydrogen atom and loses potential energy.

Which statement about glycolysis is true?

It occurs in the cytosol

Which of the following statements best describes the primary role played by oxygen in cellular respiration?

It serves as the final acceptor for electrons from the electron transport chain.

During intense exercise, muscles lack sufficient oxygen, so which process will these muscles mainly use?

lactic acid fermentation

Energy released from the electron transport chain is used to pump H+ ions into which location in eukaryotic cells?

mitochondrial intermembrane space

Inhibition of which of the following metabolic pathways would result in decreased rates of CO2 production?

oxidation of pyruvate to acetyl CoA and the citric acid cycle

Which of the following processes is driven by chemiosmosis?

oxidative phosphorylation

Which of the following products result from the oxidation of pyruvate to acetyl-CoA?

NADH and CO2

When a glucose molecule loses a hydrogen atom in an oxidation-reduction reaction, the glucose molecule is ________.

Oxidized

How are photosynthesis and cellular respiration connected?

The first produces glucose, full of energy, and the second extracts that energy.

ATP synthase at the inner mitochondrial membrane makes ATP and water from ADP and phosphate by coupling this to which other process?

allowing H+ to move down its electrochemical gradient

Which of the following types of metabolic poison would most directly interfere with glycolysis?

an agent that closely mimics the structure of glucose but is not metabolized

Which of the following reactions produces the majority of the CO2 released by the complete oxidation of glucose?

citric acid cycle

Inhibition of which of the following processes would reduce or eliminate generation of a proton-motive force in mitochondria?

pumping of hydrogen ions from the mitochondrial matrix across the inner membrane and into the intermembrane space

When electrons are passed from one atom to a more electronegative atom, the more electronegative atom is _______

reduced, and energy is released

Shape changes are important in the working of enzymes and other parts of biochemistry. In ATP production, what changes shape?

rotor

You are handed a biochemical extract from cells that were performing cellular respiration. You detect cytochromes in one fraction, so it was probably used for the study of

electron transport

Compared to the carbons in glyceraldehyde 3-phosphate, the carbons in 1,3-bisphosphoglycerate have _____, so these carbons are more _____.

fewer bonds with hydrogen and more bonds with oxygen; oxidized

Which of the following processes is incorrectly matched with its location in a eukaryotic cell?

formation of ATP by substrate-level phosphorylation—via the F1F0-ATP synthase in the inner mitochondrial membrane

In chemiosmosis, the most direct source of energy used to convert ADP + Pi to ATP is energy released ________.

from movement of protons through ATP synthase, down their electrochemical gradient

Newborn mammals have a specialized tissue called brown fat, where cells burn fat to CO2 without capturing the energy to reduce electron carriers or drive ATP formation. How might this energy be used instead?

generate heat

What has more free energy, carbon dioxide and water or glucose and oxygen, and why?

glucose and oxygen because they have not yet reacted

Which of the following sequences describes the path by which electrons move from high-energy to lower-energy molecules in aerobic respiration?

glucose → NADH → electron transport chain → oxygen

Through beta oxidation, fats are converted to acetyl CoAs. The further respiration of these acetyl CoAs typically bypasses which parts of normal aerobic respiration?

glycolysis and pyruvate oxidation

In which reactions of cellular respiration does substrate-level phosphorylation occur?

glycolysis and the citric acid cycle

cellular respiration can be best described as

taking electrons from food and giving them to oxygen to make water, using the energy released to drive ATP formation.

Which of the following events takes place in the electron transport chain?

the extraction of energy from high-energy electrons remaining from glycolysis and the citric acid cycle

What is the purpose of fermentation reactions?

to regenerate NAD+ so glycolysis can continue

Which of the following statements best summarizes ATP use and production in the catabolism of each glucose molecule in glycolysis?

two molecules of ATP are used and four molecules of ATP are produced.

If you removed the inner membrane of the mitochondrion, could the cell produce any ATP from glucose?

yes, by glycolysis and fermentation

Substrate-level phosphorylation accounts for approximately what percent of the ATP formed by the reactions of glycolysis?

100%

Which of the following is not an immediate net product of the typical mitochondrial electron transport chain?

ATP

Which of the following contains useful energy for the cell?

ATP and proton gradient (a and c)

Which of the summary statements below best describes the results of the following reaction? C6H12O6+ 6O2 → 6CO2+ 6H2O + Energy

C6H12O6 is oxidized and O2 is reduced.

The standard free energy for the complete oxidation of glucose to CO2 and water is -686 kcal/mol, and the standard free energy for the reduction of NAD+ to NADH is +53 kcal/mol. Which of the following statements best explains why only two molecules of NADH are formed in glycolysis when up to 12 molecules could theoretically be produced?

Most of the free energy available from the oxidation of glucose remains in pyruvate, one of the products of glycolysis.

Depletion of which of the following molecules from the mitochondria will most directly inhibit the citric acid cycle?

NAD+

What do cells require to sustain high rates of glycolysis under anaerobic conditions?

NAD+

Which of the following statements best describes what happens to a molecule of NAD+ (nicotinamide adenine dinucleotide) when it gains a hydrogen atom?

NAD+ becomes reduced.

Which of the following statements best describes a characteristic of NAD+?

NAD+ is reduced to NADH in glycolysis, pyruvate oxidation, and the citric acid cycle.

Upon completion of the citric acid cycle, most of the energy originally stored in each glucose molecule catabolized by cellular respiration is stored in which of the following molecules?

NADH

Which of the following statements best explains why carbohydrates and fats may be considered high-energy foods?

They contain many electrons associated with hydrogen atoms.

The hydrogen taken from glucose or a breakdown product of glucose are added to oxygen, releasing energy to

actively transport H+ into the intermembrane space