Ch.7 Launchpad Biology121

Once they have been processed through the citric acid cycle, the acetyl-CoA molecules from a single glucose molecule produce:

2 ATP, 6 NADH, 4 CO2.

After pyruvate oxidation, the chemical energy of how many carbons of the original glucose molecule is converted to chemical energy in the form of ATP in the remaining steps of cellular respiration?

4

Which of the following is a product of the breakdown of fatty acids from lipids? FAD NADH FADH2 acetyl-CoA

NADH FADH2 acetyl-CoA

When a single pyruvate is converted to acetyl-CoA, the other products of the reaction are:

NADH and CO2

Oxidation is the gain of electrons.

false

In cellular respiration, oxygen:

gains electrons and is an oxidizing agent.

Excess glucose is stored in large branched molecules of:

glycogen in animals.

Proteins can be broken down for energy. They are typically broken down into amino acids, which then enter cellular respiration by:

glycolysis or the citric acid cycle

PFK-1 is _____ by ATP and _____ by ADP.

inhibited; activated

Due to the pumping action of the electron transport chain, protons have a high concentration in the _____ and a low concentration in the _____.

intermembrane space; mitochondrial matrix

Pyruvate oxidation is an important stage in cellular respiration because:

it links glycolysis with the citric acid cycle.

In cellular respiration, glucose is _____ to CO2 and oxygen is _____ to water.

oxidized; reduced

Imagine that you exhale after a deep breath. Which of the following are you not exhaling?

waste products of glycolysis

Another name for acetyl-CoA synthesis, is:

pyruvate oxidation.

During fermentation, pyruvate is:

reduced

The _____ forms of the electron carriers NAD+/NADH and FADH/FADH2 have high potential energy.

reduced

In the absence of oxygen, fermentation:

regenerates NAD+ from the reduction of pyruvate.

How many reactions in glycolysis directly generate ATP?

2

The inputs to glycolysis do not include:

NADH

In the first three stages of cellular respiration, the chemical energy in glucose is transferred to:

ATP and electron carriers

For the potential energy of a proton gradient to be converted to the chemical energy of ATP, the movement of protons down their electrochemical gradient must be coupled with ATP synthesis. This coupling is made possible by:

ATP synthase

Malate is both the starting and ending product of the citric acid cycle.

FALSE

Pyruvate oxidation produces a large amount of ATP.

FALSE

By the time pyruvate is formed, most of the energy contained in glucose has been released.

False

Imagine that a eukaryotic cell carries a mutation impairing its ability to phosphorylate glucose during glycolysis. What is a likely result of this mutation?

Glucose could move out of the cell, slowing cellular respiration.

Some present-day bacteria use a system of anaerobic respiration characterized by an electron transport chain analogous to that found in aerobic organisms. Which of the following correctly characterizes the anaerobic electron transport chain?

It establishes a proton gradient between the cytoplasm and the extracellular fluid.

Which of the following statements is true regarding a reducing agent?

It loses electrons

Which of the following best describes how ATP synthase converts the potential energy of the proton gradient to the chemical energy of ATP? Do protons flow through the Fo or F1?

Kinetic energy from the flow of protons is converted to the kinetic energy of rotation of the Fo subunit; the rotation of the Fo subunit leads to rotation of the F1 subunit, which can then catalyze ATP synthesis.

During the citric acid cycle, the production of CO2 is the result of the _____ of intermediate compounds of the citric acid cycle coupled to the production of

Oxidation; NADH

Which of the following statements is true regarding pyruvate oxidation?

Pyruvate oxidation forms the same number of NADH (per glucose molecule) as glycolysis.

Glycolysis is:

anaerobic

We consume a variety of carbohydrates that are digested into a variety of different sugars. How do these different sugars enter glycolysis?

Sugars are converted to various forms and enter glycolysis at various stages.

Which of the following statements is true regarding the equation C6H12O6 + 6O2 →6CO2+ 6H2O + energy?

The oxygen atoms in both CO2 and H2O are electronegative, and glucose is considered a reducing agent.

Which of the following statements are true regarding pyruvate oxidation?

This process occurs within the matrix of mitochondria. This process constitutes the second stage of cellular respiration. The process produces both CO2 and acetyl-CoA. The process yields no ATP via substrate-level phosphorylation

Energy released by transferring electrons along the electron transport chain is stored as potential energy in the form of:

a proton gradient.

In which form are electrons transferred during typical redox reactions such as the oxidation of glucose?

as hydrogen atoms

Lactic acid fermentation occurs in:

bacteria and animals.

The breakdown of fatty acids takes place by a process called:

beta-oxidation.

Cellular respiration is a series of _____ reactions.

catabolic

Which one of the following does NOT actively move protons from the mitochondrial matrix to the intermembrane space?

complex II

The phosphorylation of glucose during glycolysis serves to:

destabilize the molecule, making it easier to cleave. trap imported glucose inside the cell.

Phosphorylating glucose during phase 1 of glycolysis:

destabilizes the glucose molecule so that it can be broken down in phase 2.

During what phase of glycolysis is NADH formed?

during phase 3, when glyceraldehyde 3-phosphate is phosphorylated

The majority of the energy generated in the citric acid cycle is in the form of:

electrons donated to NAD+ and FAD+.

The proteins of the electron transport chain are:

embedded in the inner mitochondrial membrane.

The first phase of glycolysis requires the input of two ATP molecules. It is therefore:

endergonic

In human cells such as muscle tissue, the product of fermentation is:

lactic acid.

During pyruvate oxidation, pyruvate is broken down into CO2 and an acetyl group. The CO2 is:

less energetic than the acetyl group.

The chemical bonds of carbohydrates and lipids have high potential energy because:

many of these bonds are C—C and C—H bonds.

The citric acid cycle takes place in the:

mitochondrial matrix.

In what organelle is pyruvate oxidation carried out in a cell?

mitochondrion

Fermentation occurs in:

ome aerobic organisms, such as yeast, even in the presence of oxygen.

The citric acid cycle begins when acetyl-CoA combines with _____ to form _____.

oxaloacetate; citrate

When an electron is transferred from NADH to CoQ, NADH is _____ and CoQ is _____.

oxidized; reduced

The final electron acceptor of the electron transport chain is:

oxygen

Which of the following does not occur during the third phase of glycolysis?

oxygen consumption

In the second phase of glycolysis:

phosphorylated sugar molecule is cleaved and the products rearranged.

In glycolysis, ATP is synthesized by:

substrate-level phosphorylation

In eukaryotic cells, the oxidation of pyruvate occurs in:

the matrix of the mitochondria.

Recall that the citric acid cycle starts with a four-carbon molecule, but that most of its intermediates are molecules that contain six carbons. How is this possible?

through the reaction of acetyl-CoA and oxaloacetate

The ATP produced during glycolysis is the result of substrate-level phosphorylation.

true

At the end of glycolysis, the carbon molecules originally found in the starting glucose molecule are in the form of:

two pyruvate molecules.