Bio 2170 Chapter 7

In eukaryotes, pyruvate oxidation takes place in the:

mitochondrial matrix.

The citric acid cycle takes place in the:

mitochondrial matrix.

What can increase PFK-1 activity?

more AMP

The citric acid cycle is a cycle because the starting molecule, _____, is regenerated at the end.

oxaloacetate

Which stages of cellular respiration use O2 as an input?

oxidative phosphorylation

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

oxidized; reduced

The final (terminal) electron acceptor of the electron transport chain is:

oxygen

Acetyl-CoA synthesis occurs during:

pyruvate oxidation

When you exhale, there is more CO2 than was present in the air that you inhaled. This CO2 comes from reactions in:

pyruvate oxidation and the citric acid cycle

In pyruvate oxidation, the electron donor is _____ and the electron acceptor is _____.

pyruvate; NAD+

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

reduced

Glucose is stored in plants as _____ and in animals as _____.

starch; glycogen

Which of the following summarizes the net final products of glycolysis?

two molecules of pyruvate, two molecules of ATP, and two molecules of NADH

True/False- Fermentation produces nearly twice as much ATP as aerobic respiration, which explains why it is a preferred pathway for bacteria.

False

True/False- Malate is both the starting and ending product of the citric acid cycle.

False

True/False- Oxidation is the gain of electrons.

False

True/False- Pyruvate oxidation produces a large amount of ATP through substrate-level phosphorylation.

False

True/False- The glycolysis stage is responsible for producing most of the ATP during cellular respiration.

False

The immediate source of electrons for the electron transport chain is:

NADH and FADH2.

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

a proton gradient.

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

electrons donated to NAD+ and FAD.

Most of the proteins of the electron transport chain are:

embedded in the inner mitochondrial membrane.

True/False- Fermentation occurs only in anaerobic conditions.

false

Which of the following is most likely to have been the first metabolic pathway or structure to evolve?

fermentation

Where does the F1 subunit of ATP synthase get its energy to catalyze the synthesis of ATP?

from rotational energy provided by the flow of protons through the channel in the Fo subunit

In cellular respiration, oxygen:

gains electrons and is reduced.

Excess glucose is stored in large branched molecules of:

glycogen in animals.

The storage carbohydrate in animals is ___________ and in plants is __________.

glycogen; starch

When a substance in a reaction is oxidized, it:

loses electrons.

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

many of these bonds are C—C and C—H bonds, in which electrons are shared equally between atoms.

Which of the following is a net product of glycolysis?

2 pyruvate

Tracing the metabolism of one glucose molecule, how many carbon atoms are fully oxidized to CO2 at the completion of glycolysis?

0

Tracing the metabolism of one glucose molecule, how many carbon atoms are available for further oxidation at the completion of the pyruvate oxidation stage?

4

Tracing the metabolism of one glucose molecule, how many carbon atoms are fully oxidized to CO2 at the completion of aerobic respiration?

6

Which of the following is required for the preparatory phase of glycolysis and then produced during the payoff phase?

ATP

During the citric acid cycle:

ATP is synthesized by substrate-level phosphorylation.

Each molecule of acetyl-CoA that enters the citric acid cycle carries two of the carbon atoms from the original starting glucose molecule. These carbon atoms will ultimately leave the citric acid cycle as carbon atoms in which of the following?

CO2

The ethanol resulting from fermentation of glucose only accounts for four of the six starting carbon atoms. In which of the following are the other two carbon atoms found?

CO2

What is the fully oxidized product that results from the pyruvate oxidation stage of cellular respiration?

CO2

Some bacteria run the citric acid cycle in reverse. Without any other modifications to the cycle, what inputs would be required to do this?

CO2, FADH2, NADH, and ATP

The first phase of glycolysis requires the input of two ATP molecules. It is therefore: (exergonic or endergonic)

Endergonic

Recall that fatty acids (such as palmitic acid) can yield substantially more ATP when compared with a similar weight of glucose. Why doesn't aerobic respiration rely solely on fatty acids as energy sources, rather than glucose?

Fatty acids cannot be used by some vital tissues in the human body, such as the brain.

Which of the following is one explanation for why glycolysis is believed to have arisen very early in the evolution of life?

It doesn't need oxygen

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

NADH and CO2.

One of the enzymatic results of the pyruvate oxidation stage of cellular respiration is the reduction of _____ to _____.

NAD+; NADH

What product of the pyruvate oxidation stage of cellular respiration will have the two electrons that are lost from pyruvate?

NADH

True/ False- When glucose is broken down in a cell, all of the energy it stores is not released simultaneously but is instead released in a stepwise process.

True

True/False- Both NAD+ and molecular oxygen serve as electron acceptors in cellular respiration

True

True/False- Conditions that reduce the strength of the proton gradient across the inner mitochondrial membrane slow the production of ATP by ATP synthase.

True

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

True

Glycolysis is:

anaerobic.

Lactic acid fermentation occurs in:

bacteria and animals.

How did the earliest organisms on Earth most likely produce ATP?

by glycolysis

Cellular respiration is a series of _____ reactions. (Catabolic or Anabolic)

catabolic

During glycolysis, pyruvate oxidation, and the citric acid cycle, the chemical energy in glucose is transferred to:

electron carriers and ATP

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

glycolysis or the citric acid cycle.

In eukaryotes, fermentation takes place:

in the cytoplasm.

What can decrease PFK-1 activity?

increased concentration of citrate

Pyruvate oxidation is an important stage in cellular respiration because:

it links glycolysis with the citric acid cycle.

On completion of either ethanol or lactic acid fermentation, the yield is only two ATP molecules per glucose molecule. The remaining chemical energy from the glucose is found primarily in:

lactic acid and ethanol.

In glycolysis, ATP is synthesized by:

substrate-level phosphorylation.

We can tell from their structure that fatty acids are a good source of energy because of:

the large number of carbon-carbon and carbon-hydrogen bonds they contain.

In addition to destabilizing glucose for subsequent breakdown, what else does phosphorylation of glucose do?

traps glucose inside the cell

Although glycolysis produces four molecules of ATP by substrate-level phosphorylation, the net gain of ATP for the cell is two molecules. This is because:

two molecules are used in the initial stage.