Biology Exam 2 Chapter 7

Which of the following serve as REACTANTS in the net reaction of glycolysis? Select all that apply.

2 NAD+ 2 ADP2- 2 Pi2-

In the first reaction of the citric acid cycle, oxaloacetate, which contains ______ carbons, is combined with acetyl-CoA, which contains ______ carbons in its acetyl group, to produce citric acid, which contains ______ carbons.

4,2,6

Energy investment phase

ATP is hydrolyzed, and its phosphate groups are attached to glucose

What reactants are required for the citric acid cycle?

Acetyl-CoA NAD+ GDP2- FAD

What happens during the fermentation reactions that occur in muscle cells?

Pyruvate is reduced to lactate. NADH is oxidized to NAD+.

True or false: Glycolysis can only occur under aerobic conditions.

false

True or false: The matrix of the mitochondrion generally has a more positive charge than the intermembrane space.

false

True or false: The redox reactions of the electron transport chain transfer electrons from components with higher electronegativity to those with lower electronegativity.

false

In the electron transport chain, electrons are transferred to molecules with increasingly higher:

electronegativity

During the energy investment phase of glycolysis, glucose is converted to:

fructose-1,6-bisphosphate

During glycolysis, one molecule of is broken down into two molecules of pyruvate, driving the synthesis of ATP.

glucose

During the first phase of glycolysis, ATP is hydrolyzed so that phosphate groups can be added to:

glucose

The rate of glycolysis is regulated primarily by the availability of substrates such as and by the process of inhibition.

glucose feedback

ATP is an allosteric inhibitor of phosphofructokinase, so when levels of ATP are high, _____ is slowed.

glycolysis

Organisms that can use only oxygen as a final electron acceptor can generate ATP via during anaerobic conditions.

glycolysis

The process of glycolysis can take place:

in the presence or absence of oxygen

In eukaryotic cells, the electron transport chain is located in the

inner mitochondrial membrane.

What molecule is produced during fermentation in muscle cells?

lactate

Bacteriorhodopsin is a proton pump found in some species or archaea. The energy that bacteriorhodopsin uses to pump protons comes from:

light

In the final stage of glucose metabolism, the high-energy electrons from NADH and FADH2 are removed and used to produce more ATP. This process is called

oxidative phosphorylation

In eukaryotic cells, which of the following metabolic pathways occur in the mitochondria?

oxidative phosphorylation the citric acid cycle the breakdown of pyruvate

ATP synthase functions like a

rotary machine

The structural components of the electron transport chain include:

small organic molecules protein complexes

During oxidative phosphorylation, ATP synthesis is coupled to:

the removal of high-energy electrons from NADH and FADH2

During the first phase of glycolysis:

there is an ATP investment

Each turn of the citric acid cycle produces:

3 NADH and 1 FADH2

All the reactions of glycolysis can be grouped into ______ phases.

3

As a result of the reactions of the citric acid cycle, the carbons from acetyl CoA are released as:

CO2

What are the products of the citric acid cycle? Select all that apply.

CO2 NADH CoA—SH FADH2 GTP

Select the organic molecules obtained from food that are most typically used as energy sources.

Carbohydrates Fats Proteins

The products of cellular respiration include:

Carbon dioxide and water

Which of the following best describes the chemical reactions of oxidative phosphorylation?

NADH is oxidized and ATP is produced

During the oxidation of glyceraldehyde-3-phosphate:

NADH is produced

When a muscle is working strenuously and becomes anaerobic, pyruvate from glycolysis is reduced to lactate to allow the oxidation of ______ to ______.

NADH to NAD+

What are the products of the breakdown of a single pyruvate molecule?

One NADH molecule One acetyl group One CO2

In aerobic respiration:

O2 is reduced to H2O

The three subunits of the membrane embedded region of ATP synthase are called:

a, b and c

The metabolic reactions that a cell uses to get energy from food molecules and release waste products are collectively called:

cellular respiration

Glucose contains covalent bonds that store a large amount of:

chemical energy

The measure of an atom's ability to attract electrons is called its

electronegativity

The iron atoms in the prosthetic groups of the electron transport chain proteins can easily accept and release ______.

electrons

In the Warburg effect, cancer cells preferentially use ______ for ATP production. This phenomenon is used to clinically diagnose cancer via PET scans.

glycolysis

Many organisms, including animals and yeasts, can only use as a final electron acceptor in their electron transport chains.

oxygen

The electron transport chain is also called the respiratory chain because it consumes

oxygen

The final electron acceptor in the electron transport chain is:

oxygen

Consider the net equation of cellular respiration. Which of the following molecules would be reactants?

oxygen, glucose

The purpose of the energy investment phase of glycolysis is to:

prime glucose for the exergonic reactions to follow

The second stage of glycolysis is called the cleavage phase. The reactions of the cleavage phase break a six-carbon molecule into:

two three-carbon molecules

Glycolysis consists of reactions or steps.

10

Glycolysis results in a net gain of ATP per glucose molecule.

2

The complete breakdown of glucose in the presence of oxygen yields 34 to 38 ATP molecules, but the breakdown of glucose to lactate or ethanol yields a net of only ATP molecules.

2

Which of the following is the best description of the process of cellular respiration?

A means to extract energy from organic molecules

In different conformations, ATP synthase may be bound to and Pi, bound to ATP, or not bound to a nucleotide.

ADP

What describes the three conformations of the β subunit of ATP synthase? Select all that apply.

ADP and Pi are bound ATP is released ATP is bound

Which of the following factors regulate the rate of glycolysis?

Availability of glucose inhibition

What field is the study of the chemistry of living organisms?

Biochemistry

Yeast cells can metabolize sugar under anaerobic conditions by breaking down pyruvate. Which of these are the end products of fermentation in yeast?

Ethanol CO2 NAD+

Why is the electron transport chain also called the respiratory chain?

It consumes O2.

Select all of the organic molecules that can be produced during fermentation reactions.

Lactate Ethanol

If an organism can use only O2 as a final electron acceptor, can it generate ATP under anaerobic conditions?

Yes, it can generate ATP through glycolysis.

In eukaryotic cells, pyruvate breakdown, the citric acid cycle, and oxidative phosphorylation occur in the:

mitochondria

During aerobic respiration, the final electron acceptor in the electron transport chain is

oxygen

True or false: Some organisms can only use oxygen as a final electron acceptor.

true

What type of fermentation is shown here?

yeast cells

The number of ATP molecules hydrolyzed during the first stage of glycolysis is

2

For every glucose molecule that enters glycolysis, the energy liberation phase (steps 6-10) generates a total of

2 NADH and 4 ATP molecules.

Glycolysis is the breakdown of glucose into

2 pyruvate molecules

The net products of glycolysis are:

2 pyruvate, 2 NADH, 2 H+, 2 ATP, and 2 H2O

The third stage of glycolysis (steps 6-10) is called the energy liberation phase. It produces a total of molecule(s) of NADH and molecule(s) of ATP for every molecule of glucose that enters the pathway. Note: This question is NOT asking about the net yield but the total.

2,4

Aerobic respiration yields ______ ATP molecules per glucose, while fermentation typically yields ______ ATP molecules per glucose.

34-38 ; 2

During the cleavage stage of glycolysis, a molecule with carbon atoms is broken into two molecules of -3-phosphate.

6 glyceraldehyde

During chemiosmosis, the energy in the form of a proton gradient is converted to chemical potential energy in molecules.

ATP

The main product of cellular respiration is

ATP

The primary aim of cellular respiration is to produce molecules of , which provide energy to the cell.

ATP

The three energy intermediates produced during cellular respiration are

ATP NADH FADH2

Energy liberation phase

ATP and NADH are synthesized

During oxidative phosphorylation, ATP is produced by the enzyme:

ATP synthase

The electron transport chain results in the oxidation of what energy intermediates produced in the earlier steps of cellular respiration?

FADH2 NADH

What energy intermediates are produced in the citric acid cycle?

GTP FADH2 NADH

Arrange the four steps of cellular respiration in the correct order. Start with the earliest on top.

Glycolysis Breakdown Citric Oxidative

Arrange the steps that occur when ATP synthase produces ATP in the correct order. The first step should be at the top.

Hydrogen The Y The B ATP is synthesized

Where does the citric acid cycle occur in eukaryotic cells?

Mitochondrial matrix

In order for glycolysis to continue in the absence of cellular respiration with oxygen, which product must be regenerated?

NAD+

Under anaerobic conditions, glycolysis slows due to the depletion of:

NAD+

What is the main function of oxidative phosphorylation?

Production of ATP

Which of the following are end products of glycolysis?

Pyruvate ATP NADH

In glycolysis, what is the net yield of ATP per molecule of glucose?

Two ATP molecules

Why does using the same pathway for the breakdown of sugars, amino acids, and fats make cellular metabolism more efficient?

The same enzymes can be used.

Why are phosphate groups added to glucose during the first phase of glycolysis?

To raise its free energy so that later reactions are exergonic

The preferential use of glycolysis for ATP production in cancer cells is called the:

Warburg effect

Cleavage phase

a six carbon molecule is converted to two three-carbon molecules

Many of the proteins of the electron transport chain contain prosthetic groups. These prosthetic groups commonly contain iron, which can easily:

accept and release an electron

Ethanol production by yeast results when NADH donates its electrons to ________.

acetaldehyde

The pyruvate molecule produced in glycolysis undergoes a reaction which results in the production of one group and one CO2 molecule.

acetyl

At high concentrations, ATP regulates the rate of glycolysis through:

allosteric inhibition of phosphofructokinase

Which of the following molecules are used as energy sources by living organisms?

amino acids sugars fatty acids

An environment where oxygen is absent is termed

anaerobic

Which type of ATP synthase subunit forms a ring in the membrane?

c

In yeast cells, fermentation regenerates NAD+ and produces which chemicals?

carbon dioxide and ethanol

During chemiosmosis, energy stored in a proton gradient is:

converted to chemical bond energy in ATP

The ______ bonds in glucose store large amounts of energy.

covalent

At the end of the electron transport chain, ______ catalyzes the transfer of electrons to O2.

cytochrome oxidase

Glycolysis occurs in the:

cytosol

While glycolysis occurs in the in eukaryotic cells, the remaining steps of respiration occur in the of the cell.

cytosol mitochondria

During the cleavage phase of glycolysis, fructose-1,6-bisphosphate is split into two different three-carbon molecules. These two molecules are:

dihydroxyacetone phosphate glyceraldehyde-3-phosphate

The first phase of glycolysis is also called the ______ phase

energy investment

Using the same pathway for the breakdown of sugars, amino acids, and fats makes cellular metabolism more efficient because the same can be used for the breakdown of many starting molecules.

enzymes

The flow of electrons through the electron transport chain is:

exergonic

True or false: Glycolysis occurs in the mitochondria.

false

True or false: The flow of electrons through the electron transport chain requires an input of energy.

false

The breakdown of glucose to lactate or ethanol as a final end product is an example of

fermentation

This figure shows the process of in muscle cells.

fermentation

In the second phase of glycolysis, a molecule of -1,6- is cleaved into two molecules of -3-phosphate.

fructose bisphosphate glyceraldehyde

The oxidation of NADH in the mitochondrion leads to an electrochemical gradient where there are more protons in the space than there are in the matrix.

intermembrane

The oxidation of NADH initially leads to a high concentration of protons in the:

intermembrane space

In eukaryotic cells, the citric acid cycle occurs in the matrix.

mitochondrial

Due to the electron transport chain, the proton concentration is the lowest in the

mitochondrial matrix.

In order for cellular respiration to continue, the pyruvate produced in glycolysis must be transported into the

mitochondrion.

As electrons travel through the electron transport chain, ions are pumped across the cristae into the space between the inner and outer mitochondrial membranes, from a low concentration to a high concentration.

protons

The energy released during the transfer of electrons in the electron transport chain is used to:

pump protons across the inner mitochondrial membrane

The electron transport chain involves a series of ______ reactions.

redox

The final step in fermentation, leading to the production of lactate or ethanol, results from pyruvate or acetaldehyde being by NADH

reduced

The final step in fermentation, leading to the production of lactate or ethanol, results from pyruvate or acetaldehyde being by NADH.

reduced

Muscle cells overcome the buildup of NADH and decrease of NAD+ under anaerobic conditions by

reducing pyruvate to lactate.

What type of motion is coupled to the synthesis of ATP by the enzyme ATP synthase?

spinning

The removal of a phosphate from 1,3-bisphosphoglycerate allows for the transfer of the phosphate to ADP, producing ATP via - phosphorylation.

substrate level

The second event in oxidative phosphorylation is the production of ATP by the enzyme ATP

synthase

The hydrolysis of ATP early in glycolysis leads directly to:

the phosphorylation of glucose

rue or false: Some organisms can only use oxygen as a final electron acceptor.

true

Glycolysis involves the breakdown of one molecule of glucose into:

two molecules of pyruvate

When electrons are transferred to oxygen in the final step of the electron transport chain, a molecule of is produced.

water

The flow of protons through ATP synthase causes the ______ subunit to turn clockwise. This causes the three ______ subunits to change their conformations in a way that favors ATP synthesis and release.

γ ; β