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-
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
All the reactions of glycolysis can be grouped into ______ phases.
3
Each turn of the citric acid cycle produces:
3 NADH and 1 FADH2
Aerobic respiration yields ______ ATP molecules per glucose, while fermentation typically yields ______ ATP molecules per glucose.
34-38 ; 2
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
During the cleavage stage of glycolysis, a molecule with carbon atoms is broken into two molecules of -3-phosphate.
6 glyceraldehyde
Energy investment phase
ATP is hydrolyzed, and its phosphate groups are attached to glucose
During oxidative phosphorylation, ATP is produced by the enzyme:
ATP synthase
What reactants are required for the citric acid cycle?
Acetyl-CoA NAD+ GDP2- FAD
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+
In aerobic respiration:
O2 is reduced to H2O
What are the products of the breakdown of a single pyruvate molecule?
One NADH molecule One acetyl group One CO2
What is the main function of oxidative phosphorylation?
Production of ATP
Which of the following are end products of glycolysis?
Pyruvate ATP NADH
What happens during the fermentation reactions that occur in muscle cells?
Pyruvate is reduced to lactate. NADH is oxidized to NAD+.
Why are phosphate groups added to glucose during the first phase of glycolysis?
To raise its free energy so that later reactions are exergonic
In glycolysis, what is the net yield of ATP per molecule of glucose?
Two ATP molecules
The preferential use of glycolysis for ATP production in cancer cells is called the:
Warburg effect
Glucose contains covalent bonds that store a large amount of:
chemical energy
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
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 can only occur under aerobic conditions.
false
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
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
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
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
In the electron transport chain, electrons are transferred to molecules with increasingly higher:
electronegativity
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 second phase of glycolysis, a molecule of -1,6- is cleaved into two molecules of -3-phosphate.
fructose bisphosphate glyceraldehyde
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
In the Warburg effect, cancer cells preferentially use ______ for ATP production. This phenomenon is used to clinically diagnose cancer via PET scans.
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.
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
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
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
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
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
The number of ATP molecules hydrolyzed during the first stage of glycolysis is
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
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
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
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
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+
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
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
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+
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.
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.
Cleavage phase
a six carbon molecule is converted to two three-carbon molecules
The three subunits of the membrane embedded region of ATP synthase are called:
a, b and c
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
The metabolic reactions that a cell uses to get energy from food molecules and release waste products are collectively called:
cellular respiration
In eukaryotic cells, pyruvate breakdown, the citric acid cycle, and oxidative phosphorylation occur in the:
mitochondria
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.
During aerobic respiration, the final electron acceptor in the electron transport chain is
oxygen
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
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.
True or false: Some organisms can only use oxygen as a final electron acceptor.
true
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
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
When electrons are transferred to oxygen in the final step of the electron transport chain, a molecule of is produced.
water
What type of fermentation is shown here?
yeast cells
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