Observations of mitochondria within living cells have shown that:

mitochondria cannot fuse with one another.
their shape is always cylindrical
they can exist as a highly branched, interconnected tubular network.
they cannot split apart.
they can exist as individual conical organelles.

they can exist as a highly branched, interconnected tubular network.

________ were responsible for the accumulation of significant levels of atmospheric oxygen on Earth between 2.4 and 2.7 billion years ago.

Aerobic bacteria
Cyanobacteria
Plants
Anaerobic bacteria
Mitochondria

Cyanobacteria

The composition of the inner mitochondrial membrane is MOST like that of:

the outer mitochondrial membrane.
the plasma membrane of a eukaryotic cell.
bacterial plasma membranes.
the nuclear membrane.
the endoplasmic reticulum (ER).

bacterial plasma membranes.

Which of the following would NOT be found as part of the mitochondrial matrix?

ribosomes larger than those in the cytoplasm of the cell
circular DNA
enzymes
tRNAs
ribosomes smaller than those in the cytoplasm of the cell

ribosomes larger than those in the cytoplasm of the cell

Each pair of electrons transferred from NADH to oxygen by means of the electron-transport chain releases sufficient energy to drive the formation of approximately how many molecules of ATP?

one
two
three
thirty-six
more than thirty-six

three

Which of the following are reduced coenzymes?

NADH and FADH₂
NAD⁺ and FAD
ATP and GTP
coenzyme A and TCA
NADP and FAD

NADH and FADH₂

Anaerobic metabolism provides energy for muscle contraction when the supply of ___________ is limited.

oxygen
ATP
creatine
glucose
glycogen

oxygen

During aerobic exercise, muscle fibers first use glycogen for energy and then they switch to use of:

creatine phosphate.
free fatty acids.
glucose.
lactic acid.
creatine.

free fatty acids.

In what form does a portion of the product of glycolysis enter the TCA cycle?

acetyl CoA
pyruvate
NADH
glucose
citric acid

acetyl CoA

At the end of the electron transport chain, low-energy electrons are transferred to ______, which is the terminal electron acceptor, forming ______.

molecular oxygen (O₂); glucose
water (H₂O); molecular oxygen (O₂)
pyruvate; lactate
molecular oxygen (O₂); water (H₂O)
NAD⁺; NADH

molecular oxygen (O₂); water (H₂O)

Creatine phosphate can be used by a muscle fiber to generate:

myosin.
ADP.
ATP.
pyruvate.
free fatty acids.

ATP.

Which component involved in the Krebs (TCA) cycle is bound to the inner mitochondrial membrane?

oxaloacetate
acetyl CoA
succinate dehydrogenase
succinate
succinyl CoA

succinate dehydrogenase

To what is the 2-carbon fragment of acetyl CoA added to make citric acid at the start of the Krebs cycle?

oxaloacetate
citric acid
succinate
ketoglutarate
isocitric acid

oxaloacetate

Types of electron carriers found in the electron transport chain of the inner mitochondrial membrane do NOT include:

flavoproteins.
cytochromes.
iron-sulfur proteins.
ubiquinone.
NAD.

NAD.

Which of the following statements is FALSE about cytochrome oxidase?

It is also known as complex IV in the electron transport chain.
It acts as a proton pump.
Activity of the enzyme leads to production of oxygen.
For every molecule of oxygen reduced, eight protons move through the complex.
Translocation of protons through the complex is coupled to conformational changes generated by the release of energy that accompanies the transfer of electrons.

Activity of the enzyme leads to production of oxygen.

Which of the following is NOT a feature of oxidative phosphorylation?

direct transfer of phosphate from a substrate molecule to ADP, also known as substrate-level phosphorylation).
an electrochemical gradient across the inner mitochondrial membrane.
transport of protons across the inner mitochondrial membrane
NADH dehydrogenase.
cytochromes.

direct transfer of phosphate from a substrate molecule to ADP, also known as substrate-level phosphorylation)

If complex III were incorporated into an artificial lipid vesicle in order to demonstrate its proton-translocating ability in isolation, which of the following would be an appropriate electron donor?

flavoprotein
ubiquinone (UQ)
ubiquinol (UQH₂)
cytochrome c oxidase
succinate dehydrogenase

ubiquinol (UQH₂)

If a cell did NOT have an electron transport chain, which mechanism would have to account for its ATP production?

oxidative phosphorylation.
substrate-level phosphorylation.
a proton pump
the TCA cycle
aerobic metabolism

substrate-level phosphorylation.

The oxygen in the blood is:

bound to hemoglobin.
dissolved in blood plasma.
bound to hemoglobin and dissolved in blood plasma.
bound to the red blood cell membrane.
mostly found in white blood cell cytoplasm.

bound to hemoglobin and dissolved in blood plasma.

There is a device made of a platinum contact and a silver contact embedded in an electrolyte solution that creates a current when voltage is placed across the contacts. The current is created by a set of oxidation-reduction reactions involving oxygen, the two metals, and chloride ions. The current is higher if more oxygen is present, so this device can be used to determine the concentration of oxygen. What is this device called?

a battery electrode
a Clark generator
an oxygen meter
a Clark electrode
a pH electrode

a Clark electrode

What is a common use of a Clark-type transcutaneous oxygen sensor?

monitoring the concentration of oxygen in a blood sample from an older person
monitoring blood oxygen levels in newborn babies in the intensive care unit
measuring the oxygen exhaled by a patient
measuring the oxygen content of the skin
measuring the oxygen exhaled by a patient and oxygen content of the skin

monitoring blood oxygen levels in newborn babies in the intensive care unit

In a pulse oximeter, what light-emitting diodes are used to determine blood oxygen?

one that emits red light at 660 nm and one that emits infrared light
one that emits green light at 550 nm and one that emits infrared light
one that emits red light at 660 nm and one that emits ultraviolet light
one that emits green light at 550 nm and one that emits ultraviolet light
one that emits blue light at 450 nm and one that emits infrared light

one that emits red light at 660 nm and one that emits infrared light

How does a pulse oximeter determine when a person’s heart beats?

It detects the peaks in redder deoxygenated blood that occur at each heartbeat.
It detects the peaks in redder deoxygenated blood that occur in between heartbeats.
It detects the peaks in redder oxygenated blood that occur at each heartbeat.
It detects the peaks in bluer oxygenated blood that occur in between heartbeats.
It detects the peaks in bluer oxygenated blood that occur at each heartbeat.

It detects the peaks in redder oxygenated blood that occur at each heartbeat.

Which one of the following can act as an “uncoupler” of glucose oxidation and ADP phosphorylation?

cytochrome oxidase
dinitrophenol
copper
proton pumps
heme groups

dinitrophenol

Maintenance of the proton-motive force requires that:

the mitochondrial matrix supplies electrons for passage down the electron transport chain.
the inner mitochondrial membrane is impermeable to protons.
the inner mitochondrial membrane is impermeable to electrons.
the plasma membrane is impermeable to protons.
protons remain lipid soluble.

the inner mitochondrial membrane is impermeable to protons.

The F_o portion of the ATP synthase:

contains a channel through which protons can move from the intermembrane space to the mitochondrial matrix.
is composed of different five polypeptides.
is located in the outer mitochondrial membrane.
has the same structure in a wide variety of different organisms.
all of these statements are true about the F_o of mitochondrial ATP synthase.

contains a channel through which protons can move from the intermembrane space to the mitochondrial matrix.

The binding change mechanism of ATP production was proposed by:

Paul Boyer.
John Walker.
Masasuke Yoshida.
Efraim Racker.
Humberto Fernandez-Moran.

Paul Boyer.

The F₁ portion of mitochondrial ATP synthase:

is composed of four polypeptides.
is coded for by mitochondrial DNA and synthesized in the matrix.
is located in the outer mitochondrial membrane.
synthesizes ATP.
is a protein that lacks quaternary structure.

synthesizes ATP.

Two types of biological structures that contain rotating parts are ATP synthase and:

cytochrome c oxidase.
sperm cells.
bacterial flagella.
invertebrate feeding structures.
the only rotating structure in the biological world is ATP synthase.

bacterial flagella.

Which one of the following statements is FALSE regarding action of the F_o portion of ATP synthase?

The c subunits are organized into a ring-shaped complex.
Subunits of the c ring move successively past a stationary a subunit.
The g subunit rotates at rates of more than 100 revolutions per second.
The movement of electrons through the membrane drives the rotation of the ring of c subunits.
Rotation of the c ring of F₀ leads to the synthesis and release of ATP by catalytic subunits of the F₁ portion of the enzyme.

The movement of electrons through the membrane drives the rotation of the ring of c subunits.

ATP synthase is located:

in the plasma membrane.
in the outer membrane of the mitochondrion.
in the matrix of the mitochondrion.
in the inner membrane of the mitochondrion.
in the intermembrane space.

in the inner membrane of the mitochondrion.

According to the rotational catalysis model, _______ energy stored in the proton gradient is transduced into ________ energy of a rotating stalk, which is transduced into __________ energy stored in ATP.

mechanical; electrical; chemical
chemical; electrical; mechanical
electrical; chemical; mechanical
electrical; mechanical; chemical
chemical; mechanical; electrical

electrical; mechanical; chemical

Which of the following BEST describes the mechanism by which ATP is synthesized by ATP synthase using the energy of proton movement?

Protons move through the F_o subunit and thereby allow ADP and P_i to bind the enzyme.
Protons move through the F_o subunit and rotate the γ subunit, inducing changes in the conformation of the β subunit catalytic sites and allowing formation and release of ATP.
Protons bind to the F₁ subunit and electrostatically join ADP and P_i.
Protons allow substrate-level phosphorylation to occur, much like that in glycolysis.
Protons are channeled through the F₁ subunit into the mitochondrial matrix where they release energy that is captured by ADP.

Protons move through the F_o subunit and rotate the γ subunit, inducing changes in the conformation of the β subunit catalytic sites and allowing formation and release of ATP.

The three catalytic sites of ATP synthase ___________.

have different substrate binding affinities
have different product binding affinities
at any one time are present in different conformations
pass sequentially through their three different conformations
All of these are correct.

All of these are correct.

Which of the following statements about mitochondrial diseases is TRUE?

Individuals with mutations in the same mitochondrial gene will all exhibit the same disorder.
All mitochondrial diseases are mild and are easily tolerated by the patient.
Oxygen radicals formed in mitochondria cause an increased mutation rate in mtDNA relative to nuclear DNA.
Scientists have described a clear connection between mutations in mtDNA and aging.
Mitochondrial diseases will always be inherited by offspring of the same father.

Oxygen radicals formed in mitochondria cause an increased mutation rate in mtDNA relative to nuclear DNA.

Which statement about the condition X-linked adrenoleukodystrophy (X-ALD) is FALSE?

It was the topic of the movie Lorenzo's Oil.
It has been successfully treated by bone marrow transplantation.
It can cause damage to the myelin sheath covering neurons in the brain.
It is being studied in a large-scale clinical trial.
It will be inherited by female children only.

It will be inherited by female children only.

Peroxisomes:

may contain a dense crystalline core.
are found only in reptilian and avian cells.
concentrate molecules of lithium peroxide within the cell.
are only found in bacterial cells.
produce ATP in the cell.

may contain a dense crystalline core.

Mitochondrial DNA:

is contributed to the fertilized egg by the sperm cell.
is contributed to the offspring exclusively by the egg cell.
may exhibit heteroplasmy, meaning that some mtDNA is contributed by the mother and some is contributed by the father.
is not subject to mutations because it is not replicated in the nucleus of the cell.
inherited from the father often leads to mitochondrial disorders.

is contributed to the offspring exclusively by the egg cell.

Using differential centrifugation, you are trying to isolate peroxisomes from a mixture of cellular organelles. After a few centrifugation steps, you think you may have a relatively pure suspension. How might you determine that your suspension does, indeed, have peroxisomes?

Do an assay for the enzyme catalase.
Do an assay for the enzyme succinate dehydrogenase.
Look in the microscope for an organelle with a double membrane.
Assay your suspension for nucleic acid.
Assay your suspension for H₂O₂.

Do an assay for the enzyme catalase.

Which of the following is a form of stored energy in plants?

starch
DNA
oils (triglycerides)
starch and oils (triglycerides)
proteins

starch and oils (triglycerides)

What is the main form of energy storage in seeds and crops like soybeans, maize, and sunflowers?

starch
DNA
oils (triglycerides)
starch and oils (triglycerides)
proteins

DNA

What organelle converts citrate into glucose by a series of enzymes of the glyoxylate cycle?

the nucleus
the glyoxysome
the peroxisome
the endoplasmic reticulum
the lysosome

the glyoxysome

When a seed is maturing, triglycerides are synthesized. Where are they stored?

peroxisomes
the nucleus
oil bodies
lysosomes
the Golgi apparatus

oil bodies

Stored fat in seeds remains inert until:

seed germination
seed planting
seed shedding
photosynthesis
aerobic respiration

seed planting

What is the name of the biochemical pathway in seeds that converts citrate into glucose?

Krebs cycle
glycolysis
non-cyclic photophosphorylation
glyoxylate cycle
electron transport

glyoxylate cycle

Which organelle below is not found in both plants and animals?

cell membrane
mitochondria
peroxisomes
glyoxysomes
vacuoles

glyoxysomes