Deck 11: Cellular Energetics

Question 1

Phosphofructokinase is _____ active in the glycolytic pathway when the levels of ATP are high in the cell because _____.

A)less;ATP is an allosteric inhibitor
B)less;ATP is a competitive inhibitor
C)more;ATP stimulates phosphofructokinase through allosteric interactions
D)more;lower ADP levels activate phosphofructokinase

Answer 1

A

Question 2

Electron transport from NADH and FADH₂ to O₂ occurs in the:

A)mitochondrial matrix.
B)cytosol.
C)mitochondrial inner membrane.
D)mitochondrial outer membrane.

Answer 2

C

Question 3

The molecule that immediately enters the citric acid cycle is formed by which process?

A)chemiosmosis
B)glycolysis
C)the light reactions
D)pyruvate conversion

Answer 3

D

Question 4

_____ is a lipid soluble molecule that acts to shuttle electrons within the mitochondrial inner membrane.

A)Cytochrome c
B)NADH
C)CoQ
D)FADH₂

Question 5

Glucose is not the only energy-containing molecule that can enter cellular respiration pathways.Which food source is most likely to enter the citric acid cycle as fatty acids?

A)fats
B)carbohydrates
C)amino acids
D)DNA

Question 6

NADH-CoQ reductase and CoQH₂-cytochrome c reductase each use the energy derived from electron transfer to transport _____ the mitochondrial matrix.

A)four protons into
B)two protons into
C)four protons out of
D)two protons out of

Question 7

Yeasts use fermentation to synthesize ATP:

A)in the absence of oxygen.
B)because fermentation produces more ATP than oxidative phosphorylation.
C)because yeasts lack mitochondria.
D)to produce lactic acid.

Question 8

During prolonged exercise,oxygen is scarce in muscle tissue.Under these conditions,muscle cells convert pyruvate to two molecules of lactic acid.What happens to the lactic acid that is generated in this way?

Question 9

In mitochondria,the proton-motive force is due largely to:

A)a voltage gradient across the outer membrane.
B)a voltage gradient across the inner membrane.
C)a pH gradient across the outer membrane.
D)a pH gradient across the inner membrane.

Question 10

Compared with glucose,oxidation of which of the following is more important in humans as a source of ATP?

A)cellulose
B)sucrose
C)proteins
D)fats

Question 11

Which of the following health-related conditions are NOT related to mitochondrial function?

A)Tay-Sachs disease
B)Parkinson's disease
C)Kearns-Sayre syndrome
D)aging

Question 12

Which of the following is FALSE regarding mitochondrial structure?

A)The inner mitochondrial membrane contains more surface area than the outer membrane and contains many of the proteins required for making ATP.
B)The outer mitochondrial membrane contacts the cellular cytosol and the mitochondrial matrix.
C)Mitochondria contain DNA in the matrix.
D)The curved morphology of cristae are due to MICOS protein complexes.

Question 13

In the glycolytic pathway,which of the following are allosterically controlled enzymes?

A)triose phosphate isomerase
B)phosphofructokinase-1
C)enolase
D)none of the above

Question 14

The four stages of glucose oxidation are listed below.Place them in the correct order.
I) pyruvate oxidation to CO₂ in the mitochondrion via a 2-carbon acetyl CoA intermediate (citric acid cycle)
II) electron transport to generate a proton motive force
III) conversion in the cytosol of one 6-carbon glucose molecule to two 3-carbon pyruvate molecules (pyruvate)(glycolysis)
IV) ATP synthesis in the mitochondrion (oxidative phosphorylation)

A)I,II,III,IV
B)II,III,I,IV
C)III,II,IV,I
D)III,I,II,IV

Question 15

The first step in the citric acid cycle occurs when acetyl CoA reacts with oxaloacetate to form:

A)succinate.
B)citrate.
C)pyruvate
D)cytochrome c

Question 16

What is the role of substrate-level phosphorylation in glycolysis?

Question 17

_____ is the carbon-containing compound produced by glycolysis.

A)Pyruvate
B)Glucose
C)CO₂
D)Acetyl CoA

Question 18

What is the function of the malate-aspartate shuttle?

Question 19

In the absence of oxygen,NAD+ is recovered by _____,which leads to a net production of _____ ATP molecules for each glucose molecule broken down.

A)fermentation;two
B)fermentation;four
C)aerobic respiration;two
D)anabolism;four

Question 20

In the overall reaction for cellular respiration,glucose is:

A)oxidized to CO₂.
B)reduced to CO₂.
C)oxidized to O₂.
D)reduced to O₂.

Question 21

Each cytochrome in the electron transport chain has a different reduction potential.What is the importance of these differences for electron transport?

Question 22

Plastoquinone,like ubiquinone,can move freely within the membrane.This is important for its function as:

A)an electron and proton shuttle.
B)an electron carrier.
C)a reaction center.
D)a pump.

Question 23

ATP synthase is composed of two oligomeric proteins,F₀ and F₁.What is the function of each protein complex and where is each found in mitochondria?

Question 24

What is the role of quinone in generating the charge separation needed to remove electrons from H₂O for use in electron transport?

Question 25

Brown-fat mitochondria uncouple oxidative phosphorylation to produce:

A)ADP.
B)oxygen.
C)heat.
D)fat.

Question 26

Early investigators thought the oxygen produced by photosynthetic plants came from carbon dioxide.In fact,it comes from:

A)water.
B)air.
C)electrons from NADPH.
D)glucose.

Question 27

In chloroplasts,light absorption,electron transport,and ATP synthesis all occur:

A)in the stroma.
B)in the thylakoid lumen.
C)in or on the thylakoid membrane.
D)in or on the inner membrane.

Question 28

During ATP synthesis,protons move "down" their electrochemical gradient through:

A)the F₀ complex of ATP synthase.
B)the F₁ complex of ATP synthase.
C)a proton channel protein.
D)CoQH₂-cytochrome c reductase.

Question 29

During cyclic electron flow,electron transport:

A)involves neither PSI nor PSII.
B)takes place only in PSI.
C)takes place only in PSII.
D)cycles electrons back and forth between PSI and PSII.

Question 30

What is the role of water in the light reactions of photosynthesis?

A)provides energy
B)accepts electrons
C)accepts protons
D)source of electrons

Question 31

Which of the following statement(s)regarding the origin of the mitochondria is(are)TRUE?

A)A bacterium invaded and established a symbiotic relationship with a eukaryotic host cell.
B)The outer mitochondrial membrane is derived from the bacterial plasma membrane.
C)The globular F₁ domain points toward the mitochondria's intermembrane space.
D)all of the above

Question 32

Transport of pyruvate into the mitochondrial matrix depends on energy provided by:

A)ATP hydrolysis.
B)ATP synthesis.
C)a Na⁺ gradient.
D)the proton-motive force.

Question 33

Which stages of photosynthesis can occur only in the light and which can also occur in the dark?

Question 34

During photosynthesis,O₂ is produced:

A)on the stromal face of the thylakoid membrane.
B)on the luminal face of the thylakoid membrane.
C)throughout the stromal space.
D)throughout the entire chloroplast.

Question 35

The "tail" of chlorophyll is hydrophobic,which is important for:

A)absorbing blue light.
B)anchoring it in the thylakoid membrane.
C)transferring electrons.
D)giving plants their green color.

Question 36

During cellular respiration,the electron transport chain utilizes the energy produced from passing electrons from one molecule to the next to create:

A)a proton gradient.
B)NADH.
C)CO2.
D)an electron gradient.

Question 37

Based on what you know about the action spectra of photosynthesis,irradiating a leaf with which of the following light types would result in the release of the greatest quantities of oxygen?

A)red and orange light
B)red and blue light
C)green and blue light
D)violet and yellow light

Question 38

In photosynthesis,all of the following reactions are directly dependent on light,except:

A)carbon fixation.
B)synthesis of ATP.
C)electron transport.
D)removal of electrons from H₂O.

Question 39

A major source of reactive oxygen species (ROS)in animal cells is:

A)glycolysis.
B)electron transport in the mitochondria.
C)the reactions catalyzed by catalase and glutathione peroxidase.
D)vitamin E and α lipoic acid.

Question 40

Cyclic electron flow in the thylakoid membrane generates:

A)oxygen.
B)a proton-motive force.
C)sulfur.
D)NADPH.

Question 41

What is photorespiration? How is it related to photosynthesis?

Question 42

Explain how the rates of photosynthesis in plants like corn and sugarcane can be two to three times faster than the rates of photosynthesis in plants like wheat or rice.

Question 43

Why doesn't the Calvin cycle end after a three-carbon sugar is produced?

A)because electrons are still excited in the photosystems
B)because O₂ must be produced to act as a final electron acceptor
C)because RuBP must be generated for the cycle to continue
D)because there are not enough carbon building blocks in the cell

Question 44

The fixation of CO₂ into carbohydrates is catalyzed by:

A)ribulose 1,5-bisphosphate carboxylase.
B)thioredoxin.
C)rubisco activase.
D)3-phosphoglycerate.

Question 45

The Calvin cycle:

A)converts glucose into energy in the form of NADH and ATP.
B)uses glucose and electrons from NADPH to make ATP.
C)uses ATP and glucose to make NADPH.
D)uses electrons from NADPH and ATP to produce glucose.

Question 46

What molecule acts as an electron donor during photosynthesis in chloroplasts? What alternative is used by some photosynthetic bacteria (e.g. ,purple bacteria)?

Question 47

All of the following statements describe the process of photorespiration,except:

A)photorespiration consumes O₂.
B)photorespiration generates CO₂.
C)photorespiration generates substantial amounts of ATP.
D)photorespiration competes with photosynthesis.

Question 48

Which components of PSII are responsible for producing the proton-motive force?

Question 49

Plants use _____ to transport sucrose to all regions of the organism.

A)the xylem
B)the phloem
C)mesophyll cells
D)root cells

Question 50

The enzymes that catalyze the Calvin cycle are found in the:

A)thylakoid lumen.
B)phloem.
C)cytosol.
D)stromal space.

Question 51

What is the source of the energy for carbon fixation?