Chapter 14

(Q011) The pH of the mitochondrial matrix is ___________, which is ___________ than that of the intermembrane space. 7.9; higher 7.2; lower 7.2; higher 7.9; lower

7.9; higher

Stage 1 of photosynthesis is, in large part, equivalent to what process? Choose one: the carbon-fixation cycle the citric acid cycle oxidative phosphorylation the production of acetyl CoA by the pyruvate dehydrogenase complex glycolysis

oxidative phosphorylation

(Q001) Which of the following correctly matches the cellular location with the production of ATP by oxidative phosphorylation in that cell type? chloroplasts—plants mitochondria—archaea cell wall—photosynthetic algae plasma membrane—bacteria

plasma membrane—bacteria

When protons move down their electrochemical gradient into the mitochondrial matrix, what do they do? Choose one: produce NAD+ consume ATP move electrons through the respiratory chain produce ATP produce NADH

produce ATP

(Q022) Chlorophyll appears green because it absorbs blue light. absorbs red light. reflects green light. reflects UV light.

reflects green light.

(Q012) The proton flow through the transmembrane H+ carrier of ATP synthase results in bending of the carrier and stalk to produce mechanical force. moving ADP and Pi across the membrane into the enzyme active site. mechanical rotation that is converted into the chemical-bond energy of ATP. binding of the proton to ADP to enhance formation of the phosphate bond.

mechanical rotation that is converted into the chemical-bond energy of ATP.

(Q013) How is pyruvate imported into the mitochondrial matrix for use in the citric acid cycle? proton gradient-driven symport sodium gradient-driven antiport ATP-driven pyruvate pump diffusion through porin complexes in the membrane

proton gradient-driven symport

The movement of electrons through the electron-transport chain in mitochondria does which of the following? Choose one: pumps protons out of the mitochondrial matrix pumps ATP across the inner mitochondrial membrane produces oxygen consumes ATP produces NADH

pumps protons out of the mitochondrial matrix

(Q014) The low redox potential of NADH means that it has a tendency to give up electrons. low free energy. high electron affinity. very stable bond.

tendency to give up electrons.

The first living cells on Earth—whether prokaryotes or primitive eukaryotes—most likely generated ATP by what process? Choose one: A. fermentation B. photosynthesis C. oxidative phosphorylation D. nitrogen fixation E. aerobic cell respiration

A. fermentation

(Q021) Stage two of photosynthesis (or the light-independent reactions) uses which input molecules to produce organic food molecules? ATP, NADPH, CO2 O2, NADH, ADP H2O, light, chlorophyll amino acids, sugars, fatty acids

ATP, NADPH, CO2

Which of these processes require a membrane? Choose one or more: generation of ATP by photosynthesis in bacteria generation of ATP by glycolysis generation of ATP by oxidative phosphorylation generation of energy by mitochondria generation of ATP by photosynthesis in plants

generation of ATP by photosynthesis in bacteria generation of ATP by oxidative phosphorylation generation of energy by mitochondria generation of ATP by photosynthesis in plants

(Q003) Individuals with inherited diseases causing mitochondrial dysfunction typically experience which of the following symptoms? heart problems sterile bone deformities light sensitivity

heart problems

(Q010) Protons are pumped across the mitochondrial inner membrane to accumulate in the mitochondrial matrix. intermembrane space. cytosol. electron-transport chain.

intermembrane space.

(Q016) The cytochrome complexes contain heme prosthetic groups, which have a higher redox potential than the iron-sulfur centers found in other electron-transport chain complexes like NADH dehydrogenase. Where in the electron-transport chain would the cytochrome complexes thus be located relative to iron-sulfur center complexes? later in the chain earlier in the chain It cannot be determined. at the same point of the chain

later in the chain

Which part of the mitochondrion contains the proteins that carry out oxidative phosphorylation?

look at 5

(Q002) Glycolysis alone captures approximately what percentage of the free energy available in a molecule of glucose? 10% 20% 50% 99%

10%

(Q015) The number of ATP molecules that could be synthesized from the energy released by the transfer of two electrons from NADH to molecular oxygen is 2.5. 4. 3. 1.5.

2.5.

Q005) Shown is the structure of a mitochondrion with different compartments labeled. Which of the numbers represents the most permeable membrane of the mitochondrion?

3

Which of the following statements are true of electron transfer in the electron-transport chain? Choose one or more: A.Each electron transfer is an oxidation-reduction reaction. B.NADH has a relatively high electron affinity and initiates the electron-transport process. C.When an electron carrier accepts an electron, it becomes oxidized. D.NADH is a strong electron donor. E.Electrons move toward molecules with a high redox potential.

A,D,E

What is true of the evolution of electron transport systems? Choose one: A. The earliest ones involved using H2O as an electron donor. B. They are evolutionarily ancient and likely provided energy for the earliest cells on Earth. C. They are a relatively recent evolutionary innovation. D. In ancient prokaryotes, they did not require the use of a membrane. E. Their requirement for oxygen as an electron acceptor means they evolved first in photosynthetic prokaryotes.

B. They are evolutionarily ancient and likely provided energy for the earliest cells on Earth.

Which activated carrier contains a high-energy bond whose hydrolysis releases a large amount of free energy? Choose one: A. high-energy electrons B. water C. ATP D. glucose E. NADH

C. ATP

in this simplified diagram of the reactions of the carbon-fixation cycle, which step is catalyzed by the enzyme Rubisco?

E 5C -> 3C Rubisco takes off two carbons

Which activated carriers are produced by the citric acid cycle? Choose one or more: ATP NADPH GTP CO2 NADH FADH2

GTP NADH FADH2

During electron transport, which serves as a ready source for protons that can be pumped across the membrane? Choose one: NADH H2O glucose O2 ATP

H2O

When an electron is removed from the reaction center of photosystem II, the missing electron is replaced by an electron from which of the following? Choose one: H+ photosystem I manganese H2O sunlight

H2O

When the difference in redox potential between two molecules is highly positive, what is true of the transfer of electrons between them? Choose one: It is highly unfavorable. It requires an input of energy. It produces ATP. It is highly favorable. It is accompanied by a rise in ΔG.

It is highly favorable.

What is true of stage 2 of photosynthesis? Choose one: It produces all of the O2 we breathe. It generates a proton gradient across the thylakoid membrane. It takes place in the chloroplast grana. It produces glyceraldehyde 3-phosphate in the stroma It begins with the production of ATP and NADPH and ends with their consumption.

It produces glyceraldehyde 3-phosphate in the stroma

(Q006) The citric acid cycle produces which activated carriers that transfer high-energy electrons to the electron-transport chain? NADPH and NADH NAD+ and FAD NADP and FAD NADH and FADH2

NADH and FADH2

(Q009) Which of the following has the lowest electron affinity? NADH dehydrogenase complex cytochrome c reductase complex cytochrome c oxidase complex oxygen

NADH dehydrogenase complex

Most of the energy for the synthesis of ATP comes from which molecule? Choose one: NADH produced by the conversion of pyruvate to acetyl CoA NADH produced by glycolysis GTP produced by the citric acid cycle NADH produced by the citric acid cycle FADH2 produced by the citric acid cycle

NADH produced by the citric acid cycle

During Earth's history, with the rise of cyanobacteria, what molecule began accumulating in the atmosphere for the first time? Choose one: N2 O2 H2O CO2

O2

(Q017) Cytochrome c oxidase catalyzes the reaction that reduces molecular oxygen (two oxygen atoms) to two water molecules. The electrons are added sequentially, and during the process cytochrome c oxidase must bind the oxygen tightly in the active site. Why? If the oxygen escapes, it will bubble out as a gas and escape quickly. Superoxide radicals are formed as an intermediate, and are dangerous to the cell. Oxygen will bind to the electron-transport chain and reverse the pumping of protons. The escaped oxygen will form carbon monoxide and kill the cell.

Superoxide radicals are formed as an intermediate, and are dangerous to the cell.

(Q004) In a sperm cell, where are the mitochondria located? The mitochondria form elongated tubes that wrap around the flagellar core. They are located in a tubular network that are just inside the plasma membrane. Mitochondria are randomly scattered around in the cytoplasm of the cell. The mitochondria surround the nucleus of the cell.

The mitochondria form elongated tubes that wrap around the flagellar core.

(Q018) Shown below is the mechanism believed to be used for pumping protons by cytochrome c oxidase across the inner mitochondrial membrane. One of the steps shown is unidirectional because it is driven by the energy of electron transport. Why must this step be performed only in one direction?The protons could be also captured from the intermembrane space and released back into the matrix. The complex would stay stuck in the closed (center conformation). The inner membrane would become porous to all molecules. The H+ affinity in the two conformations would reverse.

The protons could be also captured from the intermembrane space and released back into the matrix.

Q007) How do the high-energy electrons of activated carriers contribute to forming the high-energy phosphate bonds of ATP? They are transferred directly to ADP to form ATP. They are passed to ATP synthase to power ATP synthesis. They are used by the electron-transport chain to make a proton gradient. They are pumped across the membrane to form an electron gradient.

They are used by the electron-transport chain to make a proton gradient.

What is true of the organelles that produce ATP in eukaryotic animal cells? Choose one: They evolved from bacteria engulfed by ancestral cells billions of years ago. They reproduce sexually. They have a separate set of DNA that contains many of the same genes found in the nucleus. They contain the same genes as the chloroplasts of plant cells. They harbor eukaryotic-like biosynthetic machinery for making RNA and protein.

They evolved from bacteria engulfed by ancestral cells billions of years ago.

(Q020) In oxidative phosphorylation in mitochondria, high-energy electrons are transferred to the electron-transport chain from activated carriers like NADH. Stage 1 of photosynthesis also uses an electron-transport chain to pump protons and make ATP. In this case, where do the high-energy electrons come from? NADPH chlorophyll ADP FADH2

chlorophyll

(Q023) The first living things on Earth probably generated ATP by what mechanism? fermentation oxidative phosphorylation photosynthesis carbon fixation

fermentation

What is one reason that plants do not generally produce sugars after dark? Choose one: The enzymes involved in stage 2 of photosynthesis are inactivated in the dark. O2 is unavailable after dark. The enzymes involved in stage 2 of photosynthesis are inactivated in the light. The enzymes involved in stage 1 of photosynthesis are inactivated in the dark. CO2 is unavailable after dark.

the enzymes involved in stage 2 of photosynthesis are inactivated in the dark.

(Q019) Shown is a chloroplast with labeled structures. The photosynthetic machinery is found in which of the compartments shown? stroma thylakoid membrane inner membrane outer membrane

thylakoid membrane

(Q008) Which of the following is a mobile electron carrier in the electron-transport chain? NADH dehydrogenase complex cytochrome c reductase complex cytochrome c oxidase complex ubiquinone

ubiquinone