Learning Curve Chapter 12

In the mitochondria, pyruvate reacts with coenzyme A, producing all of the following EXCEPT: carbon dioxide. ATP. acetyl-CoA. NADH. Actually, it produces all of these.

ATP.

Allosterically regulated enzymes in the glycolytic pathway include all of the following EXCEPT: phosphofructokinase-1. phosphofructokinase-2. hexokinase. pyruvate kinase. Actually, all of these are allosterically regulated glycolytic enzymes.

Actually, all of these are allosterically regulated glycolytic enzymes.

Converting fatty acids to carbon dioxide in the mitochondria produces more: ATP than the same mass of glucose. carbon dioxide than the same mass of glucose. NADH than the same mass of glucose. All of the answers are correct. None of the answers is correct.

All of the answers are correct.

During oxidation, the energy released from the breakdown of glucose or fatty acids into CO2 is converted into high-energy electrons in the reduced coenzymes. The energy stored in these reduced coenzymes is directly converted into the proton-motive force by the: respiratory chain. electron transport chain. oxidation of NADH and FADH2 to O2. All of the answers are correct. None of the answers is correct.

All of the answers are correct.

Use the genetic code table (Table 5-1) to answer the following question. In Drosophila mitochondria, the codons AGA and AGG encode for serine. In the majority of organisms, AGA encodes for _____ and AGG encodes for _____. Click to view full size. Cys; Cys Cys; Arg Ser; Cys Arg; Arg Arg; Ser

Arg; Arg

Regarding translation, which statement is the same for nuclear genes and mitochondrial genes? Both are translated in the cytoplasm. Both follow the same genetic code. Both utilize ribosomes that are structurally identical. Both use a nucleotide triplet to encode for an amino acid. None of the statements is the same for nuclear and mitochondrial genes.

Both use a nucleotide triplet to encode for an amino acid.

Under hot, dry conditions, it is better to grow C4 plants like corn than it is to grow potatoes, which are considered C3 plants. What is one of the fundamental differences between C3 and C4 plants? C3 plants do not use photosystems for photosynthesis. C3 plants use rubisco to fix carbon. C3 plants in high CO2 conditions are much more efficient at photosynthesis. C3 plants do not utilize the Calvin cycle. C3 plants can undergo photorespiration without fixing carbon.

C3 plants can undergo photorespiration without fixing carbon.

The presence of two photosystems PSI and PSII, able to work together to greatly increase the rate of photosynthesis compared with either system by itself, is referred to as the _____ effect. Kreb Dole Warburg Emerson Calvin

Emerson

The redox state in specific regions of the chloroplast regulates the activity of numerous enzymes involved in photosynthesis. In the light, these enzymes are active, whereas in the dark, they remain inactive thereby conserving ATP. Thioredoxin (Tx) plays an integral role in maintaining the redox state of these proteins. Which statement pertaining to Tx is FALSE? In the dark, Tx has a disulfide bond. In the light, Tx is in its reduced form. In the light, Tx accepts electrons directly from PSI. In the dark, Tx is in its oxidized form. All of the statements are false.

In the light, Tx accepts electrons directly from PSI.

The overall efficiency of electron transport is facilitated by cardiolipin. Which statement pertaining to cardiolipin is FALSE? It is present in mitochondria. It is a type of diphosphatidyl glycerol. It plays a role in the assembly of electron transport supercomplexes. It is only found in cardiac tissue. It is a phospholipid.

It is only found in cardiac tissue.

The overall efficiency of electron transport is facilitated by cardiolipin. Which statement pertaining to cardiolipin is FALSE? It is present in mitochondria. It is only found in cardiac tissue. It is a type of diphosphatidyl glycerol. It plays a role in the assembly of electron transport supercomplexes. It is a phospholipid.

It is only found in cardiac tissue.

In plants, cyclic electron flow differs from linear electron flow in that it produces no: ATP. NADPH. water. All of the answers are correct. None of the answers is correct.

NADPH.

What happens in the mitochondrion during the second stage of glucose oxidation? The proton-motive force drives the production of ATP. Pyruvate is oxidized to CO2. Electrons flow from NADH and FADH2 to O2. Glucose is converted into pyruvate. All of the answers are correct.

Pyruvate is oxidized to CO2.

Which statement MOST accurately defines the endosymbiont hypothesis? The endosymbiont hypothesis describes how bacteria evolved into eukaryotes. The endosymbiont hypothesis explains why mitochondria and chloroplast have non-nuclear DNA. The endosymbiont hypothesis is the basis for how organelles evolved. The endosymbiont hypothesis explains how all symbiotic cells interact. The endosymbiont hypothesis states that before the acquisition of the prokaryotic cell (which would become the mitochondria or chloroplast), the primitive eukaryotic cell was unable to generate energy on its own.

The endosymbiont hypothesis explains why mitochondria and chloroplast have non-nuclear DNA.

Which statement does NOT pertain to mitochondria? They are the major source of ATP production in eukaryotic cells. They are the site of aerobic respiration. They are found in bacteria. Ribosomes inside are involved in protein synthesis. They have their own DNA.

They are found in bacteria.

Mitochondria generally have to import all of the following gene products EXCEPT: DNA polymerase. RNA polymerase. rRNA. They generally import none of these. Actually, they have to import all of these.

They generally import none of these.

Functional components of the ATP synthase include all of the following EXCEPT: the c ring, which holds multiple protons. a proton channel. a fixed stalk that connects the rotating c ring to hexamer. the hexameric unit that produces ATP by conformational changes. Actually, all of these are components of the ATP synthase.

a fixed stalk that connects the rotating c ring to hexamer.

In brown fat, thermogenin: converts the proton-motive force to heat. makes the inner mitochondrial membrane permeable to protons. uses ATP to produce heat. both converts the proton-motive force to heat and makes the inner mitochondrial membrane permeable to protons. both makes the inner mitochondrial membrane permeable to protons and uses ATP to produce heat.

both converts the proton-motive force to heat and makes the inner mitochondrial membrane permeable to protons.

Experiments to determine the number of protons moved during electron transport require: both purified electron-transport complexes and measurement of pH. both measurement of pH and an electric current. purified electron-transport complexes. an electric current. measurement of pH.

both purified electron-transport complexes and measurement of pH.

One drawback of mitochondrial electron transport is that, instead of water, it can produce: hydroxyl ions. both superoxide anion and hydrogen peroxide. hydrogen peroxide. both hydrogen peroxide and hydroxyl ions. superoxide anion.

both superoxide anion and hydrogen peroxide.

The surface area of the inner mitochondrial membrane is increased dramatically due to the presence of: porins. cristae. matrix proteins. villi. All of the answers are correct.

cristae.

Like the mitochondria, fatty acids are also oxidized in the peroxisome. The fundamental difference, however, is that unlike the mitochondria, this oxidation: does not require a fatty acyl CoA intermediate. preferentially relies on short-chain fatty acids. does not produce energy in the form of heat. does not produce ATP. All of the answers are correct.

does not produce ATP.

The fact that the mechanism of ATP synthesis is shared among prokaryotic and eukaryotic organisms and that primitive aerobic bacteria were probably the progenitors of mitochondria and chloroplasts lends support for the: endosymbiont hypothesis. Emerson hypothesis. De Materia Medica hypothesis. Warburg hypothesis. None of the answers is correct.

endosymbiont hypothesis.

In animal cells, which multiprotein complex is NOT associated with the movement of electrons for proton pumping? succinate-CoQ reductase cytochrome c oxidase ferredoxin-NADP+ reductase NADH-CoQ reductase CoQH2-cytochrome c reductase

ferredoxin-NADP+ reductase

Rubisco, one of the most abundant proteins on the planet, is involved primarily in: generating proton-motive force in PSI. ATP production in purple bacteria. absorption of photons. fixation of CO2 into carbohydrate precursors. None of the answers is correct.

fixation of CO2 into carbohydrate precursors.

There are two functionally different photosystems in plants, PSI and PSII. How many of the following statements are TRUE with regard to these photosystems? - PSI responds to light at wavelengths shorter than 700 nm. - PSII only responds to wavelengths shorter than 680 nm. - The protein composition in each PS differs. - Both PSI and PSII are localized to the thylakoid membrane. - Only PSI is involved electron flow. one two three four five

four

Rubisco is activated by all of the following EXCEPT: rubisco activase. high carbon dioxide levels. light. increased acidity. Actually, it is activated by all of these.

increased acidity.

Which pairs do NOT belong together? chemiosmotic coupling and proton-motive force peroxisome and β-oxidation thylakoid and chloroplast mitochondria and granum F0F1 complex and ATP synthase

mitochondria and granum

Which pairs do NOT belong together? mitochondria and granum thylakoid and chloroplast F0F1 complex and ATP synthase chemiosmotic coupling and proton-motive force peroxisome and β-oxidation

mitochondria and granum

Which of the following is produced during photoelectron transport, the primary event of photosynthesis, in plants, but NOT in purple bacteria? molecular oxygen. separation of charge. a strong oxidizing agent. a strong reducing agent. Actually, all of these are produced in both.

molecular oxygen.

ATP in glycolysis is: produced by both substrate level phosphorylation and oxidative phosphorylation. produced by substrate level phosphorylation and used to initiate the breakdown of sugar. produced by oxidative phosphorylation. used to initiate the breakdown of sugar. produced by substrate level phosphorylation.

produced by substrate level phosphorylation and used to initiate the breakdown of sugar.

To prevent the damage caused by ROS, the plant uses its _____ to quench the levels of 1O2, which would otherwise shut down ATP production. starch β-carotene chlorophyll a D1 polypeptide None of the answers is correct.

β-carotene