Cellular Respiration

The antibiotic oligomycin works by inhibiting ATP synthase. You would expect that

H+ will accumulate in the intermembrane space.

The mitochondrial cristae are an adaptation that

increases the space for more copies of the electron transport chain and ATP synthase complexes.

During glycolysis, a molecule of glucose is partially oxidized. What is the net gain of ATP and NADH for each glucose molecule during this chemical pathway?

2 ATP and 2 NADH Submit

Most bats are inactive during the day (this is known as torpor) and feed during the night. The graph below shows hypothetical data for a bat species.

A by-product of cellular respiration is heat. Submit

What is the correct general equation for cellular respiration?

C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + ATP energy Submit

Which of the following best describes the electron transport chain?

Electrons pass from one carrier to another, releasing a little energy at each step. (NADH and FADH2 deliver electrons from the breakdown products of glycolysis and the citric acid cycle to the electron transport chain, which passes these electrons from one molecule to another, releasing a small amount of energy at each step)

In the absence of oxygen, cells need a way to regenerate which compound?

NAD+

As shown below, an electron carrier, such as __________, acts as an energy-storage molecule when it is __________.

NADH ... reduced

At the end of the citric acid cycle, most of the energy remaining from the original glucose is stored in

NADH.

During fermentation, __________ that was produced during glycolysis is converted back to __________.

NADH; NAD+

Consider the figure below. __________ is to a mitochondrion as __________ is to a chloroplast.

O2 ... CO2 (Cellular respiration utilizes O2, and photosynthesis utilizes CO2.)

What is the ultimate fate of the electrons that are stripped from glucose during cellular respiration?

They are used to form water. (At the end of the electron transport chain, the electrons and hydrogen ions are used to reduce oxygen to form water.)

Which statement describes the citric acid cycle?

This process produces some ATP and carbon dioxide in the mitochondrion. (The citric acid cycle breaks down carbon molecules, releasing carbon dioxide and forming some ATP.)

Which statement describes glycolysis?

This process splits glucose in half and produces 2 ATPs for each glucose. (In glycolysis, glucose is split into two molecules of pyruvic acid. The released energy is stored in ATP and the electron carrier NADH.)

Which statement describes the electron transport chain?

This process uses energy captured from electrons flowing to oxygen to produce most of the ATPs in cellular respiration. (In the electron transport chain, electrons move from one electron carrier to another, eventually reaching oxygen. The released energy is used to make ATPs.)

Which of the following processes produces the most ATP per molecule of glucose oxidized?

aerobic respiration

A small amount of ATP is made in glycolysis _____.

by the transfer of a phosphate group from a fragment of glucose to ADP (substrate-level phosphorylation) (Remember that, at the beginning of glycolysis, phosphate is added to glucose)

Which of the following is a result of glycolysis?

conversion of glucose to two three-carbon compounds

As a scientist employed by the FDA, you've been asked to sit on a panel to evaluate a pharmaceutical company's application for approval of a new weight loss drug called Fat Away. The company has submitted a report summarizing the results of their animal and human testing. In the report, it was noted that Fat Away works by affecting the electron transport chain. It decreases the synthesis of ATP by making the mitochondrial membrane permeable to H+, which allows H+ to leak from the intermembrane space to the mitochondrial matrix. This effect leads to weight loss Fat Away prevents ATP from being made by

eliminating the H+ gradient that allows ATP synthase to work.

Which of the following metabolic pathways is common in aerobic and anaerobic metabolism?

glycolysis

Which of the following processes takes place in the cytosol of a eukaryotic cell?

glycolysis (Glycolysis, the breakdown of glucose into two molecules of pyruvic acid, takes place in the cytosol, outside the mitochondria.)

Select the correct sequence of steps as energy is extracted from glucose during cellular respiration.

glycolysis → acetyl CoA → citric acid cycle → electron transport chain (Glycolysis produces pyruvic acid, which enters the mitochondrion. There, it is converted to acetyl CoA, which enters the citric acid cycle. Electron carriers bring electrons from the first three steps to the electron transport chain, and ATP is made.)

Where does glycolysis occur in a eukaryotic cell?

in the cytoplasmic fluid

When a car engine burns gasoline, the results of the reaction are similar to when cells burn glucose. Both reactions release carbon dioxide and water. In cells, the chemical energy in food is converted to ATP and heat. In a moving car, the chemical energy in gasoline is converted to __________.

kinetic energy and heat (About 25% of the energy released from the gasoline consumed by a car is converted to the kinetic energy of the moving car. The rest is given off as heat, which explains why car engines become so hot.)

Recent data presented in the Scientific Thinking module suggests that heat-generating brown fat is most active in __________.

lean people exposed to cold temperatures

In cellular respiration, glucose _____ electrons, whereas _____ electrons.

loses ... oxygen gains (During cellular respiration, glucose loses electrons and oxygen gains electrons. Oxidation and reduction always go together, as electron transfer requires both a donor and an acceptor.)

A molecule that functions as the electron donor in a redox reaction __________.

loses electrons and becomes oxidized

In what organelle would you find acetyl CoA formation, the citric acid cycle, and the electron transport chain?

mitochondrion (All of the steps of cellular respiration except glycolysis take place in the mitochondrion.)

Some friends are trying to make wine in their basement. They've added yeast to a sweet grape juice mixture and have allowed the yeast to grow. After several days they find that sugar levels in the grape juice have dropped, but there's no alcohol in the mixture. The most likely explanation is that the

mixture needs less oxygen because yeasts only produce alcohol in the absence of oxygen.

In the electron transport chain, the final electron acceptor is

oxygen

In oxidative phosphorylation, electrons are passed from one electron carrier to another. The energy released is used to __________.

pump protons (H+) across the mitochondrial membrane (The energy harvested from many redox reactions is used to power proton pumps that span the inner mitochondrial membrane.)

The end products of the citric acid cycle include all of the following except

pyruvate

A muscle cell deprived of molecular oxygen will convert glucose to lactic acid to __________.

recycle NADH through fermentation

Where do the reactions of the citric acid cycle occur in eukaryotic cells?

the mitochondrion (The citric acid cycle, which takes place in mitochondria, completes the degradation of glucose)

Rotenone is a poison commonly added to insecticides. Rotenone binds tightly with one of the electron carrier molecules in the electron transport chain, preventing electrons from passing to the next carrier molecule. Insects exposed to rotenone will die because

they will no longer be able to produce adequate amounts of ATP.