Chapter 6 #4

The electron transport chain is a series of electron carrier molecules. In eukaryotes, where can this structure be found?

mitochondria

A scientist wants to study the enzymes of the citric acid cycle in eukaryotic cells. What part of the cell would she use as a source of these enzymes?

mitochondrial matrix

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

mitochondrion

Through respiration, humans breathe in O2 and breathe out CO2. However, what would happen if we did not breathe in O2?

We would not make enough ATP to meet our energy requirements

The function of coenzyme A in the citric acid cycle is most like

a limousine driver dropping off a couple at the school prom.

In the electron transport chain, the final electron acceptor is

an oxygen atom.

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

glycolysis → acetyl CoA → citric acid cycle → electron transport chain

To obtain energy from starch and glycogen, the body must begin by

hydrolyzing both starch and glycogen to glucose.

If you were able to stop the process of cellular respiration after completing electron transport but prior to chemiosmosis, you would find the pH of a mitochondrion to be at its lowest

in the intermembrane space.

In eukaryotes, most of the high-energy electrons released from glucose by cell respiration _____.

reduce NAD+ to NADH, which then delivers them to the electron transport chain

NADH is also used by cells when making certain molecules. Based on your knowledge of NADH's role in cellular respiration, what do you think NADH's role is in biosynthesis of molecules?

reducing molecules

Where does glycolysis occur in a eukaryotic cell?

in the cytoplasmic fluid

What is the role of oxygen in cellular respiration?

Oxygen accepts high-energy electrons after they are stripped from glucose.

Why is the citric acid cycle called a cycle?

Acetyl CoA binds to oxaloacetate and this compound is restored at the end of the cycle.

Which part(s) of cellular respiration take(s) place in the mitochondria?

All of the above.

What is the correct general equation for cellular respiration? C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + ATP energy

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

We inhale O2 and we exhale CO2. Carbon dioxide is produced _____.

In the reaction that creates acetyl CoA (coenzyme A) from pyruvate

The Pasteur effect shows that yeast consume glucose at a higher rate under anaerobic conditions than under aerobic conditions. Which of the following statements correctly explains this observation?

Less ATP is made under anaerobic conditions, so more glucose must be consumed to produce an equivalent amount of ATP.

Given the relatively modest number of calories burned by anything but the most vigorous activities, why can people consume over 2,000 kilocalories a day, yet maintain a healthy body weight?

Most of the energy consumed in food is spent maintaining the body's functions, so only a fraction of food energy needs to be burned in exercise.

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

NAD+

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+

In fermentation, ________ is ________.

NADH; oxidized

Which of the following statements regarding the movement of electrons during cellular respiration is true?

O2 is reduced when it accepts electrons and forms water.

When an organism such as a yeast lives by fermentation, it converts the pyruvate from glycolysis into a different compound, such as alcohol. Why doesn't it secrete the pyruvate directly?

The conversion is needed to regenerate the molecules needed for glycolysis.

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

They are used to form water.

NADH pills can be purchased over the counter and are often taken by sufferers of chronic fatigue syndrome (CFS). How might these pills benefit a CFS patient?

They would increase the number of electrons provided to the electron transport chain.

which statement describes the citric acid cycle?

This process produces some ATP and carbon dioxide in the mitochondrion.

Which statement describes glycolysis?

This process splits glucose in half and produces 2 ATPs for each glucose.

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 an experiment, mice were fed glucose (C6H12O6) containing a small amount of radioactive oxygen. The mice were closely monitored, and in a few minutes, radioactive oxygen atoms showed up in __________.

carbon dioxide

In nutrient-rich environments (like your mouth), bacteria can use the provided amino acids to synthesize their proteins. However, should the environmental conditions change and become nutrient-poor, bacteria would need to synthesize their amino acids. They can do this using __________.

citric acid cycle intermediates

If you consume 1 g of each of the following, which will yield the most ATP?

fat

During cellular respiration, glucose is oxidized. However, an intermediate __________ can be siphoned off and used to synthesize fats.

glyceraldehyde-3-phosphate

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

glycolysis

Sports physiologists at an Olympic training center want to monitor athletes to determine at what point their muscles begin to function anaerobically. They could do this by checking for a buildup of _____.

lactic acid

Question 10 Part A Oxidation is the ________, and reduction is the ________.

loss of electrons; gain of electrons

A mutant protist is found in which some mitochondria lack an inner mitochondrial membrane. Which of the following pathways would be completely disrupted in these mitochondria?

oxidative phosphorylation

Some human cells, such as nerve cells, are restricted to aerobic respiration to recycle NADH and FADH2. If these cells are deprived of oxygen, then _____.

oxidative phosphorylation would come to a halt because there wouldn't be any oxygen to "pull" the electrons down the transport chain

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

Cellular respiration accomplishes two major processes: (1) it breaks glucose down into smaller molecules, and (2) it harvests the chemical energy released and stores it in ATP molecules. By the end of _____, the breakdown of glucose is complete; most ATP molecules are produced during _____.

the Citric Acid cycle ... electron transport

Most NADH molecules generated during cellular respiration are produced during __________.

the citric acid cycle

The enzyme ATP synthase catalyzes the phosphorylation of ADP to form ATP. In eukaryotic cells, the energy needed for this endergonic reaction is derived from _____.

the movement of hydrogen ions across the mitochondrial membrane

As electrons move through the mitochondrial space,

the pH of the intermembrane space decreases.

The energy yield from the breakdown of a single molecule of glucose does not depend upon

the supply of carbon dioxide.

Oxidative phosphorylation could not occur without glycolysis and the citric acid cycle, because _____.

these two stages supply the electrons needed for the electron transport chain

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.

NADH and FADH 2 are important in cellular respiration because they deliver high-energy electrons to the electron transport system. Electron transport produces _____ ATP molecule(s) per NADH molecule and _____ ATP molecules(s) per FADH 2 molecule.

three ... two

In electron transport, high-energy electrons "fall" to oxygen through a series of reactions. The energy released is used to _____.

transport protons into the intermembrane space of the mitochondria, where they become concentrated. They then flow back out into the the inner compartment (matrix) of the mitochodria. On the way back, protons turn ATP

Fat is the most efficient molecule for long-term energy storage, even compared to carbohydrates, because _____.

with their numerous hydrogen atoms, fats provide an abundant source of high-energy electrons