Mastering Biology Chapter 9

Which of these enters the citric acid cycle?

Acetyl CoA

Which of these is NOT a product of glycolysis?

FADH2

Which of the following correctly pairs the process with its inputs and outputs?

Pyruvate processing-Inputs: pyruvate, NAD+; Outputs: acetyl CoA, NADH, CO2

In glycolysis, ATP molecules are produced by _____.

substrate-level phosphorylation

What stage of cellular respiration is also part of fermentation?

glycolysis

What molecules belong in spaces E and F?

carbon dioxide and water

Which step of the cellular respiration pathway can take place in the absence of oxygen?

glycolysis

Alfred has drawn a flow chart to show a time sequence of four processes of cellular respiration. Which sequence of three labels is the best choice to finish his model?

glycolysis / pyruvate processing / citric acid cycle

In cellular respiration, most ATP molecules are produced by _____.

oxidative phosphorylation

In mitochondrial electron transport, what is the direct role of O2?

to function as the final electron acceptor in the electron transport chain

True or false? The potential energy in an ATP molecule is derived mainly from its three phosphate groups.

true

True or false? The reactions that generate the largest amounts of ATP during cellular respiration take place in the mitochondria.

true

For each molecule of glucose processed during glycolysis, the net yield is ____.

two molecules of NADH, two of ATP, and two of pyruvate

Yuki has drawn a flow chart to track the major inputs and outputs in cellular respiration. Select the most suitable set of labels for the numbered arrows.

1. produces 2. produces pyruvate used in 3. transfers electrons to

Glycolysis is a series of ___ reactions that occurs in the _____ of cells.

10; cytoplasm

For each glucose that enters glycolysis, _____ acetyl CoA enter the citric acid cycle.

2

How many NADH are produced by glycolysis?

2

In glycolysis there is a net gain of _____ ATP.

2

Maria has drawn a flow chart using stars to track electron carriers (NADH and FADH2) during cellular respiration, but she hasn't completed her model. If twelve electron carriers are delivered to the electron transport chain (ETC) per molecule of glucose, how many stars should she show being produced during glycolysis and pyruvate processing?

2 stars + 2 stars

David has drawn a flow chart to track the ATP inputs and outputs in cellular respiration per molecule of glucose entering glycolysis. According to David's model, how many ATP are gained overall?

29 ATP

For each glucose that enters glycolysis, _____ NADH + H+ are produced by the citric acid cycle.

6

In glycolysis, what starts the process of glucose oxidation?

ATP

At the end of cellular respiration, protons flow through a protein called ATP synthase, which drives the formation of __________________.

ATP from ADP and inorganic phosphate

What does the chemiosmotic hypothesis claim?

ATP is generated using a proton-motive force that is produced by the electron transport chain.

Structure A is _____.

ATP synthase

How would anaerobic conditions (when no O2O2 is present) affect the rate of electron transport and ATPATP production during oxidative phosphorylation? (Note that you should not consider the effect on ATPATP synthesis in glycolysis or the citric acid cycle.)

Both electron transport and ATPATP synthesis would stop.

Which of the below is the general reaction for cellular respiration?

C6H12O2 + 6 O2 → 6 CO2 + 6H2O + Energy

What molecule is produced in the citric acid cycle as a by-product of glucose oxidation and is considered a waste product?

Carbon dioxide

Which stage of glucose metabolism produces the most ATP?

Electron transport and chemiosmosis

Cellular respiration produces more lactate per mole of glucose than fermentation.

False

Cellular respiration produces more pyruvate per mole of glucose than fermentation.

False

The missing label for the bottom pair of arrows should be "Electron transport chain."

False

The model shows that the number of carbons decreases over time.

False

Why would fermentation alone not be sufficient to keep your cells alive?

Fermentation has a much lower yield of ATP than the ETC.

Which statement best explains why more ATP is made per molecule of NADHNADH than per molecule of FADH2?

Fewer protons are pumped across the inner mitochondrial membrane when FADH2 is the electron donor than when NADH is the electron donor.

What molecules belong in space A and B?

Glucose and oxygen

What process occurs in Box A?

Glycolysis

What is the correct sequence of steps in cellular respiration, starting with glucose?

Glycolysis, pyruvate processing, citric acid cycle, electron transport, oxidative phosphorylation

Where does the citric acid cycle occur in eukaryotes?

In the matrix of mitochondria

Which of the following correctly describe the fermentation pathway?

It includes a reaction that reduces NAD+ to NADH.

In the oxidation of pyruvate to acetyl CoA, one carbon atom is released as CO2. However, the oxidation of the remaining two carbon atoms—in acetate—to CO2 requires a complex, eight-step pathway—the citric acid cycle. Consider four possible explanations for why the last two carbons in acetate are converted to CO2 in a complex cyclic pathway rather than through a simple, linear reaction.

It is easier to remove electrons and produce CO2 from compounds with three or more carbon atoms than from a two-carbon compound such as acetyl CoA.

Pyruvate, a three-carbon molecule, is processed into acetyl CoA, a two-carbon molecule. What happened to the missing carbon?

It is lost as carbon dioxide (CO2)

What purpose does fermentation serve?

It regenerates NAD+ from NADH to keep glycolysis going in the absence of oxygen.

5. _________ is the compound that functions as the electron acceptor in glycolysis.

NAD+

6. The reduced form of the electron acceptor in glycolysis is _________ .

NADH

After glucose is fully oxidized by glycolysis, pyruvate processing, and the citric acid cycle, where is most of its energy stored?

NADH

Based on the data in this graph, which high-energy molecules produced during glucose oxidation would you expect to carry the highest amount of chemical energy?

NADH

Which of the following products of cellular respiration would accumulate if there were no final electron acceptor in the electron transport chain (ETC)?

NADH

During electron transport, energy from _____ is used to pump hydrogen ions into the _____.

NADH and FADH2 ... intermembrane space

Which of the following statements about the electron transport chain is true?

NADH and FADH2 donate their electrons to the chain.

What molecule is indicated by the letter D?

Oxygen (O2)

What process occurs in Box B?

The citric acid cycle

Early estimates suggested that the oxidation of glucose via aerobic respiration would produce 38 ATP. Why do biologists now think this amount of ATP per molecule of glucose is not achieved in cells?

The proton-motive force is used in other transport steps, and there is loss of energy due to inefficiency in the system reducing the ATP yield

How would an increase in ATP affect the rate of glycolysis?

The rate would slow down as ATP binds to the regulatory site, lowering phosphofructokinase activity.

During the citric acid cycle FADH2 and NADH are produced. What purpose do these molecules serve in the electron transport chain (ETC)?

They serve as electron donors in the ETC.

Both the red circles and the orange circles represent carbons.

True

Cellular respiration produces more ATP per mole of glucose than fermentation.

True

Cellular respiration produces more CO2 per mole of glucose than fermentation.

True

Cellular respiration produces more NADH per mole of glucose than fermentation.

True

Each pyruvate molecule yields one 2-carbon acetyl CoA and one CO2.

True

The horizontal lines represent covalent bonds between carbons.

True

The orange circles represent the carbons in CO2.

True

Which of these is NOT a product of the citric acid cycle?

acetyl CoA

Into which molecule are all the carbon atoms in glucose ultimately incorporated during cellular respiration?

carbon dioxide

Which process is not part of the cellular respiration pathway that produces large amounts of ATP in a cell?

fermentation

3. In glycolysis, the carbon-containing compound that functions as the electron donor is _______.

glucose

Which molecule is metabolized in a cell to produce energy "currency" in the form of ATP?

glucose

In eukaryotes, the components of citric acid cycling and the electron transport chain are located in the ____.

inner mitochondrial membrane

The proximate (immediate) source of energy for oxidative phosphorylation is _____.

kinetic energy that is released as hydrogen ions diffuse down their concentration gradient

In muscle cells, fermentation produces _____.

lactate and NAD+

What organelle is indicated by the Letter C?

mitochondrion

1. When a compound donates (loses) electrons, that compound becomes _______. Such a compound is often referred to as an electron donor.

oxidized

The final electron acceptor of cellular respiration is _____.

oxygen

What process occurs in structure H?

photosynthesis

4. Once the electron donor in glycolysis gives up its electrons, it is oxidized to a compound called _______ .

pyruvate

In fermentation _____ is reduced and _____ is oxidized.

pyruvate ... NADH

Among the products of glycolysis, which compounds contain energy that can be used by other biological reactions?

pyruvate, ATP, and NADH

2. When a compound accepts (gains) electrons, that compound becomes ______. Such a compound is often referred to as an electron acceptor.

reduced

In the citric acid cycle, ATP molecules are produced by _____.

substrate-level phosphorylation