chapter 6 biology

The O2 required for __________ is supplied by __________.

cellular respiration ... breathing

Each turn of the citric acid cycle processes one two-carbon acetyl molecule, which generates one ATP and ___ additional energy-rich molecules: __________.

four; 3 NADH and 1 FADH2

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

loses electrons and becomes reduced

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

the citric acid cycle

The electron transport chain is, in essence, a series of redox reactions that comprise the last stage of aerobic cellular respiration. During these redox reactions, __________.

NADH is reduced as it donates electrons to the first complex involved in the electron transport chain

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

NADH.

Which statement regardingphotosynthesis and cellular respiration is true?

Photosynthesis occurs in the chloroplasts, and cellular respiration occurs in mitochondria

What is the purpose of embedding the electron transport chain in the membrane of a cell?

The electron acceptors can transport H+ across the membrane, which is otherwise impermeable to H+.

Which process produces the most ATP per molecule of glucose oxidized?

aerobic respiration

In eukaryotes, most of the high-energy electrons extracted from glucose by cellular respiration __________.

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

Using the ATP generated during cellular respiration, the intermediates of glycolysis and the citric acid cycle, such as pyruvate and acetyl CoA, can be siphoned off and used to __________.

build amino acids, fats, and sugars

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

carbon dioxide

During the first step of a redox reaction, what does the enzyme dehydrogenase strip from organic fuel?

hydrogen atoms

Primarily, cellular respiration serves to __________.

make ATP to power the cell's activities

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

pump hydrogen ions (H+) across the mitochondrial membrane

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

recycle NADH through fermentation

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

recycle NADH through fermentation

In biological systems, an important enzyme involved in the regulation of redox reactions is

dehydrogenase.

Which of the following is the source of the energy that produces the chemiosmotic gradient in mitochondria?

electrons

Which metabolic pathway is common to aerobic and anaerobic metabolism?

glycolysis

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

reducing molecules

In glycolysis, ATP molecules are produced by _____.

substrate-level phosphorylation

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

the mitochondrion

Which organism can make organic molecules from water and carbon dioxide?

wheat

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

the movement of hydrogen ions across the mitochondrial membrane

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

In glycolysis there is a net gain of _____ ATP.

2

In glycolysis, what starts the process of glucose breakdown?

ATP

In the first stage of cellular respiration (glycolysis), two molecules of pyruvate are produced in the cytosol. In the remaining stages of cellular respiration, a number of additional products are produced, such as __________. These other stages occur in the __________.

ATP ... mitochondria

Which of the following best describes the electron transport chain?

Electrons are passed from one carrier to another, releasing a little energy at each step.

Which of these is NOT a product of glycolysis?

FADH2

The energy production per each glucose molecule through the citric acid cycle is __________.

The two-carbon acetyl group is transferred to the citric acid cycle utilizing Coenzyme A (CoA) where it binds to oxaloacetate, thereby regenerating citrate in cyclical fashion.

What is the ultimate destination of the electrons that are extracted from glucose during cellular respiration?

They are used during the formation of water.

How do cells capture the energy released by cellular respiration

They produce ATP.

Which of these enters the citric acid cycle (also called the Krebs cycle)?

acetyl CoA

The mitochondrial cristae are an adaptation that

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

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

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

loses ... oxygen gains

In the citric acid cycle (also called the Krebs cycle), ATP molecules are produced by _____.

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 serve as an electron acceptor at the transport chain

In the electron transport chain, the final electron acceptor is

oxygen

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