mastering bio chapter 6

The function of cellular respiration is to __________.

extract usable energy from glucose

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

What is the role of oxygen in cellular respiration?

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

acteria have no membrane-enclosed organelles. However, some still generate ATP through cellular respiration. Where might the electron transport chain be found in these organisms?

Plasma membrane

In glycolysis, what starts the process of glucose breakdown?

Pyruvate

Which statement describes the citric acid cycle?

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

Which statement describes glycolysis?

This process uses energy captured from electrons flowing to oxygen to produce most of the ATPs in cellular respiration.

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.

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

Besides sugars and fats, organisms can use other molecules as fuel for cellular respiration. When protein molecules are used, __________ are produced as waste.

amino groups

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

In muscle cells, fermentation produces _____.

lactate and NAD+

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

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

loses ... oxygen gains

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

loses electrons and becomes oxidized

A molecule is oxidized when it __________.

loses one or more electrons

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

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

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 ATPmolecules are produced during _____.

the Citric Acid cycle ... electron transport

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

the Citric Acid cycleand the electron transport chain

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

the citric acid cycle

For each glucose that enters glycolysis, _____ NADH enter the electron transport chain.

10

How many NADH are produced by glycolysis?

2

In glycolysis there is a net gain of _____ ATP.

2

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

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

2 ATP, 6 NADH, 2 FADH2

Substrate-level phosphorylation directly generates ATP during a chemical reaction. As a single molecule of glucose is completely oxidized in the presence of oxygen, what is the net yield of molecules of ATP made by substrate-level phosphorylation?

4 ATP

In cellular respiration, which of the following outcomes is the result of electrons moving through the electron transport chain (or its components)?

A proton gradient is formed.

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.

What happens to the energy that is released by electrons as they move through the electron transport chain?

It pumps H+ through a membrane.

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

NAD+

What molecule releases the electrons used in the electron transport chain?

NADH

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

NADH and FADH2 ... intermembrane space

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

NADH; NAD+

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+

Why is the citric acid cycle called a cycle?

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.

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

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

electrons

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

Glycolysis is the multi-step breakdown of _____. Several different _____ play a role in this process.

glucose ... enzymes

In the equation for cellular respiration shown below, __________ is oxidized, and __________ is reduced.

glucose ... oxygen

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

glycolysis

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

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

A chemist has discovered a drug that blocks phosphoglucoisomerase, an enzyme that catalyzes the second reaction in glycolysis. He wants to use the drug to treat people with bacterial infections. However, he can't do this because __________.

human cells also perform glycolysis; the drug might also poison them

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

hydrogen atoms

Aerobic cellular respiration completely breaks down a glucose molecule through glycolysis and the citric acid cycle. However, these two processes yield only a few ATPs. The majority of the energy the cell derived from glucose is __________.

in NADH and FADH2

Unlike the Citric Acid cycle and electron transport, glycolysis occurs _____.

in the cytoplasm

Where does glycolysis occur in a eukaryotic cell?

in the cytosol

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, most 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

The final electron acceptor of cellular respiration is _____.

oxygen

Cellular respiration requires fuel (glucose) and oxygen gas. The main process that produces these inputs is _____.

photosynthesis

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

recycle NADH through fermentation

Glycolysis is the only stage of cellular respiration that __________.

requires ATP to make ATP

A small amount of ATP is made in glycolysis by __________.

substrate-level phosphorylation

In glycolysis, ATP molecules are produced by _____.

substrate-level phosphorylation

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

substrate-level phosphorylation

Sunlight is essential for the varied life on Earth. Sunlight provides energy to photosynthetic organisms by providing __________.

the energy necessary to power the rearrangement of chemical bonds in H2O and CO2 to make organic molecules such as glucose

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

the mitochondrion

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

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) perFADH 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 synthase turbines and produce ATP.

What is/are the most important output(s) of glycolysis?

two pyruvic acid and two NADH molecules

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