BIO160 Chapter 7

Formation of ATP within the electron transport chain is catalyzed by the enzyme _ _?

ATP synthase

Some species of bacteria have evolved specialized enzymes that work like cytochrome c to pass electrons to molecules other than O2. This allows them to live in _ conditions

Anaerobic

Some organisms can metabolize organic molecules in the absence of oxygen by using a substance other than O2 as the final electron acceptor of an electron transport chain. This process is called ______

Anaerobic respiration

Fatty acids can be broken down to acetyl groups, which bind to CoA and enter ______

CAC

As a result of the reactions of the citric acid cycle, the carbons from acetyl CoA are released as:

CO2

Yeast cells can metabolize sugar under anaerobic conditions by breaking down pyruvate. Which of these are the end products of fermentation in yeast?

CO2, NAD+, ethanol

In yeast cells, fermentation regenerates NAD+ and produces which chemicals?

CO2, ethanol

The sources of high-energy electrons for oxidative phosphorylation include ______

NADH FADH2

The electron transport chain results in the oxidation of what energy intermediates produced in the earlier steps of cellular respiration?

NADH and FADH2

The high-energy electrons that are used for oxidative phosphorylation come from molecules of _ and _?

NADH and FADH2

What happens during the fermentation reactions that occur in muscle cells?

NADH is oxidized to NAD+ Pyruvate is reduced to lactate

Energy stored in a proton gradient is used to synthesize ATP from ADP and Pi during the process of _?

Chemiosmosis

The breakdown of pyruvate results in the production of acetyl-CoA, which then enters the _ _ cycle?

Citric Acid

When a muscle is working strenuously and becomes anaerobic, pyruvate from glycolysis is reduced to lactate to allow the oxidation of _ to _

NADH to NAD+

What type of pathway produces ATP by substrate-level phosphorylation without any net oxidation of organic molecules?

Fermentation

What energy intermediates are produced in the citric acid cycle?

NADH, GTP, FADH2

The component of the ETC that receives electrons from NADH is _ dehydrogenase, while _ reductase receives electrons from FADH2.

NADH, succinate

Bacterial species that live in anaerobic conditions can carry out anaerobic respiration using an electron transport chain that donates electrons to a molecule other than _

O2

What are the products of the breakdown of a single pyruvate molecule?

One NADH mol One CO2 One acetyl group

Glucose contains covalent bonds that store a large amount of ______

chemical energy

The use of energy stored in a proton gradient to drive the synthesis of ATP is called ______

chemiosmosis

A series of redox reactions makes up the _ transport chain

electron

In the electron transport chain, electrons are transferred to molecules with increasingly higher ______

electronegativity

During the first phase of glycolysis, ATP is hydrolyzed so that phosphate groups can be added to ______

glucose

ATP is an allosteric inhibitor of phosphofructokinase, so when levels of ATP are high, _____ is slowed

glycolysis

Organisms that can use only oxygen as a final electron acceptor can generate ATP via _ during anaerobic conditions

glycolysis

The process of glycolysis can take place ______

in the presence or absence of O2

During glycolysis, one molecule of _ is broken down into two molecules of _, driving the synthesis of ATP

glucose, pyruvate

During aerobic respiration, the final electron acceptor in the electron transport chain is:

oxygen

The purpose of the energy investment phase of glycolysis is to:

prime glucose for the exergonic reactions to follow

The hydrolysis of ATP early in glycolysis leads directly to ______

the phosphorylation of glucose

Each turn of the citric acid cycle produces:

1 FADH2, 3 NADH

The complete breakdown of glucose in the presence of oxygen yields 34 to 38 ATP molecules, but the breakdown of glucose to lactate or ethanol yields a net of only _ ATP mols

2

Which of the following serve as REACTANTS in the net reaction of glycolysis?

2 ADP2-, 2Pi2-, and 2 NAD+

Glycolysis is the breakdown of glucose into ______

2 pyruvate molecules

The net products of glycolysis are ______

2 pyruvate, 2 NADH, 2 H+, 2 ATP, and 2 H2O

Aerobic respiration yields ______ ATP molecules per glucose, while fermentation typically yields ______ ATP molecules per glucose

38-42; 2

In the first reaction of the citric acid cycle, oxaloacetate, which contains ______ carbons, is combined with acetyl-CoA, which contains ______ carbons in its acetyl group, to produce citric acid, which contains ______ carbons

4; 2; 6

Which of the following statements is true about all forms of anaerobic respiration?

A molecule other than O2 is used as the final electron acceptor.

During oxidative phosphorylation, ATP synthase adds a phosphate group to:

ADP

During oxidative phosphorylation, what enzyme produces ATP?

ATP synthase

Which of the following molecules are used as energy sources by living organisms?

Amino acids, sugars, fatty acids

Glycolysis is the pathway for glucose breakdown in which of the following?

Bacteria, archaea, and eukaryotes

What molecules become oxidized during oxidative phosphorylation?

FADH2, NADH

True or false: Glycolysis can only occur under aerobic conditions

FALSE

True or false: NADH and FADH2 donate electrons to the electron transport chain at the same point

FALSE

True or false: The flow of electrons through the electron transport chain requires an input of energy

FALSE

True or false: The matrix of the mitochondrion generally has a more positive charge than the intermembrane space

FALSE

True or false: The redox reactions of the electron transport chain transfer electrons from components with higher electronegativity to those with lower electronegativity

FALSE

Amino acids can be broken down or modified so that they can enter which pathways?

Glycolysis, CAC

As electrons travel through the electron transport chain, _ ions are pumped across the cristae into the space between the inner and outer mitochondrial membranes, from a low concentration to a high concentration

Hydrogen/protons

The energy that allows for the phosphorylation of ADP to produce ATP is provided by the flow of _ ions through ATP synthase

Hydrogen/protons

What happens to the acetyl-CoA that is produced from pyruvate?

It enters the CAC

In eukaryotic cells, pyruvate breakdown, the citric acid cycle, and oxidative phosphorylation occur in the:

Mitochondria

Due to the electron transport chain, the proton concentration is the lowest in the ______

Mitochondrial Matrix

In eukaryotic cells, which of the following metabolic pathways occur in the mitochondria?

Oxidative Phosphorylation Breakdown of pyruvate Citric Acid Cycle

What is the source of energy for the synthesis of ATP by the enzyme ATP synthase?

The flow of protons down their electrochemical gradient

What evidence suggests that glycolysis arose very early in the evolution of life?

The steps of glycolysis are found in bacteria and archaea as well as eukaryotes

Why are phosphate groups added to glucose during the first phase of glycolysis?

To RAISE its free energy so that later reactions are EXERGONIC

If an organism can use only O2 as a final electron acceptor, can it generate ATP under anaerobic conditions?

Yes, it can generate ATP through glycolysis

When a carbon dioxide is removed from pyruvate, the product is a(n) _ group, which then attaches to coenzyme A

acetyl

The breakdown of fatty acids results in the production of ______

acetyl-CoA

At high concentrations, ATP regulates the rate of glycolysis through ______

allosteric inhibition of phosphofructokinase

After a molecule of CO2 is removed from pyruvate, the remaining acetyl group is attached to ______

coenzyme A

Because the citric acid cycle regenerates one of the molecules that is necessary to start the reactions, it is considered ______

cyclical

Glycolysis occurs in the ______

cytosol

Pyruvate is oxidized to acetyl-CoA and CO2 by an enzyme called pyruvate _?

dehydrogenase

The flow of electrons through the electron transport chain is ______) (endergonic or exergonic)

exergonic

In eukaryotic cells, the electron transport chain is located in the ______

inner mitochondrial membrane

In eukaryotes, pyruvate dehydrogenase is a ______ enzyme that ______ pyruvate

mitochondrial, oxidizes

The energy released during the transfer of electrons in the electron transport chain is used to ______

pump protons across the inner mitochondrial membrane

The electron transport chain involves a series of ______ reactions

redox

During cellular respiration, acetyl-CoA is formed during a reaction that also:

removes CO2 from pyruvate

ATP synthase functions like a _

rotary machine

The structural components of the electron transport chain include which of the following?

small organic mols, protein complexes

What type of motion is coupled to the synthesis of ATP by the enzyme ATP synthase?

spinning

How is ATP produced during fermentation?

substrate-level phosphorylation