Chapter 9: Cellular Respiration (MasteringBiology- Pearson)

NADH and pyruvate

In addition to ATP, what are the end products of glycolysis?

pyruvate ... NADH

In fermentation _____ is reduced and _____ is oxidized.

one

Starting with one molecule of isocitrate and ending with fumarate, how many ATP molecules can be made through substrate-level phosphorylation (see the figure)?

100%

Substrate-level phosphorylation accounts for approximately what percentage of the ATP formed by the reactions of glycolysis?

ATP levels would fall at first, decreasing the inhibition of PFK and increasing the rate of ATP production

Suppose that a cell's demand for ATP suddenly exceeds its supply of ATP from cellular respiration. Which statement correctly describes how this increased demand would lead to an increased rate of ATP production?

oxygen

What molecule is indicated by the letter D?

it is stored in NADH and FADH2

A glucose molecule is completely broken down to carbon dioxide and water in glycolysis and the citric acid cycle, but together these two processes yield only a few molecules of ATP. What happened to most of the energy that the cell obtains from the oxidation of glucose?

has an increased chemical potential energy; it is primed to do cellular work

A molecule that is phosphorylated _____.

his mitochondria lack the transport protein that moves pyruvate across the outer mitochondrial membrane

A young animal has never had much energy. He is brought to a veterinarian for help and is sent to the animal hospital for some tests. There they discover his mitochondria can use only fatty acids and amino acids for respiration, and his cells produce more lactate than normal. Of the following, which is the best explanation of his condition?

What effect does the mutation have on the amount of ATP synthesized during cellular respiration?

ATP synthase is a key enzyme of mitochondrial energy conversion. Mitochondrial ATP synthase deficiency is due to a mutation in a gene important for the formation of a subunit in the ATP synthase complex. Scientists could use cells with this gene mutation to investigate which of the following questions?

is a facultative anaerobe

An organism is discovered that thrives both in the presence and absence of oxygen in the air. Curiously, the consumption of sugar increases as oxygen is removed from the organism's environment, even though the organism does not gain much weight. This organism _____.

ATP synthesis will decrease, and heat generation will increase

Brown fat cells produce a protein called thermogenin in their mitochondrial inner membrane. Thermogenin is a channel for facilitated transport of protons across the membrane. What will occur in the brown fat cells when they produce thermogenin?

all respiring cells, both prokaryotic and eukaryotic, using either oxygen or other electron acceptors

Chemiosmotic ATP synthesis (oxidative phosphorylation) occurs in _____.

molecular oxygen (O2)

During aerobic respiration, H2O is formed. Where does the oxygen atom for the formation of the water come from?

FADH2

During aerobic respiration, which of the following directly donates electrons to the electron transport chain at the lowest energy level?

mitochondrial matrix

During cellular respiration, acetyl CoA accumulates in which location?

glucose utilization would increase a lot

During strenuous exercise, anaerobic conditions can result if the cardiovascular system cannot supply oxygen fast enough to meet the demands of muscle cells. Assume that a muscle cell's demand for ATP under anaerobic conditions remains the same as it was under aerobic conditions. What would happen to the cell's rate of glucose utilization?

four

For each mole of glucose (C6H12O6) oxidized by cellular respiration, how many moles of CO2 are released in the citric acid cycle (see the figure)?

twelve

For each molecule of glucose that is metabolized by glycolysis and the citric acid cycle (see the figure), what is the total number of NADH + FADH2 molecules produced?

hydrogen, polar

Gaseous hydrogen burns in the presence of oxygen to form water: 2H2 + O2 → 2H2 O + energy Which molecule is oxidized and what kind of bond is formed?

two

How many NADH are produced by glycolysis?

two

How many carbon atoms are fed into the citric acid cycle as a result of the oxidation of one molecule of pyruvate?

six

How many oxygen molecules (O2) are required each time a molecule of glucose (C6H12O6) is completely oxidized to carbon dioxide and water via aerobic respiration?

-the basic function of fermentation is the regeneration of NAD+, which allows continued ATP production by glycolysis

Identify all correct statements about the basic function of fermentation. Select all that apply.

fourteen

If a cell is able to synthesize 30 ATP molecules for each molecule of glucose completely oxidized to carbon dioxide and water, approximately how many ATP molecules can the cell synthesize for each molecule of pyruvate oxidized to carbon dioxide and water?

a proton gradient across a membrane

In cellular respiration, the energy for most ATP synthesis is supplied by _____.

two

In glycolysis there is a net gain of _____ ATP.

substrate-level phosphorylation

In glycolysis, ATP molecules are produced by _____.

ATP

In glycolysis, what starts the process of glucose oxidation?

it increases the surface for oxidative phosphorylation

In liver cells, the inner mitochondrial membranes are about five times the area of the outer mitochondrial membranes. What purpose must this serve?

lactate and NAD+

In muscle cells, fermentation produces _____.

two ATP

In the absence of oxygen, what is the net gain of ATP for each glucose molecule that enters glycolysis?

substrate-level phosphorylation

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

glucose is consumed, and carbon dioxide is produced

In the combined processes of glycolysis and cellular respiration, what is consumed and what is produced?

acetyl CoA, NADH, H+, and CO2

In the presence of oxygen, the three-carbon compound pyruvate can be catabolized in the citric acid cycle. First, however, the pyruvate (1) loses a carbon, which is given off as a molecule of CO2, (2) is oxidized to form a two-carbon compound called acetate, and (3) is bonded to coenzyme A. These three steps result in the formation of ______.

carbon dioxide

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

form when one atom gives up one or more electrons to another atom. These bonds can form between a pair of atoms or between molecules and are the type of bond found in salts

Ionic Bond

during fermentation lactate levels increase, which indicates insufficient oxygen is reaching the muscles causing athletic performance to suffer

New biosensors, applied like a temporary tattoo to the skin, can alert serious athletes that they are about to "hit the wall" and find it difficult to continue exercising. These biosensors monitor lactate, a form of lactic acid, released in sweat during strenuous exercise. Which of the statements below is the best explanation of why athletes would need to monitor lactate levels?

a type of chemical bond where two atoms share a pair of electrons with each other

Nonpolar Covalent Bond

oxidize NADH to NAD+.

One function of both alcohol fermentation and lactic acid fermentation is to _____.

a type of chemical bond where a pair of electrons are unequally shared between two atoms

Polar Covalent Bond

a chemical reaction in which the oxidation states of atoms are changed. Any such reaction involves both a reduction and oxidation process

Redox Bond

in order for the cycle to continue, oxidized electron carriers must be available

Select the best explanation for why the eventual reoxidation of NADH and FADH2 is crucial for the continuation of the citric acid (Krebs) cycle.

2 NADH, 2 pyruvate, and 2 ATP

Starting with one molecule of glucose, the energy-containing products of glycolysis are _____.

the proton-motive force across the inner mitochondrial membrane

The direct energy source that drives ATP synthesis during respiratory oxidative phosphorylation in eukaryotic cells is _____.

water

The electrons stripped from glucose in cellular respiration end up in which compound?

NADH, FADH2, and O2

The figure shows the electron transport chain. Which of the following is the combination of substances that is initially added to the chain?

an endergonic reaction coupled to an exergonic process

The synthesis of ATP by oxidative phosphorylation, using the energy released by movement of protons across the membrane down their electrochemical gradient, is an example of _____.

true

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.

in the absence of oxygen, electron transport stops. NADH is no longer converted to NAD+, which is needed for the first three stages of cellular respiration

Under anaerobic conditions (a lack of oxygen), the conversion of pyruvate to acetyl CoA stops. Which statement is the correct explanation for this observation?

ionic

What kind of bond is formed when lithium and fluorine combine to form lithium fluoride?

the citric acid cycle

What process occurs within Box B?

oxidized

When a glucose molecule loses a hydrogen atom as the result of an oxidation-reduction reaction, the molecule becomes

creation of a proton-motive force

When hydrogen ions are pumped from the mitochondrial matrix across the inner membrane and into the intermembrane space, the result is the _____.

cytosol

Where does glycolysis take place in eukaryotic cells?

glycolysis, pyruvate oxidation, the citric acid cycle, and oxidative phosphorylation, using an electron acceptor other than oxygen

Which catabolic processes may have been used by cells on ancient Earth before free oxygen became available?

glycolysis

Which metabolic pathway is common to both cellular respiration and fermentation?

glucose

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

transforming the energy in glucose and related molecules in a chemical form that cells can use for work

Which of the following best describes the main purpose of the combined processes of glycolysis and cellular respiration?

it represents the first stage in the chemical oxidation of glucose by a cell

Which of the following describes the process of glycolysis?

each electron carrier alternates between being reduced and being oxidized

Which of the following most accurately describes what is happening along the electron transport chain in the figure?

glycolysis and fermentation

Which of the following occurs in the cytosol of a eukaryotic cell?

oxidative phosphorylation (chemiosmosis)

Which of the following produces the most ATP when glucose (C6H12O6) is completely oxidized to carbon dioxide (CO2) and water?

the chemiosmotic synthesis of ATP requires that the electron transport in the inner mitochondrial membrane be coupled to proton transport across the same membrane

Which of the following statements about the chemiosmotic synthesis of ATP is correct?

NADH and FADH2 donate their electrons to the chain

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

NAD+ is reduced to NADH during glycolysis, pyruvate oxidation, and the citric acid cycle

Which of the following statements describes NAD+?

C6H12O6 is oxidized and O2 is reduced

Which of the following statements describes the results of this reaction? C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + Energy

a hydrogen atom is transferred to the atom that loses an electron

Which of the following statements is not true of most cellular redox reactions?

oxygen holds electrons more tightly than hydrogen does, and the net charge is zero

Which of the following statements is true of the bonds in a water molecule?

acetyl CoA

Which of these enters the citric acid cycle?

FADH2

Which of these is NOT a product of glycolysis?

acetyl CoA

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

acetyl CoA

Which one of the following is formed by the removal of a carbon (as CO2) from a molecule of pyruvate?

the redox reactions of the electron transport chain are directly coupled to the movement of protons across a membrane

Which one of the following statements about the redox reactions of the electron transport chain is correct?

fermentation

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

electron transport and chemiosmosis

Which stage of glucose metabolism produces the most ATP?

the last reaction in the citric acid cycle produces a product that is a substrate for the first reaction of the citric acid cycle

Which statement about the citric acid cycle is correct?

glycolysis

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

electronegativity

Which term describes the degree to which an element attracts electrons?

anion and cation

Which terms describe two atoms when they form a bond in which electrons are completely transferred from one atom to the other?

They have a lot of electrons associated with hydrogen.

Why are carbohydrates and fats considered high energy foods?

electrons are being moved from atoms that have a lower affinity for electrons to atoms with a higher affinity for electrons

Why does the oxidation of organic compounds by molecular oxygen to produce CO2 and water release free energy?

it does not involve organelles or specialized structures, does not require oxygen, and is present in most organisms

Why is glycolysis considered to be one of the first metabolic pathways to have evolved?