Bio Pre lab 6

During aerobic respiration, NADH delivers electrons to ______, and then ______ captures electrons at the end and joins with hydrogen to form water.

the electron transport chain; oxygen

Order the reactions in the citric acid cycle from the first step following condensation (on top), to the last (at the bottom).

1. Isomerization 2. The first oxidation 3. The second oxidation 4. Substrate-level phosphorylation 5. The third oxidation 6. Regeneration of oxaloacetate

Order the complexes in the electron transport chain from first (electrons enter) to last (electrons exit). Start at the top.

1. NADH dehydrogenase 2. The bc1 complex 3. The cytochrome oxidase complex

Place the events of the formation of ATP by ATP synthase in the order that they occur, beginning with the first event at the top.

1. Protons move across the membrane down their concentrations gradient. 2. The rotor and stalk structures rotate. 3. Mechanical energy changes the conformation of ATP synthase. 4. ATP formation is catalyzed.

A cell oxidizes an organic molecule producing 3 NADH molecules and 3 FADH2 molecules. How many ATPs (total) can be synthesized in the ETC from these molecules?

12

Select all of the following that are produced by one round of the Krebs cycle.

3 molecules of NADH 2 molecules of CO2

The number of ATP molecules generated per one molecule of glucose by aerobic respiration is ______ in prokaryotes and ______ in eukaryotes.

32; 30

What molecule enters the citric acid cycle and combines with oxaloacetate to form citric acid?

Acetyl-CoA

Select the molecules produced by the oxidation of pyruvate.

Acetyl-CoA NADH Carbon dioxide

Select the events that occur in the reaction that produces acetyl-CoA.

An acetyl group is attached to coenzyme A (CoA) NAD+ is reduced CO2 is removed from pyruvate

The P/O ratio takes into account the fact that, in the electron transport chain, there are Blank 1 protons pumped across the membrane per NADH Blank 2 and protons pumped across the membrane per FADH2.

Blank 1: 10 or ten Blank 2: 6 or six

Citrate synthase is inhibited by excess levels of Blank 1 and Blank 2.

Blank 1: ATP Blank 2: NADH

During oxidative phosphorylation, the enzyme Blank 1 Blank 2 uses energy stored in a proton gradient to phosphorylate ADP and make ATP.

Blank 1: ATP Blank 2: synthase

Blank 1-CoA enters the Krebs cycle and combines with oxaloacetate to form the 6-carbon molecule Blank 2 acid.

Blank 1: Acetyl Blank 2: tricarboxylic, citric, or citrate

The Blank 1 subunit of ATP synthase contains a channel through which protons move across the mitochondrial membrane down their concentration gradient.

Blank 1: F0

The final step of the Krebs cycle is the regeneration of oxaloacetate, which is produced when NAD+ is reduced to Blank 1.

Blank 1: NADH

The two electrons in Blank 1 can be used to synthesize 2.5 ATPs in the ETC.

Blank 1: NADH

When a carbon dioxide is removed from pyruvate, the product is a(n) Blank 1 group, which then attaches to coenzyme A.

Blank 1: acetyl

When a cell needs ATP, fatty acids are degraded to provide Blank 1-Blank 2 for the citric acid cycle.

Blank 1: acetyl Blank 2: CoA

During the process of Blank 1, energy stored in a proton gradient is used to synthesize ATP from ADP and Pi.

Blank 1: chemiosmosis

When ATP is in excess in cells, acetyl-CoA is used to produce Blank 1 Blank 2.

Blank 1: fatty Blank 2: acids

In eukaryotes, the electron transport chain occurs in the inner membranes of Blank 1.

Blank 1: mitochondria, mitochondrion, or the mitochondria

When electrons reach the end of the electron transport chain in mitochondria, the final electron acceptor is Blank 1.

Blank 1: oxygen, O, or O2

ATP is synthesized as Blank 1 flow down their concentration gradient through ATP synthase.

Blank 1: protons or H+

Excess levels of NADH prevent the enzyme, Blank 1 Blank 2 from catalyzing the conversion of pyruvate to acetyl-CoA.

Blank 1: pyruvate Blank 2: dehydrogenase

The flow of highly energetic electrons through the electron transport chain changes the Blank 1 of the pump proteins, which causes them to transport protons across the membrane.

Blank 1: shape or conformation

Which of these statements correctly indicate the location of pyruvate oxidation?

In eukaryotic cells, oxidation of pyruvate occurs in the mitochondria. In prokaryotic cells, oxidation of pyruvate occurs in the cytoplasm.

Energy stored in a proton gradient is used to synthesize ATP from ADP and Pi during what process in oxidative phosphorylation?

Chemiosmosis

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

Chemiosmosis

During formation of ATP by ATP synthase, rotation of the ______ causes a conformational change in the ______, which has the enzymatic activity.

F0 complex and stalk; F1 complex

Which of the following parts of ATP synthase is composed of the stalk and a knob?

F1

True or false: During aerobic respiration, the actual yield of ATP from a molecule of glucose is higher than the theoretical yield.

False

True or false: During aerobic respiration, the oxidation of pyruvate is coupled with the oxidation of NADH.

False

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

False

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

False

Select all of the following that are true statements describing one round of the Krebs cycle.

Four pairs of electrons are removed from four of the intermediates in the cycle. A 2-carbon group from acetyl-CoA enters the cycle. One molecule of ATP is produced.

Which molecule, produced via substrate level phosphorylation in the citric acid cycle, is used to make ATP during the sixth reaction of the Krebs cycle.

GTP

In the process of aerobic respiration, what molecule is entirely consumed?

Glucose

ATP is an allosteric inhibitor of the enzyme phosphofructokinase. As a result of this feedback mechanism, when levels of ATP are high, what process is directly inhibited?

Glycolysis

Select the main control points for the Krebs cycle.

Inhibition of pyruvate dehydrogenase by NADH Inhibition of citrate synthetase by ATP

How does the actual yield of ATP compare to the theoretical yield of ATP during aerobic respiration in mitochondria?

It is lower

Select the processes that need to occur in order to release all three carbon atoms from pyruvate (once it has been produced by glycolysis) in the form of carbon dioxide.

Krebs cycle acetyl-CoA production

In the electron transport chain, the electrons from FADH2 release which of the following?

Less energy than those of NADH

In eukaryotes, the remaining energy in pyruvate is extracted in which organelle?

Mitochondria

In eukaryotic cells, the oxidation of pyruvate produced from glycolysis takes place in what organelle?

Mitochondrion

During the oxidation of pyruvate, this molecule is reduced.

NAD+

Select the products yielded by the passage of glucose through glycolysis and the citric acid cycle.

NADH ATP CO2

In the electron transport chain, how do NADH and FADH2 donate their electrons?

NADH donates to NADH dehydrogenase; FADH2 donates to ubiquinone

The mitochondrial matrix has what charge compared with the intermembrane space?

Negative

During the second half of the Krebs cycle, succinate undergoes several reactions to become which compound?

Oxaloacetate

What molecule is regenerated in the final step of the citric acid cycle?

Oxaloacetate

Oxidative respiration is made possible by its final electron acceptor which is which of the following?

Oxygen

The calculation of the P/O ratio depends on the number of binding sites for ATP on ATP synthase and the number of which of the following?

Protons required for rotation

The F0 subportion of ATP synthase contains the membrane-bound complex, and the F1 subportion consists of which of the following?

Stalk and catalytic head

The product of the second segment of the citric acid cycle is a four carbon molecule called which of the following?

Succinate

The first step of the citric acid cycle involves which of the following?

The attachment of an acetyl group to oxaloacetate

Prior to being transferred to oxygen, the last site of electrons in the electron transport chain is which of the following?

The cytochrome oxidase complex

Select the carrier molecules that move electrons from complex to complex in the electron transport chain.

Ubiquinone Cytochrome c

Of the following choices, which are not products of the citric acid cycle?

acetyl-CoA FAD

The complex of enzymes that removes CO2 from pyruvate is called pyruvate ______.

dehydrogenase

During each step of the electron transport system, electrons move to a more electronegative carrier, and thus move

down an energy gradient.

Match each cell type with the location of pyruvate oxidation.

eukaryotes <-> mitochondria prokaryotes <-> cytoplasm

During the breakdown of 1 molecule of glucose by aerobic respiration, the predicted yield of ATP for prokaryotes is

higher than the predicted yield of ATP for eukaryotes.

The electron transport chain is composed of a series of membrane-associated

proteins

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

removes a CO2 from pyruvate

The electrons donated to the electron transport chain by NADH activate ______ proton pumps, while those donated by FADH2 activate ______ proton pumps.

three; two