Exam 4 (set does not include cumulative material)

1 pyruvate = _________ ATP

12. 5

1 glucose = __________ ATP

32

2 pyruvate = _________ ATP (glycolysis)

25

1 Acetyl CoA = ________ ATP

10 (CAC)

1 NADH = ________ ATP

2.5

1 FADH2 = ________ ATP

1.5

What is the conversion of pyruvate to acetyl coA catalyzed by?

pyruvate dehydrogenase complex (PDH)

What three enzymes does the PDH complex use?

2 dehydrogenase, transferase

What is the main role of thiamine?

it is acidic and creates an electron sink

it is regenerated in the next step

Thiamine allows for _________ of the substrate.

decarboxylation

What is the main role of lipoic acid?

it is a prosthetic group and linked to LYS

very flexible

it is regenerated in the next step

Lipoic acid undergoes ___________ and _____________.

oxidation and reduction

What can lipoic acid transfer?

acyl groups

Is the conversion of pyruvate to acetyl CoA reversible or irreversible?

irreversible step in metabolism

What makes the conversion of pyruvate to acetyl CoA irreversible?

the loss of CO2

Can the body convert acetyl CoA to glucose?

NO

What is the major role of Coenzyme A?

it is a carrier of acyl groups

Enzymatic control for the conversion of pyruvate to acetyl coA involves?

product feedback ratios and reversible phosphorylation of a Ser

Increased [pyruvate] (the substrate) causes _____________ of the enzyme.

stimulation

Hormones and alpha-adrenergic agonists _________ the PDH complex by ________ Ca2+

stimulate, increasing

What is Ca2+ a signal for?

excitation-contraction coupling

Insulin ___________ the enzyme.

stimulates

Is the citric acid cycle reversible or irreversible?

irreversible

Step 1 of the CAC includes what enzyme?

synthase

Step 2 of the CAC includes what enzyme?

aconitase

Step 3 of the CAC includes what enzyme?

dehydrogenase

Step 4 of the CAC includes what enzyme?

dehydrogenase

Step 5 of the CAC includes what enzyme?

synthetase

Step 6 of the CAC includes what enzyme?

dehydrogenase

Step 7 of the CAC includes what enzyme?

fumarase

Step 8 of the CAC includes what enzyme?

dehydrogenase

Which steps of the CAC are irreversible?

1, 3, 4

What is the main purpose of step 2 in the CAC?

to allow the oxygen to be available for oxidation in the next step, and is also a set up step (No resources gained or lost)

What is lost and gained in step 3 in the CAC?

CO2 is lost (in ox/red reaction), NADH is gained

What is lost and gained in step 4 in the CAC?

CO2 is lost (in ox/red reaction), NADH is gained

What is the main purpose of steps 5-8 in the CAC?

to regenerate the oxaloacetate

What is regenerated in step 5 in the CAC?

CoA-SH

What does step 5 in the CAC require?

a Histidine

What is gained in step 5 in the CAC?

GTP, which can then be converted to ATP (through substrate level phosphorylation)

What is gained in step 6 in the CAC?

FADH2

What reaction is in step 7 in the CAC?

a reversible hydration/dehydration

this is a set up step, no resources are gained or lost

What is gained in step 8 in the CAC?

NADH

If we go through the CAC, 1 molecules of Acetyl CoA = _________ ATP?

10

What is the purpose of Anaplerotic Reactions?

to replenish CAC intermediates if they are low/diminished

What is the enzyme in Anaplerotic Reactions?

amino-transferase, which converts an amino acid to a keto acid

What are the three reactions that use an amino-transferase enzyme?

Alpha-ketoglutarate --> Glutamate

Oxaloacetate --> Asparate

Pyruvate --> Alanine

What is the role of biotin?

it is a carrier of CO2

ATP is required to add CO2 to biotin

Similar to lipoic acid, biotin is a prosthetic group that is covalently bound to ___________.

Lys

What is the type of enzyme that biotin uses?

carboxylase (adds a CO2)

What steps does enzymatic control involve for the CAC?

the three irreversible reactions (1, 3, and 4)

What is the CAC stimulated by?

1. increased concentrations of ADP (will signal that fuel sources are getting depleted)

2. calcium

What is the CAC inhibited by?

1. succinyl CoA

2. ATP and NADH

3. Citrate

What is the electromotive force in oxidative phosphorylation?

when electrons from NADH and FADH2 move through 4 multi-enzyme complexes

What is the goal of the electromotive force in oxidative phosphorylation?

to reduce O2 to H2O

Where does the electromotive force move protons?

from the mitochondrial matrix, across the inner mitochondrial member, to the inter-membrane space

What does the electromotive force create?

a gradient

The mitochondrial matrix is ____________ and the inter-membrane space is ____________.

negative, positive

What does the protomotive force do?

moves the protons back into the matrix through a protein channel

ATP is converted to what during the protomotive force?

ADP

What are the two major electron carriers of oxidative phosphorylation?

Ubiquinone and Cytochrome C

How many electrons does Ubiquinone carry?

2

How many electrons does Cytochrome C carry?

1

What is Cytochrome C?

a protein that can change oxidation states

What reactions do all 4 of the multi-enzyme complexes carry out?

oxidation/reduction

Where does NADH enter in the multi-enzyme complexes?

at complex I BUT does not use complex II

Where does FADH2 enter in the multi-enzyme complexes?

at complex II BUT does not use complex I

How many protons move across the membrane of complex I?

4

What is regenerated in complex I?

NADH --> NAD+

What is regenerated in complex II?

FADH2 --> FAD

How many protons move across the membrane of complex II?

NONE

How many protons move across the membrane of complex III?

4

Where do the electrons move from in complex III?

QH2 --> cyt c

How many electrons move across the membrane in complex IV?

2

What is formed in complex IV?

H2O

What is regenerated in complex IV?

cyt c molecules

What enzyme is ATP synthesis catalyzed by?

ATP synthase

What is F0?

the protein channel

What is F1?

the catalytic domain

How many protons are required to make the ATP during ATP synthesis?

3

What does the movement of ATP from the mitochondrial matrix to the cytosol require?

one additional proton

How many protons are required to move ATP from the matrix to the cytosol?

1

How many total protons are used during ATP synthesis?

4

For NADH, _________ H+ total move across the membrane.

10

For FADH2, ___________ H+ total move across the membrane.

6

What is the purpose of shuttles?

to move NADH made in step 6 of glycolysis into the matrix, which allows it to go into one of the complexes

During a shuttle, NADH exchanges its electrons and forms _____________.

FADH2, meaning that 4 less proteins are pumped across the membrane

By shuttle, glutamate is readily reversible with _____________.

Alpha-ketoglutarate

By shuttle, oxaloacetate is readily reversible with ______________.

aspartate

What enzyme do the shuttle reactions use?

amino-transferase

What does an amino-transferase convert?

an amino acid to a keto acid

What two molecules does an amino-transferase require?

carboxylase and lipase

What does a carboxylase do?

adds a carboxylic acid to a methyl group

What does carboxylase require?

biotin

What does a lipase do?

hydrolyzes a fatty acid from a triacylglycerol (frees the fatty acid)

How many double bonds does a saturated fatty acid have?

none

How many double bonds does a unsaturated fatty acid have?

at least 1

What is a monounsaturated fatty acid?

only has one double bond

What is a polyunsaturated fatty acid?

more than 1 double bond

Most naturally occurring fatty acids have?

an even # of C atoms

Double bonds are designated by _________ and are usually in ________ conformation.

a triangle, cis