FOM 3.2.1

Question 1

Where in the cell does the TCA cycle occur? ___________

Answer 1

Mitochondria

Question 2

What does “TCA” in the TCA cycle stand for? ___________

Answer 2

TriCarboxylic Acid

Question 3

What is another common name for the TCA cycle? ___________

Answer 3

The citric acid cycle

Question 4

In what area of the mitochondria does the TCA cycle occur? ___________

Answer 4

In the matrix

Question 5

Name the two membranes that make up the mitochondria? ___________ and ___________

Answer 5

Outer and Inner membrane

Question 6

In what area of the mitochondria does β-oxidation occur? ___________

Answer 6

In the matrix

Question 7

The acetyl-CoA that enters the TCA cycle can come from oxidation of both ______ and _____ from the diet.

Answer 7

Fatty acids and sugars

Question 8

The mitochondrial pyruvate transporter transports pyruvate produced by glycolysis into the mitochondria. The mitochonrial pyruvate transporter residues on the _______ membrane of the ___(cellular organelle)______.

Answer 8

Inner, mitochondria

Question 9

The pyruvate dehydrogenase complex is localized in the _______ of the cell.

Answer 9

matrix of the mitochondria

Question 10

The pyruvate dehydrogenase complex converts ______ into ________.

Answer 10

pyruvate, acetyl-CoA

Question 11

True or false: With regards to oxidation of acetyl-CoA, we can summarize the TCA cycle as a fancy way to accomplish a very challenging chemical problem, primarily the cleavage of the bond between two carbons in a molecule with only two carbons.

Answer 11

True

Question 12

Propionyl-CoA is produced from the oxidation of ______. Propionyl-CoA is converted to ________, which can enter the TCA cycle for further oxidation.

Answer 12

odd chain fatty acids, succinyl-CoA

Question 13

True or false: Oxidation of the carbon skeletons of several amino acids involves the TCA cycle.

Answer 13

True

Question 14

Before acetyl-CoA can enter the TCA cycle, there must be some ___(chemical)____ present to initiate the reaction.

Answer 14

oxaloacetate

Question 15

The _(inclusive name)______ reactions are those that provide TCA intermediates if needed. These produce either __(chemical A)_____ or _(chemical B_______. The former reacts with acetyl-CoA. The latter can be converted to the former by __(enzyme)_______.

Answer 15

anaplerotic,
oxaloacetate or malate,
malate dehydrogenase

Question 16

True or false: The metabolism of odd chain fatty acids and amino acids can both produce the oxaloacetate necessary for acetyl-CoA to enter the TCA cycle.

Answer 16

True

Question 17

The oxidation-hydration-oxidation reaction series that converts succinate into oxaloacetate is the same reaction series that occurs in _(pathway)____.

Answer 17

Beta-oxidation

Question 18

Products of the TCA cycle include ____, _____, ____, and _______.

Answer 18

CO2, GTP, FADH2, NADH

Question 19

True or false: oxaloacetate can be used as a substrate for gluconeogenesis to build glucose.

Answer 19

True

Question 20

True or false: If blood glucose is low, then fatty acids can be oxidized to acetyl-CoA, acetyl-CoA can be converted to oxaloacetate, and oxaloacetate can then be converted to glucose.

Answer 20

False

Question 21

True or false: Even though there is no net flux of carbon from even chain fatty acids to glucose, if radioactive carbon were present in a fatty acid, that radio activity could wind up in a glucose molecule after metabolism in our bodies.

Answer 21

True

Question 22

True or false: Breathing is required for anaerobic metabolism.

Answer 22

False

Question 23

True or false: The flow of electrons in the electron transport chain is from NADH to complex I to complex II to coenzyme Q to complex III to complex IV to O2.

Answer 23

False

Question 24

The electron transport chain is located in the _________ of the mitochondria.

Answer 24

Inner membrane

Question 25

The _________shuttle and the _________ shuttle are two systems to shuttle electrons from cytosolic NADH from the cytosol into the mitochondria. However, each shuttle results uses unique compounds as acceptors of those electrons inside the mitochondria.

Answer 25

malate-aspartate,

glycerophosphate

Question 26

True or false: The glycerophosphate shuttle results in NADH inside the mitochondria.

Answer 26

False

Question 27

In addition to H2O and NAD+, the other “product” of the electron transport chain is probably better described as a condition than a chemical product. This “product” is the ___________.

Answer 27

proton gradient accros the inner mitochondrial membrane

Question 28

Proteins in the electron transport chain involve a large number of cofactors. The type of cofactor that is targeted by azide poisoning is a ________.

Answer 28

Heme

Question 29

The enzyme that uses the proton gradient to generate ATP is _______.

Answer 29

ATPase or F0F1-ATPase

Question 30

True or false: Releasing the proton gradient using a mechanism that does not produce ATP has a minimal consequence on health.

Answer 30

False

Question 31

Where does pyruvate dehydrogenase reside in the mitochondria?

Answer 31

Matrix

Question 32

How does pyruvate make its way into the matrix of the mitochondria?

Answer 32

It readily diffuses through the outer membrane and requires MPC to pass through the inner membrane

Question 33

What are two ways that Acetyl-CoA can be derived?

Answer 33

Glycolysis in the cytosol, beta-oxidation within the mitochondria

Question 34

What is the 3-carbon molecule derived from odd chain beta-oxidation?

Answer 34

Succinyl-CoA

Question 35

How oxaloacetate generated within the cell?

Answer 35

PEP (PEP carboxylase)
Pyruvate (Pyruvate carboxylase)
Pyruvate (Malic enzyme) -> L-Malate (NAD+ -> NADH)

Question 36

What type of reaction is Thiamine (coenzyme form) used for?

Answer 36

Cleavage of C-C bond

Question 37

Riboflavin and Niacin are used in what type of reactions?

Answer 37

Oxidation-Reduction

Question 38

What molecule is converted to PEP (phosphoenol-pyruvate) by PEPCK during gluconeogenesis?

Answer 38

Oxaloacetate

Question 39

Is there a net flux of C from acetyl-CoA to PEP?

Answer 39

No!!! Fats are broken down into acetyl-CoA, which isn’t fed into the gluconeogenesis pathway.

Question 40

What cannot be converted to sugars?

Answer 40

Fats

Question 41

Which three complexes of the four complex ETC pump H+’s and how many?

Answer 41

Complex 1: 4 H+
Complex 3: 2 H+
Complex 4: 2 H+

Question 42

What are the two ways the electrons carried by cytosolic NADH can enter the mitrochondria?

Answer 42

malate-aspartate shuttle,

glycerophosphate shuttle

Question 43

What are the prosthetic groups in the redox centers of these protein complexes?
NADH dehydrogenase
Succinate dehydrogenase
Cytochrome bc1
Cytochrome oxidase

Answer 43

NADH dehydrogenase: Fe
Succinate dehydrogenase: Fe
Cytochrome bc1: heme
Cytochrome oxidase: heme

Question 44

2,4-dinitrophenol (DNP) is an uncoupler. How does this affect the mitochondia?

Answer 44

As an uncoupler, DNP allows H+ to flow freely across the inner membrane destroying the H+ in the matrix of the mitochondria, which prevents ATP from being synthesized.

Question 45

Sodium azide poisoning disrupts the heme of the final cytochrome in the ETC. How might this affect the mitochondira? Energy production? Digestive pathways?

Answer 45

By disrupting the final cytochrome, the ETC chain can no longer pass e-‘s down the chain. This prevents their function haulting energy prod. Additionally, NADH can no longer dissociate creating an imbalance that will slow and possibly even stop the TCA. By slowing/stopping the citric acid cycle, there will be a build of pyruvate that may enter alternate pathways.