intermediary metabolism 3- bioenergetics

Question 1

what is the product of anaerobic metabolism vs. aerobic metabolism?

Answer 1

anaerobic = glucose - pyruvate product

aerobic= glucose - CO2 and H2O product

Question 2

Describe the two ways ATP is produced

Answer 2

a) directly - substrate level phosphorylation
b) indirectly - oxidative phosphorylation - NADH and FADH2- act as carriers of energy in the form of ‘reducing power’ electrons

Question 3

how many ATP does one NADH or one FADH2 produce?

Answer 3

NADH = 3 ATP

FADH2= 2 ATP

Question 4

what is the end product of glycolysis?

Answer 4

pyruvate

Question 5

Pyruvate is converted to what molecule that enters the TCA cycle?

Answer 5

converted to acetyl CoA - which enters the TCA cycle

Question 6

1 glucose produces how much ATP max under aerobic metabolism?

Answer 6

38 ATP

Question 7

what cycle is responsible for the bulk of ATP production in oxidative metabolism?

Answer 7

the TCA cycle

Question 8

where does glycolysis occur?

the TCA cycle?

Answer 8

glycolysis= in the cytoplasm

TCA= mitochondrion

Question 9

where does the pyruvate transporter exist?

Answer 9

in the inner mitochondrial membrane

Question 10

where is pyruvate converted into acetyl - coA?

Answer 10

in the matrix

Question 11

What enzyme converts pyruvate into acetyl-CoA?

Answer 11

pyruvate dehydrogenase ocmplex (which contains 3 distinct enzymes)

Question 12

what regulates the activity of pyruvate dehydrogenase?

Answer 12

it is allosterically inhibited by Acetyl-CoA and NADH

Question 13

what is the advantage of the pyruvate dehyrogenase complex?

Answer 13

the complex (consisting of 3 distrinct enzymes) allows pyruvate to be converted to Acetyl CoA without releasing any of the intermediate molecules

Question 14

What occurs in pyruvate dehydrogenase deficiency?

Answer 14

pyruvate cannot be converted to Acetyl Co A - and it is insted converted to lactic -acid - even in the presecne of oxygen.

Symptoms of this include developmental defects, muscular spacticity, and early death

Question 15

What does arsenic poisoning effect?

Answer 15

arsenic poisoning -

arsenic is an inhibitor of enzymes that use lipoic-acid as a cofactor- therefore, it will inhibit pyruvate dehydrogenase - symptoms include neurological disturbances and death

Question 16

what four vitamins are essential for pyruvate dehydrogenase function?

Answer 16

1. panthotenic acid
2. niacin
3. riboflavin
4. thiamine

b/c these vitamins are required to synthesize CoA, NAD, FAD, and TPP

Question 17

what is the importance of the TCA cycle?

Answer 17

generation of NADH from NAD +

now the NADH is ‘loaded’ with electrons that it can use to make ATP

Question 18

Describe the reaction of alpha-ketoglutarate dehydrogenase

Answer 18

this is a complex that reduces NAD+ to NADH

by transforming alphaketoglutarate into succinyl coA

Question 19

Describe the reaction of succinate thiokinase

Answer 19

succinate thiokinase involves substrate level phosphorylation producing GTP

from the reaction converting succinyl CoA to succinate

Question 20

what enzyme generates FADH2?

Answer 20

Succinate Dehydrogenase

Question 23

What is the role of Fumarase?

Answer 23

it hydrates fumarate converting it to malate

Question 24

for each turn of the TCA cycle, how many NADH, FADH2, and GTP are produced?

Answer 24

3 NADH

1FADH2

1 GTP

Question 25

what is the rate limiting step of the TCA cycle?

Answer 25

isocitrate dehydrogenase

Question 26

What are the three key points of regulation in the TCA cycle?

Answer 26

• citrate synthase
• isocitrate dehydrogenase
• alphaketoglutarate dehydrogenase

Question 27

the TCA cycle is amphibolic… what does that mean?

Answer 27

it is involved in both anabolic and catabolic pathways