Mitochondrial Bioenergetics

Question 1

What are the different fates of pyruvate after glycolysis

Answer 1

Pyruvate can either be converted into lactate from anaerobic glycolysis(no oxygen)
Pyruvate can also be further used in the mitochondria to turn into acetal COA which can then enter the ica/ krebbs cycle

Question 2

What is the final step in the glycolytic pathway

Answer 2

The conversion of private into lactate through a redox reaction where pyruvate is reduced into lactate by lactate dehydrogenase

Question 3

What is regenerated when pyruvate is reduced into lactate? Where does this go?

Answer 3

NAD+ is regenerated to go back into the glycolytic pathway

Question 4

What is metabolic acidosis

Answer 4

This is when your body is using ATP faster than it is being generated and H+ is being produced

Question 5

What is the fate of lactate in the body

Answer 5

Lactate can be converted into glucose via gluconeogenesis in the liver after being generated in glycolysis

Question 6

What contains all the enzymes necessary for the krebbs cycle

Answer 6

Mitochondrial matrix

Question 7

Pyruvate dehydrogenase complex

Answer 7

Links the production of pyruvate in the cytoplasm with the krebbs cycle in the mitochondria
It is a large complex with 3 subunits and 5 cofactors

Question 8

What is an advantage of having a complex of enzymes

Answer 8

It allows for more coupling, leading to efficient reactions, helping with thermodynamics making the reactions more favorable

Question 9

Explain why the pyruvate dehydrogenase complex reaction has such a large negative delta G value

Answer 9

Going from pyruvate to acetal coa by PDC is highly favorable because CO2, one of the products is very stable and will leave quickly

Question 10

What are the products of the pdc reaction

Answer 10

Its main product is acetal COA from pyruvate through a redox decarboxylation with CO2 and NADH

Question 11

What are the main regulatory step of PDC

Answer 11

High energy by high acetal coa, ATP, and NADH will inhibit PDC
PTM like phosphorylation by Pd kinase will also inhibit PDC

Pd phosphates will dephosphorylate PDC activate it

Question 12

How ds NADH and acetal co A inhibit PDC

Answer 12

The two will stimulate Pd kinase

Question 13

What happens to PDC activity while muscles are at rest

Answer 13

Muscles at rest indicate a high energy situation so NADH and acetal COA will stimulate Pd kinase inhibiting PDC activity

Question 14

What happens to PDC activity when muscles are in use

Answer 14

The body is in a low energy state, so pyruvate and ADP inhibit Pd kinase (allosteric regulation) and calcium will trigger Pd phosphates stimulating PDC activity

Question 15

Describe the 3 regulatory steps of the PDC

Answer 15

1. Product inhibition by NADHand acetal coa on E2 and E3
2. PTM by Pd kinase (inhibit) and Pd phosphates (activation)
   3.allosteric control of pdkinaseby acetal COA, NADH, ADP, and calcium

Question 16

Why is acetylco A considered a funnel for metabolism fuel

Answer 16

Because all metabolites can be converted into acetal coa

Question 17

What is the TCA cycle

Answer 17

This cycle follows the breakdown of fuel molecules to ATP production through oxidative phosphorylation

Question 18

In the TCA cycle, where does the FADH move to after being generated from succinate dehydrogenase

Answer 18

It will move to complex 2 of the etc

Question 19

What are the regulatory steps for TCA

Answer 19

Activation: low energy and calcium, nad+, and fad+
Inhibition: High energy,nadh, FADH

Question 20

Fill in the blank.
TCA cycle is considered a _____________pathway TCA

Answer 20

Amphibolic meaning it has both catabolic and anabolic pathways

Question 21

What metabolites can be used to make acetal coa in the ICA

Answer 21

Sugars, pyruvate, glucose, fatty acids and amino acids