BCHM 316 Chapter Notes - Chapter **15.2: Pyruvic Acid, Alanine, Gluconeogenesis

58 views6 pages

coppermosquito74

6 May 2018

School

Department

Course

Professor

For unlimited access to Textbook Notes, a Class+ subscription is required.

Anapleurotic Step

- A step involved in “filling up” or replenishing citric acid cycle intermediates

In a well-fed liver, we are getting glucose and fatty acid from the diet.

> The glucose can become pyruvate and then oxaloacetate via pyruvate carboxylase

> The glucose can also become pyruvate and then acetyl CoA

> Fatty acids can become acetyl-CoA via B-oxidation

Fatty acid B-oxidation produces acetyl-CoA, but not oxaloacetate.

In well-fed liver, glucose provides pyruvate to replenish oxaloacetate from citric acid cycle

to operate and burn acetyl- COA from fatty

acids

In starvation, there is no glucose/ fatty acids...

find more resources at oneclass.com

Unlock document

This preview shows pages 1-2 of the document.
Unlock all 6 pages and 3 million more documents.

Already have an account? Log in

Therefore, gluconeogenic precursors (lactate,

alanine, glycerol) are mobilized to generate

oxaloacetate.

Acetyl coA can be generated from fatty

acid that comes from adipose tissue or

from pyruvate from gluconeogenic

precursors.

Oxaloacetate is converted into glucose!

When we are fasting/starving, we

have low blood glucose -- so our

gluconeogenic precursors are

becoming oxaloacetate which

becomes glucose.

Our fatty acids and some of our

gluconeogenic precursors are still

becoming acetyl-CoA --- since we

have no oxaloacetate to combine

with acetyl-coA , we have a build up

of acetyl CoA

The role of liver pyruvate carboxylase during starvation

find more resources at oneclass.com

Unlock document

This preview shows pages 1-2 of the document.
Unlock all 6 pages and 3 million more documents.

Already have an account? Log in

Document Summary

A step involved in filling up or replenishing citric acid cycle intermediates. In a well-fed liver, we are getting glucose and fatty acid from the diet. > the glucose can become pyruvate and then oxaloacetate via pyruvate carboxylase. > the glucose can also become pyruvate and then acetyl coa. > fatty acids can become acetyl-coa via b-oxidation. Fatty acid b-oxidation produces acetyl-coa, but not oxaloacetate. In well-fed liver, glucose provides pyruvate to replenish oxaloacetate from citric acid cycle to operate and burn acetyl- coa from fatty acids. In starvation, there is no glucose/ fatty acids Therefore, gluconeogenic precursors (lactate, alanine, glycerol) are mobilized to generate oxaloacetate. Acetyl coa can be generated from fatty acid that comes from adipose tissue or from pyruvate from gluconeogenic precursors. When we are fasting/starving, we have low blood glucose -- so our gluconeogenic precursors are becoming oxaloacetate which becomes glucose.

Related Questions

1. Choose the TWO correct statements describing the citrate cycle.

	ATP is an indirect product of the citric acid cycle
	Acetyl CoA can increase the pool of citric acid cycle intermediates
	Fatty acids can increase the pool of citric acid cycle intermediates
	ADP inhibits Î±-ketoglutarate dehydrogenase
	The pool of mitochondrial oxaloacetate can be increased by pyruvate
	All enzymes of the citric acid cycle are found soluble and free in the mitochondrial matrix

2.Which molecule in the net reaction of the citrate cycle contributes to the inhibition of pyruvate dehydrogenase?

	NADH
	H⁺
	H₂O
	FAD

3. How would a high NADH to NAD⁺ ratio be expected to affect the pyruvate dehydrogenase reaction?

	The E1 subunit is phosphorylated by pyruvate dehydrogenase kinase, and the catalytic activity of pyruvate dehydrogenase decreases.
	The last step of the pyruvate dehydrogenase reaction is blocked, resulting in a decrease in activity.
	The pyruvate dehydrogenase phosphatase-1 enzyme would increase, resulting in pyruvate dehydrogenase activation at an accelerated rate.
	The pyruvate dehydrogenase kinase enzyme activity would increase, resulting in an increase in pyruvate dehydrogenase activity.

force times distance

Question 48

Soccer (assuming field player) is a sport which is 90% aerobic.

True

False

Question 50

Glucose is necessary for fatty acid oxidation because...

		its derivative, pyruvate, is condensated with carbonic acid to form oxaloacetate, which in turn is a necessary carbon compound in the citric acid cycle
		it is needed to convert fatty acids to fatty acyl-CoA which in turn is oxidized to acetyl CoA
		glucose is decarboxylated into cytochrome oxidase which is a necessary intermediate in the citric acid cycle
		its derivative, acetyl CoA, is condensated with carbonic acid to form lactase, which in turn is a necessary carbon compound in the citric acid cycle

Question 51

In aerobic ATP production, the role of oxygen is to...

		to keep the electron transport chain operational
		to accept electrons from the 3rd cytochrome and thereby oxidizing it so it can accept new electrons
		act as a oxidizing agent by accepting electrons from the electron transport chain and combining with hydrogen ions (protons)
		all of the above

Question 52

The primary purpose of the citric acid cycle is...

aerobic glycolysis

gluconeogenesis using lactate

the decarboxylation of carbon compounds to produce NADH.

the shuttling of hydrogen ions through the inner mitochondrial membrane

Question 55

Which of the following is the best predictor of marathon running performance?

	A.	Maximal rate of pyruvate oxidation
	B.	Maximal rate of lactate formation
	C.	Amount of adipose tissue triglycerides
	D.	Pre-race blood glucose concentration

emeraldfly517

16- When the body is deficient in oxaloacetate

a) acetyl CoA from the b-oxdiation pathway cannot enter the citric acid cycle

b) oxaloacetate is diverted to gluconeogenesis

c) acetyl CoA is diverted to form the ketone bodies

d) all of the above are true

e) none of the above

17- The synthesis of ketone bodies involves

a) synthesis of acetoacetyl-CoA by reversal of the thiolase reaction of fatty oxidation

b) synthesis of b-hydroxy-b-methylglutaryl-CoA (HMG-CoA)

c) cleavage of HMG-CoA to acetoacetate.

d) b-Hydroxybutyrate is produced by reduction of acetoacetate.

e) all of the above

18- Which of the statements about ketone body production is FALSE?

a) Ketone bodies are produced when there is more acetyl-CoA in the liver than can be oxidized in the citric acid cycle.

b) Ketone bodies production is not a normal process, and occurs only in diabetes or starvation

c) The ketone bodies produced in the body are the free acids and not the CoA esters.

d) When fatty acid oxidation in the liver is uncontrolled, ketone body production becomes excessive and life-threatening because these acidic compounds lower the pH of blood

e) When fatty acid oxidation

19- In which of the following ways can the 4-carbon compound acetoacetyl CoA produced in fatty acid degradation be further metabolized?

a) It can break down further to form acetyl CoA,

b) It can be converted to the ketone bodies

c) It can be used for synthesis of cholesterol and its many derivÂatives.

d) It can do all of the above

e) It can do none of the above

20- Acetyl CoA from the beta-oxidation pathway cannot enter the citric acid cycle in which of these circumstances?

a) periods of fasting

b) periods of starvation

c) diabetes

d) when the body is deficient in oxaloacetate

e) all of the above

taupemarten625

BCHM 316 Chapter Notes - Chapter **15.2: Pyruvic Acid, Alanine, Gluconeogenesis

Document Summary

Get access

Related Documents

BCHM 316 Lecture Notes - Lecture 1: Pentose Phosphate Pathway, Pyruvate Carboxylase, Glycogen Phosphorylase

Related Questions