BCH210H1 Lecture Notes - Lecture 31: Lactate Dehydrogenase, Pyruvate Decarboxylase, Alcohol Dehydrogenase

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amethystfly536

25 May 2018

School

UTSG

Department

Biochemical Engineering and Applied Chemistry

Course

BCH210H1

Professor

Stavroula Andreopoulos

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

Lecture 31: Anaerobic Metabolism and Gluconeogenesis

Lactate Dehydrogenase

• In the absence of oxygen, oxidative phosphorylation cannot occur in the

mitochondria and pyruvate is converted to lactate, replenishing NAD+

• NADH and FADH2 increase (build up) due to backing of ETC

- NADH can inhibit CREB steps

- Excess pyruvate will go into side reaction

• Pyruvate will use NADH to reduce pyruvate to form lactate

• NADH from CREB will be converted to NAD+ for glycolysis to make a little bit of energy

Anaerobic metabolism

• During periods of limited oxygen, anaerobic metabolism occurs

• Glycolysis is the only means of generating ATP (NADH cannot be used for energy)

• Lactate dehydrogenase depletes NADH levels so no ATP is made from NADHcyt. by oxidative phosphorylation

• This reaction does however, replenishes NAD+ for glycolysis to continue

• Glucose + 2 ADP + 2 Pi → 2 Lactate + 2 ATP + 2 H2O

Alcohol Fermentation in yeast

• Step 6 of glycolysis make

NADH

• Final step of glycolysis

make pyruvate

• In yeast, two consecutive

reactions produce CO2 and

ethanol and also replenish NAD+ for glycolysis

- Pyruvate decarboxylase instead of lactate dehydrogenase to produce acetaldehyde which is converted to

ethanol through alcohol dehydrogenase (makes NADH from glycolysis, oxidize to make NAD+ which can go

back into glycolysis for yeast to use glucose for breakdown to make ethanol

The many fates of pyruvate

• Pyruvate → lactate (when O2 is low)

• Fermentation to ethanol (anaerobic metabolism)

• Pyruvate → acetyl CoA (by PDC in mitrochondria)

• Pyruvate → oxaloacetate (for CREB to produce ATP)

Gluconeogenesis

• Need to have an alternate sources in addition to liver glycogen to supply glucose (limited)

• New carbon source must be accessible in the blood in significant supply (i.e. lactate, glycerol, alanine)

• The liver (and kidney) can convert lactate/pyruvate into glucose via gluconeogenesis

- 2 glycerol used to produce 1 glucose (due to 3 carbons present)

• Other non-carbohydrate precursors (glycerol, alanine) can be used

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BCH210H1 Full Course Notes

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Document Summary

In the absence of oxygen, oxidative phosphorylation cannot occur in the mitochondria and pyruvate is converted to lactate, replenishing nad: nadh and fadh2 increase (build up) due to backing of etc. Excess pyruvate will go into side reaction: pyruvate will use nadh to reduce pyruvate to form lactate, nadh from creb will be converted to nad+ for glycolysis to make a little bit of energy. Lactate dehydrogenase depletes nadh levels so no atp is made from nadhcyt. by oxidative phosphorylation. Alcohol fermentation in yeast: step 6 of glycolysis make. Nadh: final step of glycolysis make pyruvate. In yeast, two consecutive reactions produce co2 and ethanol and also replenish nad+ for glycolysis. The many fates of pyruvate: pyruvate lactate (when o2 is low, fermentation to ethanol (anaerobic metabolism, pyruvate acetyl coa (by pdc in mitrochondria, pyruvate oxaloacetate (for creb to produce atp)

Related Questions

QUESTION 1

Which of the following is the correct order of the three stages of cellular respiration?

	a.	Krebs cycle, glycolysis, electron transport
	b.	electron transport, glycolysis, Krebs cycle
	c.	Krebs cycle, electron transport, glycolysis
	d.	glycolysis, Krebs cycle, electron transport
	e.	electron transport, Krebs cycle, glycolysis

1 points

QUESTION 2

Consider a bacterial cell that performs anaerobic respiration. If that bacterial cell had access to six molecules of glucose to use, how many ATP molecules would it be able to produce?

	a.	2
	b.	34
	c.	36
	d.	6
	e.	12

1 points

QUESTION 3

The oxygen that organisms need to live is used exclusively in which of the following metabolic pathways?

	a.	Electron transport chain
	b.	Anaerobic respiration
	c.	Glycolysis
	d.	Krebs cycle
	e.	ATP-Synthase

1 points

QUESTION 4

The electron transport chain uses the energy in NADH and FADH₂ to pump H⁺ ions from the matrix to the innermembrane space. The H⁺ gradient is then used to power ATP-Synthase. Enough H⁺ is pumped from the energy in a molecule of NADH to produce ______ ATP molecules, while enough H⁺ is pumped from the energy in a FADH₂ molecule to produce ______ ATP molecules.

	a.	three; two
	b.	three; three
	c.	two; two
	d.	two; three

1 points

QUESTION 5

Which of the following list contains only products of cellular respiration?

	a.	glucose, oxygen, ADP
	b.	ATP, carbon dioxide
	c.	oxygen, ADP, carbon dioxide
	d.	ATP, glucose, oxygen
	e.	glucose, ATP

1 points

QUESTION 6

What powers the enzyme ATP-Synthase?

	a.	NADH molecules
	b.	oxygen (O₂)
	c.	ATP
	d.	NADH and FADH₂ molecules
	e.	The H⁺ gradient between the matrix and inner-membrane space

1 points

QUESTION 7

Organisms exist which are able to survive using only glycolysis (i.e. without using oxidative phosphorylation).

True

False

1 points

QUESTION 8

Each ADP molecule contains ________ phosphates, and each ATP molecule contains ________ phosphates.

	a.	three; three
	b.	two; two
	c.	one; two
	d.	two; three
	e.	one; three

1 points

QUESTION 9

Adding a phosphate group to ADP to form ATP is an endergonic reaction.

True

False

1 points

QUESTION 10

The majority of ATP produced during cellular respiration is produced during glycolysis.

True

False

1 points

QUESTION 11

Glycolysis occurs:

	a.	on enzymes located in the inner-membrane.
	b.	in the cytosol.
	c.	in the inner-membrane space.
	d.	in the nucleus of the cell.
	e.	in the matrix of mitochondria.

1 points

QUESTION 12

Muscle soreness associated with strenuous exercise is due to:

	a.	the production of alcohol during anaerobic respiration.
	b.	a buildup of lactic acid.
	c.	an excessive amount of ATP that builds up during exercise.
	d.	the large amounts of CO₂ building up in the muscle.

1 points

QUESTION 13

A required reactant for glycolysis is:

	a.	the electron transport chain.
	b.	carbon dioxide.
	c.	oxygen.
	d.	NAD+.
	e.	mitochondria.

1 points

QUESTION 14

NADH is produced in all of the following except:

	a.	the electron transport chain.
	b.	the Krebs cycle.
	c.	glycolysis.

Question 1 Organisms exist which are able to survive using only glycolysis (i.e. without using oxidative phosphorylation).
True
False

Question 2 Glycolysis occurs:
a. in the matrix of mitochondria.
b. in the inner-membrane space.
c. in the cytosol.
d. in the nucleus of the cell.
e. on enzymes located in the inner-membrane.

Question 3 Muscle soreness associated with strenuous exercise is due to:
a. the large amounts of CO2 building up in the muscle.
b. an excessive amount of ATP that builds up during exercise.
c. a buildup of lactic acid.
d. the production of alcohol during anaerobic respiration.

Question 4 Each ADP molecule contains ________ phosphates, and each ATP molecule contains ________ phosphates.
a. two; three
b. two; two
c. three; three
d. one; three
e. one; two

Question 5 The oxygen that organisms need to live is used exclusively in which of the following metabolic pathways?
a. Glycolysis
b. Electron transport chain
c. Krebs cycle
d. Anaerobic respiration
e. ATP-Synthase

Question 6 NADH is produced in all of the following except:
a. the electron transport chain.
b. glycolysis.
c. the Krebs cycle.

Question 7 Consider a bacterial cell that performs anaerobic respiration. If that bacterial cell had access to six molecules of glucose to use, how many ATP molecules would it be able to produce?
a. 36
b. 6
c. 12
d. 34
e. 2

Question 8 The majority of ATP produced during cellular respiration is produced during glycolysis.
True
False

Question 9 What powers the enzyme ATP-Synthase?
a. The H+ gradient between the matrix and inner-membrane space
b. ATP
c. oxygen (O2)
d. NADH molecules
e. NADH and FADH2 molecules

Question 10 Which of the following list contains only products of cellular respiration?
a. ATP, glucose, oxygen
b. ATP, carbon dioxide
c. oxygen, ADP, carbon dioxide
d. glucose, ATP
e. glucose, oxygen, ADP

Question 11 Adding a phosphate group to ADP to form ATP is an endergonic reaction. True False

Question 12 The electron transport chain uses the energy in NADH and FADH2 to pump H+ ions from the matrix to the innermembrane space. The H+ gradient is then used to power ATP-Synthase. Enough H+ is pumped from the energy in a molecule of NADH to produce ______ ATP molecules, while enough H+ is pumped from the energy in a FADH2 molecule to produce ______ ATP molecules.
a. two; three
b. three; three
c. three; two
d. two; two

Question 13 Which of the following is the correct order of the three stages of cellular respiration?
a. glycolysis, Krebs cycle, electron transport
b. Krebs cycle, electron transport, glycolysis
c. electron transport, Krebs cycle, glycolysis
d. electron transport, glycolysis, Krebs cycle
e. Krebs cycle, glycolysis, electron transport

Question 14 A required reactant for glycolysis is:
a. carbon dioxide.
b. mitochondria.
c. NAD+.
d. the electron transport chain.
e. oxygen.

maroonguinea-pig450

1. Plants need which of the following to carry on photosynthesis?

a. H2O

b. CO2

c. O2

d. both O2 and CO2

e. both H2O and CO2

2. Organisms that derive their chemical energy either from the process of chemosynthesis or photosynthesis are classified as

a. autotrophs.

b. parasites.

c. heterotrophs.

d. saprophytes.

e. mutualists.

3. The carbon source for organisms that derive their energy from photosynthesis is

a. carbon monoxide.

b. carbon dioxide.

c. hydrocarbons.

d. methane.

e. glucose.

4. The oxygen released in photosynthesis comes from

a. carbon dioxide.

b. glucose.

c. ribulose bisphosphate.

d. water.

5. When chlorophyll a molecules absorb energy, the molecules

a. release electrons.

b. release X-rays.

c. release energy.

d. release electrons and X-rays.

e. release electrons and energy.

6. The flow of what particle across the thylakoid membrane powers the production of ATP?

a. electrons

b. hydrogen ions

c. oxygen

d. carbon dioxide

e. phosphate ions 2

7. The light-independent reactions were discovered by

a. M. D. Hatch.

b. Andrew Benson.

c. Melvin Calvin.

d. Robert Hill.

e. both Andrew Benson and Melvin Calvin.

8. For each six atoms of carbon dioxide fixed in the light-independent reactions, how many molecules of PGAL (phosphoglyceraldehyde) are produced?

a. 2

b. 3

c. 6

d. 12

e. 15

Chapter 7

9. The ultimate source of energy for living things is

a. the Krebs cycle.

b. fossil fuels.

c. the sun.

d. glycolysis.

e. aerobic respiration.

10. When molecules are broken apart in respiration

a. the heat produced is used to drive biological reactions.

b. the oxygen in the compounds that are broken apart is used as an energy source.

c. the energy released in respiration is channeled into molecules of ATP.

d. ATP is converted into ADP.

e. ADP is released as a waste product.

11. ATP

a. can be produced by photosynthesis.

b. is produced in the degradation of organic compounds such as glucose.

c. is generated in anaerobic respiration.

d. is released in aerobic respiration.

e. all of these

12. Which part of the energy-releasing pathway can convert all carbon that enters to carbon dioxide?

a. fermentation

b. glycolysis

c. Krebs cycle

d. electron transport

e. phosphorylation

13. Which liberates the most energy in the form of ATP?

a. aerobic respiration

b. anaerobic respiration

c. alcoholic fermentation

d. lactate fermentation

e. All liberate the same amount, but through different means.

14. Aerobes use ________ as the final electron acceptor in electron transport phosphorylation.

a. hydrogen

b. carbon

c. oxygen

d. H2O 3

15. Glycolysis depends on a continuous supply of

a. NADP.

b. pyruvate.

c. NAD+.

d. NADH.

e. H2O.

16. Glycolysis

a. occurs in the mitochondria.

b. results in the production of pyruvate.

c. occurs in the cytoplasm.

d. occurs in the mitochondria and results in the production of pyruvate.

e. results in the production of pyruvate and occurs in the cytoplasm.

17. The end product(s) of glycolysis is(are)

a. acetyl CoA.

b. carbon dioxide.

c. pyruvate.

d. glucose.

e. glucose and carbon dioxide.

18. Which is capable of being reduced during both glycolysis and the Krebs cycle?

a. NAD+

b. FAD+

c. ADP

d. NADH

e. NADP+

19. The Krebs cycle takes place in the

a. ribosomes.

b. cytoplasm.

c. nucleus.

d. mitochondria.

e. chloroplasts.

20. The breakdown of pyruvate in the Krebs cycle results in the release of

a. energy.

b. carbon dioxide.

c. oxygen.

d. energy and oxygen.

e. energy and carbon dioxide.

ochremole959

BCH210H1 Lecture Notes - Lecture 31: Lactate Dehydrogenase, Pyruvate Decarboxylase, Alcohol Dehydrogenase

BCH210H1 Full Course Notes

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