Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biochem 2 > Gluconeogenesis (midterm) > Flashcards

Gluconeogenesis (midterm) Flashcards

1
Q

Gluconeogenesis is creating new glucose from….

A

non-carbs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the 5 substrates for gluconeogenesis?

A

1) glucogenic AAs
2) glycerol
3) pyruvate
4) lactate
5) intermediates of TCA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Which AAs are glucogenic?

A

ALL standard AAs EXCEPT lysine and leucine (so theres 18 glucogenic AAs)

this means these AAs can change to glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Muscles that are breaking down for protein is a major substrate for gluconeogenesis. Which muscles breakdown first?

A

skeletal muscles that are not used or infrequently used are broken down to get glucogenic AAs for gluconeogenesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How are the intermediates from TCA cycle used in gluconeogenesis?

A

Glucogenic AAs (everything besides lys and leu) can have the amino group removed and become an intermediate for TCA, which will then allow it to become glucose

ex: aspartate can change to OAA and then go through malate shuttle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How long does glycerol last and where is it found?

A

12 hours and is found in fats/TG

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

T/F: you get lactate from RBCs if you don’t exercise, and if you do exercise then lactate also comes from skeletal muscle

A

true

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Is this an oxidation reaction or reduction reaction?

pyruvate to lactate with LDH

A

reduction reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Is this an oxidation reaction or reduction reaction?

lactate to pyruvate with LDH

A

oxidation reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Glycogen is in the _____________ of liver. It can change to blood glucose

A

cytoplasm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

where does gluconeogenesis occur?

A

in mitochondria and cytoplasm of liver

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Which 2 enzymes are used in both glycogenolysis and and gluconeogenesis?

A

G6Pase and F1,6BPase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

There are 3 rate limiting steps in glycolysis. So in gluconeogenesis, it has to bypass all 3 rate limiting steps/enzymes. What are the 3 steps of glycolysis and RLEs?

A

step 1 of glycolysis with GK or HK

step 3 with PFK1

step 10 with pyruvate kinase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is required in gluconeogenesis to make 1 glucose?

A

-2 pyruvate
-6 ATP
-2 NADH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is gluconeogenesis stimulated by?

A

-glucagon
-hypoglycemia
-fasting

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

T/F: gluconeogenesis is essentially the glycolytic pathway in reverse

A

true

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are the 4 key enzymes in gluconeogenesis?

A

1) pyruvate carboxylase
2) PEP carboxykinase
3) F1,6BPase
4) G6Pase

all other enzymes are the same as in glycolysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Is gluconeogenesis an anabolic or catabolic reaction?

A

anabolic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What pathways are most commonly involved in gluconeogenesis?

A

reverse glycolysis and TCA

20
Q

Which enzyme is only found in liver mitochondria and is why gluconeogenesis is in both mitochondria and cytoplasm?

A

pyruvate carboxylase

21
Q

First bypass of gluconeogenesis is 2 steps. What is the first step?

A

Pyruvate gets converted to OAA with pyruvate carboxylase (ABC enzyme)

note: this step requires biotin, 2 ATP, and carbon dioxide

22
Q

First bypass of gluconeogenesis is 2 steps. What is the second step?

A

OAA gets converted to PEP with PEP CK

note: 2 GTP is required and the reaction will release carbon dioxide

23
Q

Pyruvate has 2 ways to enter the TCA. What are they?

A

1) convert to acetyl CoA with pyruvate dehydrogenase (glycolysis/TCA)
2) convert to OAA with pyruvate carboxylase (gluconeogenesis)

24
Q

Where is PEP CK located?

A

in both cytoplasm and mitochondria

25
Q

Is PEP a VIP molecule?

A

yes

26
Q

2 pyruvate are used to make one glucose. What energy sources are needed to do this?

A

6 ATP (4 ATP, 2 GTP) and 2 NADH will be used to convert 2 pyruvate to 1 glucose

27
Q

2 glycerol 3 phosphates are used to make one glucose. What energy source is made?

A

2 NAD+

28
Q

2 lactates are converted to 2 pyruvate, which then makes 1 glucose. What energy is needed to do this?

A

lactate to pyruvate makes 2 NADH

pyruvate to glucose uses 6 ATP and 2 NADH

so the net energy LOSS is -6 ATP (was used)

29
Q

How much ATP is required for first bypass of gluconeogenesis?

A

2 ATP, 2 GTP (so 4 ATP)

30
Q

When cytosolic NADH levels are high, PEP is generated in the….

A

mitochondria

31
Q

What is the 2nd bypass of gluconeogenesis?

A

This reaction bypasses reaction 3 of glycolysis (catalyzed by PFK1)

32
Q

What is the 3rd bypass of gluconeogenesis?

A
33
Q

1 glucose makes 2 pyruvate. What energy sources are made?

A

2 ATP, 2 NADH

34
Q

To prevent the waste of a futile cycle, glycolysis and glucoenogenesis are….

A

reciprocally regulated

35
Q

At the first control point of glycolysis/ gluconeogenesis, If the energy demands of the cell are being met, the TCA cycle slows and __________ will accumulate

A

acetyl CoA

36
Q

High concentrations of acetyl coa inhibits _______ and activates _______

A

pyruvate dehydrogenase (PDH) and pyruvate kinase, pyruvate carboxylase (PC)

37
Q

What is the most important control step for gluconeogenesis?

A

2nd control step, to bypass PFK1 in glycolysis

this is done with F1,6 biphosphatase

this step is regulated by 2 mechanisms:
-indicators of cell energy demand
-hormones

38
Q

The second control step in gluconeogenesis is bypassing PFK1 with F1,6 BPtase. One of the mechanisms to regulate this is indicators of cell energy demand. What would elevated AMP do?

A

stimulate PFK1 but inhibit F1,6 BPtase

When ATP is low, AMP is high, the cell does not expand energy in synthesizing glucose

39
Q

The second control step in gluconeogenesis is bypassing PFK1 with F1,6 BPtase. One of the mechanisms to regulate this is indicators of cell energy demand. What would elevated ATP do?

A

inhibit PFK1, stimulate F 1,6 BPtase

when cellular ATP is high, AMP is low, glucose is not degraded to make ATP

40
Q

The second control step in gluconeogenesis is bypassing PFK1 with F1,6 BPtase. One of the mechanisms to regulate this is indicators of cell energy demand. What would elevated citrate do?

A

inhibit PFK1, stimulate F1,6 BPtase

41
Q

What 2 molecules inhibit PFK1 but stimulate F1,6 BPtase?

A

high ATP and citrate levels

42
Q

What hormones enhance gluconeogenesis by removing the inhibitory effects of F2,6 BP?

A

glucagon or epi

43
Q

When insulin increases, what 2 pathways are stimulated and 2 inhibited?

A

stimulated= glucogenesis and glycolysis

inhibited= glycogenolysis and gluconeogenesis

44
Q

When glucagon increases, what 2 pathways are stimulated and 2 inhibited?

A

stimulated= glycogenolysis and gluconeogenesis

inhibited= glucogenesis and glycolysis

45
Q

When ATP increases, what 2 pathways are stimulated and 2 inhibited?

A

stimulated= glucogenesis and gluconeogenesis

inhibited= glycogenolysis and glycolysis

46
Q

When ADP/AMP increases, what 2 pathways are stimulated and 2 inhibited?

A

stimulated= glycogenolysis and glycolysis

inhibited= glucogenesis and gluconeogenesis

47
Q

Glucagon and insulin will always overpower…

A

ATP and ADP

Biochem 2 (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions