Brainscape's Knowledge GenomeTM

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


See full index

Biochem > Glycolysis > Flashcards

Glycolysis Flashcards

0
Q

True commitment step

Primary regulatory site

A

6-phosphofructo-1-kinase (PFK1)

Fructose 6-phosphate->Fructose 1,6-bisphosphate (ATP->ADP)

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

Enzyme that traps glucose in the cell

A

Hexokinase

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

Hexokinase

A

Mg2+ is a cofactors, bound to ATP commits glucose to metabolic pathway, traps glucose in cell

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

Aldolase

A

Fructose 1,6-biphosphate->dihydroxyacetone phosphate (DHAP) + glyceraldehyde 3-phosphate (GAP)

Convert DHAP ->GAP via triose phosphate isomerase

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

1st substrate level phosphorylation:
Coupled rxns/enzymes
Common intermediate

A

Coupled rxns/enzymes:

1) glyceraldehyde 3-phosphate dehydrogenase
2) 3-phosphoglycerate kinase

Intermediate: 1,3 bisphosphoglycerate

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

Production of 2,3 BPG

A

Erythrocytes have another mutase that converts 1,3-biphosphoglycerate->2,3 BPG

Biphosphoglycerate mutase

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

2nd substrate level phosphorylation
Coupled rxns/enzymes
Common intermediate

A

Coupled rxns/enzymes

1) Enolase
2) Pyruvate Kinase

Intermediate: phosphoenolpyruvate (PEP)

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

Why is ATP production decreased in PK deficiency?

A

PK catalyzes one of the ATP-producing rxns of glycolysis (2nd substrate level phosphorylation)

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

Why might ATP synthesis from glyceraldehyde-3-phosphate dehydrogenase/3-phosphoglycerate kinase be inhibited by PK deficiency?

A

No PK->Pyruvate can’t be produced->no way in the RBC to re-ox NADH generated in the glyceraldehyde-3-phosphate dehydrogenase rxn because they lack mitochondria, thus can’t generate 1,3-biphosphoglycerate

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

Why are RBC especially vulnerable to the reduction in ATP from glycolysis?

A

RBC lack mitochondria->Pyruvate is reduced to lactate (anaerobic glycolysis) which enters plasma
RBC unable to completely oxidized glucose to CO2+H2O, and so are dependent on glycolysis for ATP production

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

In PK deficiency, levels of 2,3-BPG may increase three-fold. Why?

A 
Build up in substrate makes minor pathways into major ones
PK->buildup of PEP
Reversible rxns going backwards:
Enolase
Phosphoglycerate mutase
3-
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

10 enzymes of aerobic glycolysis

A 
Hexokinase
Phosphoglucose isomerase
PFK-1
Aldolase
Triose phosphate isomerase
Glyceraldehyde 3-phosphate dehydrogenase
3-phosphoglycerate kinase
Phosphoglycerate mutase
Enolase
Pyruvate kinase*
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Enzyme special to anaerobic tissue glycolysis.

What does it do?

A

Lactate dehydrogenase
Reduces: Pyruvate->lactate
Oxidizes: NADH->NAD
Anaerobic tissues lack mitochondria, thus need different way of re-oxidizing NADH to continue the cycle

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

Pyruvate Kinase Deficiency

A

Not really a deficiency->mutation
Increased Km=lower affinity for its substrate PEP
Premature hemolysis of RBC’s: hemolytic anemia
Amish-auto recessive
Most common enzymopathy of glycolysis

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

Enzymes that catalyze irreversible reactions

A

Hexokinase
PFK-1/6 phosphofructo-1-kinase
Pyruvate kinase

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

PFK-1

A

3rd step
2nd irreversible, true commitment step of glycolysis, primary regulatory site
Fructose 6 phosphate-> fructose 1,6-bisphosphate uses one ATP

16
Q

Dehydroxyacetone Phosphate

A

DHAP
Produced w/GAP from fructose 1,6-bisphosphate by aldolase
Not used in glycolysis
Need triose phosphate isomerase to convert DHAP->GAP

17
Q

Pyruvate Kinase

A

Last irreversible rxn of aerobic glycolysis

PEP->Pyruvate+ATP

18
Q

Substrate and Products for aldolase

A

Substrate:fructose 1,6-bisphosphate

Products : DHAP(ketose) & GAP(aldose)

19
Q

Oxidation of 1 mol glucose to lactate generates a net of _ ATP

A

2 ATP

20
Q

Substrate level phosphorylation

A

SLP

synthesis of ATP via 2 coupled reactions involves a high-energy common intermediate

21
Q

Enzyme that generates NADH

A

Glyceraldehyde 3 phosphate dehydrogenase
(1st SLP)
GAP-> 1,3 bisphosphoglycerate

22
Q

What happens to NADH in aerobic conditions?

A

NADH is oxidized by a substrate such as oxaloacetate, whose reduced form (malate) can be transported across a mitochondrial membrane

23
Q

In glycolysis one mole of orthophosphate (Pi) is consumed in a reaction catalyzed by what enzyme?

A

Glyceraldehyde 3-phosphate
Reduces NAD to NADH
First enzyme in first SLP
GAP -> 1,3 bisphosphoglycerate

24
Q

Enzyme that uses ATP

A

1) Hexokinase
Cosubstrate ATP, Mg2+ is a cofactor bound to ATP
Irreversible, traps glucose as glucose 6-phosphate
2) PFK-1
Irreversible, true commitment step, primary regulatory step
Fructose 6 phosphate + ATP -> fructose 1,6 bisphosphate + ADP

Biochem (13 decks)

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