Brainscape's Knowledge GenomeTM

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


See full index

Biochem 102 > Glycolysis > Flashcards

Glycolysis Flashcards

1
Q

Glycolysis

A

Metabolic pathway converting glucose to pyruvate

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

Where does glycolysis occur?

A

Cytoplasm

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

Where is Glycolysis Used?

A

Used in all cells where glucose is broken down to provide ATP and intermediated for other pathways

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

Phases of GLycolysis

A

Stage 1: Energy Investment Phase (first 5 rxns)
Stage 2: Energy generation phase
(final 5 rxns)

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

Energy Investment Phase

A
  • Step 1 and 3 are regulatory steps; reguire ATP
  • 1 glucose has been oxidized to two G3P
  • 2 ATP are consumes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Energy Generation Phase

A
  • start w/ two molecules of G3P
  • Generate 2 NADH, 4ATP, 2 pyruvate
  • pyruvate and NADH can be further ox. in TCA and ETC respectively (produce more ATP)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What happens to pyruvate under aerobic conditions?

A
  • Pyruvate is converted to Acetyl-CoA and enters further oxidation
  • NADH is oxidized via ETC
  • In order for glycolysis to continue must oxidize NADH to resupply NAD+ (NAD+ is limited in cell)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Fates of Pyruvate

A
  • acetaldehyde
  • lactate
  • Acetyl CoA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Anaerobic Glycolysis

A
  • when there is a lack of O2 cells use lactic acid fermentation to regenerate NAD+
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Aerobic glycolysis yield

A

Gain 2 ATP/glucose
- ongoing glycolysis req. ox. of NADH by ETC

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

Anaerobic glycolysis yield

A

Gain 2 ATP/glucose
- no net production or consumption of NADH

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

3 key regulatory rxns of glycolysis

A
  • Hexokinase; catalyzes 1st rxn
  • Phosphofructokinase; catalyzes 3rd rxn
  • Pyruvate Kinase; catalyzes last rxn
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

PFK-1

A
  • P from ATP transferred to fructose 6-P by PFK to form fructose 1,6-bisphosphate
  • commited step
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Hexokinase

A
  • P from ATP is added to glucose to form glucose 6-phosphate
  • catalyzed by hexokinase or glucokinase (liver)
  • traps glucose in cell
  • product inhibition; Hex. inhibited by G-6P
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Pyruvate Kinase

A
  • transfers P from PEP to ADP
  • forms ATP and pyruvate
  • all three rxns are irreversible steps
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Glycolysis plays 2 roles

A

1-degrades glucose to generate ATP
2-provides building blocks for biosynthetic rxns

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

How is glycolysis regulated?

A
  • by 3 regulatory enzymes
  • by reversible binding of allosteric effectors and/or covalent modifications
12
Q

Regulation of glycolysis in muscle w/ PFK

A
  • ratio of ATP/AMP indicates energy level of cell
  • PFK; the most important regulatory point for glycolysis
  • inhibited by high levels of ATP
  • activated by AMP
13
Q

Primary role of glycolysis in muscle?

A

Provide ATP

13
Q

Regulation of glycolysis in muscle w/ Hexokinase

A
  • phosphorylates glucose in first step
  • inhibited by product - G-6P
  • G-6P also increases when PFK is inhibited, PFK inhibited - hexokinase inhibition
14
Q

Regulation of glycolysis in muscle w/ Pyruvate kinase

A
  • catalyzes final step of glycolysis
  • allosterically inhibited by ATP
  • activated by Fructose 1,6-bisphosphate (product of PFK)
15
Q

Regulation of glycolysis in liver

A
  • Liver is amore biochemically diverse tissue
  • Liver maintains blood glucose conc.
  • more complex tissue leads to more complex reg.
15
Q

How does liver maintain bloodglucose conc.

A
  • stores glucose as glycogen
  • synthesizes new glucose via gluconeogenesis
  • uses glucose to make building blocks for other molecules
16
Q

Regulation of glycolysis in liver w/ PFK

A

Regulated by ATP, similar to liver
- less ATP, therefore less sig. regulation
- liver also produces C skeletons for biosynthesis, thus availability of these molecules regulates PFK
- Citrate; inhibit
- high levels of citrate indicate high levels of biosynthetic precursors
- elevated blood glucose signalled by fructose 2,6-bisphosphate conc.

17
Q

Regulation of glycolysis in liver w/ Hexokinase

A
  • Hexokinase/Glucokinase are isozymes
  • isozymes; enzymes encoded by diff. genes that catalyze the same rxn
18
Q

Glucokinase

A
  • Primary enzyme for phosphorylation of glucose in the liver
  • Also found in pancreatic cells where glucose 6-P stimulates release of insulin
19
Q

When does glucokinase phosphorylate gluicose

A
  • when glucose levels are high
20
Q

Regulation of glycolysis in liver w/ Pyruvate kinase

A
  • pyruvate kinase; muscle and liver cells have diff. isozymes
  • both respond to allosteric regulation
  • inhibited by ATP
  • Activated by Fructose 1,6-BP
21
Q

What is liver isozyme also regulated by?

A
  • By phosphorylation
  • triggered by glucagon
22
Q

What is PFK-1 in muscles inhibited by?

A

ATP

22
Q

What is hexokinase in muscles activated by?

A

Substrate

22
Q

What is PFK-1 in muscles activated by?

A

AMP

22
Q

What is hexokinase in muscles inhibited by?

A

G-6P

23
Q

What is pyruvate kinase in muscles activated by?

A

Fructose 1,6-bisphosphate

23
Q

What is pyruvate kinase in muscles inhibited by?

A

ATP

23
Q

What is hexokinase/glucokinase in liver inhibited by?

A

G-6P

24
Q

What is hexokinase/glucokinase in liver activated by?

A

Glucose

25
Q

What is PFK-1 in liver activated by?

A
  • Fructose 2,6-BP
    -AMP
26
Q

What is PFK-1 in liver inhibited by?

A
  • ATP
  • Citrate
27
Q

What is pyruvate kinase in liver activated by?

A
  • Fructose 1,6-BP
  • Dephosphorylation
27
Q

What is pyruvatekinase in liver inhibited by?

A
  • ATP
  • Phosphorylation

Biochem 102 (13 decks)

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