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Flashcards in Carbohydrates 3 Deck (29)
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1
Q

How many molecules of G-3-P enter the payoff phase?

A

2

2
Q

How many ATP are used in the prepatory phase?

A

2

3
Q

How many ATP are made during the payoff phase?

A

4

4
Q

What is the first reaction of glycolysis?

A

Phosphorylation of glucose

5
Q

How many ATP is used during the first stage of glycolysis? (phosphorylation of glucose) And what enzyme is used?

A

1 ATP

Hexokinase

6
Q

What is the second stage of glycolysis? And what is the enzyme?

A

Conversion of G - 6 - P to F-6-P

Phosphohexose Isomerase

7
Q

Why does the second step of glycolysis proceed in both directions?

A

Reaction has a low free energy

8
Q

What is the stage of glycolysis apart from step 1 (phosphorylation of glucose) that requires ATP?

A

Phosphorylation of F-6-P to F-1,6 - bisP (stage 3)

9
Q

What is the catalyst for phosphorylation of F-6-P?

A

Phosphofructokinase -1

10
Q

What is the splitting part of Glycolysis?

A

Step 4 - which is the cleavage F-1, 6-bisP, forms two different triose sugars
Catalyst is aldolase

11
Q

What is stage 5 of glycolysis?

A

Interconversion of triose sugars
Enzyme used it triose phosphate isomerase
Dihydroxyacetone phosphate is converted to glyceraldehyde -3-phosphate
Forming 2 molecules of G-3-P
G-3-P is the only molecule that can enter the payoff phase

12
Q

Which stage in glycolysis produces 2 molecules of NADH?

A

Stage 6, the oxidation of G-3-P to 1,3-bisPG

The catalyst is glyceraldehyde - 3 - phosphate dehydrogenase

The first payoff reaction in glycolysis

13
Q

Reaction 6 (the oxidation of G-3-P to 1,3-bisPG) is coupled to which other reaction and why?

A

6 is coupled to 7 because 6 requires a lot of energy whilst 7 gives off a a lot of energy.

14
Q

Describe reaction 7 and what is the substrate?

A

P transfer from 1,3-bisPhosphoglycerate to ADP, 2 ATP produced, phosphoglycerate kinase enzyme used
Spontaneous since highly exergonic

15
Q

What is stage 8?

A

Conversion of 3, phosphoglycerate to 2, phosphoglycerate

Enzyme is phosphoglycerate mutase

16
Q

What step of glycolysis is enolase used in?

A

Dehydration 2-PG to PEP (phosphoenolpyruvate)

17
Q

Where does the ADP in the last stage of glycolysis get the phosphate?

A

PEP

18
Q

Describe the last stage of glycolysis

A

Transfer of P from PEP to ADP
2 ATP produced, highly exergonic,
Pyruvate produced
Enzyme is pyruvate kinase

19
Q

Where does NAD+ come from in the cell?

A

Niacin an essential vitamin

20
Q

What is the difference between substrate level phosphorylation and respiration linked phosphorylation ?

A

Substrate level - requires soluble enzymes and chemical intermediates
Respiration linked means membrane bound enzymes and gradients of protons

21
Q

What compound is used to replenish NAD+?

A

The different fates of pyruvate

22
Q

What is NAD+ used for?

A

The reduction of various intermediate metabolites

23
Q

What are the three fates of pyruvate?

A

Citric acid cycle, producing water and carbon dioxide
Fermentation to lactate
Fermentation to CO2 and Ethanol

24
Q

How is pyruvate converted into ethanol?

A

Pyruvate + pyruvate carboxylase = Acetaldehyde

Acetaldehyde + Alcohol dehydrogenase + NADH = Ethanol + NAD+

25
Q

Why can’t we make ATP via oxidative phosphorylation during intense exercise?

A

Not enough oxygen

26
Q

How is ATP made instead during intense exercise?

A

Substrate level phosphorylation producing lactate

27
Q

Where is the lactate converted into glucose, and what is this process called?

A

Liver, gluconeogenesis

28
Q

What is the interaction between the muscle and the liver called?

A

The cori cycle

29
Q

What is pyruvate converted into in aerobic conditions?

A

Acetyl Co-A, in mitochindria, NADH is formed