Glycolysis

Question 1

Where does glycoloysis occur?

Answer 1

Cytosol

Question 2

In glycolysis, you start with ________ and end with _________

Answer 2

Start with: 1 molecule of glucose, end w/ 2 molecules of pyruvate

Question 3

True or False: Pyruvate can be shunted into a ton of different pathways

Answer 3

True, it can go into the citric acid cycle, lactic acid fermentation, gluconeogenesis, or fatty acid synthesis

Question 4

How many NAD+ are reduced in glycolysis?

Answer 4

2

Question 5

What is the net gain per glucose molecule in glycolysis?

Answer 5

2

Question 6

What does adding a phosphate with hexokinase do?

Answer 6

This traps the glucose in the cell, it expends ATP, it also makes it polar (2-)

Question 7

What is the first irreversible step of glycolysis?

Answer 7

PFK1, this enzyme adds a phosphate to F6P. It is irreversible. It COMMITS IT TO GLYCOLYSIS and is a highly regulated step and is rate limiting.

Question 8

What molecule feeds into the energy payoff phase of glycolysis?

Answer 8

G3P

Question 9

For every molecule of G3P that enters the energy payoff, what is produced?

Answer 9

For every 1 G3P, you get 1 NADH, 2 ATP, and 1 Pyruvate

Question 10

Place the following in order in the energy payoff phase: G3P dehydrogenase Phosphoglycerate mutase Enolase Pyruvate kinase Phosphoglycerate kinase

Answer 10

G3P dehydrogenase Phosphoglycerate kinase Phosphoglycerate mutase Enolase Pyruvate kinase

Question 11

The “committed step” is a regulatory mechanism employed in many metabolic pathways. One feature of a reaction that occurs at a committed step is that it is irreversible. In the committed step the cell commits to producing products from that pathway. What is considered the commitment step of glycolysis?

Answer 11

The conversion of F6P to F1,6P

Question 12

Substrate level phosphorylation

Answer 12

In substrate-level phosphorylation, a phosphate group is moved onto a biochemical substrate and then transferred to ADP to form ATP.

Question 13

What is the only step in glycolysis that involved substrate level phosphorylation?

Answer 13

1,3-bisphosphoglycerate + ADP –> 3 Phosphoglycerate + ATP

Question 14

What molecules does the cell detect to monitor for energy balance?

Answer 14

AMP (higher in low), ADP (Higher in low), ATP (Higher in high), NADH (Higher in high), Citrate (Higher in high)

Question 15

Insulin or Glucagon: I upregulate glycolysis

Answer 15

Insulin

Question 16

Insulin or Glucagon: I downregulate glycolysis

Answer 16

Glucagon

Question 17

What does Hexokinase do?

Answer 17

Glucose–> G6P

Question 18

What are the three most regulated steps in glycolysis?

Answer 18

Hexokinase (G->G6P), PFK1 (F6P-> F1,6BP), PK (PEP-> Pyruvate)

Question 19

How is hexokinase regulated?

Answer 19

It is inhibited by G6P (negative feedback inhibition),

Question 20

How is glucokinase regulated?

Answer 20

NOT inhibited by G6P. This is because the liver cells with glucokinase are taking in more glucose than your other tissues would.

Question 21

How is PFK1 regulated?

Answer 21

Downregulated by high levels of ATP and Citrate. Upregulated by high ADP, allosterically regulated by F26BP!!!

Question 22

What is the role of F26BP?

Answer 22

It upregulates PFK1. Its like super important.

Question 23

How does insulin regulate glycolysis (what specifically)?

Answer 23

Insulin upregulates PFK2 which is responsible for making F26BP

Question 24

How does glucagon regulate glycolysis (what specifically)?

Answer 24

Glucagon upregulates Fructose 2,6 bisphosphatase and inhibits PFK2 to decrease the concentration of F26BP.

Question 25

High ATP and Citrate indicates a high or low energy state and will upregulate or downregulate glycolysis?

Answer 25

They indicate a high energy state and will downregulate glycolysis.

Question 26

How is pyruvate kinase regulated?

Answer 26

PK is allosterically inhibited by ATP and its inhibited by acetylcoa and fatty acids.

Question 27

True or False: Citrate indicates low energy in the cell

Answer 27

False, it is high energy

Question 28

True or false: A high concentration of citrate inhibits glycolysis via negative feedback.

Answer 28

This statement is true. Citrate is a key intermediate in the citric acid cycle, which occurs after glycolysis in aerobic respiration. High levels of citrate indicate that the cell has plenty of raw materials to produce energy through this pathway, so it does not need to continue breaking down glucose through glycolysis.

Question 29

True or False: Glucokinase is not inhibited by its product

Answer 29

True

Question 30

What adds a phosphate to glucose as soon as it enters the cell?

Answer 30

Hexokinase (or Glucokinase in liver)

Question 31

What enzyme is responsible for F6P–> F16P?

Answer 31

PFK1

Question 32

What enzyme is responsible for F6P–> F26P?

Answer 32

PFK2

Question 33

What is the following structure?

Answer 33

Pyruvate

Question 34

Answer 34

Glucose

Question 35

How many NADH, ATP, and Pyruvate per G3P that enter into the energy payoff phase?

Answer 35

1 NADH, 2 ATP (not net gain), and 1 pyruvate per G3P

Question 36

Triose Phosphate Isomerase

Answer 36

This enzyme converts DHAP to G3P in the energy investment phase

Question 37

This step in glycolysis has substrate level phophorylation that is so favorable you dont need ATP

Answer 37

The first step in the energy payoff phase. G3P–> 1,3PG by G#P dehydrogenase

Question 38

If oxygen is present, where is pyruvate shunted?

Answer 38

Most likely to TCA

Question 39

In animal cells, if oxygen is not present where does pyruvate go?

Answer 39

Lactic Acid Fermentation

Question 40

PFK2 shares dual action with which enzyme?

Answer 40

F26Bisphosphatase