Glycolysis

Question 1

What is glycolysis

Answer 1

The catabolism of glucose

Question 2

Chemical structure of glucose

Answer 2

C6 H12 O6, 6 carbon structure, hexose, numbering starts from aldehyde group 1-6

Question 3

Explain glucose symporters

Answer 3

Simultaneous transport of sodium and glucose in the same direction that is controlled by the sodium concentration created by sodium-potassium pumps

Question 4

What does a low Km value of a transporter correspond to

Answer 4

High activity as they’re easily activated

Question 5

Why do glucose transporters (GLUT1) in the brain need to have low Km values

Answer 5

They need to be sensitive to changes in glucose concentration because the brain exclusively uses glucose as an energy source

Question 6

How does GLUT1 transporter work

Answer 6

Changes conformation when glucose binds to the outside so that it gets exposed to the inside of the cell and down the concentration gradient

Question 7

Glucose to pyruvate overall reaction pathway (products and reactants)

Answer 7

Glucose + 2 ADP + 2 Pi + 2 NAD+
->
2 pyruvate + 2 ATP + 2 H2O + 2 NADH + 2H+

Question 8

Glucose -> glucose 6-phosphate (G6P) enzyme

Answer 8

Hexokinase, glucose os phosphorylated on carbon 6

Question 9

Glucose 6-phosphate -> Fructose 6-phosphate (F6P) enzyme

Answer 9

Phosphoglucose isomerase

Question 10

Fructose 6-phosphate -> Fructose 1,6-bisphosphate enzyme

Answer 10

Phosphofructokinase adds a phosphate

Question 11

Why does fructose 1,6-bisphosphate get broken down quickly

Answer 11

Unstable due to two phosphates in close proximity so does not require much energy to break down

Question 12

Fructose-1, 6- bisphosphate is cleaved down the middle by _____ to form two isomers

Answer 12

Aldolase
Dihydroxyacetone phosphate (DAP) and glyceraldehyde 3-phosphate (G3P)

Question 13

Isomerase interconverts the products of FBP breakdown between each other, which one participates in the next reaction

Answer 13

G3P, it gets used up before isomerase has a chance to convert it (back) to DAP

Question 14

Why does every reaction happen twice after the breakdown of FBP

Answer 14

For every molecule of glucose that is broken down 2 G3P molecules are produced

Question 15

Glyceraldehyde-3-phosphate (G3P) -> 1,3-bisphosphoglycerate (BPG) enzyme and side product

Answer 15

Glyceraldehyde dehydrogenase removes hydrogen and donates to NAD+, harvesting high-energy electrons and producing NADH

Question 16

1,3-bisphosphoglycerate (BPG) -> 3-phosphoglycerate (3PG) enzyme and side product

Answer 16

phosphoglycerate kinase removes phosphate and adds it to ADP releasing ATP

Question 17

3 phosphoglycerate (3PG) -> 2 phosphoglycerate (2PG) enzyme

Answer 17

phosphoglycerate mutase

Question 18

2 phosphoglycerate (2PG) -> phosphoenolpyruvate (PEP) enzyme and side product

Answer 18

enolase
water

Question 19

phosphoenolpyruvate (PEP) -> pyruvate enzyme and side product

Answer 19

pyruvate kinase
ATP

Question 20

What are the 3 control points in glycolysis

Answer 20

glucose –hexokinase–> glucose 6-phosphate

fructose 6-phosphate –phosphofructokinase–> fructose 1,6-bisphosphate (FBP)

phosphoenolpyruvate –pyruvate kinase–> pyruvate

Question 21

What inhibits hexokinase at the first control point of glycolysis

Answer 21

glucose 6-phosphate

Question 22

what inhibits phosphofructokinase and pyruvate kinase

Answer 22

ATP

Question 23

What type of reactions are inhibited at glycolysis checkpoints and why

Answer 23

catabolic
prevents excess energy production when not needed

Question 24

what does an abundance of ATP/AMP mean

Answer 24

how charged the cell is
high ATP = charged
high AMP = discharged