Week 12: Glycolysis

Question 1

What cell types require glucose?

Answer 1

erythrocytes, retina, renal, brain

Question 2

What is the straight chain structure of glucose called?

Answer 2

hexose

Question 3

What 2 carbons link to make a ring structure?

Answer 3

Carbon 1 (on the aldehyde) & Carbon 5

Question 4

beta-D-glucose structure?

Answer 4

OH points up on carbon 1

Question 5

alpha-D-gluose structure?

Answer 5

OH points down on carbon 1

Question 6

When 2 glucose form a linkage, what is the biproduct?

Answer 6

H2O, Carbon 1 gives the H and the other structure gives the OH.

Question 7

How to make surcose?

Answer 7

alpha glucose and fructose

Question 8

How to make maltose?

Answer 8

alpha glucose + beta glucose

Question 9

How to make cellabiose?

Answer 9

beta and beta glucose

Question 10

How to make polysaccharides?

Answer 10

many glucose molecules

Question 11

What do proteins, lipids and carbohydrates breakdown to form?

Answer 11

amino acids, fatty acids, glucose

Question 12

What needs to happen before the stages of glucose catabolism can occur?

Answer 12

Glucose transport into cells via Na+/glucose symporters

Question 13

where are the Na+/glucose symporters located?

Answer 13

gut

Question 14

What is the Na+ concentration outside the cell?

Answer 14

high Na+

Question 15

What is the Na+ concentration inside the cell?

Answer 15

low Na+

Question 16

What pump is used to push Na+ out of cell, against its concentration gradient?

Answer 16

Na+/K+ antiport/pump

Question 17

What substance is needed to drive glucose into cell?

Answer 17

Na+

Question 18

what tissue is GLUT 1&3 receptors?

Answer 18

brain

Question 19

Does the brain GLUT receptors operate at low Km

Answer 19

Yes, continue to operate at high affinity even when low glucose. even when energy supply is low
keeps you alive.

Question 20

What tissue are GLUT 2 receptors located?

Answer 20

Liver & pancreatic beta cells

Question 21

Do GLUT 2 receptors operate at low Km?

Answer 21

no, really sensitive to changes in glucose conc.

Drop in glucose conc, drop activity of receptor.

Question 22

What cells produce insulin?

Answer 22

pancreatic beta cells

Question 23

What receptors/cells do insulin bind to?

Answer 23

GLUT 4 on the muscle and adipose tissue (where it is stored)

Question 24

what does the GLUT 5 receptor do?

Answer 24

Gut
fructose transport
transports glucose

Question 25

How does the GLUT 1 receptor work?

Answer 25

glucose binds outside confo change and binding site moves inside cell low conc of glucose inside so very little probability of binding to receptor on the inside receptor is unoccupied, confo change and regenerates binding site to outside

Question 26

catabolism of glucose to 2Xpyruvate equation?

Answer 26

glucose+2ADP+2Pi+2NAD+--> | 2Xpyruvate+ 2ATP + 2H20 +2NADH +2H+

Question 27

What is the first intermediate product of glucose?

Answer 27

fructose 1,6biphosphate | conversion of 2ATP-->2ADP

Question 28

What does fructose 1,6 biphosphate change to in the glucose pathway?

Answer 28

2 triose phosphates G3P

Question 29

what does 2 triose phosphates change to in the glucose pathway?

Answer 29

2X pyruvate conversion of 4ADP-->4ATP 2NAD+ --> 2NADH + 2H+

Question 30

What is the first control point in glycolysis?

Answer 30

enzyme hexokinase glucose to glucose-6-phosphate not reversible, big energy diff

Question 31

What is the second control point in glycolysis?

Answer 31

phosphofructokinase fructose-6-phosphate to fructose-1,6-biphosphate not reversible, big energy diff

Question 32

What is the third control point in glycolysis?

Answer 32

pyruvate kinase phosphoenolpyruvate to pyruvate not reversible, big energy gap

Question 33

what are the 2 cellular needs for control points in glycolysis?

Answer 33

1. production of ATP 2. provision of building blocks for synthetic reactions >don't need to breakdown pathway, breakdown precursors if needed

Question 34

What is stage 1 called in glycolysis?

Answer 34

energy investing reactions

Question 35

what stage 3 called in glycolysis?

Answer 35

energy harvesting reactions

Question 36

If you have enough energy do you need to proceed at control points?

Answer 36

don't need to proceed | no need to source more energy in the body

Question 37

what are negative modulators of phosphofructokinase?

Answer 37

ATP, H+ & citrate (citric acid)

Question 38

How does citric acid work as a negative modulator of phosphofructokinase in glycolysis?

Answer 38

early intermediate in the citric acid cycle biosynthetic precursors are abundant no need to breakdown glucose

Question 39

How does H+ work as a negative modulator of phosphofructokinase in glycolysis?

Answer 39

Low pH inside cell Under anaerobic conditions, breakdown of glucose = lactic acid slowly poisoning itself doesn't want to metabolise glucose at the detriment to itself slow down glycolysis, lactic acid will clear --> allow glucose metabolism to continue

Question 40

what are positive modulators of phosphofructokinase?

Answer 40

AMP & fructose-2,6-biphosphate (FBP)

Question 41

what is the ATP/AMP ratio called?

Answer 41

energy charge

Question 42

When is a cell fully charged/uncharged?

Answer 42

all adenalate nucleotides are in ATP form = fully charged | cell contains only AMP+P = uncharged

Question 43

What does energy charge in a cell tell us?

Answer 43

2ADP-->ATP+AMP. depleted enough ATP, need to start converting 2ADP-->ATP+AMP