Andrew Shore's Lectures

Question 1

What are the energy requirements for females?

Answer 1

2000 Kcal

Question 2

How is glucose taken up by cells of any tissue?

Answer 2

By the glucose transporters GLUT-1, and GLUT- 3

Question 3

What glut transporters are found at pancreatic Beta cells?

Answer 3

Glut-2, also found at the liver

Question 4

What Glut transporter is found in muscle or fat?

Answer 4

Glut-4

Question 5

What glut transporter is found in the small intestine and what is its function?

Answer 5

Glut-5, mainly fructose uptake

Question 6

What is differences between the different glucose transporters apa from location?

Answer 6

1) they have different affinities for glucose because they have… 2) Different Km values 3) GLUT-2 has a Km value of **15,20** which means it has a lowwww affinity for glucose

Question 7

Glut 1 and 3 have high affinities for glucose (km = 1) but what ablut Glut2 and 4?

Answer 7

They have high Km values, so a lower affinity for glucose. - Glut-2 regulates blood glucose levels (responds to insulin) - Glut-4 also responds to insulin

Question 8

What are the three regulatory steps of glycolysis?

Answer 8

Steps 1,3 and 10 in glycolysis

Question 9

What inhibits hexokinase?

Answer 9

Glucose 6 phophate (the product if the first step in glycolysis)

Question 10

What is the hexokinase isozyme called in the liver?

Answer 10

Glucokinase

Question 11

What are the energy requirements for males?

Answer 11

2500 kcal

Question 12

What is phophofructokinase inhibited by?

Answer 12

1) By ATP 2) downregulatedby citrate

Question 13

What is phophofructokinase activated by?

Answer 13

• AMP - fructose 2,6 bispohphate (increases affinity for fructose 6 phosphate, diminished inhibitory effect of ATP)

Question 14

How does ATP inhibit phosphofructokinase?

Answer 14

At high concentrations, ATP bins to a regulatory site rather than the catalytic site of the enzyme

Question 15

Hoe is phosphofructokinase under adenylate control?

Answer 15

Adenylate kinase; 1) When ATP being used up rapidly 2) ATP is formed from ADP 3) ADP + ADP to ATP + AMP (ATP used up, AMP becomes the signal for low- energy state)

Question 16

What is substrate level phosphorylation?

Answer 16

“This type of phosphorylation involves the direct synthesis of ATP from ADP and a reactive intermediate, typically a high energy phosphate-containing molecule” Excerpt From: Kevin Ahern & Indira Rajagopal. “Biochemistry Free and Easy.” v2.0. DaVinci Press, 2012. iBooks. This material may be protected by copyright. Check out this book on the iBooks Store: https://itun.es/gb/iDeRG.n

Question 17

What are the inputs of the link reaction?

Answer 17

Ipyruvate Cofactors: thiamine pyrophosphates (Vitamin B1), lipoic acid, CoA, NAD Enzyme: pyruvate dehydrogenase complex

Question 18

How is the link reaction regulated?

Answer 18

ATP inhibits the link reaction Ca2+ and ADP activate pyruvate dehydrogenase

Question 19

What are the products of the link reaction?

Answer 19

NADH Acetyl CoA (2 carbons) CO2+

Question 20

Where does nadh get produced in the krebs cycle?

Answer 20

1) isocitrate to alpha ketogluterate 1) alpha ketogluterate to succinyl coA 1) malate to oxaloacete

Question 21

How is Fructose 2,6 bisphosphate controlled?

Answer 21

• By the enzymes that are present on the same polypeptide chain;
• Phophofructokinase-1 phospohorylates Fructose 6-phophate to F2,6BP
• Fructose bisphosphatase 2 dephosphorylates Fructose 2,6 bisphosphate

Question 22

What is the result of fructose 2,6 bisphosphate formation in the substrate cycle?

Answer 22

• Stimulates PFK-1 so
• Glycolysis is activated
• Gluconeogenesis is inhibited

Question 23

What is the result of dephosphorylation of fructose 2,6 bisphosphate?

Answer 23

• Glycolysis is inactive
• Gluconeogenesis is active

Question 24

How does glucagon regulate the substrate cycle involving fructose 2,6 bisphosphate?

Answer 24

1. Increase in glucose levels
2. Glucagon binds to Gs coupled receptor
3. Andeylate cyclase, cAMP pathway produces protein kinase A
4. Protein Kinase A shifts to cause FBPase 2 to dephosphorylate Fructose 2,6 bisphosphate so in the end you get less glycolysis and more gluconeogenesis

Question 25

What activated pyruvate kinase in the 10th step of glycolysis?

Answer 25

Fructose 1, 6 bisphosphate

Question 26

How does ATP regulate pyruvate kinase?

Answer 26

• ATP required to form fructose 1,6 bisphosphate in the 3rd step of glycolysis
• If no ATP, no fructose 1,6 bisphosphate so pyruvate kinase is not activated

Question 27

How is the L form (in the liver) of pyruvate kinase regulated?

Answer 27

• Activated: Feed forward by Fructose 1,6 bisphosphate
• Inhibited allosterically by: ATP and alanine