Regulation of Respiration and Gluconeogenesis

Question 1

When there is high blood glucose

Answer 1

B cells in pancreas release insulin telling cells to uptake glucose.

Question 2

Steady State

Answer 2

Glucose moves through the pathway smoothly, high glucose levels can cause traffic, of one substrate/product concen gets too high, it will allosterically inhibit the enzyme before it

Question 3

Hexokinase/Glucokinase

Answer 3

First reaction in glycolysis, regulated by steady state conditions, high product will negatively modulate the the enzyme HK/GK

Question 4

PFK-1

Answer 4

Second rxn in glycolysis, rate limiting. F2,6bisP made if glucose is high, positively modulates PFK-1, PFK-2 can be phosphorylated and PFK-1 is not

Question 5

PEP

Answer 5

Last reaction of glycolysis. PEP is turned from PK to pyruvate with PDH to acetyl-CoA, acetyl-CoA carboxylase moves it into the krebs cycle.

Question 6

When glucose is not needed…

Answer 6

It is stored as triglycerides in adipose tissues.

Question 7

Phosphorylation

Answer 7

Turns off enzymes

Question 8

Gluconeogenesis

Answer 8

The synthesis of new glucose, done in the liver, a reaction must occur using PC, turning pyruvate into OAA, which goes to malate, then converts back to OAA and PEP. Done because the reaction of PEP to pyruvate is irreversible

Question 9

In low glucose

Answer 9

The glycolytic path is shut down

Question 10

Difference in HK and GK

Answer 10

Liver has GK, which has a higher Km, and decreased attraction between enzyme and substrate. Brain has HK, lower Km.

Question 11

The Brain

Answer 11

Most other tissues can brun fatty acids, the brain can only use glucose, and the brain always requires glucose