Glucose regulation and formation Q5

Question 1

What cells are released by the pancreas and what are their function?

Answer 1

Islet cells, release insulin, glucagon, and numerous hormones.

Question 2

What cells are released from the liver and what are their function?

Answer 2

Hepatocyte, maintain metabolic homeostasis by normalizing blood glucose, storing glycogen as well as synthesis and degrading various substrates.

Question 3

What are the two steps of glycolysis that can be aerobic or anaerobic?

Answer 3

Glycolysis and citric acid cycle.

Question 4

Where are the primary sources of glycogen found?

Answer 4

Liver most and some muscle.

Question 5

What is the starter for glycogen formation?

Answer 5

Glycogenin

Question 6

What are the bonds for glycogen?

Answer 6

Long chains of alpha 1-4 and branching with alpha 1-6.

Question 7

What is the purpose of phosphorylating glucose?

Answer 7

Keeps glucose from leaving the cell and allows for future energy for enzymatic activity.

Question 8

Starting from glucose, outline the steps and enzymes to form glycogen. What is the regulation point?

Answer 8

Question 9

How many glucose residues are in each glycogen chain?

Answer 9

12-14.

Question 10

What are the two fates when glucose-6-phosphate has been created from glycogen?

Answer 10

One is to enter glycolysis or to be exported to the ER of the liver.

Question 11

Where is glucose-6-phosphates and what is its purpose?

Answer 11

It is only found in the liver and it serves to create glucose where blood sugar is low.

Question 12

What is the point of regulation when converting glycogen into glucose.

Answer 12

First step when creating glucose 1-phosphate by the glycogen phosphorylase.

Question 13

What is responsible for regulating glycogen synthase?

Answer 13

Glycogen synthase kinase 3. It will add phosphates to glycogen synthase leaving it deactivated. When the are replaced by OH, it will activate it.

Question 14

What is the key enzyme responsible for glycogenolysis and how is it regulated?

Answer 14

Glycogen phosphorylase. Phosphorylase b is the inactive form and the non phosphorylated form. When it is in the active form (a) it removes glucose 1-phosphate from glycogen allowing for formation of glucose.

Question 15

How does insulin activate glycogenesis?

Answer 15

Insulin is released in response to high blood sugar activating GLUTs, hexokinase, glycogen synthase. Glycogen synthase then adds glucose to glycogen chains.

Question 16

What are the two hormones that activate glycogenolysis? What cells do they work on and what is the end product?

Answer 16

Epinephrine for myocyte and glucagon for hepatocyte.

For liver Epinephrine and glucagon produce glucose 6-phosphate which will yeild blood glucose

In musculater epinephrine will induce glycogenolysis and increase rate of glycolysis.

Question 17

Where is the primary site for gluconeogenesis?

Answer 17

The liver. Note that glucose 6-phosphatase is in the ER of the liver.

Question 18

What are the two substrates converted to glucose?

Answer 18

Lactate or pyruvate.

Question 19

What are the input costs for 1 glucose molecule to be made?

Answer 19

4 ATP, 2 GTP, and 2 NADH + H+

Question 20

What is the point of regulation for gluconeogenesis?

Answer 20

Converting fructose 1,6-bisphosphatse into fructose 6-phosphate by fructose 1,6-bisphosphatase-1.

Question 21

What is the cori cycle?

Answer 21

It is the process of converting the lactate produced in the muscles into glucose again in the liver.

Question 22

What is the major enzyme in responding to cellular energetics? What is it activated by?

Answer 22

AMP kinase by detecting intracellular AMP. It is activated in the large changes in AMP.

Question 23

What happens to the pancreas, liver, adipose, and muscle in a state of feeding?

Answer 23

Pncrease releases insulin, liver produces glycogen and fatty acids, adipose produces and stores lipids, msucles undergo glycolysis and glycogen production.

Question 24

What happens to the pancreas, liver, adipose, and muscle in a state of fasting?

Answer 24

Pancreas releases glucagon, liver undergoes gluconeogenesis, glycogenolysis, ketone and glucose release, adipose undergoes fatty acid and glycerol release, muscle undergoes ketone metabolism, and reduced glycolysis.