Hormonal Control of glycogen

Question 1

what 2 polypeptide hormones control Glycogen metabolism in the liver

Answer 1

Glycogen metabolism in the liver is largely controlled by the polypeptide hormones insulin and glucagon acting in opposition

Question 2

where is glucagon synthesized

Answer 2

in the pancreas

Question 3

where do the adrenal hormones epinephrine and norepinephrine exert control

Answer 3

In muscles and various tissues, control is exerted by insulin and by the adrenal hormones epinephrine and norepinephrine.

Question 4

what is molecule that helps to upregulate cyclic AMP level (camp)

Answer 4

glucagon

Question 5

if we have excess glucagon how does that affect protein kinase A

Answer 5

glucagon up regulates camp which stimulates more protein kinase A which eventually means more glycogen breakdown

Question 6

is glucagon a signal of a well fed or starvation state?

Answer 6

starvation

Question 7

is insulin related to breakdown or storage of

Answer 7

storage

Question 8

is insulin a signal of a well fed or starvation state

Answer 8

well fed

Question 9

what kind of covalent modfication is stimulated by the adrenal hormones epinephrine and norepinephrine.

Answer 9

they Stimulate covalent modification (phosphorylation) of regulatory enzymes.

Question 10

define second messenger

Answer 10

Release inside the cell of molecules collectively known as second messengers = intracellular mediators of the externally received hormonal message.

Question 11

give an example of 2 second messengers

Answer 11

Different receptors cause the release of different second messengers ex: cAMP, Ca2+

Question 12

insulin is the ____ cascade

Answer 12

dephosphorylation cascade

Question 13

give 3 examples of molecules that would stimulate a phosphorylation cascade

Answer 13

epinephrine, norepinephrine, cAMP

Question 14

When hormonal stimulation increases the intracellular cAMP concentration will phosphorylation increase or decrease?

Answer 14

When hormonal stimulation increases the intracellular cAMP concentration, PKA activity increases, increasing the rates of phosphorylation of many proteins and decreasing their dephosphorylation rates as well.

Question 15

When [cAMP] decreases, phosphorylation rates will increase or decrease?

Answer 15

When [cAMP] decreases, phosphorylation rates decrease, dephosphorylation rates increase, and the fraction of enzymes in their dephospho forms increases.

Question 16

when Glucagon binds to its receptor on liver cells what does it generate intracellularlly?

Answer 16

Generates intracellular cAMP,

Question 17

when Muscle cells come into contact with glucagon what happens?

Answer 17

Muscle cells do not respond to glucagon because they lack the appropriate receptor.

Question 18

what kinds of receptors are found for Epinephrine and norepinephrine

Answer 18

Two types of receptors for these hormones: the β-adrenoreceptor (β-adrenergic receptor), which is linked to the adenylate cyclase system, and the α-adrenoreceptor (α-adrenergic receptor), whose second messenger causes intracellular [Ca2+] to increase

Question 19

the second messenger of Epinephrine and norepinephrine

causes what to increase

Answer 19

second messenger causes intracellular [Ca2+] to increase

Question 20

when muscle cells come into contact with epinephrine what happens?

Answer 20

Muscle cells, which have the β-adrenoreceptor respond to epinephrine by breaking down glycogen for glycolysis, thereby generating ATP and helping the muscles cope with the stress that triggered the epinephrine release.

Question 21

How do Liver cells respond to epinephrine indirectly?

Answer 21

Epinephrine promotes the release of glucagon from the pancreas, and glucagon binding to its receptor on liver cells stimulates glycogen breakdown

Question 22

How do Liver cells respond to epinephrine directly?

Answer 22

Epinephrine also binds directly to both α- and β-adrenoreceptors on the surfaces of liver cells. Increased ca and camp

Question 23

what is an auxillary way to turn on and off synthesis and breakdown of glycogen

Answer 23

hormones

Question 24

when insulin kicks in , what happens to camp levels

Answer 24

they go down and lead to synthesis

Question 25

where is insulin released from and why

Answer 25

Insulin is released from the pancreas in response to high levels of circulating glucose (e.g., immediately after a meal).

Question 26

where are glut 4 transporters found and what are they used for

Answer 26

insulin receptors and insulin sensitive glucose transporters called GLUT4 on their surfaces (e.g., muscle and fat cells, but not liver and brain cells).