Metabolic regulation Flashcards Preview

MCBM > Metabolic regulation > Flashcards

Flashcards in Metabolic regulation Deck (60)
Loading flashcards...
1

glucose and intracellular ATP maintaine at ___mM to maintain homeostasis

5

2

Hexokinase is an ____which catalyze the same reaction although they have slightly different properties. Made from different genes with diff regulatory aspects.

isoenzyme

3

ATP, ADP and AMP bind to ___enzymes and change their activity level. They are examples of ____modifiers

regulatory; allosteric

4

Covalent modification is

phosphorolation

5

What is a futile pathway

ATP is hydrolyzed and nothing is gained when glycolyis and gluconeogenis is happening at the same time. So they are reciprocally regulated

6

Glucose gets into cell via ___

GLUT 4

7

GLUT 4 is ___dependent

insulin; otherwise sequestered internally in vesicles

8

What are 3 points of regulation for glycolysis

1. Hexokinase
2. Phosphofructokinase 1
3. Pyruvate kinase

9

What are 3 points of regulation for gluconeogenesis

1. Glucose 6-phosphatase
2. Fructose-1, 6-bisphosphatase
3. Pyruvate carboxylase + PEP carboxykinase

10

Glucokinase is liver specific____

isozyme; will forgoe glucose to make sure brain has enough.

11

Hexokinase 4 is sequestered in ____when glucose concentration is low.

nucleus. Cant encounter glucose and phosphorolate it so its kept in cell.

12

When glucose levels are ____ it binds to hexokinase 4 and releases it from the nucleus so it can start phosphorolating glucose so that it can be stored as glycogen

high

13

PFK 1 in glycolysis is an ____regulator

allosteric

14

High [ATP] and [citrate] allosterically signal that energy needs are met and inhibit:

PFK-1

15

High [ADP] and [AMP] allosterically signal need for ATP production and activate ____ and inhibit ___

PFK-1; FBPase-1

16

In the liver, the most important allosteric regulator of PFK-1 is _____ which is synthesized by _____

fructose, 2-6 bisphosphate; PFK-2

17

Glycogen stores in muscle can't help maintain blood glucose levels bc it is never:

released. Doesn't have glucose 6 phosphatase. Only uses glycogen for itself

18

Muscles have _____ receptors but no ____receptors; therefore it does not produce the enzymes for gluconeogenesis.

epinephrine; glucagon

19

What are the 3 principle hormones of fuel metabolixm

1. insulin: fed
2. glucagon: hungry
3. epinephrine: terrified

20

Where does epinephrine come form

adrenal medulla; its actually a catacholamine

21

What is a phenol ring with two hydroxyl groups called

catecolamine. Derived directly from aa - tyrosine; have cell membrane associated receptors and trigger a second messenger

22

What is the classical second messenger

cyclic AMP

23

Where does glucagon come from

alpha cells of pancreas-->islets of Langerhaans

24

Pancreas has ___ and ___ functions

exocrine: digestive enzymes
endocrine: releases proteins into bloodstream so it can go throughout the body

25

Beta cells make

insulin

26

Glucagon is a ____hormone

protein

27

What are the targets of glucagon and epinephrine

Use cyclic amp signaling to change metabolic activity.

28

What is a serpentine receptor

External ligand binding to receptor activates an intracellular GTP binding protein which regulates an enzyme that generates an intracellular second messenger. Go back and forth across cell membrane and when hormone binds it activates G protein

29

What are the 5 proteins involved in epinephrine and glucagon signaling

1. beta adrenergic receptor/glucagon receptor
2. Gs protein
3. adenylate cyclase
4. protein kinase A
5. cyclic nucletodie phosphodiesterase

30

1. Epeniphrine binds its specific receptor -->changes conformation of receptor site and G protein. When receptor binds it knocks off ___ and GTP associates. Alpha subunit loses affinity for its receptor and moves into cell membrane and binds to target enzyme: ______GDP falls off and GTP binds. Now has high affinity for target enzyme.

GDP; adenylate cyclase