Regulation of Carbohydrate and Lipid Metabolism

Question 1

What are the seven metabolic pathways?

Answer 1

Glycolysis, Gluconeogenesis, Glycogen metabolism, fatty acid metabolism, citric acid cycle, oxidative phosphorylation and amino acid metabolism

Question 2

NADH carries e- from _____ is called _____.

Answer 2

Breakdown, catabolism

Question 3

NADPH carries e- for ____ is called _____.

Answer 3

Biosynthesis, anabolism

Question 4

What is the link between glucose pathways?

Answer 4

Glucose 6-phosphate

Question 5

What are the three pathway products that become of glucose breakdown?

Answer 5

Glycogen, pyruvate, ribose 5-phosphate

Question 6

What are the key links between all pathways?

Answer 6

Glucose-6-P, pyruvate, acetyl CoA

Question 7

What step causes pyruvate to become acetyl CoA and why is it impossible to reverse the reaction?

Answer 7

Deccarboxylation

The reverse rxn is not energetically favorable

Question 8

How are the major metabolic pathways regulated?

Answer 8

Compartmentalization in the cell
Reciprocal regulation of metabolic pathway enzyme
Organ specialization
Hormone regulation

Question 9

What are the regulatory organs for metabolic pathways ?

Answer 9

Brain, muscle, cardiac muscle, adipose, kidney, liver

Question 10

What is the primary fuel for the brain and what does it use in the absence of that fuel?

Answer 10

Glucose, ketone bodies

Question 11

Why are fatty acids not generally used as brain fuel?

Answer 11

Take to long to break down, though they can cross the BBB

Question 12

If the glucose level in the brain is less than 2.2 mM what could occur?

Answer 12

Coma and death

Question 13

What fuels can muscles use?

Answer 13

Glucose, fatty acid, ketone bodies

Question 14

Pyruvate is used to generate ____ which regenerates NAD+ for ____.

Answer 14

Lactate, glycolysis

Question 15

What are the two factors that decrease the efficiency of muscles?

Answer 15

Lactic acid and dec of pH

Question 16

Lactate is moved to the liver and what cycle does it enter to be made useful again?

Answer 16

Gluconeogenesis after being converted back to pyruvate

Question 17

What substance in skeletal muscle has the ability to regenerate ATP from ADP?

Answer 17

Phosphocreatine

Question 18

In the starvation state what substance does muscle break down?

Answer 18

Amino acids

Question 19

Because muscles cannot breakdown ammonia, what happens to the amino group instead?

Answer 19

Alanine aminotransferase transfers the amino group to pyruvate to make alanine

Question 20

Does the cardiac muscle store its glycogen reserves?

Answer 20

No where because it doesn’t have any

Question 21

What are the primary fuel of cardiac muscle?

Answer 21

Fatty acids

Ketone bodies are second

Question 22

Once converted to triaglycerols where are fatty acids shipped to and what takes them there?

Answer 22

Adipose, VLDL

Question 23

What cuts up the free fatty acids?

Answer 23

Lipase

Question 24

What must be generated to make TAG?

Answer 24

Glycerol-3-P

Question 25

When blood glucose is low _____ activates lipase to hydrolze adipose ____ to release free fatty acids/glycerol.

Answer 25

Glucagon, TAG

Question 26

What does glycerol stimulate in the liver?

Answer 26

Gluconeogenesis

Question 27

What is the primary role of the kidney?

Answer 27

Excrete water soluble waste

Question 28

What can the kidney do during prolonged starvation?

Answer 28

Produce up to 50% of blood glucose

Question 29

What are the general functions of the liver in metabolic regulation?

Answer 29

Maintains blood glucose Regulates all metabolites in the blood Can store up to a day of energy as glycogen Produced fatty acids for storage in the fed state Produces ketone bodies in starvation

Question 30

Why does the liver use glucokinase instead of hexokinase?

Answer 30

Glucokinase has a lower Km for glucose and the liver doesn't want to use too much of the glucose it makes

Question 31

What are the only organ which have glucose-6-P for maintain glucose levels?

Answer 31

Kidney and liver

Question 32

Can the liver use ketone bodies? Why or why not?

Answer 32

No because the liver doesn't have CoA transferase

Question 33

Where is (nor)epinephrine released from?

Answer 33

Adrenal gland

Question 34

What does epinephrine stimulate in the liver?

Answer 34

Gluconeogenesis and glycogen phosphorylase

Question 35

What does epinephrine inactive in the liver?

Answer 35

Glycogen synthase (no glucose metabolism)

Question 36

What does epinephrine promote in muscles?

Answer 36

Glycolysis (raises Fruc-2,6,BP to activate PFK)

Question 37

What does epinephrine promote in adipose?

Answer 37

Mobilization of fatty acids`

Question 38

What are the metabolic effects of epinephrine on physiological rate?

Answer 38

Inc heart rate Inc blood pressure In dilation of respiratory passage Inc delivery of O2 to tissues

Question 39

What are the metabolic effects of epinephrine on the actual metabolism?

Answer 39

``` Inc glycogen breakdown (muscle, liver) Dec glycogen synth (muscle liver) Inc Gluconeogenesis (liver) Inc glycolysis (muscle) Inc fatty acid mobilization (adipose) Inc glucagon secretion Dec insulin secretion ```

Question 40

Low blood glucose causes release of _____ from ____ in pancrease islet cells.

Answer 40

Glucagon, a-cells

Question 41

What does glucose stimulate in the liver?

Answer 41

Glycogenolysis and gluconeogenesis

Question 42

What does glucose inhibit in the liver?

Answer 42

Glycogen synth and glycolysis

Question 43

What does glucose activate in adipose?

Answer 43

Lipase to mobilize fatty acids and glycerol

Question 44

High blood glucose causes release of ____ from ____ in pancreas is

Answer 44

Insulin, b-cells

Question 45

What does insulin increase is tissues?

Answer 45

Rate of glucose uptake

Question 46

What does insulin activate in the liver?

Answer 46

Glycogen synthase, stimulates FA biosynth

Question 47

What does insulin inactivate in the liver?

Answer 47

Phosphorylase (storage)

Question 48

What does insulin stimulate in adipose?

Answer 48

Uptake of FAs from VLDLs and TAG synth

Question 49

What is cortisol?

Answer 49

Steroid hormone that indicates long-term stress

Question 50

Where is cortisol produced from and how does it work?

Answer 50

Adrenal cortex, acts slowly by changing expression of metabolic enzyme genes Passes thorugh plasma membrane and binds to nuclear receptors

Question 51

What does cortisol stimulate in adipose?

Answer 51

Release of FAs

Question 52

What does cortisol stimulate in muscle?

Answer 52

Breakdown of proteins, export of AA for gluconeogensis

Question 53

What does cortisol increase in the liver?

Answer 53

Levels pf pyruvate carboxylase to stimulate gluconeogensis