Lecture 7 - Carbohydrate, lipid and amino acid metabolism

Question 1

What is the absorptive state

Answer 1

Energy comes from oxidizing nutrients that enter bloodstream from gut

Question 2

What is the postabsorptive state

Answer 2

Nutrients mobilized from body’s stores (NOT starvation)

Question 3

How many hours does it take for absorption after a meal for carnivores and omnivores?

Answer 3

4 hours

Question 4

How long does it take for absorption in ruminants

Answer 4

Digestion/absorption more continuous

Question 5

What is energy stored as

Answer 5

Glycogen and fat

Question 6

The process of making glycogen is called..

Answer 6

Glycogenesis

Question 7

What happens to aa in the liver

Answer 7

They are modified (created and broken down)

Question 8

What amino acids can be synthesized by the body?

Answer 8

Non-essential amino acids

Question 9

Amino acid composition of diet matters less in…

Answer 9

ruminants

Question 10

What is converted to glucose in the liver

Answer 10

Galactose and fructose

Question 11

What processes is the liver a key player in

Answer 11

Anabolic and catabolic

Question 12

What happens to glucose in the liver

Answer 12

Phosphorylated in cell (accumulates until dephosphorylation). Glucose-6-phosphatase allows it to exit

Question 13

Lack of glucose-6-phosphatase in dogs is…

Answer 13

Glycogen storage disease (hypoglycemia + mental depression)

Question 14

What takes up glucose and converts it to triglycerides

Answer 14

Adipocytes

Question 15

What % of liver mass does glycogen need to be for glycogenesis to stop

Answer 15

5%

Question 16

What happens to excess glucose once we reach 5% liver mass

Answer 16

Converted to triglycerides, released as lipoproteins, taken up by adipose and mammary

Question 17

What is equine polysaccharide storage myopathy

Answer 17

Genetic glycogen storage disease
Incurable but manageable (diet and exercise)

Question 18

Two types of PSSM

Answer 18

Type 1: increase expression of glycogen synthase (GSY1), but not branching enzyme (glycogen with no branches harder to breakdown)
Type 2: Abnormal glycogen deposition without GSY1 or GBE1 mutation

Question 19

Where are lipoproteins produced? What do they do

Answer 19

Liver
Transport triglycerides to rest of body

Question 20

What are lipoproteins made of

Answer 20

Triglycerides, phospholipids, cholesterol, transport proteins, apolipoprotein

Question 21

Role of apolipoprotein

Answer 21

Tell lipoprotein where to go, recognized by specific cell membrane receptors

Question 22

Main enzyme of lipoproteins

Answer 22

Lipoprotein lipase

Question 23

What happens to triglycerides after lipid degradation? Fa?

Answer 23

TG stored
Some fa used as energy source, most ffa diffuse into adipose, mammary and other cells (or converted back to TG)

Question 24

What happens to chylomicron remnants after lipid degradation

Answer 24

Back to liver = liver enriched with cholesterol

Question 25

How are ffa transported? Other lipids?

Answer 25

FFA = albumin Other = lipoproteins

Question 26

Where are lipoproteins synthesized

Answer 26

Liver

Question 27

What is VLDL? LDL? HDL?

Answer 27

VLDL = very low density lipoprotein LDL = low density lipoprotein HDL = high density lipoprotein

Question 28

What are "bad cholesterol" what does it do

Answer 28

LDL and VLDL Transport cholesterol to cells (taken up by endocytosis)

Question 29

What is "good cholesterol" what does it do

Answer 29

HDL Collects cholesterol from cells and transports to liver (then excreted as bile)

Question 30

Slide 13

Answer 30

HDL, VLDL, LDL

Question 31

What happens to aa in the liver

Answer 31

Used to make many things (e.g. albumin, fibrinogen, complement) Some converted to keto acids, converted to glucose and FAs Low glucose = used as cellular fuel

Question 32

Deamination is when...

Answer 32

amino group is separated from organic acids

Question 33

What part of the aa is used as an energy source

Answer 33

organic acids

Question 34

How do liver cells replenish glycogen stores

Answer 34

Glucose and aa's

Question 35

What does the liver do with lipids

Answer 35

Exports them around the body

Question 36

Slide 18***

Answer 36

CHO, lipid and aa metabolism

Question 37

What is glycogenolysis

Answer 37

If glucose concentrations fall below a certain level, liver mobilizes glycogen reserves

Question 38

Why can't skeletal muscle release glucose in to the blood

Answer 38

Lack glucose-6-phosphate (needed to dephosphorylate and release glucose from cell)

Question 39

What does skeletal muscle do to get glucose out

Answer 39

Produce pyruvate and lactate

Question 40

What is gluconeogenesis? What organs are involves? What are the sources?

Answer 40

Making glucose from non-carbohydrate sources Liver and kidney Pyruvate from aa breakdown, lactate and glycerol

Question 41

Precursor of glucose

Answer 41

Propionic acid

Question 42

What is the cori cycle

Answer 42

Lactate produced in muscle cells is converted to glucose in the liver and can return to muscle cells

Question 43

Slide 21

Answer 43

Cori cycle

Question 44

What is utilized as the main energy source in a postabsorptive state? Referred to as..

Answer 44

Lipids (glucose sparing) TGs broken down, FA diffuse in blood, taken up by tissues, oxidized to make energy

Question 45

Insulin is secreted by __________ in response to _________________

Answer 45

Beta cells High blood glucose

Question 46

What does insulin do (4)

Answer 46

Increase uptake of glucose in the cells of organs Stimulates synthesis of glycogen, inhibits degradation Increases consumption of glucose for ATP production Inhibits gluconeogenesis

Question 47

Glucagon is secreted by _____________ in response to ____________________

Answer 47

Alpha cells Low blood glucose

Question 48

What does glucagon do

Answer 48

Stimulates glycogenolysis in the liver Stimulates gluconeogenesis in the liver Stimulates lipolysis in adipose

Question 49

Keys to regulating blood glucose levels

Answer 49

Insulin and glucagon

Question 50

Slide 26**

Answer 50

Insulin and glucagon and proteins/aa

Question 51

What is lipolysis

Answer 51

Lysing lipoproteins

Question 52

Slide 27**

Answer 52

Glucagon effects

Question 53

___________________ causes mobilization of glucose from glycogen

Answer 53

Epinephrine

Question 54

What is fatty liver

Answer 54

Occurs when excessive fa mobilization occurs, or impaired ability to export it via apolipoproteins (VLDL packaging low) Excessive mobilization from adipose

Question 55

Severe fatty liver can...

Answer 55

impair liver function

Question 56

Fatty liver most common in

Answer 56

Early lactation dairy cows Late gestation beef cattle

Question 57

Slide 30, 31**

Answer 57

Glucose metabolism

Question 58

What does hormone sensitive lipase do

Answer 58

Break down TG into ffa and glycerol