Lecture 9

Question 1

how are lipids digested

Answer 1

emulsification

Question 2

what do bile salts increase

Answer 2

surface area

Question 3

what happens first, emulsification, digestion, or absorption

Answer 3

emulsification then digestion then absoprtion

Question 4

what are mixed micelles

Answer 4

• allow for easier transportation
  Monoglycerides + FFA + Bile slats + Phospholipids + Cholesterol

Question 5

what create larger mixed micelles

Answer 5

mixed micelles combines with cholesterol and fat-soluble vitamins

Question 6

where is the main sight of absorption

Answer 6

upper jejunum

Question 7

what happens to lipids upon entering mucosal cell

Answer 7

• fats reassembled into triglycerides
• protein coating occurs to form chylomicrons
• chylomicrons enter lacteals via intercellular space

Question 8

how do mammals absorb long chain FA lipids

Answer 8

via lymph system

Question 9

lipoprotein

Answer 9

lipids + proteins

Question 10

what is different with chickens when absorbing long chain FA lipids

Answer 10

absorb it directly into portal blood

Question 11

how are lipids transported

Answer 11

• blood lipids
• as lipoproteins

Question 12

blood lipids

Answer 12

• chylomicrons
• lipids arising from mobilized depot stores
• lipids synthesized in body tissues

Question 13

what are the 4 major classes of lipids transported as lipoproteins

Answer 13

1. chylomicrons (smallest)
2. VLDL (very low density lipoprotein)
3. LDL (low density lipoprotein)
4. HDL (high density lipoproteins)

Question 14

which lipoprotein has the highest ratio of lipids to protiens

Answer 14

HDL

Question 15

which lipoprotein has the smallest amount of proteins

Answer 15

chylomicrons

Question 16

What is associated with bad cholesterol

Answer 16

LDL
promote plaque formation blood vessels

Question 17

what is associated with good cholesterol

Answer 17

HDL
break down plaque in blood vessels

Question 18

how is triglyceride stored

Answer 18

• all cells in body store lipids
• adipocytes (fat cells) are most notable

Question 19

what happens when there is a negative balance of energy

Answer 19

tissues used by body because it needs energy

Question 20

lipogenesis

Answer 20

building fatty acids and triglycerides from precursors

Question 21

where does lipogenesis occur

Answer 21

1. liver
2. mammary gland
3. adipose tissue

Question 22

FA and TG metabolism in liver

Answer 22

degradation of:
- FA phospholipids
- saturation, desaturation, lengthening, shortening, deposit of liver lipids

Question 23

biosynthesis of fatty acids process

Answer 23

• begins with acetyl-CoA
• assembled in 2C units
• desaturation in tissue limited
• start with a base and continuously add 2C

Question 24

what do microbes convert FA’s to become in ruminants

Answer 24

more saturated

Question 25

triglyceride catabolism

Answer 25

- adipose tissue

Question 25

how does adipose tissue play a part in catabolism of triglyceride

Answer 25

- composed primarily of triglycerides - dynamic tissue= synthesis and degradation of triglycerides - lipoprotein lipase= hydrolysis of TG - activity under hormone control

Question 26

in the hydrolysis of TG, when is activity high and low

Answer 26

high- fed state low- fasted state

Question 27

what is the hormone in TG catabolism

Answer 27

- lipolysis: fat breakdown - stimulated by: paylean and GH - inhibited by: prostaglandins and insulin

Question 28

what is involved in the control of net fat accretion

Answer 28

- complex regulatory systems - lipolysis and lipogenesis

Question 29

fatty acid catabolism

Answer 29

-FA released from hydrolysis= transported to tissues as oxidative energy - beta oxidation

Question 30

beta oxidation

Answer 30

stepwise enzymatic removal of 2C units to be used for: - re-synthesis of FA - synthesis of steroids and ketones - entry into TA cycle where energy comes from

Question 31

where does beta oxidation occur

Answer 31

- mitochondria - what comes in: FA and dehydrogenase - what comes out: shorter FA, electrons, and acetyl-CoA

Question 32

what makes fats so energy dense

Answer 32

high ratio of C and H to O

Question 33

steroid metabolism

Answer 33

- cholesterol (most abundant sterol and precursor) - biosynthesis of acetyl-CoA - cholesterol excreted in bile - used for steroid synthesis

Question 34

phospholipid metabolism

Answer 34

- lecithin most abundant animal tissue because of lipid bilayer

Question 35

ketone metabolism

Answer 35

- formation of ketones= continous - energy source in skeletal muscle and other peripheral tissue - can have overproduction

Question 36

fatty liver abnormality

Answer 36

- negative energy balance - excessive fat mobilization from adipose tissue - fat dpeosited in liver slower than net lose

Question 37

how do you prevent fatty livers

Answer 37

- transition period is important - feeding protected choline - dairy cattle

Question 38

ketosis

Answer 38

- rapid mobilization of fat depot - reduced intakes - lack of ability to metabolize acetyl-CoA in TCA cycle

Question 39

obesity

Answer 39

- over consumption of calories= factor - genetic=factor - net deposition greater than normal - cell size and number

Question 40

what can occur postnatally to cause obesity

Answer 40

proliferation