Lecture 31 Unit 4

Question 1

how can lipids be transported in blood

Answer 1

if they combine with a protein

Question 2

describe lipoproteins

Answer 2

spheres containing hundreds of molecules

Question 3

how are lipoproteins categorized

Answer 3

by function and density

Question 4

what are the 4 major classes of lipoproteins

Answer 4

• chylomicrons
• very low density
• low density
• high density

Question 5

what makes up chylomicrons

Answer 5

2% protein, 85% TG

Question 6

where to chylomicrons form

Answer 6

in intestinal epithelial cells to transport dietary fats to adipose cells

Question 7

what makes up very low density lipoproteins

Answer 7

10% protein 50% TG

Question 8

where do VLDLs form

Answer 8

in hepatocytes to transport triglycerides to adipose cells

Question 9

what makes up low density lipoproteins

Answer 9

25% protein 50% cholesterol (bad cholesterol)

Question 10

what do LDLs do

Answer 10

carry blood cholesterol to body cells

Question 11

what makes up high density lipoproteins

Answer 11

40% protein 20% cholesterol (good cholesterol)

Question 12

what do HDLs do

Answer 12

carry cholesterol from cells to liver for elimination

Question 13

what is the “fate of lipids”

Answer 13

oxidized to produce ATP

Question 14

where are excess lipids stored

Answer 14

in adipose tissue or liver

Question 15

what do lipids synthesize

Answer 15

• phospholipids for plasma membranes
• lipoproteins that transport cholesterol
• thromboplastin for blood clotting
• myelin sheaths to speed up nerve conduction
• cholesterol used to synthesize bile salta nod steroid hormones

Question 16

what is thromboplastin made of

Answer 16

phospholipids and tissue factor

Question 17

what happens in lipolysis

Answer 17

triglycerides are broken down into glycerol and fatty acids within liver or adipose cells in the presence of epinephrine, norepinephrine, or cortisol

Question 18

what happens in lipogenesis

Answer 18

triglycerides are synthesized from amino acids or glucose within liver or adipose cells in the presence of insulin

Question 19

what do fatty acids in lipolysis undergo in mitochondria and what do they produce?

Answer 19

they undergo beta oxidation to produce acetyl CoA and lots of ATP

Question 20

where does ketogenesis occur

Answer 20

in liver cells

Question 21

what are ketone bodies use by and for?

Answer 21

used by heart muscle and kidney cortex for ATP production

Question 22

what are the fuel sources for lipogenesis

Answer 22

1. amino acids, glycolysis metabolites, and ketone bodies for fatty acid production from Acetyl CoA
2. glycolysis metabolites for glycerol production

Question 23

what is the “fate of proteins”

Answer 23

they are broke down into amino acids which are transported to the liver

Question 24

what could happen to amino acids

Answer 24

1. deaminated to enter Krebs cycle
2. donate amino group to form new amino acid-transamination
3. used to synthesize new proteins throughout the body

Question 25

what are excess amino acid s converted to

Answer 25

either glucose or triglycerides

-there is no storage

Question 26

what is absorption of AA into body cells stimulated by

Answer 26

insulin like growth factors and insulin