Kaplan Biochemistry: Chapter 11 Lipid and AA Metabolism

Question 1

four components that make up a micelle

Answer 1

free fatty acids, cholesterol and 2 monoglycerol and bile salts

Question 2

bile salts are actively reabsorbed in the ____

Answer 2

ileum

Question 3

before being absorbed, fats in the lumen of the intestine must be

Answer 3

emulsified, by the help of bile salts, pigements, and cholesterol.

Question 4

micelles of fat diffuse to the brush boarder where they are ______ to formed ___ and ___ ____, to form ____

Answer 4

micelles of fat diffuse to the brush boarder where they are REESTERFIED to formed TRIACYGLYCEROLS and CHOLESTEROL ESTERS, to form CHYLOMICRONS

Question 5

once the micelle becomes a chylomicron in the villi, the chylomicron leaves the intestine via ____, and re-enter the blood stream via the ___ ___

Answer 5

once the micelle becomes a chylomicron in the villi, the chylomicron leaves the intestine via LACTEALS, and re-enter the blood stream via the THORACIC DUCT.

Question 6

fall of insulin levels activate ___-__ ___ that hydrolyzes triacylglycerols

Answer 6

hormone-sensitive lipase

Question 7

in addition to insulin, what other chemical can activate hormone-sensitive lipase?

Answer 7

epinephrine.

Question 8

where can you find hormone-sensitive lipase

Answer 8

in adipose tissue.

Question 9

cortisol effects on hormone-sensitive lipase

Answer 9

activates hormone sensitive lipase to hydrolyze triacyl glycerols into glycerol and fatty acids.

Question 10

when being transported in the blood, fatty acids are bound to

Answer 10

albumin

Question 11

what organ does beta oxidation take place

Answer 11

liver

Question 12

most triacylglycerols are SYNTHESIZED by the ___ and transported as _____ to ____ ___ for storage.

Answer 12

most triacylglycerols are SYNTHESIZED by the LIVER and transported as VLDL to ADIPOSE TISSUE for storage.

VLDL (very low density lipoprotein)

Question 13

____ transport dietary TGAs and cholesterol from intestine to tissues. its assembly occurs in the intestinal lining

Answer 13

chylomicrons

Question 14

____ transports TGAs from liver to tissues. Where are htey made?

Answer 14

VLDL. made in the liver cells.

Question 15

____ delivers cholesterol into cells

Answer 15

LDL

Question 16

___ picks up cholesterol accumulating in blood vessels and delivers cholesterol to liver and steroidgenic tissuesH

Answer 16

HDL

Question 17

where does de novo cholesterol synthesis occur

Answer 17

in the liver

Question 18

___ promotes cholesterol synthesis

Answer 18

insulin

Question 19

main enyzme in cholesterol synthesis? what does it do

Answer 19

lecithin cholesterol acyltransferase. found in the blood stream and activated by HDL apoproteins.

adds a fatty acid to cholesterol, which produces a soluble cholesterylester such as those in HDL.

Question 20

where does fatty acid synthesis occur

Answer 20

in the liver. then they are stored in adipose tissue. the fatty acids are moved from the liver to the adipose tissue via VLDL

Question 21

primary end product of fatty acid synthesis

Answer 21

palmitic acid

Question 22

acetyl coa accumulate in the ___ ___ and is moved to the ____ for fatty acid biosynthesis. How does it do this?

Answer 22

acetyl coa accumulate in the MITOCHONDRIAL MATRIX and is moved to the CYTOSOL for fatty acid biosynthesis.

Moved to the cytosol by first combining with OAA to form citrate, which can freely move across the mitochondrial membrane. in the cytosol, citrate lyase splits citrate back into acetyl coA and OAA.

Question 23

rate limiting step of fatty acid synthesis.

Answer 23

acetylcoA + CO2 –> malonyl coA via acetyl-coA carbozylase.

this occurs in the cytoplasm.

Question 24

main reducing agent in fatty acid synthesis

Answer 24

NADPH

Question 25

beta oxidation occurs in the ___, fatty acid synthesis occurs in the ___

Answer 25

beta oxidation occurs in the MITOCHONDRIA, fatty acid synthesis occurs in the CYTOSOL.

Question 26

WHAT shuttle is emplyed to bring fatty acids into the mitochondrial matrix for oxidation?

Answer 26

carnitine shuttle. fatty acyl-coA are transported using carnitine shuttle.

Question 27

what are the products of ONE cycle of beta oxidation

Answer 27

1) acetyl coA - goes to krebs 2) NADH - to ETC 3) FADH - to ETC

Question 28

FAD, in its fully oxidized form, or quinone form, accepts ____ electrons and ____ protons to become FADH2

Answer 28

FAD, in its fully oxidized form, or quinone form, accepts two electrons and two protons to become FADH2

Question 29

NAD+, in its fully oxidized form, accepts ___ electrons and ___ to become NADH

Answer 29

a charged hydrogen molecule (H+) and next, two electrons.

Question 30

4 steps of beta oxidation

Answer 30

1) oxidation of fatty acid to form DB at alpha-beta site. produces FADH 2) hydration of DB to form OH group on beta 3) oxidation of OH gorup to form C=O, forms NADH 4) splitting of betaketoacid into a shorter acyl-coA and acetyl coA. the C=O on the previous beta carbon is now the acyl group of the fatty acid.

Question 31

for beta oxidation of odd-numbered fatty acids, the last cycle yields ___ acetyl coA and ____ ____ rather than 2 acetyl coA molecules.

Answer 31

for beta oxidation of odd-numbered fatty acids, the last cycle yields ONE acetyl coA and PROPRIONYL-COA rather than 2 acetyl coA molecules.

Question 32

T/F: ketogenesis can only occur in the liver

Answer 32

FALSE. ketogenesis primarily occurs in the liver, but it cannot be used by the liver. Though it is the source of ketone bodies, the liver itself cannot use them for energy because it lacks the enzyme thiophorase

Question 33

where in the cell does ketogenesis occur

Answer 33

mitochondria

Question 34

name three pancreatic proteases

Answer 34

trypsin, chymptrypsin, caboxypeptidase

Question 35

is a dipeptidase synthesized in the pancreas?

Answer 35

false. it is a brushboarder enzyme found in the duodenum

Question 36

how are amino acids and small peptides absorbed in the small intestine

Answer 36

accomplished by secondary active transport linked to sodium. amino acids and sodium in the lumen of the small intestine move into the epithelial cells/brushboarder cells via secondary active transport. in the brushboarder cell, any remaining peptides are broken down into amino acids. at the basal membrane, simple and facilitated diffused transports amino acids into the blood stream.

Question 37

name the ketogenic amino acids

Answer 37

leucine and lysine. everything else are glucogenic and can be converted to glucose via gluconeogenesis rather than ketone bodies or acetyl coA.