BB451 exam 2 - Fatty Acid Metabolism

Question 1

fats stored in

Answer 1

adipocytes

Question 2

fatty acids travel in blood stream by…

Answer 2

serum albumin

Question 3

degradation (summary)

Answer 3

in mitochondria and peroxisome

oxidation, hydration, oxidation, cleavage

Question 4

synthesis (summary)

Answer 4

in cytoplasm and ER and mitochondrion

reduction, dehydration, reduction, condensation

Question 5

lipases

Answer 5

break down fats to fatty acids and glycerol

Question 6

glycerol

Answer 6

only part of fat that can be made into glucose (via gluconeogenesis)

Question 7

across intestine wall…

Answer 7

monoacylglycerol + fatty acids –> across wall

then reassembled and go to chylomicrons

Question 8

triacylglycerol lipase

Answer 8

hormone sensitive
only regulated enzyme of fat or fatty acid breakdown
in adipocytes
cute first one off?

Question 9

oxidation in mitochondrial matrix

Answer 9

in cells: fatty acids attached to CoA (acyl-CoA)
at mitochondria: CoA replaced by carnitine
in matrix: carnitine replaced by CoA again

Question 10

steps in beta oxidation mirror…

Answer 10

oxidation of succinate to oxaloacetate in CAS

Question 11

step 1 beta oxidation

Answer 11

dehydrogenation

enzyme: acyl-CoA dehydrogenases
- -> FADH2 and intermediate w/ double bond in trans

Question 12

step 2 beta oxidation

Answer 12

hydration: add water across double bond

- -> hydroxyl group on 3rd C from CoA in L form

Question 13

step 3 beta oxidation

Answer 13

oxidation –> NADH and ketone

Question 14

step 4 beta oxidation

Answer 14

thiolytic cleavage

catalyzed by thiolase : cleave off acetyl CoA –> fatty acyl-CoA with 2 fewer Cs

Question 15

thiolase

Answer 15

catalyzes thiolytic cleavage (step 4 in beta oxidation)

Question 16

acyl-CoA dehydrogenase

Answer 16

catalyzes dehydrogenation (step 1 in beta oxidation) 
specialized form for long, medium, and short chain fatty acids 
pulls out protons and e's between C2-3

Question 17

short and medium chain acyl-CoA dehydrogenases ….

Answer 17

in mitochondria
short : 8-10 or smaller
medium - some instances of sudden infant death syndrome if deficient

Question 18

long chain acyl-CoA dehydrogenases

Answer 18

in peroxisomes (>16C)
e to oxygen --> hydrogen peroxide instead of FADH2 (less efficient)

Question 19

most common fatty acid

Answer 19

palmitic acid / palmitoyl - CoA
16 carbons
cycle 7 times –> 8 acetyl CoAs

Question 20

enoyl -CoA - isomerase

Answer 20

converts cis (or trans) bonds between 3-4 to trans between 2-3

Question 21

beta oxidation normally has ___ bonded intermediates between __

Answer 21

trans bonds intermediates between 2-3

Question 22

2,4 - dienoyl - CoA reductase

Answer 22

acts on intermediates that have double bonds between 2-3 and 4-5.
uses NADPH to reduce 2 double bonds to 1 in cis between 3-4
the enoyl-CoA isomerase can act

Question 23

oxidation of fatty acids with odd number of carbons

Answer 23

propionyl - CoA (3 carbons) (not acetyl-CoA)

propionyl CoA –> succinyl CoA requires enzyme that uses coenzyme B12

Question 24

steps in oxidation of fatty acids with odd number of carbons

Answer 24

addition of carboxyl to middle carbon, 2 unusual isomerizations and movement of methyl group that uses cobalt atom of B12

Question 25

ketone bodies

Answer 25

produced when glucose precursors are not available to make glucose ex: acetoacetate and hydroxybutyrate

Question 26

sign of diabetic..

Answer 26

acetone on breath | acetoacetate unstable --> acetone, very volatile

Question 27

thiolase

Answer 27

thiolase reaction in ketone body formation is reversal of same reaction in fatty acid metabolism (between oxidation and synthesis)

Question 28

synthesis up to palmitate occurs in...

Answer 28

cytoplasm

Question 29

fatty acids built using

Answer 29

acyl carrier proteins (ACP)

Question 30

___ used to donate e's in synthesis

Answer 30

NADPH

Question 31

malonyl-ACP...

Answer 31

3 carbons donated 2 Cs to growing fatty acid chain CO2 lost in process

Question 32

synthesis of fatty acids longer than ____ occur in___

Answer 32

longer than 16C occur in ER or mitochondria

Question 33

in synthesis, a ___ intermediate is formed at ___

Answer 33

a D-hydroxyl intermediate is formed at C3

Question 34

beta oxidation occurs in

Answer 34

mitochondrial matrix

Question 35

beta oxidation uses ___

Answer 35

CoA

Question 36

___ used to accept e's in oxidation

Answer 36

NAD and FAD

Question 37

beta oxidation yield

Answer 37

2 carbon acetyl - CoA units

Question 38

oxidation of fatty acids longer than ___ occurs on ___

Answer 38

longer than 16 in peroxisome

Question 39

in oxidation and __ intermediates is formed at ___

Answer 39

L-hydroxyl intermediate at C3

Question 40

acetyl - CoA carboxylase

Answer 40

addition of carboxyl group to acetyl CoA --> malonyl coA (3C)

Question 41

regulation of acetyl-CoA carboxylase

Answer 41

alloserically - inhibited by palmitoyl-CoA (first end product, feedback inhibition), activated by citrate covalent modification - phosphorylation inhibits

Question 42

CoA from malonyl-CoA swapped for ...

Answer 42

swapped for ACP to start synthesis --> malonyl-ACP

Question 43

acetyl-CoA gets into cytoplasm from mitochondria by....

Answer 43

citrate shuttle acetyl-CoA linked to oxaloacetate in mitochondria --> citrate -->transported out --> citrate cleaved --> acetyl CoA + oxaloacetate in cytoplasm

Question 44

only enzyme regulated in synthesis

Answer 44

acetyl CoA carboxylase

Question 45

malonyl ACP is...

Answer 45

adding block for synthesis

Question 46

acetyl ACP is ...

Answer 46

starting block

Question 47

decarboxylation of malonyl ACP -->

Answer 47

2 carbon addition to growing chain (onto carboxyl end)

Question 48

1st reaction in saturated fatty acid synthesis

Answer 48

malonyl ACP + acetyl ACP | condensation - CO2 lost (CO2 on then off...)

Question 49

saturated fatty acid synthesis ....

Answer 49

malonyl ACP + acetyl ACP reduce - use NADPH --> alcohol dehydration --> trans double bond reduction - use NADPH --> 4C fatty acid (combine with new malonyl - ACP) continues until 16 carbons (palmitoyl - CoA)

Question 50

fatty acid synthase

Answer 50

multi enzyme complex catalyzes all reaction up to 16 carbons rotates through reactions like clock

Question 51

desaturases

Answer 51

produce unsaturated fatty acids in ER use unusual e transferring initiated by donation of e from NADH to oxygen

Question 52

essential fatty acids

Answer 52

must be in diet, cant make in animals: linoleic and linolenic acids cant make double bond past delta - 9

Question 53

fatty acids longer than 16 produced by...

Answer 53

elongases - 2 carbons at a time | in ER and mitochondria

Question 54

trans fatty acids produced by

Answer 54

partial hydrogenation of vegetable oil

Question 55

prostaglandins

Answer 55

hormone like compounds made from arachidonic acid by prostaglandin synthase

Question 56

prostaglandin synthase

Answer 56

many in body | reactions are forming cyclic oxygen containing compounds --> cyclooxygenases (COX)

Question 57

prostaglandin effects

Answer 57

``` vasoconstriction/dilation uterine contractions aggregation/stickiness of platelets inflammation/pain maintenance of stomach lining ```

Question 58

linoleic acid released from ___ by ___

Answer 58

released from glycerophospholipids by PLA2

Question 59

PLA2 inhibited by

Answer 59

corticosteroids | treat sever inflammation/pain

Question 60

linoleic acid--->

Answer 60

arachidonic acid

Question 61

leukotrienes

Answer 61

from arachidonic acid via linear pathway mucus production and bronchial constriction cause asthma attacks and allergies

Question 62

cyclic pathway from arachidonic acid

Answer 62

prostaglandins --> thromboxanes

Question 63

thromboxanes

Answer 63

help make platelets sticky favoring aggregation

Question 64

asprin and blood clotting

Answer 64

reduce synthesis of prostaglandins --> reduce thromboxanes --> reduce stickiness of platelets

Question 65

prostaglandins get out of cell by

Answer 65

multi drug resistance protein

Question 66

prostaglandins are a ___ hormone

Answer 66

local - only effects in location synthesized