BB451 exam 1 - Biosynthesis of Membrane Lipids

Question 1

phosphatidic acid

Answer 1

glycerol backbone with 2 fatty acids and phosphate

precursor of glycerophospholipids and fats

Question 2

to create a fat…

Answer 2

replace phosphate of phosphatidic acid with fatty acid

phosphatidate –> DAG –> triglycerol

Question 3

to make a glycerophospholipid…

Answer 3

add something to phosphate of phosphatidic acid –> phosphatidal compound
phosphatidate –> CDP-diacylglycerol–> glycerophospholipid

Question 4

CDP - diacylglycerol

Answer 4

activated intermediate

donates phosphatidate part to something else (ex: serine –> phasphatidalserine)

Question 5

activated intermediate

Answer 5

high energy to donate part of itself to something else

Question 6

cells that contain fat

Answer 6

lipocytes

Question 7

synthesis of DNA requires

Answer 7

energy, nucleotides, and other molecules made with them (proteins, glycogen, glycerophospholipids)

Question 8

measure of nucleotides gives good measure of…

Answer 8

measure of nucleotides gives cells good measure of energy assessment, ability to use energy going forward

Question 9

2 ways to make glycerophospholipids

Answer 9

activate diacylglycerol
activate thing that gets put onto diacylglycerol (ex: activate ethanolamine, add to CDP-diacylglycerol –> phosphatidylethanolamine
*both use activated intermediate and produce CMP

Question 10

3 classes of sphingolipids

Answer 10

ceramides, cerebrosides, gangliosides

Question 11

ceramide

Answer 11

collection of sphingolipids with fatty acid on them (addition of fatty acid to the amine group)

Question 12

sphingolipids made from

Answer 12

palmitoyl CoA + serine manipulated to a ceramide

Question 13

cerebroside or ganglioside formed by

Answer 13

addition of sugar to ceramide

Question 14

sphingomyelin formed by

Answer 14

addition of phosphate group from phosphatidyl choline to ceramide

Question 15

activated sugar has ..

Answer 15

nucleotide attached ex: UDP

Question 16

deficiencies in enzymes that degrade sphingolipids lined to

Answer 16

neural disorders

ex: Tay-Sachs disease

Question 17

cholesterol made from

Answer 17

Acetyl CoA

Question 18

acetoacetyl CoA

Answer 18

2 acetyl CoA put together

Question 19

HMG-CoA

Answer 19

3rd acetyl CoA added to acetoacetyl CoA

branch point for synthesis of ketone bodies or cholesterol

Question 20

mevalonate

Answer 20

from HMG-CoA, path towards cholesterol

uses HMG CoA reductase

Question 21

primary regulated enzyme in synthesis of cholesterol

Answer 21

HMG CoA reductase

regulated by feedback inhibition by cholesterol

Question 22

statins

Answer 22

drugs to reduce cholesterol
target HMG CoA reductase
competitive inhibitors of enzyme (resemble HMG CoA, the substrate)

Question 23

pathway of cholesterol synthesis

Answer 23

HMG CoA (6C) –> mevalonate (6C) –>isoprenes (5C) –> geranyl pyrophosphate (10C) –> farnesyl pyrophosphate (15C) —> squalene (30C) –> lanosterol –> 19 more steps to get to cholesterol

Question 24

isoprenes

Answer 24

isopentenyl pyrophosphate and dimethylallyl pyrophosphate 
precursors to cholesterol 
can go back and forth between 2 
each have 5 carbons 
come together --> geranyl pyrophosphate

Question 25

farnesyl pyrophosphate formed by

Answer 25

addition of 5C isopentenyl pyrophostate to 10C geranyl pyrophosphate

Question 26

squalene formation

Answer 26

2 farnesyl pyrophosphates | last linear intermediate

Question 27

lanosterol

Answer 27

cyclic intermediate | look like cholesterol but still 19 mores steps

Question 28

___ ATPs to get to squalene

Answer 28

18 ATPs to get to squalene

Question 29

cholesterol important for synthesis of

Answer 29

``` steroid hormones (and vit. D) bile acids/salts ```

Question 30

isoprenoid

Answer 30

made from isoprenes | ex: cholesterol, steroids, vit A and vit E

Question 31

steroids

Answer 31

all compounds synthesized from cholesterol | ex: steroid hormones, vit D, bile acids

Question 32

SREBP

Answer 32

plays role in controlling whether or not HMG-CoA reductase is made

Question 33

3 components of SREBP

Answer 33

``` R = regulatory M = membrane portion D = DNA binding portion (bind to SRE) ```

Question 34

when normal cholesterol levels, SREBP...

Answer 34

SREBP - ER | not need to make cholesterol

Question 35

when cholesterol levels fall, SREBP...

Answer 35

moves to Golgi = SREBP-G

Question 36

SREBP-G

Answer 36

serine protease cleaves to release MD regions MD regions move to metaloprotease, cleaves D fro M D enters nucleus, binds to promoter region (SRE) and HMG-CoA reductase is synthesized