Blomquist: Lipids part II

Question 1

What three things make up phospholipids?

Answer 1

1. glycerol
2. fatty acids
3. bases

Question 2

What are some common bases that make up phospholipids?

Answer 2

ethanolamine
choline
serine
glycerol

Question 3

What is the most abundant phospholipid?

Answer 3

phosphatidylcholine

Question 4

Double bonds in fatty acids make membranes more (blank); cholesterol makes membranes less (blank)

Answer 4

fluid; fluid

Question 5

(blank) are structures outside of the cell membrane facing the extracellular fluid.

Answer 5

glycolipids

Question 6

Components of cell membranes

Answer 6

cholesterol, integral proteins, peripheral proteins, glycoproteins, carbohydrate, glycolipids

Question 7

Phospholipid comprised of two phosphatidic acids joined by a glycerol
Comprises about 20% of the inner mitochondria membrane
Abundant in bacteria

Answer 7

cardiolipin

Question 8

Phospholipid with an ether linkage

Answer 8

plasmalogen

Question 9

Mediates hypersensitivity, allergic responses, others. Inactivated by hydrolysis of acetyl group and reacylation with fatty acyl group to form ether-type membrane phospholipid. First phospholipid shown to have special function.

Answer 9

Platelet activating factor

Question 10

What group is at the R2 position of platelet activating factor?

Answer 10

acetyl group

Question 11

A type of phospholipid that is rapidly turned over and is a part of a second messenger signal cascade

Answer 11

phosphoinositol (IP3)

Question 12

oxytocin
vasopressin
histamine
angiotensin II

Answer 12

Hormones that use the IP3 pathway

Question 13

Discuss the IP3 pathway in an example with activation by vasopressin.

Answer 13

Vasopressin binds to GPCR, takes GDP to GTP, GTP activates phospholipase C which cleaves PIP2 into IP3 and DAG. IP3 causes the release of calcium ions, and DAG activates PKC

Question 14

When PKC is activated, it can stay active for a long time. However, Ca+ and DAG do not. What happens to each?

Answer 14

Ca+ will be pumped out of the cytoplasm (either into SR or out of cell) and DAG will turn back into a phospholipid

Question 15

What cleaves PIP2 to IP3 and DAG?

Answer 15

Phospholipase C

Question 16

Steps in phospholipid biosynthesis. What does it start with? What does it end with? Name an intermediate

Answer 16

Glycerol 3-phosphate
Lysophosphatidic acid
Phosphatidic acid
DAG
TAG

Question 17

One route to forming phospholipids involves activation of a head group or base to a (blank). What does this require? Give an example.

Answer 17

CDP-base (cytidine diphosphate)
CTP
choline –> CDP choline

Question 18

So, one way to generate phospholipids is to use a cytosine-nucleotide derivative, a CDP-[base], to donate a polar head group via a phospho[base] transferase. Give an example.

Answer 18

DAG —> phosphocholine transferase –> phosphatidylcholine

Question 19

If you start with phosphatidylethanolamine, S-adenosylmethionine can donate a methyl group to form what major membrane lipid?

Answer 19

phosphatidylcholine

Question 20

Phosphatidylserine can be formed by exchanging an (blank) for a serine

Answer 20

ethanolamine

Question 21

Phosphatidylserine can be decarboxylation to form (blank)

Answer 21

phosphatidylethanolamine

Question 22

A second way to synthesize phospholipids, such as PI and PS, is to activate (blank) with a cytosine-nucleotide lipid derivative, and form (blank).

Answer 22

DAG; CDP-DAG

Question 23

(blank) can be added to CDP-DAG to form phosphatidylserine

Answer 23

serine

Question 24

Important phospholipase in eicosanoid production (cuts at R2 position of phospholipid)

Answer 24

phospholipase A2

Question 25

Important phospholipase in IP3 signaling pathway

Answer 25

phospholipase C

Question 26

Phopholipase A2 releases arachidonic acid from the 2-position of phospholipids to initiate (blank) production. (blank) represses phopholipase synthesis –long acting anti-inflamatory steroid.

Answer 26

eicosanoid; Cortisone

Question 27

Components of a sphingolipid

Answer 27

sphingosphine fatty acid base

Question 28

What two things come together before being activated by a fatty acid to form ceramide?

Answer 28

palmitoyl-CoA and serine

Question 29

a sphingosine with an acyl (FA) group

Answer 29

ceramide

Question 30

Why is a serine necessary for the sphingosine backbone?

Answer 30

provides the amine

Question 31

Ceramide can form sphingomyelin through the addition of what? Ceramide can form cerebrosides through the addition of what?

Answer 31

phospho-choline head group | sugar added from UDP-galactose

Question 32

A glucocerebroside is a ceramide with a (blank) residue

Answer 32

glucose

Question 33

A galactocerebroside is a ceramide with a (blank) residue

Answer 33

galactose

Question 34

Where are glucocerebrosides and galactocerebrosides primarily found?

Answer 34

In brain tissue

Question 35

Galactocerebroside with a sulfate group

Answer 35

sulfolipid

Question 36

Disease resulting from inability to degrade a ganglioside, so lysosomes fill up with undegraded gangliosides and cause weakness, retardation, blindess, and death by age 3 or 4.

Answer 36

Tay-Sachs disease

Question 37

Tay-Sachs is an inability to breakdown (blank)

Answer 37

gangliosides

Question 38

What's the enzyme deficiency in Tay-Sachs disease?

Answer 38

hexosaminidase A