MEMBRANE LIPIDS: PHOSPHOLIPIDS

Question 1

Up to _____ of the mass
of a cell membrane can be lipid materials; the rest is primarily protein.

Answer 1

80%

Question 2

There are three common types of membrane lipids:

Answer 2

phospholipids, sphingoglycolipids, and
cholesterol

Question 3

____________ are the most abundant type of membrane lipid.

Answer 3

Phospholipids

Question 4

A phospholipid is a lipid that contains:

Answer 4

a. one or more fatty acids, a phosphate group
b. a platform molecule to which the fatty acid(s) and the phosphate group are attached,
c. an alcohol that is attached to the phosphate group

Question 5

The platform molecule on
which a phospholipid is built may be the 3- carbon alcohol glycerol or a more complex C18 aminodialcohol called _______________.

Answer 5

sphingosine

Question 6

Glycerol-based phospholipids are called:

Answer 6

glycerophospholipids

Question 7

Spingosine-based phospholipids are called:

Answer 7

sphingophospholipids

Question 8

A ______________ is a lipid that contains two fatty acids and a phosphate group
esterified to a glycerol molecule and an alcohol esterified to the phosphate group.

Answer 8

glycerophospholipid

Question 9

All attachments (bonds) between groups in a
glycerophospholipid are ___________, though they have four ______ as contrasted to three ______ in triacylglycerols.

Answer 9

ester linkages

Question 10

___________ is the parent source for the minus one charged phosphate group used in the formation of glycerophospholipids.

Answer 10

Phosphoric acid

Question 11

The alcohol attached to the phosphate group in a glycophospholipid is usually one of three amino alcohols: __________, ________, and __________.

Answer 11

choline, ethanolamine, or
serine

Question 12

Glycerophospholipids containing these three amino alcohols are respectively known as:

Answer 12

a. phosphatidylcholines
b. phosphatidylethanolamines
c. phosphatidylserines

Question 13

The fatty acid, glycerol, and phosphate portions of a
glycerophospholipid structure constitute a ________________.

Answer 13

phosphatidyl group

Question 14

Triacylglycerols serve as storage molecules for metabolic fuel.
Glycerophospholipids function almost exclusively as _____________________.

Answer 14

components of cell membranes and are not stored

Question 15

A ___________ is a lipid that contains both a fatty acid and a carbohydrate component attached to a sphingosine molecule.

Answer 15

sphingoglycolipid

Question 16

A fatty acid is attached to the sphingosine through an
___________.

Answer 16

amide linkage

Question 17

A monosaccharide or
oligosaccharide is attached to the sphingosine at the terminal -OH carbon atom through a ___________.

Answer 17

glycosidic linkage

Question 18

The simplest sphingoglycolipids, which are
called _________, contain a single monosaccharide unit—either glucose or galactose.

Answer 18

cerebrosides

Question 19

More complex sphingoglycolipids, called _______________, contain a branched chain of up to seven monosaccharide residues.

These substances occur in the gray matter of the brain as well as in the myelin sheath.

Answer 19

gangliosides

Question 20

________ is a steroid. A steroid is a lipid whose structure is based on a fused ring
system that involves three 6-membered rings and one 5-membered ring

Answer 20

Cholesterol

Question 21

Cholesterol’s structure differs markedly from that of other membrane lipids in that:

Answer 21

(1) there are no fatty acid residues present
(2) neither glycerol nor sphingosine is present as
the platform molecule.