Lipids part 2

Question 1

Semi-permeable structure that defines the boundaries of all cell types

a double layer of
lipids, which acts as a barrier to the passage of polar molecules and ions.

Answer 1

Cell membrane

The cell membrane has many roles:
1. Controlling the flow of ions into and out of the cells
2. Uptake of nutrients and disposal of waste
3. Cell recognition and communication

Question 2

The fluid Mosaic model which includes lipids, proteins, and carbohydrates allows ___

Answer 2

lateral diffusion

Question 3

Two types of backbones in membranes which are linked to fatty acids:

Answer 3

Glycerol - simple 3 carbon tri-alcohol
Sphingosine - more complex hydrocarbon (two alcohols, amine, long-chain alkene)

Question 4

Glycerophospholipids are also known as:

Answer 4

phosphoglycerides

Unsaturated fatty acids are commonly found connected to C2 of glycerol-3-phosphate

Question 5

The major component of most eukaryotic cell membranes.

Answer 5

Phosphatidylcholine

Question 6

Type of Ether Lipid

Vinyl ether analog of phosphatidylethanolamine
* Common in vertebrate heart tissue
* Also found in some protozoa and anaerobic bacteria

Answer 6

Plasmalogen

Question 7

Type of Ether Lipid

Aliphatic ether analog of phosphatidylcholine
Acetic acid has esterified
First signaling lipid
Stimulates aggregation of blood platelets
Plays role in mediation of inflammation

Answer 7

Platelets-Activating Factor

Question 8

T or F: The backbone of sphingolipids is glycerol

Answer 8

False, the backbone is the amino alcohol sphingosine

Question 9

Subclasses of sphingolipids (3)

Answer 9

Sphingomyelins
Glycosphingolipids
Gangliosides

Question 10

Ceramide (sphingosine + amide-linked fatty acid) + phosphocholine attached to the alcohol

is abundant in myelin sheath that surrounds some nerve cells in animals.

Answer 10

Sphingomyelins

Question 11

Contains both a fatty acid and carbohydrate
contains a single monosaccharide unit - either glucose or galactose
– They occur primarily in brain (7% of dry mass)

Two types:
globosides
gangliosides

Answer 11

Glycosphingolipids

Question 12

glycosphingolipids with two or more sugars usually D- glucose, D-galactose, or N-acetyl-D-galactosamine

Answer 12

globosides

Question 13

Most complex glycosphingolipids

contains an oligosaccharide head group with one or more residues of the charged monosaccharide, sialic acid.
Sialic acid gives gangliosides a negative charge at neutral pH.

Answer 13

Gangliosides

Question 14

Blood groups are determined by the ___ in glycosphingolipids.

Answer 14

type of sugars located on the head groups

Question 15

Individuals with no active glycosyltransferase will have the ___.

Individuals with a glycosyltransferase that transfers an N-acetylgalactosamine group have ___.

Individuals with a glycosyltransferase that transfers a galactose group have ___.

Answer 15

O antigen

A blood group

B blood group

Question 16

a lipid whose structure is based on a fused ring system of three 6
carbon rings and one 5 carbon ring

Answer 16

Steroid

Question 17

The most abundant animal steroid. Related sterols are present in the membranes of most eukaryotic cells.

• modulate fluidity and permeability (stabilizes membranes)
• thicken the plasma membrane
• no sterols in most bacteria

Answer 17

Cholesterol

Question 18

Important features of biological membranes (4)

Answer 18

Membrane fluidity

Selective permeability

Self-sealing capability

Assymmetry

Question 19

fluidity of biological membranes is determined by the proportions of saturated and unsaturated fatty acid groups

Cholesterol is able to fit in between the fatty acid side chains of the lipid bilayer.

Answer 19

Membrane fluidity

Question 20

Each membrane exhibits its own transport capability or selectivity based on its protein component.

Answer 20

Selective permeability

Question 21

When lipid bilayers are disrupted, they immediately and spontaneously reseal.

Answer 21

Self-sealing capability

Question 22

Biological membranes are asymmetric, that is, the lipid composition of each half of a bilayer is different.

Answer 22

Assymmetry

Question 23

A substance moves across a cell membrane by diffusion from a region of higher concentration.

Answer 23

Passive transport

Question 24

A substance moves across a cell membrane with the aid of a membrane protein.

Answer 24

Facilitated transport