CMB1004/L02 Cell Membranes

Question 1

Name 2 common lipids in eukaryotes.

Answer 1

Phospholipids (mainly phosphoglycerides)
Cholestrol
Glycolipids

Question 2

Name 3 of the 5 major phospholipids.

Answer 2

Phosphotidylethanolamine
Phosphotidylserine
Phosphotidylcholine
Sphingomyelin

Question 3

Why does membrane fluidity need to be maintained?

Answer 3

Ensure cell survival

Question 4

Give the 2 key parameters that influence membrane fluidity.

Answer 4

Lipid composition
Temperature

Question 5

Give the 3 types of membrane-associated proteins.

Answer 5

Integral membrane proteins
Attached proteins
Peripheral, membrane-associated proteins

Question 6

Give 3 functions of membrane proteins.

Answer 6

Transporters
Linkers
Receptors
Enzymes

Question 7

What is the function of transporter membrane proteins?

Answer 7

To move nutrients, metabolites or ions across membranes

Question 8

What is the function of membrane linker proteins?

Answer 8

To join membranes to intra- or extracellular macromolecules

Question 9

What is the function of receptor proteins?

Answer 9

To transduce signals from the environment
To transport ligands

Question 10

What is the glycocalix?

Answer 10

A cell coat which protects against chemical, physical and biological damage

Question 11

Name 2 examples of glycoproteins.

Answer 11

N-glycans
O-glycans
Proteoglycans

Question 12

Name 2 ways in which glycans affect health and disease.

Answer 12

Modulate inflammatory responses enabling viral immune escape
Promote cancer cell metastasis

Question 13

Give 3 functions of the glycocalix.

Answer 13

Protection
Adhesion
Recognition
Storage

Question 14

What is FRAP?

Answer 14

Fluorescent Recovery after Photobleaching

Question 15

How do proteins move within the membrane?

Answer 15

Diffusion along membrane plane

Question 16

What are membrane proteins restricted to?

Answer 16

Domains or membranes

Question 17

What traps agrin between neurones and muscles?

Answer 17

Basal lamina

Question 18

What does agrin do?

Answer 18

Initiates AchR clustering

Question 19

What maintains AchR clustering?

Answer 19

Rapsyn

Question 20

What is present in the intercellular space between T cells and APCs? (2)

Answer 20

T-cell receptors & CD2AP

Question 21

What is a result of alternative splicing in several positions along cDNA?

Answer 21

Multiple isoforms of agrin

Question 22

What is a B/z+ agrin isoform?

Answer 22

Agrin with a peptide insert in the -COOH terminal region

Question 23

What is a B/z0 agrin isoform?

Answer 23

Agrin without a peptide insert

Question 24

What makes up the majority of eukaryotic cytoskeletons?

Answer 24

Spectrin

Question 25

Give 3 examples of energy-driven transport.

Answer 25

Coupled transport
ATP driven transport
Light/redox driven transport

Question 26

Give 3 examples of membrane bending via proteins.

Answer 26

Vesicle budding
Cell movements
Cell division

Question 27

What 3 mechanisms mediate membrane curvature and stabilisation?

Answer 27

Nanoscopic curvature
Microscopic curvature
Macroscopic curvature

Question 28

What does nanoscopic composition involve? (2)

Answer 28

Lipid composition
Protein motif insertion

Question 29

What does microscopic composition involve? (1)

Answer 29

Protein scaffolding

Question 30

What does macroscopic composition involve? (1)

Answer 30

Cytoskeletal scaffolding

Question 31

Name 3 cellular processes requiring membrane deformation.

Answer 31

Organelle shaping
Protein sorting
Membrane scission
Membrane fusion
Enzyme activation