Week 11 *

Question 1

Name all structures in the cell membrane

Answer 1

protein, bilayer, lipid molecules

Question 2

Name the 3 types of lipids

Answer 2

phospholipid (phosphatidyyline)
sterol (cholesterol)
glycolipid (galactocerbreside)

Question 3

What is fluidity?

Answer 3

Allows proteins and lipids to move around by diffusion

Question 4

What do animals use cholesterol for?

Answer 4

To stiffen membranes

Question 5

What is transfer carried out by?

Answer 5

Flippase enzymes

Question 6

Where are glycolipids made?

Answer 6

In the golgi

Question 7

Name the 4 types of membrane proteins

Answer 7

Transporters, linkers, receptors, enzymes

Question 8

What is the function of transporters?

Answer 8

pumps na+ out of cells and k+ in to cells

Question 9

What is the function of linkers?

Answer 9

Links intracellular filaments to extracellular matrix proteins

Question 10

Receptors function

Answer 10

Binds extracellular pdgf, produces intracellular signals causing cell to grow and divide

Question 11

Enzymes function

Answer 11

catalyses the production of intracellular amp in response to extracellular signals

Question 12

What are used to cross the membrane?

Answer 12

Protein motifs

Question 13

Cell cortex function

Answer 13

supports the plasma
membrane and gives the
cell shape
*formed by framework of
intracellular proteins
linked to transmembrane
anchor proteins

Question 14

Function of glycocalyx

Answer 14

protects the cell
*lubricates the cell surface (white blood cells)
*cell-cell recognition
eg egg-sperm recognition
inflammatory response
*cell adhesion

Question 15

Medical example in this section

Answer 15

Hereditary spherocytosis, rbc disease

Question 16

Transport across the membrane

Question 17

Medical example in this section and explain

Answer 17

Familial Hypercholesterolemia; causes high cholesterol greater chance of heart attack

Question 18

How do large molecules move across the membrane?

Answer 18

By vesicles

Question 19

Name the 2 classes of transporter proteins

Answer 19

carriers, channels

Question 20

Describe carriers and channels

Answer 20

Carriers
swing action
for small organics or ions
Passive or active transport

Channels
tiny hydrophilic pores
usually for ions only
passive transport only

Question 21

What is the electrochemical gradient?

Answer 21

pressure” exerted by both differences in concentration and charge for a solute on either side of the membrane

Question 22

Name the 2 types of channels and examples

Answer 22

Large, non-selective, always open
eg. porins (bacteria)
gap junctions (eucaryotes)

Narrow, selective, usually closed
eg. ion channels

Question 23

Describe the structure of the large channel

Answer 23

b-barrel structure

Question 24

Exocytosis

Answer 24

vesicles are used to export secreted proteins like insulin from the cel

Question 25

What do signal sequences in proteins do?

Answer 25

Tells the cell where it should go

Question 26

How is a disulfide bridge formed?

Answer 26

Formed between cysteine side-chains
Requires oxidation
Protects secreted proteins vs pH and degradation

Question 27

glycosylation

Answer 27

Protect from degradation
Retain in ER until properly folded
Act as signal for organelle destination
Form part of glycocalyx

Question 28

Cholesterol circulates in the bloodstream as

Answer 28

lipoproteins