the cell surface membrane

Question 1

what cells have cell surface membranes?

Answer 1

all

Question 2

what are the 3 main roles of cell surface membranes?

Answer 2

1. separates the internal cell environment from the external environment
2. forms compartments in cells
3. control the exchange of materials

Question 3

are membranes partially or fully permeable?

Answer 3

partially

Question 4

what is the name of the model used to show the structure of a membrane?

Answer 4

the fluid mosaic model

Question 5

why is it called the fluid mosaic model?

Answer 5

fluid because phospholipids and proteins can move around, mosaic as the proteins produce a scattered pattern

Question 6

how many contents does the membrane have?

Answer 6

4

Question 7

what are the 4 contents of the membrane?

Answer 7

1. phospholipids
2. cholesterol
3. glycoproteins and glycolipids
4. transport proteins

Question 8

what are phospholipids?

Answer 8

the basic structure of a membrane (phospholipid bilayer)

Question 9

describe the structure of a phospholipid

Answer 9

the head faces externally and is hydrophilic whereas the tail faces internally and is hydrophobic

Question 10

what is the role of cholesterol in the membrane?

Answer 10

increases fluidity

Question 11

how does cholesterol increase fluidity?

Answer 11

at low temperatures it stops the phospholipids from packing together too closely

Question 12

what are glycoproteins and glycolipids?

Answer 12

lipids and proteins attached to carbohydrates

Question 13

what is the role of a glycoprotein?

Answer 13

to signal/communicate

Question 14

give an example of a glycoprotein

Answer 14

a receptor for insulin

Question 15

what is the role of a glycolipid?

Answer 15

maintain cell stability

Question 16

give and example of a glycolipid

Answer 16

an antigen

Question 17

what substances cannot pass through membranes?

Answer 17

polar molecules, large molecules or ions

Question 18

how do polar molecules or ions pass through membranes?

Answer 18

using transport proteins

Question 19

give the 2 names of the transport proteins

Answer 19

channel and carrier

Question 20

how do channel proteins work?

Answer 20

act as a passageway

Question 21

how do carrier proteins work?

Answer 21

change shape to fit a specific substance to transport it