fluid mosaic model

Question 1

what is the cell membrane mostly made up of ?

Answer 1

phospholipids and proteins

Question 2

what can phospholipids form?

Answer 2

bilayers
with one sheet of phospholipid molecules opposite another

Question 3

what are the tails?

Answer 3

hydrophobic fatty acid tails

Question 4

what are the heads?

Answer 4

hydrophillic phosphate head

Question 5

are phosphate heads hydrophillic or hyfrophobic?

Answer 5

hydrophillic

Question 6

are fatty acid tails hydrophillic or hydrophobic?

Answer 6

hydrophobic

Question 7

what does the phospholipid component allow ?

Answer 7

alllow lipid soluble molecules across but not water soluble

Question 8

which way do the hydrophillic heads point?

Answer 8

outwards`

Question 9

which way do hydrophobic tails face ?

Answer 9

inwards

Question 9

what do the hydrophillic heads interact with ?

Answer 9

water in the cyptoplasm for rhe inner layer

the outer layer interacts with water surrounding the cell

Question 10

what are extrinsic proteins?

Answer 10

they are proteins on either surface of the bilayer

Question 11

what do extrinsic proteins do ?

Answer 11

they provide structural support and form recognition sites by identifying cells
and receptor sites for hormone attachment

Question 12

what are intrinsic proteins?

Answer 12

they have hydrophobic and hydrophillic parts

some are channel proteins

span the membrane

Question 13

what is the function of intrinsic proteins?

Answer 13

some are carriers and trasnport water soluble substances

others allow active transport of ions across by forming channels

Question 14

is the hydrophillic phosphate head polar ?

Answer 14

yes
it interacts with other polar molecules such as water

Question 15

protein hormones such as insulin and adrenaline are insoluble in lipids so cant diffuse through the phospholipid membrane of the cell

intead they ?

Answer 15

they bond to extrinsic protein receptor molecules which influences behaviour of cells

Question 16

why is the membrane structure called fluid mosaic ?

Answer 16

fluid : phospholipids can move within a layer relative to one another

mosaic: proteins embedded vary in size shape and pattern

Question 17

what are the components of a cell membrane

Answer 17

hydrophillic phosphate head

hydrophobic fatty acid tail

channel, carrier, intrinsic, extrisnic proteins

cholesterol

glycolipid

glycoprotein

Question 18

where is cholesterol found in the membrane ?

Answer 18

between phospholipid molecules

in the hydrophobic layer

Question 19

what does cholesterol do to membrane?

Answer 19

makes it more rigid and stable

Question 20

where are glycoproteins and glycolipids found?

Answer 20

on the outer layer of the membrane

Question 21

what is the glycocalyx?

Answer 21

the carbohydrate layer around the membrane

some molecules in the glycocalyx have roles as hormone receptors

or in cell to cell recognition

Question 22

what does the membrane being selectively permeable mean?

Answer 22

they are permeable to water molecules and some other small molecules

but not to large molecules

barrier to some molecules but lets others cross

Question 23

what is it called when proteins are bonded to lipid molecules on the membrane?

Answer 23

lypoproteins

Question 24

what is it called when proteins are bonded to carbohydrate groups on the membrane?

Answer 24

glycoproteins

Question 25

Short chain carbohydrates attached to proteins are called?

Answer 25

glycoproteins.

Question 26

Short chain carbohydrates attached to phospholipids are called?

Answer 26

glycolipids

Question 27

what happens if there is not enough cholesterol in the membrane?

Answer 27

membrane becomes too fluid

Question 28

what happens if there is too much cholesterol in the membrane?

Answer 28

membrane becomes too rigid

Question 29

what is the role of channel proteins?

Answer 29

allows the passage of polar molecules by facilitated diffusion