Cell membrane

Question 1

Cell membrane structure

Answer 1

Phospholipid bilayer
Also known as fluid mosaic structure

Question 2

Function of cell membrane

Answer 2

Structural integratiy/support
Transport of material in & out of the cell

Question 3

Components of cell membrane

Answer 3

1)Phospholipid
2)Membrane Lipid
3)Cholesterol
4)Glycocalyx (Glycolipid & Glycoprotein)

Question 4

Components of phospholipid

Answer 4

1)A glycerol molecule
2)2 fatty acid chain
3)Phosphate head

Question 5

Phospholipid is _______.Why?

Answer 5

Amphipathic
Hydrophilic due to phosphate head
Hydrophobic due to fatty acid tail

Question 6

Phospholipid forms as _______ in cell.

Answer 6

lipid bilayer (hydrophobic inside & phodrophilic outside)

Question 7

Two phospholipids layers have different composition.True or False?

Answer 7

True
bcus of the attachment of head gp(choline,spingosine) at the phosphate.

Question 8

Types of membrane protein

Answer 8

1)Integral protein
2)Periphral protein

Question 9

Integral protein

Answer 9

Transmembrane proteins that entirely or partially penerate the lipid bilayer

Question 10

Peripheral protein

Answer 10

Loosely attached to the membrane surface (inner or outer side)

Question 11

Glycocalyx are

Answer 11

Oligosacchride chain is attached to
Membrane protein-glycoprotein
Membrane lipid-glycolipid

Question 12

Function of membrane protein

Answer 12

1)Cell junction
2)Recognation (glycoprotein)
3)Channel & carrier protein
4)Receptor
5)Enzymes
6)Attachment to outside or inside of the cell

Question 13

Is cholesterol amphipathic?

Answer 13

Slightly amphipathic bcus of the -OH gp

Question 14

Function of glycoprotein & glycolipid

Answer 14

Cell to cell recognition
eg.blood type

Question 15

To be able to function properly,cell membrane can’t be

Answer 15

too fluid or too rigid

Question 16

Fluditiy of cell membrane is controlled by

Answer 16

1)Phospholipid
2)Cholesterol
3)Temperature

Question 17

What will happen when membrane phospholipid contain many unsaturated fatty acid tail?

Answer 17

Prevent tightly packing of phospholipid>increase membrane fluidity

Question 18

What will happen when membrane phospholipid contain many saturated fatty acid tail?

Answer 18

Tightly packing of phospholipid>decrease fluidity

Question 19

Temperature & memebrane fluidity

Answer 19

Increase temp>increase fluidity
Decrease temp>decrease fluidity

Question 20

What control the membrane fluidity according to temperature ?

Answer 20

Cholesterol

Question 21

How cholesterol control membrane control membrane fludity at high temeprature?

Answer 21

High temperature>increase fluidity

*Cholesterol reduces the membrane fluidity

Question 22

How cholesterol control membrane control membrane fludity at low temperature?

Answer 22

Low temperature>decrease fluidity>rigid

*Cholesterol increases the membrane fluidity

Question 23

Cell membrane is______.

Answer 23

Semipermeable(selectively permeable) bcus of the amphipathic character

Question 24

______ can pass through the cell membrane by DIFFUSION.

Answer 24

Small nonpolar molecules(hydrocarbon,steroid hormones & O2,CO2)

Ions(small) & water molcules can diffuse but slow

Question 25

Do large,polar substance can pass the cell membrane by diffusion?

Answer 25

No They must be transporated by transport protein (channel protein & carrier protein)

Question 26

Lateral diffusion

Answer 26

Movement of phospholipid & membrane sideway in the membrane. (Protein can do but slower)

Question 27

Transverse diffusion

Answer 27

Flip flop movement of phospholipid (Outer layer to inner & Inner layer to outer)

Question 28

Membrane protein can do transverse diffusion.True or False?

Answer 28

False Only phospholipids can do flip-flop movement.

Question 29

Peripheral protein exist only on the outside of the cell membrane.True or False?

Answer 29

False They exist on both inside and outside

Question 30

______ can attached to the cytoskeleton & extracellular matrix.

Answer 30

Peripheral protein

Question 31

Membrane proteins are amphipathic.True or False?

Answer 31

True Peripheral proteins may not always be strongly amphipathic

Question 32

_____ are strongly bonded to the membrane lipids by covalent bonds.

Answer 32

Membrane proteins

Question 33

Peripheral proteins are loosely bonded to the membrane lipid by ______.

Answer 33

H bonds

Question 34

Membrane lipids are _____ with increase temperature & ____ with decrease temperature.

Answer 34

Increase temp>liquifies Decrease temp>solidifies