1.3 Cell membrane and transport

Question 1

Function of cell membrane

Answer 1

-Structural support
-Secretes chemicals
-Cell recgonition
-Collects nutriens

Question 2

Name the 8 parts of the cell membrane

Answer 2

1. Gloycoprotein
2. Glycolypid (carbohydrate chain)
3. Phosphate head (hydrophilic head)
4. Fatty acid tail (hydrophoic tail)
5. Intrinsic protein (carrier or channel)
6. Extrinsic protein
7. Cholestrol (rigididy)
8. Phospholypid bilayer

Question 3

When looking at a cell membrane using a light microscope, how many lines does it apear as?

Answer 3

1

Question 4

When looking at a cell membrane using a electron microscope, how many lines does it apear as?

Answer 4

2

Question 5

Function of intrinsic protein

Answer 5

(accross both layers both layers)
Act as a carrier/channel proteins, enzymes + transprot -facilitated diffusion and active transport

Question 6

Function of extrinsic protein

Answer 6

Act as a receptor, antigen and recognition centers spam through
-stuctural suppot
-recognition site
-Receptor sites for homone attatchment

Question 7

Function of cholestrol

Answer 7

Rigididy - stabalize the cell and increases melting point

Question 8

Function of Glycoprotein

Answer 8

Help to recognise and atatch cells

Question 9

Function of Glycolypid

Answer 9

maintain stability and facilitate cell to cell intreaction
(outer layer)

Question 10

Glycocalyx

Answer 10

Provent the entery of pathogen into the cell outer layer of membrane glycolypids and glycoproteins are found

Question 11

Name the bond, reaction and the hydrophilic and hydrophobic part of a phospholipid

Answer 11

Ester bond
Condensation reaction
Hydrophobic - fatty acid tail
Hydrophilic - phosphate head

Question 12

Phospholipids

Answer 12

They can form layers
Hydrophilic heads
Hydrophobic tail - repel water
Allows lipid-solube molecules across, not water

Question 13

Whats the name of the model for the cell membrane?

Answer 13

Fluid mosaic model

Question 14

What part of the cell membrane represents the fluid in the fluid mosaic model?

Answer 14

Phosphholipids are free to move in the membrane

Question 15

What part of the cell membrane represents the mosaic in the fluid mosaic model?

Answer 15

Proteins move on the surface of the membrane

Question 16

3 factors that affect the permeability of a cell membrane

Answer 16

1. Heat
2. Ethanol
3. pH

Question 17

How does heat affect the cell membrane?

Answer 17

denatures the membrane

(makes membrane more permeable - more holes in it)

Question 18

How does pH affect the cell membrane?

Answer 18

denatures the membrane

(makes membrane more permeable - more holes in it)

Question 19

How does ethanol affect the cell membrane?

Answer 19

Ethanol disolves the lipid components of the membrane

(makes membrane more permeable - more holes in it)

Question 20

Name the 6 modes of transoprt

Answer 20

1. Diffusion
2. Facilitated diffusion
3. Active transport
4. Co transport
5. Osmosis
6. Endo/Exocytosis

Question 21

Definition of diffusion

Answer 21

The passive movement of mlecules from a** high concentration to a low concentration** untill they are equally distributed

Question 22

Meaning of passive

Answer 22

Does not require energy

Question 23

6 factors that affect the rate of diffusion

Answer 23

1. Concentration gradient
2. Distance of travel
3. Surface area of a membrane
4. Thickness of exchange surface
5. Size of moecules
6. Temperature - Kenetic energy

Question 24

Examples of molecules that pass through the membrane by diffusion

Answer 24

CO2, O2

Small
Uncharged
Lipid solubles

Question 25

Definition of facilitated diffusion

Answer 25

The passive transfer of molecules/ ions down a concentration gradient -high to low -by carrier proteins in the membrane

Question 26

Examples of molecules that pass through the membrane by facilitated diffusion

Answer 26

Na+ K+, glucose, amino acids Large Charged Water solubles

Question 27

Active transport defintition

Answer 27

Movement of ions/molecules accross the membrane from a low to high concentration against the concentartion gradient **Requires energy**

Question 28

Factors that affect the rate of uptake - active transport

Answer 28

1. Respiritory inhibitor - Cyanide 2. Number of carrier proteins 3. Oxygen availability

Question 29

Co transport

Answer 29

Type of facilitated diffusion that brings molecules and ions into the cell together on the same transport protein e.g Sodium and glucose co transport into cell together

Question 30

What does hydrophobic and hydrophilic mean ?

Answer 30

Hydrophobic - water hating Hydrophilic - water loving

Question 31

What does hydrophobic and hydrophilic mean ?

Answer 31

Hydrophobic - water hating Hydrophilic - water loving

Question 32

What is the 2 types of proteins in cell membranes

Answer 32

Intrinsic and extrinsic

Question 33

What is the 2 types of proteins in cell membranes

Answer 33

Intrinsic and extrinsic

Question 34

Intrinsic proteins

Answer 34

Across both layers of the membrane Carriers/channels

Question 35

Extrinsic proteins

Answer 35

On surface if the bilayer Structural support Recognition sites Receptor sites for hormone attachment

Question 36

Define osmosis

Answer 36

Movement of water from a high to a low water potential through a selectively permanent membrane Negative to more negative

Question 37

What is water potential

Answer 37

1. Water potential is the pressure exerted by water molecules. The tendency of water to leave a system 2. Measured in kilopascale (kPa) 3. Pure water has a water pitential of 0kpa 4. A solution with a high water potential has a large number of water molecules that are free to move

Question 38

I why is the equation to find out water potential

Answer 38

Water potential = solute + pressure

Question 39

What is pressure potential

Answer 39

The pressure exerted by the small cell wall and membrane on the cell contents

Question 40

What is the solute potential

Answer 40

The concentration of dissolved substance in the cell vacuole

Question 41

Define hypertonic

Answer 41

Water potential of external solution is lower than solution inside the cell wall. Water flows out the cell

Question 42

Define hypertonic

Answer 42

Water potential of external solution is higher than solution inside the cell. Water flows into cell

Question 43

Define isotonic

Answer 43

Water potential of cell the same as water potential surrounding the cell

Question 44

What is incipient plasmolysis

Answer 44

-cell membrane begins to pull away from the cell wall - 50% of cells viewed under microscope are plasmolysed -

Question 45

What Is fully turgid

Answer 45

- h20 moved in by osmosis - placed in hypertonic solution

Question 46

What is plasmalised

Answer 46

- cell members and pulled away from cell wall (h20 moved out) - placed in hypertonic solution

Question 47

What solution creates a turgid cell

Answer 47

Hypotonic solution

Question 48

What solution makes an incipient plasmolysis cell and a plasmolysed cell ?

Answer 48

Hypertonic

Question 49

What is the difference between incipient plasmolysis and plasmolysed ?

Answer 49

Incipient plasmolysis’s cytoplasm only starts to pull away from the cell wall where as in a plasmolysed cell it is completely pulled away