2.3 Membraes And Transport

Question 1

What are the functions of the cell membrane

Answer 1

-Control internal conditions
-partially permiable
-keep components inside
-allow selective molecules in and out
-compartmentalisation
-can allow the cell to change shape

Question 2

What are membranes made up of

Answer 2

Phospholipids

Question 3

What part of the phospholipid is hydrophlillic

Answer 3

The head which is polar, so can interact with water

Question 4

What part of the phospholipid is hydrophobic

Answer 4

The tail which is non polar so can not interact with water

Question 5

What is another name for the membrane

Answer 5

The phospholipid bilayer

Question 6

Why do phospholipids form a bilayer in the plasma membrane

Answer 6

-triglycerides form a layer
-hydrophilic heads face towards the liquid away from the bilayer, as they interact with the water as they are polar
-the hydrophobic tails face eachother towards the inside of the plasma membrane
-which forms a phospholipid bilayer

Question 7

What are the different types of proteins in a bilayer

Answer 7

Glycoprotein- carbohydrate chain
Integral carrier protein
Attachment protein
Channel protein

Question 8

What are the different types of transport through the membrane

Answer 8

-Diffusion
-active transport
-osmosis
-eco utopia and endocytosis

Question 9

How does simple diffusion work through a bilayer (include particles)

Answer 9

Through a bilayer
Down a conc gradient
-small
-lipid soluble
-non polar

Question 10

What is facilitated diffusion in a channel protein

Answer 10

Down a conc gradient
-charged ions
-specific to the channel

Question 11

What is facilitated diffusion in a carrier protein

Answer 11

Down a conc gradient
-large, water soluble particles
- specific

Question 12

What transport happens in a carrier protein

Answer 12

Active transport-
Uses ATP
Against a conc gradient
Specific

Question 13

What is co-transport

Answer 13

More than one molecule going through the membrane at once
-sodium potassium pump

Question 14

How does glucose move from the intestine to the blood stream

Answer 14

1) Na moved into blood stream by active transport and out of the cell
2) Na conc in the cell Dec (creating a conc gradient between cell and lumen)
3) Na moves by facilitated diffusion down a conc gradient through a sodium glucose carrier protein bring glucose with it into the cell
4) glucose moves into blood by diffusion through a carrier protein as the glucose conc has increased

Question 15

What factors affect the rate of diffusion through a membrane

Answer 15

SA x diff in conc
/
Distance

-temperature
-num of carrier/channel proteins