Plasma Membranes

Question 1

Structure of plasma membranes

Answer 1

Consists of a phosphate molecule, glycerol and 2 fatty acids
They orientate themselves: fatty acid inwards and phosphate head outwards due to water

Question 2

What does the fluid mosaic model show about plasma membranes

Answer 2

The phospholipids can move, giving them fluidity so their flexible shape can change

Question 3

Structure and function of a glycoprotein

Answer 3

Carbohydrate chain attcatched to a protein
Has receptors for cell recognition and cell attachment and act as hormones and neurotransmitters

Question 4

Function of a glycolipid

Answer 4

Chemical stability and cell attachment

Question 5

What is an intrinsic protein and name 2 types

Answer 5

Goes through the membrane
Channel proteins
Carrier proteins

Question 6

What is a channel protein for

Answer 6

Let’s water soluble molecules through

Question 7

What is a carrier protein

Answer 7

Responsible for active transport, energy, protein changing shape and transfers molecule

Question 8

What is an extrinsic protein

Answer 8

Protein at the surface for mechanical support

Question 9

What is cholesterol

Answer 9

Lipid which is hydrophobic

Question 10

Function of cholesterol

Answer 10

Hydrophobic and nestled so stops cell leaking water and dissolved ions
Attached to fatty acid tails to stop too much fluidity of molecules esp at high temps

Question 11

What type of molecules can get through plasma membranes

Answer 11

Water soluble, lipid soluble, polar molecules

Question 12

What type of molecules cannot get in through plasma membranes

Answer 12

Large molecules, charged molecules
Glucose

Question 13

Two factors that affect plasma membranes

Answer 13

Temp
Solvents

Question 14

How does increasing temp affect plasma membranes

Answer 14

Phospholipids gain kinetic energy so move around more, if they move too much this causes gaps in the bilayer so its more permeable so cell contents leak out, too much permeability is not good

Question 15

What happens if temp gets way too high

Answer 15

Proteins will denature as they overcome the intermollecular forces leading to huge gaps in the membrane so lots of leakage occurs as permeability increases

Question 16

What happens to membranes at very low temps

Answer 16

Also leads to high permeability as proteins are destroyed so ice crystals can pierce the bilayer

Question 17

How do solvents affect bilayer, what are they

Answer 17

Ethanol or alcohol
Non polar
Can interact and interrupt fatty acids bcs they dissolve fatty acid tails making the membrane more permeable