2. cell surface membrane

Question 1

what is number 1?

Answer 1

glycolipid

Question 2

what is number 2?

Answer 2

carbohydrate chain

Question 3

what is number 3?

Answer 3

extrinsic protein

Question 4

what is number 4?

Answer 4

glycoprotein

Question 5

what is number 5?

Answer 5

cholesterol

Question 6

what is number 6?

Answer 6

Phospholipid

Question 7

what is number 7?

Answer 7

channel/transport protein

Question 7

label the structure from top to bottom?

Answer 7

• phosphate group
• phosphoester bonds
• glycerol
• ester bond
• fatty acids

Question 8

what is the function of the cell surface membrane?

Answer 8

• controls which substances enter and leave the cell (partially permeable membrane)
• membranes allow recognition by other cells
• site of cell communication (cell signalling)

Question 9

Are all organelles in plant and animal cells membrane bound?

Answer 9

yes

Question 10

what is the function of membranes within cells?

Answer 10

• separates the content from the cytoplasm
• can form vesicles to transport substances through the cytoplasm
• allowing selected molecules to enter and leave the cell
• a site for biochemical reactions
• allows the organelle/cell to change shape
• provides attachment site for enzymes

Question 11

what is this called?

Answer 11

phospholipid bilayer

Question 12

what is the head? (water)

Answer 12

hydrophilic. It attracts water

Question 13

what is the tail? (water)

Answer 13

hydrophobic. It repels water

Question 14

what does the membrane not allow through it via simple diffusion?

Answer 14

water-soluble substances
(fat-soluble substances can travel through the the membrane via simple diffusion down a concentration gradient)

Question 15

why can’t water and lipids mix?

Answer 15

water and lipids can’t mix because lipids can not form hydrogen bonds with water

Question 16

what is this called?

Answer 16

Micelle

Question 17

what is this called?

Answer 17

Bilayer

Question 18

Do you know this?

Answer 18

Question 19

what are the different types of intrinsic proteins?

Answer 19

• channel proteins
• carrier proteins
• glycoproteins

Question 20

what are the different types of extrinsic proteins?

Answer 20

• peripheral proteins

Question 21

how does diffusion occur through the membrane?

Answer 21

diffusion occurs through the membrane by moving from a high to low concentration. Down a concentration gradient

Question 22

channel proteins

Answer 22

• form (water-liking) pores/channels in the membrane
  for charged particles (smaller ions and polar
  molecules) to diffuse through.
• Down their concentration gradient.
• Different channel proteins facilitate the diffusion of
  different charged particles.

Question 23

carrier proteins

Answer 23

• moves large molecules (including polar
  molecules and ions) into or out of the cell.
• Down their concentration gradient.
• Different carrier proteins facilitate the diffusion of
  different molecules.
• Carrier proteins change shape when a specific
  molecule binds.

Question 24

glycoproteins

Answer 24

* Glycoproteins are intrinsic proteins with an attached carbohydrate chain. * Stabilise the membrane by forming hydrogen bonds with surrounding water molecules. * They are also sites where drugs, hormones and antibodies bind – cell recognition. * They act as receptors for cell signalling. * Cell adhesion.

Question 25

glycolipids

Answer 25

* Glycolipids are lipids with an attached carbohydrate (sugar) chain. * Act as receptor molecules * They act as cell markers or antigens. * Can be recognised by the cells of the immune system as self (cells of the organism) or non-self (cells from another organism).

Question 26

Answer 26

got it ;)

Question 27

what are extrinsic proteins involved in?

Answer 27

* Cell signalling * Cell recognition * Act as receptors for other molecules e.g. hormones

Question 28

Cholesterol

Answer 28

* Cholesterol is a type of lipid. * It is present in all cell membranes (except bacterial membranes). * Cholesterol molecules fit between phospholipids. * This makes the membrane less fluid and more rigid, therefore stabilising the membrane.

Question 29

why is cell fluidity essential?

Answer 29

Phagocytosis

Question 30

what is cell signalling?

Answer 30

* Cell signaling is how cells communicate with each other. * Cells need to communicate with each other to control processes inside the body and respond to changes in the environment. E.g. low blood glucose levels.

Question 31

Receptors in the cell surface membrane

Answer 31

* Proteins in the cell surface membrane (e.g. glycoproteins act as receptors for the messenger molecules e.g. drug/hormone. * They are called ‘membrane bound receptors’. * Membrane bound receptors have a specific shape so only messenger molecules with a complementary shape can bind to them. * A cell that can respond to a particular messenger molecule is called a ‘target cell’.

Question 32

what is the model of the cell surface membrane called?

Answer 32

fluid mosaic model