Membranes

Question 1

What is the role is cholesterol ?

Answer 1

adds strength

Question 2

What is the fluid - mosaic model?

Answer 2

the structure of membrane

Question 3

what is an intrinsic protein ?

Answer 3

spans the whole membrane

Question 4

What is the arrangement of phospholipids

Answer 4

phospholipid bilayer

Question 5

What is the hydrophobic region?

Answer 5

fatty acid tails

Question 6

What is the hydrophilic region?

Answer 6

the phosphate head

Question 7

what is the majority lipid in a membrane

Answer 7

phospholipid

Question 8

what is an extrinsic protein?

Answer 8

loosely bound to outside of a membrane

Question 9

What is a passive process

Answer 9

does not require ATP

Question 10

What is osmosis?

Answer 10

movement of water down water potential gradient

Question 11

what is a glycoprotein?

Answer 11

a protein with a carbohydrate attached

Question 12

what is a glycolipid?

Answer 12

a lipid with a carbohydrate attached

Question 13

What is a carrier protein?

Answer 13

changes shape to transport substances across membrane

Question 14

What is the role of proteins in membranes

Answer 14

enzymes
receptors
transport
recognition

Question 15

what is a channel protein?

Answer 15

molecules travel through them in facillitated diffusion

Question 16

what is diffusion?

Answer 16

random movement of molecules from high to low concentration

Question 17

What is active transport?

Answer 17

move against concentration gradient

Question 18

what is endocytosis?

Answer 18

moving large molecules into cells

Question 19

What is exocytosis?

Answer 19

Moving large molecules out of cells

Question 20

Why are membranes fluid?

Answer 20

hydrophobic and hydrophilic interactions

phospholipids and proteins can move horizontally

no bonds

Question 21

What is the importance of a membrane being fluid?

Answer 21

can repair itself

flexible

for endocytosis and exocytosis

Question 22

How does a protein stay in the membrane?

Answer 22

Has no charge in the middle, and charge in the outside

Charged amino acids are either highly hydrophobic or hydrophilic, uncharged amino acids go in the middle

Question 23

What travels through channel proteins?

Answer 23

ions, water solvable substances

Question 24

What is the structure and properties of a membrane?

Answer 24

phosphate head - hydrophilic

Fatty acid tails - hydrophobic

selectively permeable

Question 25

What is diffusion

Answer 25

high concentration to low concentration down a concentration gradient passive

Question 26

How to calculate rate of diffusion

Answer 26

amount diffused / time taken

Question 27

What factors effect rate of diffusion?

Answer 27

temperature, surface area, different in concentration and thin exchange surface

Question 28

What is facilitated diffusion?

Answer 28

larger water soluable molecules carrier proteins with binding sites specific passive

Question 29

What is osmosis?

Answer 29

cytoplasm contains soluable molecules and ions which attract water net movement of solvent molecules from an area lower loconcentration to higher concentration of solute depends of water potential

Question 30

osmosis what happens if an animal cell in solution with a lower water potential?

Answer 30

net movement out of cell

Question 31

osmosis what happens to a plant cell in solution with lower water potential

Answer 31

contents shrink away from cell wall

Question 32

Osmosis what happens to an animal cell in solution with higher water potential

Answer 32

bursts

Question 33

osmosis what happens to a plant cell in solution with higher water potential

Answer 33

becomes firm and rigid

Question 34

what is active transport?

Answer 34

against a concentration gradient uses carrier proteins and requires ATP

Question 35

What is an example of active transport?

Answer 35

epithelial cells lining the intestine, lots of mitochondria which produces ATP for active transport

Question 36

How does active transport occur?

Answer 36

molecules bind to receptor site atp binds to protein , hydrolysed into ADP and Pi Protein changes shape Molecule is released Pi is released, protein reverts to original shape

Question 37

what is water potential

Answer 37

the tendency of water to move from one area to another by osmosis measured in kPa

Question 38

what is the water potential of pure water

Answer 38

0

Question 39

what is hypertonic

Answer 39

higher concentration of solutes when compared to another solution

Question 40

what is hypotonic

Answer 40

lower concentration of solute when compared to another solution

Question 41

what is isotonic

Answer 41

same solute concentration in two or more solutions