Biological Membranes

Question 1

Fluid mosaic model

Answer 1

Theory of cell membrane structure with proteins embedded in the sea of phospholipids

Question 2

Glycolipid

Answer 2

Lipid/phospholipid with a chain of carbohydrate molecules attached

Question 3

Glycoprotein

Answer 3

Protein with a chain of carbohydrate molecules attached

Question 4

Plasma membrane

Answer 4

Cell surface membrane

Question 5

osmosis

Answer 5

water moves from high water potential to low water potential down a water potential gradient through a partially permeable membrane

Question 6

features of osmosis

Answer 6

the more concentration, the more solute so the more water molecules tied therefore, there are less water molecules free to take part in osmosis
passive process (requires no energy)
partially permeable 
water potential gradient
equilibrium

Question 7

hypotonic solution

Answer 7

a dilute solution with not many solutes

Question 8

hypertonic solution

Answer 8

concentrated solution with many solutes

Question 9

isotonic solution

Answer 9

equal concentration of solutes and water

Question 10

cytolysis

Answer 10

in animal cells, if a lot water molecules enter, the cell will swell and burst as the plasma membrane breaks

Question 11

turgid

Answer 11

in plant cells, the rigid and strong cellulose wall will prevent bursting. the cell will swell up to a certain size when its contents push against the cell wall which will resist any further swelling. turgidity of plant cells help support plants especially those that aren’t woody

Question 12

crenated

Answer 12

when animal cells shrivel

Question 13

plasmolysed

Answer 13

when the cytoplasm of plant cells shrink and the membrane pulls away from the cellulose wall, they suffer a degree of dehydration and their metabolism can’t proceed as enzyme-catalysed reactions need to be in solution

Question 14

flaccid

Answer 14

plant tissue with plasmolysed cells

Question 15

diffusion

Answer 15

movement of molecules from an area of high concentration of that molecule to an area of low concentration (may/may not be across a membrane, doesn’t need ATP)

Question 16

facilitated diffusion

Answer 16

movement of molecules from high concentration to an area of low concentration across a partially permeable membrane via channel proteins (doesn’t involve ATP)

Question 17

water potential

Answer 17

measure of the tendency of water molecules to diffuse from one region to another

Question 18

active transport

Answer 18

the movement of substances against their concentration gradient (from low to high concentration) across a cell membrane using ATP and carrier proteins

Question 19

endocytosis

Answer 19

bulk transport of molecules too large to pass through a cell membrane into a cell, an active process via vesicles that ‘fuse’ with the cell using ATP

Question 20

exocytosis

Answer 20

bulk transport of molecules too large to pass through a cell membrane out of a cell, an active process via vesicles that are ‘pinched off’ using ATP

Question 21

what is active transport affected by

Answer 21

low temperature and lack of carbon dioxide

Question 22

sodium-potassium pump

Answer 22

the mechanism in active transport of moving sodium and potassium ions across the membrane

Question 23

bulk transport

Answer 23

some cells need to transport large molecules and particles that are too large to pass in and out the plasma membrane so they move via vesicles in endocytosis and exocytosis

Question 24

All proteins in the plasma membrane

Answer 24

Transmembrane
Carrier
Peripheral
Channel
Glycoproteins

Question 25

Other parts to plasma membrane

Answer 25

Phospholipids Glycolipids Carbohydrate molecules Cholesterol

Question 26

In high water potential, cells can become

Answer 26

Cytolysed (animal) | Turgid (plant)

Question 27

In low water potential, cells can become

Answer 27

Crenated (animal) | Plasmolysed (plant)

Question 28

Does high water potential have high or low pressure

Answer 28

Low

Question 29

Does low water potential have high or low pressure

Answer 29

High

Question 30

function of phospholipids

Answer 30

control what enters/exits cell

Question 31

function of integral (inside membrane) proteins

Answer 31

transport molecules in/out of cell

Question 32

function of glycolipids/glycoproteins

Answer 32

cell recognition, cell signalling, receptors

Question 33

function of peripheral (outside membrane) proteins

Answer 33

enzymes

Question 34

function of cholesterol

Answer 34

maintains stability and fluidity of the cell by preventing it becoming too stiff when temperature is too high/low

Question 35

glycocalyx

Answer 35

chain of carbohydrate molecules

Question 36

function of glycocalyx

Answer 36

very hydrophilic on the outside, attracting water with dissolved solutes, helping the cell to interact with its watery environment and obtain dissolved substances

Question 37

hydrophilic...

Answer 37

head

Question 38

hydrophobic...

Answer 38

tail

Question 39

betalain

Answer 39

red pigment that leaks out of beetroot when temp increases and membrane becomes more permeable