Membranes

Question 1

function of a membrane

Answer 1

separation of the content of the cell from the outside

and the separation of the individual organelles and the cytosol

Question 2

compartmentalisation

Answer 2

formation of separate membrane-bound areas in a cell

Question 3

why is compartmentalisation important to the cell

Answer 3

metabolism contains incompatible reactions & the specific chemical conditions like pH, etc. can be provided

Question 4

how can you distinguish membranes that enclose cells from membranes of the organelles? (by name)

Answer 4

cell membrane is called cell-surface/ plasma mebrane

Question 5

structure of a membrane

Answer 5

phospholipid bilayer

Question 6

types of proteins in the cell-surface membrane

Answer 6

intrinsic and extrnsic

Question 7

intrinsic proteins

Answer 7

embedded through both layers of the membrane

Question 8

channel proteins

Answer 8

hydrophilic channel

–> passiv transport of ions and polar molecules

Question 9

carrier proteins

Answer 9

passiv and active transport through membrane

Question 10

passive transport

Answer 10

along a gradient

Question 11

aktive transport

Answer 11

against a gradient

Question 12

extrinsic proteins

Answer 12

present in one side of the bilayer

Question 13

why does temperature affect the cell membrane structure?

Answer 13

phospholipids move continuously –> increased temperature –> increased kinetic energy

Question 14

do cell membranes denature?

Answer 14

no they are destroyed or disrupted

Question 15

what influences the structure of cell membranes?

Answer 15

• temperature

- solvents

Question 16

why can alcohol be used as an disinfectant?

Answer 16

it destroys the cell membrane of the bacteria

Question 17

why are there changes in the behavior of people who drank alcohol?

Answer 17

the alcohol disrupted the neuronal membranes and nerve impulses are no longer transmitted as normal

Question 18

does passive transport utilise energy?

Answer 18

yes, but it does not need metabolic energy and instead uses the natural motion of particles

Question 19

equilibrium

Answer 19

balance of concentrations

Question 20

does equilibrium mean that the particles stop moving?#

Answer 20

no, there is just a balance in movements

Question 21

selectively permeable membrane

Answer 21

membrane with protein channel

Question 22

term for cell-surface membrane bends inwards

Answer 22

invaginates

Question 23

solute

Answer 23

substance that is solved in a solvent to form a solution

Question 24

solvent

Answer 24

dissolves substances to form a solution

Question 25

water potential

Answer 25

pressure that is exerted by water molecules as they collide with a membrane or container

Question 26

when does osmosis occur

Answer 26

when water solutions of two different water potentials are separated by a partially permeable membrane

Question 27

what moves during osmosis

Answer 27

water molecules two equal concentrations

Question 28

cytolysis

Answer 28

water potential outside of cell is higher --> cell bursts (animal cells)

Question 29

crenation

Answer 29

water potential outside of cell is lower --> cell shrinks (animal cells)

Question 30

turgor

Answer 30

pressure that cell wall experiences when water enters the cell

Question 31

turgid

Answer 31

cell wall resists entry of more water

Question 32

plasmolysed

Answer 32

cell membrane pushed away from cell wall