transport across cell membranes

Question 1

Plasma membranes

Answer 1

Partically permeable which controls which substances can enter and leave the cell. They act as a barrier that can create a separate environment.

Question 2

What organelles have a single membrane

Answer 2

Endoplasmic reticulum, golgi, lysosomes, vesicles and vacuoles

Question 3

What organelles have a double membrane

Answer 3

Mitochondria, chlorplast and the nucleus

Question 4

Arrangement of phospholipids

Answer 4

They are in a bilayer, they have integrated proteins, glycoproteins and glycolipids. Known and fluid mosaic model

Question 5

the function of the phospholipid bilayer

Answer 5

forms a barrier to dissolved substances. its hydrophobic so doesn’t allow water through

Question 6

function of intrinsic proteins

Answer 6

they allow large polar molecules into the membrane

Question 7

glycoproteins

Answer 7

proteins with carbohydrate attached. they act as antigens.

Question 8

glycolipids

Answer 8

lipids and a carbohydrate attached. act as antigens.

Question 9

function of cholestrol

Answer 9

a type of lipid which fits between the phospholipids. gives stability. hydrophobic so is waterproof.

Question 10

how does temperature affect the membrane

Answer 10

below zero degrees- thaws and ice crystals will pierce the membrane making it more permeable. intrinsic proteins denature.
0-45 degrees- more freely and membrane is partially permeable.
over 45 degrees- phospholipid starts to melt and membrane becomes more permeable.

Question 11

how do solvents impacts membranes

Answer 11

they can insert themselves into bilayer. pushes the phospholipids out of their orderly placement and increases their movement.

Question 12

how to know if membrane is more permeable

Answer 12

beetroot cells has red pigment in the vacuole. you know the membrane is more permeable as the water will turn red when boiled.

Question 13

how to test for membrane permeability

Answer 13

colorimeter

Question 14

how to used a colorimeter

Answer 14

select a filter which will maximise the accuracy of the experiment which is opposite to the colour tested on the colour wheel. to determine the concentration of unknown sample, use several solutions you know the concentration of. create a calibration curve. compare unknown with known samples.

Question 15

what is diffusion

Answer 15

the net movement of molecules from an area of high concentration to an area of low concentration.

Question 16

factors effecting simple diffusion

Answer 16

concentration gradient, membrane thickness, surface area, temperature.

Question 17

how does concentration gradient effect diffusion

Answer 17

the greater the concentration gradient the fast the diffusion

Question 18

how does membrane thickness effect diffusion

Answer 18

the thinner the membrane the faster the diffusion.

Question 19

how does surface area effect diffusion

Answer 19

the larger the surface area the faster the rate of diffusion.

Question 20

how does temperature effect diffusion

Answer 20

the higher the temperature the faster the diffusion

Question 21

what is facilliated diffusion

Answer 21

larger molecules and polar molecules move through intrinsic proteins and through the membrane structure.

Question 22

factors affecting facilliated diffusion

Answer 22

concentration gradient, number of intrinsic proteins

Question 23

how does concentration gradient affect facilitated diffusion

Answer 23

the greater the concentration gradient the faster the diffusion

Question 24

how does the number of intrinsic proteins affect facilitated diffusion

Answer 24

the grater the number of intrinsic proteins the faster the diffusion

Question 25

what is osmosis

Answer 25

the diffusion of water molecules across a partially permeable membrane from a high concentration to a low concentration

Question 26

what is water concentration also know as

Answer 26

water potential

Question 27

types a water potential

Answer 27

the more negative the water potential the solutes it has in it. zero water potential is pure water.

Question 28

higher water potential in animal calls and plant cells

Answer 28

in animal cells the cell can become lysed and explode whereas in plant cells the cell becomes turgid was the cell wall prevents it from bursting

Question 29

isotonic solution in animal and plant cells

Answer 29

in animal cells the cell becomes normal and in plant cells the cell becomes flaccid

Question 30

lower water potential in animal and plant cells

Answer 30

in animal cells the cell becomes shrivelled and in plant cells the cells become plasmolyzed

Question 31

what factors effect the rate of osmosis

Answer 31

water potential, membrane thickness, surface area

Question 32

how does water potential affect osmosis

Answer 32

the higher the water potential gradient the faster the osmosis

Question 33

how does membrane thickness affect osmosis

Answer 33

the thicker the membrane the less osmosis

Question 34

how does surface area affect osmosis

Answer 34

the larger the surface area the faster the osmosis

Question 35

how to calculate the serial dilution

Answer 35

dilution factor= initial volume of the stock solution/ final solution volume

Question 36

sucrose practical

Answer 36

fill test tube with 10cm3 of the 2M sucrose solution. fill 5 test tubes with 5cm3 of distilled water. use a pipette to transfer 5cm3 of sucrose from the test tube of 5cm3 of water.

Question 37

what is active transport

Answer 37

moves molecules across a plasma membrane from a low concentration to a high concentration.

Question 38

what do cells which go through active transport have a lot of

Answer 38

the have a lot of mitochondria to produce ATP which gives energy to the cells to move molecules up the gradient.

Question 39

what is co transport

Answer 39

uses carrier proteins called co transporters. the bind 2 molecules together, one moves down the concentration gradient and the other is brought with it.

Question 40

best example of co transport

Answer 40

in the lumen of the ileum with sodium and glucose

Question 41

factors affecting active transport

Answer 41

speed of carrier proteins, number of carrier proteins, rate of respiration

Question 42

how does the speed of carrier proteins affect active transport

Answer 42

the faster they work the faster the rate of active transport

Question 43

how does the number of carrier proteins affect active transport

Answer 43

the more carrier proteins, the faster the rate of active transport

Question 44

how does the rate of respiration affect active transport

Answer 44

when there is more respiration there is more energy so a faster rate of active transport

Question 45

what is endocytosis

Answer 45

the process of capturing a substance or particle from outside the cell by engulfing it with the cell membrane.

Question 46

what is exocytosis

Answer 46

the process by which materials are removed from or transported out of the cells. packed into secretory vesicles formed by the Golgi body.