movement of substances in and out of cells

Question 1

diffusion is

Answer 1

the moving of particles from an area of high concentration to an area of low concentration

Question 2

osmosis

Answer 2

the moving of water particles through a semi permeable membrane from an area of high solute concentration to an area of low solute concentration

Question 3

active transport

Answer 3

the movement of particles from an area of low concentration to an area of high concentration using energy released during respiration

Question 4

is the cell membrane permabeable

Answer 4

it is partially permeable

Question 5

in living organisms does diffusion happen and through what

Answer 5

yes, the cell membrane

Question 6

diffusion allows living organisms to : (3)

Answer 6

• gain nutrients in the digestive system
• gain oxygen in the lungs
• remove waste products in the lungs and kidney

Question 7

osmosis is the ____ of water

Answer 7

diffusion

Question 8

in osmosis, water moves ___ concentration gradient

Answer 8

down

Question 9

partially permeable membranes prevent

Answer 9

the movement of larger molecules but allow the movement of smaller permeables

Question 10

osmosis an have a severe effect in animal cells because

Answer 10

there is no cell wall

Question 11

in animal cells, osmosis can lead them to become :

Answer 11

crenated ( dehydrated)

lysis ( bursting because of too much water)

Question 12

in plant cells, there is a cell wall so it prevents them from ( due to osmosis)

Answer 12

bursting

Question 13

can plant cells become shrivelled due to osmosis

Answer 13

yes

Question 14

what is a turgid cell (plant cells)

Answer 14

when in osmosis, the cell gains water, and the membrane pushes against the cell wall, making it turgid

Question 15

turgid cells provide (2)

Answer 15

structural support
and prevent wilting ( loss of support)

Question 16

is energy needed for active transport, why

Answer 16

yes because particles are being moved against a concentration gradient

Question 17

what energy does active transport use

Answer 17

energy from cellular respiration

Question 18

is active transport an active or passive process

Answer 18

active

Question 19

example of active transport

Answer 19

absorption of mineral ions from the soil into the root of hair cells of plants

Question 20

the bigger the cell, the smaller its surface to area volume ratio so the rate of diffusion

Answer 20

decreases

Question 21

many cells that are adapted for diffusion have

Answer 21

• large surface area

Question 22

example of cell adaptations for diffusion

Answer 22

• small intestine has villi and is folded highly so as to have a high surface area

Question 23

the smaller the distance molecules need to travel the ____ transport will occur

Answer 23

faster

Question 24

why do alveoli have cells that are one cell thick

Answer 24

to ensure the rate of diffusion across them is as fast as possible

Question 25

factors that affect diffusion (4)

Answer 25

surface area
temperature
distance
pH

Question 26

the higher the temperature ( diffusion) the ____ the molecules will move because ___

Answer 26

faster
they have more kinetic energy, so there are more collisions against the cell membrane

Question 27

the bigger the difference in concentration on wither side of the membrane, the ___ the movement across it will happen

why

Answer 27

faster

because on the side with the higher concentration, more random collisions against the membrane will occur

Question 28

PRACTICAL- factors that affect diffusion, TEMPERATURE

Answer 28

Add 5cm3 starch solution to a test tube and heat to a set temperature using beaker of water with a Bunsen burner

Add a drop of Iodine to each of the wells of a spotting tile

Use a syringe to add 2cm3 amylase to the starch solution and mix well

Every minute, transfer a droplet of solution to a new well of iodine solution (which should turn blue-black)

Repeat this transfer process until the iodine solution stops turning blue-black (this means the amylase has broken down all the starch)

Record the time taken for the reaction to be completed

Repeat the investigation for a range of temperatures (from 20°C to 60°C)

RESULT ANALYSIS

• At hotter temperatures (above optimum) the iodine turned blue-black throughout the whole investigation
• At colder temperatures (below optimum), the iodine took a longer time to stop turning blue-black
• At the optimum temperature, the iodine stopped turning blue-black the fastest

Question 29

Practical investigating factors that affect osmosis

Answer 29

• prepare sugar solutions from 0mol/dm³ to 1 mold/dm³
• set up 6 labelled test tubes with 10cm³ of each of the sucrose solutions
• using a knife and a ruler and a cork borer, cut 6 equally sized potato cylinders
• blot each one with paper towel and weight them
• Put 1 piece into each concentration of sucrose solution
• After 4 hours, remove them, blot with paper towels and reweigh them

WHAT HAPPENS

• The potato in distilled water will gain the most mass due to a high concentration gradient, causing water to move into the cells by osmosis
• The potato in the strongest sucrose solution will lose the most mass as water moves out of the cells by osmosis, making them flaccid and the potato soft