4.1.3 transport in cells

Question 2

what is being described?
the random movement of particles from an area of high concentration to an area of low concentration (down a concentration gradient) until there is no net movement (particles are evenly distributed/equilbrium reached)

Answer 2

diffusion

Question 3

A concentration gradient is

Answer 3

the difference in concentration between one area and another - the bigger the difference the bigger the gradient

Question 4

What factors affect rate of diffusion

Answer 4

temperature, concentration gradient and surface area

Question 5

Give an example of diffusion in real life

Answer 5

synapses, leaves, gut, lungs, roots,

Question 6

What part of a cell do molecules have to cross in diffusion?

Answer 6

cell membrane

Question 7

In cells what diffuses?

Answer 7

oxygen and glucose diffuses IN and carbon dioxide diffuses OUT

Question 8

What is an alveoli?

Answer 8

air sac found in the lungs - this is where diffusion of gases occurs

Question 9

How are exchange surfaces adapted for exchange?

Answer 9

large surface area, moist, extensive blood supply, thin

Question 10

If a cube has a length of 2 cm calculate its surface area, volume and surface area: volume ratio

Answer 10

surface area: 24
volume: 8
surface area: volume ratio 3:1

Question 11

Osmosis is

Answer 11

the movement of WATER particles from an area of low solute concentration to an area of high solute concentration across a selectively permeable membrane

Question 12

Osmosis occurs in the

Answer 12

roots of a plant

Question 13

When carrying out a practical to determine the solute concentration inside a potato, why do you calculate % change in mass?

Answer 13

because the mass of potatoes can vary

Question 14

When carrying out a practical to determine the solute concentration inside a potato, why do you blot the potatoes dry?

Answer 14

to remove any excess water as this may affect the final mass

Question 15

Active transport is

Answer 15

the movement of particles from an area of low concentration to an area of high concentration (up or against a concentration gradient). Energy is required which comes from respiration.

Question 16

Active transport in plants occurs in

Answer 16

the roots for the absorption of mineral ions

Question 17

Active transport in animals occurs in

Answer 17

the small intestine (gut) for the absorption of glucose/sugar

Question 18

What type of organism can rely of simple diffusion to meet its metabolic needs?

Answer 18

A singled cells organisms

Question 19

Feature of single celled organisms is

Answer 19

it has a large surface area to volume ratio

Question 20

Large multicellular organisms need exchange surfaces and a transport system because

Answer 20

they have a small surface area to volume ratio and CAN NOT obtain the materials they need by simple diffusion

Question 21

plants require mineral ions for

Answer 21

healthy growth

Question 22

Plants obtain mineral ions from the soil by

Answer 22

active transport

Question 23

Structures in the small intestine are called

Answer 23

villi

Question 24

These cells are adapted to absorb water and minerals from the soil

Answer 24

root hair cells

Question 25

root hair cells absorb mineral ions by what process?

Answer 25

active transport

Question 26

water is absorbed in the roots by what process?

Answer 26

osmosis

Question 27

Active transport is also used in humans, name the location

Answer 27

Gut - small intestine

Question 28

What can be said about the SA:volume ratio of a single celled organism?

Answer 28

it is large

Question 29

What can be said about the SA:volume ratio of a multicellular organism

Answer 29

it is small

Question 30

Exchange surfaces are adapted for exchange - how?

Answer 30

large SA
thin
extensive blood supply

Question 31

exchange surfaces include

Answer 31

lung(alveoli), small intestine (villi), roots, leaf

Question 32

In the alveoli what is exchanged?

Answer 32

oxygen IN

carbon dioxide OUT

Question 33

In the small intestine what is exchanged?

Answer 33

glucose into blood
amino acids into blood
fatty acids and glycerol into blood

Question 34

What are the lungs composed of?

Answer 34

alveoli

Question 35

How is a leaf adapted for exchange?

Answer 35

thin, many stomata, large surface area, air spaces inside leaf

Question 36

At the leaf surface what is exchanged during the day?

Answer 36

carbon dioxide in

oxygen out

Question 37

At night what is exchanged at the leaf surface?

Answer 37

water out
carbon dioxide out
oxygen in

Question 38

What does a plant use carbon dioxide for?

Answer 38

photosynthesis

Question 39

When does photosynthesis take place?

Answer 39

during the day

Question 40

During the day what opens on the leaf to allow for exchange to occur?

Answer 40

stomata

Question 41

At night what happens to the stomata?

Answer 41

they close

Question 42

What other molecule diffuses out of the leaf?

Answer 42

water

Question 43

What is the exchange surface of fish called?

Answer 43

gills

Question 44

How are the gills of a fish adapted for exchange?

Answer 44

large SA, thin, extensive blood supply = maximises diffusion!