Unit 4.1.3 Transport In Cells

Question 1

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 1

diffusion

Question 2

A concentration gradient is

Answer 2

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

Question 3

What factors affect rate of diffusion

Answer 3

temperature, concentration gradient and surface area

Question 4

Give an example of diffusion in real life

Answer 4

synapses, leaves, gut, lungs, roots,

Question 5

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

Answer 5

cell membrane

Question 6

In cells what diffuses?

Answer 6

oxygen and glucose diffuses IN and carbon dioxide diffuses OUT

Question 7

What is an alveoli?

Answer 7

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

Question 8

How are exchange surfaces adapted for exchange?

Answer 8

large surface area, moist, extensive blood supply, thin

Question 9

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

Answer 9

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

Question 10

Osmosis is

Answer 10

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 11

Osmosis occurs in the

Answer 11

roots of a plant

Question 12

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

Answer 12

because the mass of potatoes can vary

Question 13

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

Answer 13

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

Question 14

Active transport is

Answer 14

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 15

Active transport in plants occurs in

Answer 15

the roots for the absorption of mineral ions

Question 16

Active transport in animals occurs in

Answer 16

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

Question 17

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

Answer 17

A singled cells organisms

Question 18

Feature of single celled organisms is

Answer 18

it has a large surface area to volume ratio

Question 19

Large multicellular organisms need exchange surfaces and a transport system because

Answer 19

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

Question 20

plants require mineral ions for

Answer 20

healthy growth

Question 21

Plants obtain mineral ions from the soil by

Answer 21

active transport

Question 22

Structures in the small intestine are called

Answer 22

villi

Question 23

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

Answer 23

root hair cells

Question 24

root hair cells absorb mineral ions by what process?

Answer 24

active transport

Question 25

water is absorbed in the roots by what process?

Answer 25

osmosis

Question 26

Active transport is also used in humans, name the location

Answer 26

Gut - small intestine

Question 27

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

Answer 27

it is large

Question 28

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

Answer 28

it is small

Question 29

Exchange surfaces are adapted for exchange - how?

Answer 29

large SA
thin
extensive blood supply

Question 30

exchange surfaces include

Answer 30

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

Question 31

In the alveoli what is exchanged?

Answer 31

oxygen IN

carbon dioxide OUT

Question 32

In the small intestine what is exchanged?

Answer 32

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

Question 33

What are the lungs composed of?

Answer 33

alveoli

Question 34

How is a leaf adapted for exchange?

Answer 34

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

Question 35

At the leaf surface what is exchanged during the day?

Answer 35

carbon dioxide in

oxygen out

Question 36

At night what is exchanged at the leaf surface?

Answer 36

water out
carbon dioxide out
oxygen in

Question 37

What does a plant use carbon dioxide for?

Answer 37

photosynthesis

Question 38

When does photosynthesis take place?

Answer 38

during the day

Question 39

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

Answer 39

stomata

Question 40

At night what happens to the stomata?

Answer 40

they close

Question 41

What other molecule diffuses out of the leaf?

Answer 41

water

Question 42

What is the exchange surface of fish called?

Answer 42

gills

Question 43

How are the gills of a fish adapted for exchange?

Answer 43

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