Organisms Exchange Substances With Their Environment (6)

Question 1

All cells and organisms exchange material between what?

Answer 1

Themselves and the enviornment

Question 2

To enter or leave an organism, substances must do what to get across the plasma membrane?

Answer 2

Pass across

Question 3

The amoeba acmmcan exchange materials across its entire body surface by diffusion. True or False

Answer 3

True

Question 4

How do we calculate volume?

Answer 4

Length × width ×height

Question 5

How do we calculate surface area?

Answer 5

(Length × width) × number of faces

Question 6

Diffusion is directly proportional to what?

Answer 6

(Surface area × difference in concentration) ÷ length of diffusion path

Question 7

The tracheae are supported by strengthened rings to prevent them from what?

Answer 7

Collapsing

Question 8

The tracheae divide into smaller dead end tubes called what?

Answer 8

Tracheoles

Question 9

What are the 3 ways respiratory gases move in and out of the tracheal system?

Answer 9

1) Along a diffusion gradient
2) mass transport
3) the ends of tracheoles are filled with water

Question 10

Along the diffusion gradient: how is a diffusion gradient formed?

Answer 10

When all of the oxygen is used up and so it’s concentration towards of the tracheoles falls.

Question 11

In mass transport, contraction of the muscles in insects can squeeze the trachea, enabling what?

Answer 11

Mass movements of air in and out

Question 12

When an insect is very active, the muscle cells around the tracheoles maybe have to use what?

Answer 12

Anaerobic respiration

Question 13

The ends of the tracheoles are filled with water: In anaerobic respiration, lactate is produced and lowers the water potential in the muscles cells causing what to happen?

Answer 13

Water at the end of the tracheoles have more water in them

Question 14

With less water in the the tracheoles, the diffusion of oxygen into cells and carbon dioxide out into the tracheoles is more what?

Answer 14

Rapid

Question 15

Increasing gas exchange leads to what?

Answer 15

Greater water evaporation

Question 16

What are spiracles?

Answer 16

Tiny holes on the side of the abdomen

Question 17

Spiracles can be opened and closed by what?

Answer 17

A valve

Question 18

Why do spiracles open and close?

Answer 18

To prevent water loss

Question 19

Insects have waterproof covering, how?

Answer 19

They have a chitin protein and a waxy cutie substance forming an exoskeleton

Question 20

What is a limitation of insect gas exchange?

Answer 20

Relies mostly on diffusion so short diffusion pathway needed and restricts the size of insects

Question 21

What is a limitation of insect gas exchange?

Answer 21

Relies mostly on diffusion so short diffusion pathway needed and restricts the size of insects

Question 22

What is the flao above the gills in a fish called?

Answer 22

Operculum

Question 23

What does the Gill lamelle do?

Answer 23

Increases the surface area of the gills

Question 24

What is counter current flow?

Answer 24

When blood and water flow in opposite directions at a constant rate of diffusion across the entire length of the Gill lamelle of which 80% of oxygen from the water is absorbed into the blood

Question 25

What is parallel flow?

Answer 25

When blood and water flow in the same direction when the diffusion gradient only maintainee across a part of the Gill lamelle of which 50% of oxygen from the water is absorbed into the blood

Question 26

How might the gills of an active fish be different to the gills of a flat fish which spends most of its time on the sea bed?

Answer 26

• would need more oxygen in the blood
• so Gill lamelle needs to have a larger surface area and more filaments
• because it needs to efficiently absorb oxygen into the blood as they are using more oxygen when contracting their muscles

Question 27

When the rate of photosynthesis is the same as the rate of respiration what happens?

Answer 27

There is no diffusion of oxygen or carbon dioxide out of or into the leaf

Question 28

When it Is dark, oxygen is diffusing into the leaf as what is diffusing out of the leaf?

Answer 28

Carbon dioxide

Question 29

When it is light, carbon dioxide diffused only if the factors that enable photosynthesis are high enough. What arte these 2 factors?

Answer 29

Light intensity and temperature

Question 30

When it is light, oxygen only diffuses out if the rate of photosynthesis is what?

Answer 30

Greater than the rate of respiration

Question 31

Where is the stomata located?

Answer 31

Underside of a leaf

Question 32

Guard cells can do what to the stomata pores?

Answer 32

Change the stomata shape, which can open and close the stomata pores

Question 33

What are mesophytes?

Answer 33

A plant needing a moderate amount of water

Question 34

What are hydrophytes?

Answer 34

A plant that grows in or out water

Question 35

What is a halophyte?

Answer 35

A plant growing in saltmarsh

Question 36

What is a xerophyte?

Answer 36

A plant which needs very little water and has adaptations to prevent excessive water loss

Question 37

How does a thick cuticle minimise water loss?

Answer 37

As the cuticle gets thicker and thicker, the less the water can escape as it is a waterproofing layer made of lipid-wax

Question 38

How does the rolling up of the leaves minimise water loss?

Answer 38

It protects the lower epidermis from the outside and helps to trap still air that is In the rolled lead so no water potential is between the inside and outside of the leaf.

Question 39

How do hairy leaves and stomata in pits minimise water loss?

Answer 39

The hairs trap still air next to the leafs surface. The water potential between inside and outside is reduced so less water lost by evaporation.

Question 40

How is a reduced SA:V of the leaves prevent or minimise water loss?

Answer 40

The rate of diffusion is slower as the leaves cross section are circular