Exchnage - Gas Exchnage In Plants And Animals

Question 1

Describe counter current system in fish

Answer 1

Blood flows through lamellae in one direction and water flows in opp direction, this manga is a large conc gradient between water and blood as the conc of oxygen is always higher in the water than blood so diffusion takes place

Question 2

Describe adaptations of fish

Answer 2

Water with O2 enters fish’s mouth and passes out trough the gills
The gills have gill filaments which provide large surface area, these are also covered in lamellae which provide an even larger surface area
They also have blood capillaries and a thin layer of cells for fast diffusion

Question 3

What do insects use for gas exchange

Answer 3

Trachae

Question 4

How does air move into the trachae in insects

Answer 4

Via pores called spiracles
The trachae branch into tracheoles which have thin permeable walls so oxygen is diffused to cells and carbon dioxide from cells to spiracles and released into the atmosphere
Insects use abdominal movement to move air in and out of spiracles

Question 5

What do mesophyll cells provide

Answer 5

Large SA

Question 6

Role of stomata

Answer 6

Gases move through special pores in epidermis called stomata and stomata open to allow exchange and close to trap water
Controlled by guard cells

Question 7

What do insects do if they are losing too much water

Answer 7

They close they’re spiracles via muscles
They have a waxy waterproof cuticle and tiny hairs around spiracles to reduce evaporation

Question 8

What are Xenophytes

Answer 8

Plants adapted in warm/dry/windy conditions where water loss is a problem
They’re adaptations are, stomata sunk in pits to trap moist are and reduce evaporation
Hairs on epidermis to trap moist air
Curled leaves with stroma to protect from wind which causes evaporation
They have less stomata so less places for water to escape
Waxy cuticle to reduce evaporation