Gas Exchange Flashcards
what are the main adaptations that gas exchange surfaces require?
- large SA
- thin- for a short diffusion pathway
- steep concentration gradient
what do these adaptations/ features do?
they increase the rate of diffusion
what don’t single celled organisms need?
they do not need a gas exchange system
what system do fish use for gas exchange?
they use a counter-current system
what adaptations do fish have to increase the efficiency of gas exchange?
- they have gill filaments and lamellae which increase the SA
- thin cell surfaces for a short diffusion pathway
- have lots of blood capillaries
- use a counter-current system
describe the counter-current system
- blood flows through the lamallae in one direction, and water flows in the opposite
- this creates a large concentration gradient as there’s more pressure in the water
- meaning oxygen can diffuse across to the blood more efficiently
what do insects use for gas exchange?
they use the trachea for gas exchange
what are trachea?
they are microscopic, air filled pipes
describe the process of gas exchange within an insect?
- air moves into the trachea, through spiracles
- oxygen travels down the concentration gradient through the trachea, towards the cells
- trachea branch into tracheoles, which have thin walls for gas exchange efficiency
- CO2 moves towards the spiracles and is released via its concentration gradient
what are spiracles?
they are pores found on the surface of the insect
how can insects control water loss?
- they can close their spiracles using muscles
- they have a waxy cuticle surface
- have tiny hairs on their surface
what are xerophytic plants?
plants adapted to hot, dry, windy climates, where water loss is a problem
how are xerophytic plants adapted for these harsh conditions?
- have stomata sunk in pits to trap moist air
- ‘hair’ on the epidermis
- curled leaves with stomata on, to protect from the wind
- reduced number of stomata
- waxy, waterproof cuticles
