Gas Exchange (in plants and insects) Flashcards
What 3 major adaptations do gas exchange surfaces have?
Large surface area
Thin
Maintained concentration gradient
What system do fish use for gas exchange?
Counter-current system
Where does water enter and leave fish?
Enters through mouth, leaves via gills
Gills have thin plates attached to them, what are they called?
Gill filaments
What are the tiny structures on gill filaments called?
Lamellae
How are lamellae adapted to increase rate of diffusion?
Lots of capillaries - maintain concentration gradient
They also increase surface area
How does the counter current system maximise gas exchange?
Maintains large concentration gradient
Concentration of oxygen in water is higher than in blood- maximum diffusion
In insects air enters through pores on their surface. What are the pores called?
Spiracles
What are the microscopic air filled pipes which insects use for gas exchange?
Tracheae
In insects, tracheae branch into smaller pipes called tracheoles. How are the tracheoles adapted for gas exchange?
They have thin permeable walls
How do insects move air in and out of spiracles?
By rhythmic abdominal movements
What are the pores in plants which allow gas exchange to happen and which cells control their opening?
Stomata and guard cells
Where are stomata found on leaves?
Lower epidermis
How do guard cells close stomata?
Water is lost from guard cell when plant is dehydrated. Causes the guard cells to become flaccid
How do guard cells open stomata?
Plant is hydrated, water enter guard cells and makes them turgid (keeps stomata open)
