Gas Exchange in Fish, Insects, Plants Flashcards
1
Q
Gill structure (+ function)
A
- Gill filaments and lamellae (large surface area, increasing rate of diffusion)
- Many capillaries with thin epithelium (short diffusion distance)
- Counter current flow system (maintains steep concentration gradient)
2
Q
Counter current flow system in gills
A
- Blood and water flow in opposite directions, maintaining a steep concentration gradient of oxygen
- Water always next to blood with lower concentration of oxygen
- Diffusion gradient maintained throughout length of gill
- Circulation of blood replaces blood saturated with oxygen
- Ventilation of water replaces water low in oxygen
3
Q
Dicotyledonous plant structure (+ function)
A
- Spongy mesophyll layer (gas exchange of carbon dioxide for photosynthesis)
- Stomata which can be opened and closed by guard cells (reduce water loss)
4
Q
Insect structure (+ function)
A
- Spiracles (air moves in and out)
- Air filled trachea (oxygen diffuses down steep concentration gradient)
- Tracheloes highly branched (short diffusion distance and large SA)
- Tracheoles have thin walls (short diffusion distance to muscle cells)
- Ventilation (helps maintain concentration gradient)
5
Q
Insect adaptions to reduce water loss
A
- Waterproof waxy cuticle
- Close spiracles
6
Q
Xerophytic plant adaptions to reduce water loss
A
- Stomata sunk in pits (trap water vapour, reducing water potential gradient)
- Hairs on epidermis (trap water vapour)
- Curled leaves (trap water vapour)
- Fewer stomata
- Thick waxy waterproof cuticle (reduces evaporation)
7
Q
Fish dissection
A
- Place on cutting board
- Gills located either side of fish head
- Push back operculum
- Use scissors to remove gills
- Cut each gill arch through the bone at top and bottom
- View with optical microscope
8
Q
Insect dissection
A
- Pin insect to cork board
- Cut open exoskeleton
- Identify trachea (tracheoles too small)
- Remove piece of internal organ
- View with optical microscope
