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Exchange - Coggle Diagram
Exchange
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Starch, protein and lipids
Starch
- Mouth - amylase, hydrolyses starch to maltose
- Small intestine - amylase, any remaining starch to maltose
- Maltase hydrolyses maltose to glucose
- Sucrase hydrolyses sucrose in to glucose and fructose
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Gas exchange in insects
1
- O2 used up in respiring mucles.
- Creates a concentration gradient.
2
- CO2 is produced in muscles.
- Creates a concentrationn gradient.
3
- Lactate decreases water potential of muscle.
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- Muscles produce lactate -> soluble.
- Increases tracheole volume.
- Ends of tracheoles contain H2O.
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- Which maintains ventilation and O2 and CO2 concentartion gradient.
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Defintions
- Pulmonary pressure - lung pressure.
- Thoracic volume - chest cavity.
Gas exchange in fish
Ventilation in fish
- Water is taken in through the mouth
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- Water is pushed from the mouth through the gills
Countercurrent exchange
- Oxygen diffuses into blood
- Deoxygenated blood meets water with low levels of oxygen
- Oxygenated blood meets wate with high levels of oxygen
- Blood flows in the opposite direction to water flow
- Oxygen diffuses into blood
- 80% of oxygen in water diffuses into the blood
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Gas exchange in plants
- Only specialised plant cells with chloroplasts photosynthesise, in light conditions.
- During photosynthesis, C02 diffuses into the leaf, O2 diffuses out.
- All plant cells are always respiring (except xylem which are dead).
- When photosynthesis is not occuring, O2 diffuses nto the leaf and CO2 diffuses out.
Structure of a leaf
- Many interconnect air spaces, so no living cell is far from external air.
- Diffusion happens in the gas phase.
- Leaves are adapted for gas exchange.
- Many stomata, so short diffuion pathway.
- Dicotyledons are plants that have two embryonic leaves in their seeds and include most cultivated and ornamental plants.
- Large surface area of mesophyll cells for rapid diffusion.
Stomata
- Guard cells swell up when full of water, stoma open.
- Guard cells shrink and flatten when water is scarce, stoma close.
- Water is lost by evaporation, but water is needed for photosynthesis.
- Prevents water loss when water is scarce, BUT prevents gas exchange.
- Each stoma is surrounded by two guard cells.