7.4 Gas Exchange In Plants And Animals Flashcards
Net gas exchange depends on the ______ of photosynthesis be respiration
Relative rates
Daytime
net uptake, release
Photosynthesis, respiration
In presence of light, photosynthesis rate > respiration rate
Net uptake of carbon dioxide
Net release of oxygen
Night
Net uptake, release
Photosynthesis stops, respiration takes place
Net uptake of oxygen
Net release of carbon dioxide
Hydrogencarbonate indicator colours in diff c02 content
<0.03% purple
=0.03% (normal air)
>0.03% yellow
Why Hydrogencarbonate indicator turns purple
(Leaf w indicator under light)
Carries out photosynthesis and respiration
Photosynthesis rate is higher, net uptake of co2
Thus it turns purple
A) Hydrogencarbonate indicator colour after being in the sun for 4 hours
1. Leaf, hydrogencarbonate indicator
2. Hydrogencarbonate indicator
3. Leaf, Hydrogencarbonate indicator, aluminium foil
4. Hydrogencarbonate indicator, aluminium foil
B) control set-ups?
- Purple
- Red
- Yellow
- Red
2 and 4, shows light isn’t cause of changes
Exhaled VS Inhaled air
Less oxygen (16%) More oxygen (21%)
More co2 (4%) Less co2 (0.03%)
More water vapour
More temp.
Mealworm, wire gauze, Hydrogencarbonate indicator
Colour + conclusion
Yellow
Mealworm gives out carbon dioxide in gas exchange
Air -> [ soda lime ] -> [limewater A] -> [mouse] -> [limewater B]
What happens to limewater
A- colourless
B- milky
Soda lime absorbs co2, air flow into A no co2
Mouse gives out co2, air flow into B has co2
Why humans hv breathing system
Gas exchange
Gas exchange purpose (humans)
Continuous supply of oxygen to body cells for respiration + remove co2
energy in food can be released and used by body
Human breathing system
- Nasal cavity 7. Rib
- Trachea 8. Lung
- Bronchus / 2 bronchi 9. Diaphragm
- Bronchioles
- Air sacs
- Intercostal muscle
Air sacs are surrounded by
Capillaries (small blood vessels)
Where gas exchange take place
Air sacs
_____ passes fr air sacs to blood
_____ passes fr blood to air sacs
Oxygen
Carbon dioxide
*氣吸入血
