5.2 - Gas Exchange in Plants Flashcards
Which gasses make up the air we breathe?
Oxygen, CO2, water vapour, nitrogen and other
Which gas makes up most of our air?
Nitrogen! (78%)
In what function do both plants and animals consume oxygen? What do they produce?
Both plants and animals (us!) need to perform cellular respiration. During this process we/they take in oxygen and produce carbon dioxide and water.
What process enabless plants to clean the air by taking in CO2?
Plants are capable of photosynthesis - they take in CO2 and Water to produce oxygen and glucose.
What is the formula for cellular respiration?
C6H12O6(s) + 6O2(g) —> 6H20(l) + 6CO2(g) + ENERGY
- The reverse of the photosynthesis formula
- During cellular respiration the glucose and the oxygen are converted into ATP.
What is the formula for photosynthesis?
6CO2(g) + 6H2O(l) + LIGHT ENERGY —> C6H12O6(s) + 6O2(g)
*During photosynthesis: plants consume greater CO2 than they release during cellular respiration (hence the “cleaning the air”)
What is the most important gas-exchange organ in the plant?
The leaf is considered the plants most important gas exchange organ (yes, it is an organ, b/c its made up of tissues)
Explain the process of CO2 entering the leaf and what happens.
Carbon dioxide enters the leaf through the stomata. They then diffuse through the cell membrane of the spongy tissue cells and once dissolved, are used by photosynthesis.
At what point does oxygen leave the cells? How does it leave?
After photosynthesis, oxygen diffuses out of the cells and exits the leaf through the stomata.
How does water move into and out of the cell?
Water is pulled up from the roots by the xylem and exits as water vapour through the stomata.
What perforations allow gas exchange in woody plants?
Lenticels - lens-shaped openings perforating the bark. They allow gas exchange between the bark (outer bark is dead old cells and the inner bark is living) and the living cells
What causes water loss in a plant?
Air diffusion out of the stomata causes water loss.
What is transpiration
THe evaporation of water from leaves
What prevents plant cells from drying out?
Guard cells are able to change their shape to cause the stomata to open and close. When the stomata are closed, gas exchange and water exchange are reduced.
Why are high rates of photosynthesis possible when stomata are open?
When the stomata are open CO2 can enter the leaf and oxygen and water vapour exit. Plants require CO2 and water for photosynthesis which results in oxygen and glucose.
