Exercise
Mention the function of each of the followings:
1. Guard cells
They control opening and closing of stoma
2. Plant leaf
They make food for plant during photosynthesis process
3. Stomata
They are used to aerate the leaf
4. Chloroplasts
They contain chlorophyll that helps in making photosynthesis
5. Cuticle
It reduces the water loss by evaporation
6. Iodine
It is used to test starch in plant leaf
7. Alcohol (ethanol)
It is used to remove chlorophyll
8. Photosynthesis
It helps plant to make their food
9. Xylem
It carries water and dissolved salts from root to all parts of plant
10. Phloem
It carries food from leaves to all parts of plant
1.
2.
3.
4.
5.
6.
7.
Explain on scientific bases:
Before testing starch in leaf, we put it in boiling water.
To kill living cells
Before testing the importance of light for plant we put it in dark place for 48 hours.
To destarch plant
Oxygen still in air even combustion and respiration take place all the time.
Because plants take carbon dioxide and produce oxygen
We can't live without green plants
Because they are the main source of food and oxygen
Plants need phosphate and nitrate salts
Because phosphate makes DNA while nitrate build protein
Plant needs xylem and phloem
Because xylem carries water and dissolved salts from root to all parts of plant while phloem carries food
from leaves to all parts of the plant
The upper surface of the leaf is greener than lower surface.
Because near the upper surface there is a palisade tissue that contain larger amount of chloroplast than
spongy tissue which present near the lower surface