Bio- Nutrition in plants(h) Flashcards
What is photosynthesis? What is the chemical formula of photosynthesis? Where does the water go?
Photosynthesis is the process in which green plants take in carbon dioxide and water in the presence of light. Chemical formula: 6CO2+6H20->C6H12O6+6O2+6H2O. (light energy on top of the arrow, chlorophyll below the arrow).It is released via the stomata as water vapour.
How do we test for photosynthesis?
We use the starch test. If iodine remains brown, starch is not present. If iodine turns blue black, starch is present. But before conducting starch experiment, remember to destarch the leaves. Putting the plant in a dark room for two days destarches the leaves, ensuring that the starch produced is solely during the experiment, not produced before the experiment.
Remember to refer to notes for diagram of the structures in the leaf.
What are the amounts of photosynthesis in each respective part?
palisade mesophyll layer: highest amount of photosynthesis.
spongy mesophyll layer: significant amount of photosynthesis.
guard cells: photosynthesis is present.
What is the adaptation of the cuticle?
It is waxy to prevent the excessive loss of water and prevent the entry and exit of water molecules.
What is the adaptation of the upper epidermis?
It does not contain chloroplasts and is transparent. This allows light to pass through into the inner layers.
What is the adaptation of the palisade mesophyll layer?
The cells are long and cylindrical and are vertically packed. The vertical arrangement exposes many cells to light rays.
What are the adaptations of the spongy mesophyll layer?
It has air spaces for gaseous exchange. The cells are also surrounded by a thin film of water. So the gases exchanging in the cell can dissolve in water.
What is the vein(vascular bundle)?
It extends within leaf between every mesophyll cell. It supports the leaf and keeps it flat.
What are the differences between the guard cell and epidermal cells?
- The guard cell’s cell wall is thicker near the stoma, while the epidermal cells’ cell wall is uniformly thick.
- The guard cell is bean shaped, while the epidermal cells are irregular in shape
3.The guard cells have chloroplasts while the epidermal cells don’t have chloroplasts.
What is the function of the guard cell and where is it located?
It surrounds the stomata. It regulates the opening of the stomata for CO2 and O2 in and out of the leaf.
How do we identify the xylem and phloem?
The xylem has a thick outline and a hollow centre. Xylem is on the inside and phloem is on the outside.
Why do the guard cells open during the day?
Potassium ions enter the guard cell, thus increasing the concentration in guard cells. This results in a lower water potential in the leaves than the surrounding. Thus the water moves into the cell via osmosis causing the cell to become turgid and swell, thus opening the stomata.
Why do guard cells close during the night?
at night, the glucose is used during respiration. This results in a higher water potential in the cells than the surroundings. Water then moves out of the cell via osmosis, causing the cell to become flaccid and the stomata to close.
How does light intensity affect the rate of carbon dioxide and oxygen intake and output?
When there’s a higher light intensity, the rate of photosynthesis increases, as a result, there is more oxygen produced in the leaf cells, and more carbon dioxide is consumed by the leaf cells. Thus there is a higher rate of oxygen diffusing out of the leaf as the leaf contains a higher concentration of oxygen than the surroundings. Thus more carbon dioxide is taken in as there is a higher concentration of carbon dioxide in the surroundings than in the leaf.
