The main variables which affect photosynthesis are light, water, CO2 concentration and temperature.
On a deeper level, other factors like amount of chlorophyll, availability of nutrients (eg Mg is needed for chlorophyll synthesis) will also affect the rate of photosynthesis, though these are rarely covered in discussion of this topic.
The thing is that photosynthesis will be held back by whichever factor is in shortest supply.
As I sit in my study in England, the sun is shining brightly, but the temperature outside is only 5ºC. I suspect the rate of photosynthesis is limited by temperature today.
Yesterday was a dull day, but in the middle of the day it was not cold and I suspect there wasn't enough light for photosynthesis. If I had turned the security lights on my house on, the plants in my garden might (possibly) have photosynthesised faster.
In summer, some farmers growing crops in glasshouses actually increase the amount of carbon dioxide in the air as all their plants have plenty of water and light and the temperature is near the best possible for photosynthesis.
A good way to investigate this might be with the help of algae and you can use the 'Immobilised Algae' practical for this.
Although water is needed as a raw material for photosynthesis, don't bother trying to investigate water as a variable - plants normally wilt and wither long before water restricts photosynthesis at the biochemical level. They need water to support the plant to face the sun as well as a raw material of photosynthesis.
The simplest equation for photosynthesis:-
Carbon dioxide + water -----(in light, with chlorophyll and enzymes)----> sugar + oxygen
Temperature speeds up all chemical reactions - photosynthesis is no exception.
Enzymes work better in warm conditions (up to about 50ºC when enzymes start to be destroyed by heat).
The idea to get across is that different conditions will be most important on different occasions. This morning, my garden could do with more warmth - yesterday, it could do with more light / sun!
Answer:
Four daughter cells are produced each with 40 chromosomes. The daughter cells would exhibit genetic variations and would not be genetically identical to each other.
Explanation:
Meiosis is a cell division that forms four daughter cells from one parent cell as two sequential division meiosis I and meiosis II do not include any DNA replication between them. Crossing over during prophase-I of meiosis-I includes the exchange of genetic segments and occurs between the homologous chromosomes. It produces new gene combinations in the daughter cells which were otherwise not present in the parent cell.
Since there is no DNA replication between meiosis I and meiosis II, the daughter cells have half the number of the chromosomes compared to the parent cell. This occurs as homologous chromosomes move towards the opposite pole during anaphase I.
Therefore, a parent cell with 80 chromosomes will make a total of 4 daughter cells by meiosis. Each daughter cell would have 40 chromosomes. These daughter cells would have some new gene combinations and would be genetically dissimilar among themselves.
<h2>Answer:</h2>
The water will move in and out freely. The material transport which is due to the water transport will be affected.
<h3>
Explanation:</h3>
- Water is a partially polar molecules. Many ionic compounds and ions travel inside and outside the cell due to attachment with water molecule.
- As well as water movement is controlled due to its polar nature through cell membrane. and the cytoplasm and outer environment is separate due to non polar cell membrane.
- If the water become non polar then the movement through cell membrane will be easy for water. And the molecules dissolved in water will also be transported uncontrollably.
Answer:
4. B cells become activated by interacting with helper T cells.
1. B cells display antigens in MHC class II receptors on the cell surface.
2. Antibodies released by plasma cells bind to the antigen so they will be destroyed by other cells of the immune system.
3.B cells rearrange their DNA to create a unique B-cell receptor.
5. B cells undergo clonal expansion.
6. B cells digest antigens that bind to the antibodies on their surface.
Explanation:
B-cells get activated by interacting with helper T cells when they bind to the antigen to receptors i.e (MHC class II receptors on the cell surface) on the surface of the cell. Series of activities such as release by plasma cells which cause rearrangement of B cells causes the cell to divide and proliferate. The process through which daughter cells arise from a parent cell called clonal expansion.
