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:
b. diffusion and osmosis across semi-permeable membranes
Explanation:
ATP (adenosine triphosphate) is a high energy carrying molecule in the system of living organisms. It posseses the ability to store and release energy for use by organisms during biochemical activities. However, some processes do not require ATP to occur and are called PASSIVE TRANSPORT while those that require energy (ATP) are called ACTIVE TRANSPORT.
In the above options, the processes listed as follows require ATP to occur:
- The active transport of glucose from the small intestine to the blood
- The movement of the flagella of sperm for motility
- Exocytosis of waste substances across a semi-permeable membrane
However, the diffusion and osmosis across semi-permeable membranes, which is a passive transport does not require ATP.
almost all weather occurs in are troposphere
Answer:
See the answer below
Explanation:
It may seem that the question is incomplete. The complete question reads:
Match each statement to the type of behavior it describes. Jenna published the results of her latest experiment for the public to see. Malcolm altered an experiment to be able reach his desired conclusion. Elena keeps complete records of all her experiment results. Neal shared the results of his field study even though they didn’t support his hypothesis. <em>Put each description to the group it belongs to. 1.Responsible 2.Irresponsible.</em>
<em>To answer the question:</em>
<em>Responsible behavior</em>
- <em>Jenna published the results of her latest experiment for the public to see.</em>
- <em>Elena keeps complete records of all her experiment results.</em>
- <em>Neal shared the results of his field study even though they didn't support his hypothesis.</em>
<em>Irresponsible behavior</em>
- <em>Malcolm altered an experiment to be able to reach his desired conclusion</em>
Responsible behaviors are those that support responsible scientific practices and do not jeopardize the objective nature of research. Every data during experiments must be well kept and after thorough analysis, results must be published fro the public to see irrespective of whether it agrees or disagrees with the original hypothesis.
Altering an experiment in order to achieve the desired result is grossly irresponsible, as this eliminates the objectivity that should be the main goal of every experiment. Bias must be eliminated from every scientific experiment.
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Potential evapotranspiration is higher in the summer, on less cloudy days, and closer to the equator, because of the higher levels of solar radiation that provides the energy for evaporation. Evapotranspiration is the sum of evaporation and plant transpiration from the Earth's land and ocean surface to the atmosphere. Evaporation accounts for the movement of water to the air from sources such as the soil, canopy interception, and water bodies. Transpiration accounts for the movement of water within a plant and the subsequent loss of water as vapor through stomata in its leaves.
