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  • Created by: lucy
  • Created on: 15-10-11 21:38


Photosyntheis is an important chemical reaction for plants in which carbon dioxide and light energy is changed for glocuse and oxygen. Without plants there would be a very bad carbon balance in the world.

There are many things that affect the rate of photosynthesis

These include light intensity

-Light intensity affects the rate of Photosynthesis, the higher the light intensity on general the faster the rate of photosynthesis.

Tempeture also affects the rate of Photosynthesis.

The higher the tempeture the faster the rate of photosynthesis.

However, because photosynthesis occurs because of enzymes, enzymes become denatured at to high tempetures, therefore that about 40c, tempeture will affect the rate of photosynethis negativley.

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Other factors that affect Photosynthesis

Carbon Dioxide levels

Carbon Dioxide also affects carbon dioxide levels. Plants need carbon dioxide to make glucose. Increasing the carbon dioxide levels increase the rate of Photosynthesis. Carbon dioxide levels tend to rise in the nights as the plant respires but doesnt photoynthesis due to no light being present.

Plants make glucose when they Photosynthesis. Plant cells like every living cells respire all the time. The break down glucose using oxygen to provide energy for their cells.

Some of the glucose made is converted to starch for storage. Plants also use glucose to build up sugars like celluse which make new plant cell walls.

Plants also use respiration to combine sugars with nutrients from the soil to make amino acids.

Amino acids are built up into proteins to be used in cells.

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Transport and Storage

When plants make glucose in the leaves from Photosynthesis, they need to transport it around the plant.

There are 2 transport systems in plants. Phloem is made up from living tissue.

Phloem- this transports sugars from the leaves to the rest of the plants.

Xylem- Xylem is another transport tissue. It carries water and mineral ions from the soil around the plant.

Plants use some of the Glucose in photosynthesis into starch. Glucose is soluble and could affect the balance of the plant. Starch on the other hand is insoluble this is good and means plants can have lots of starch without it having nay effect on the plant.

Starch is also very important as it is what is stored to keep a plant alive through winter.

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Why do plants need minerals

Plants need Minerals as well as light and carbon dioxide to survive. All the products of Photosynthesis are all carbahydrates. Although carabahydrates are important for Plants, plants also need proteins which they can't get from Photosynthesis.

Proteins- Act as enzymes and take up a large part of cytoplasm and membranes

Plants need nitrates from the soil to make proteins.

When plants die and decay the nitrates and other minerals when they die.

Plants also need Magnesium. This is because magnesium makes chlorophlyl which is important in photosynthesis.

Nitrate- Makes protein, without it they have stunted growth.

Magnesium- Makes chlorophyll, without it a plant will have pale yellow leaves.

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