How plants produce food

photosynthesis, limiting factors, how plants use glucose, why do plants need minerals

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  • Created by: Anna
  • Created on: 27-11-11 17:34

Photosynthesis

Only happens in plants

Equation:

carbon dioxide + water (+light energy) ---->  glucose + oxygen

Carbon Dioxide: Taken in by the leaves and from respiration

Water: Taken in by the roots

Light Energy: Energy from the Sun is traped by the chlorophyll when needed for    phototsynthesis

Glucose: The carbohydrate is made.

Oxygen: Given off as a waste gas

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Limiting factors

Lack of Light Energy: Slow down the rate of photosynthesis beacause light provides energy for the process. Even on a sunny day, light can be limited on the floor of a wood or rain forest

Temperature: If it is cold the rate is decreased = enzymes in the plant cannot work properly in cold temperatures or very hot temperatures

Lack of Carbon Dioxide: If there is little CO2 the rae will slow down. CO2 can be limited in an enclosed space e.g. in a green house on a hot day and can be caused by a low concentration of CO2 in the air.


There is no point increasing one factor if one is already limited = waste of money!

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How Plants use Glucose and Why Plants need Mineral

Glucose is a product of photosynthesis, used in respiration in the plant

It is combined with other nutrients(mineral ions) by the plant to produce new materials

Glucose is soluble but can be stored by some plants as insoluble starch. It is stored as an insoluble substance so that it has no effect on osmosis (it cannot leave the cell) It can be turned back into glucose for respiration

Plant roots take up minerals salts for healthy growth

Nitrates: From soil to produce amino acids - produce proteins for growth

                                                                                    Deficient: Stunted growth

Magnesium ions: Essential for making chlorophyll     Deficient: Yellow leaves

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