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The Control of Photosynthesis - Coggle Diagram
The Control of Photosynthesis
Requirements for photosynthesis
The availability of light
The presence of a pigment to absorb the light
A supply of carbon dioxide and water
A temperature suitable for enzyne activity
Factors
:
If any of these factors is in short supply --> the rate of photosynthesis will be less than its maximum possible rate
Limiting factor:
Controls the rate of the overall process
Factors affecting photosynthesis
Availability of light
--> light provides the energy that drives photosynthesis
Chlorophyl
--> essential for the absorbption of light energy
Temperature
--> affects the rate of enzyne energy
Carbon dioxide concentration
--> has a mayor influence on the rate of photosynthesis
Water availability
--> a shortage of water
Rate of reaction
2) Second limiting factor --> bottleneck --> the number of molecules of product formed is limited by how quickly the enzymes can work.
3) By raising the temperature, more substrate molecules can be converted to product.
1) The reaction will go faster if more substrate becomes available --> in this situation
substrate concentration is the limiting facto
r
Photosynthesis and respiration
glucose + oxygem --> carbon dioxide + water
If photosynthesis exeeds respiration (in the light), plants will remove carbon dioxide and add oxygen
if photosynthesis is less than respiration (in the dark), plants will remove oxygen and add carbon dioxide
Demostrating gas exchange
hydrogencarbonate indicator
--> overall change in carbon dioxide levels in the atmosphere
carbonic acid
--> in water this indicator is sensitive to the changes in PH caused by the acid
In the dark --> the rate of respiration greatly exceeds the rate of photosynthesis
The compensation point
--> light intensity is at the point where the rate of photosynthesis is equal to the rate of respiration.
The products of photosynthesis
Plants manufacture all of their food requirements, starting from the glucose molecule
The products that the plant makes --> available to the plant and to any organism that eats the plant
Atoms are recycled between simple and complex molecules, through the bodies of plants, animals, etc.
Oxidation --> energy which is used to drive all of the other reactions
Condensation --> Sucrose: transport form of carbohydrate / Starch: storage form of carbohydrate / Cellulose: structural form of carbohydrate
Reduction --> energy storage and oils
Plants and minerals
Minerals in soil
depend on the type of rock beneath the soil and on the decomposition of animal and plant remains lying on the soil
Minerals are taken out of the soil by plants, and are also washed out by the rain
Natural fertillisers --> sewage sludge, animal manure, compost or artificial fertilisers
The plant uses minerals to make food molecules (amino acids, proteins, nucleic acids
Plants absorb minerals from the soil in the form of ions
Problems with fertilisers
Excessive use of the fertilisers can cause problems of eutrophication
Water becomes oxygen-deficient, and larger animals (fish and insects) die.
Fertiliser runs off into nearby streams, rivers and lakes