Factors affecting photosynthesis

• Plants make their own food using photosynthesis, which is important not only for the plants themselves, but for the other organisms that feed on the plants.
• There are several ways of measuring the rate of photosynthesis in the lab, including the rate of oxygen output, the rate of carbon dioxide output, and the rate of carbohydrate uptake.
• Carbon dioxide is a gaseous compound of carbon and oxygen, which is a by-product of respiration, and which is needed by plants for photosynthesis.
• Carbohydrates are vital for energy in humans and are stored as fat if eaten in excess.
• In plants, carbohydrates are important for photosynthesis.
• The rate of photosynthesis can be affected by several factors: light intensity, carbon dioxide concentration, temperature, the amount of chlorophyll, and the effects of some plant diseases.
• Without enough light, a plant cannot photosynthesise very quickly - even if there is plenty of water and carbon dioxide and a suitable temperature.
• Increasing the light intensity increases the rate of photosynthesis, until some other factor – a limiting factor – becomes in short supply.
• At very high light intensities, photosynthesis is slowed and then inhibited, but these light intensities do not occur in nature.
• At some point, a factor may become limiting in photosynthesis.
• Increasing the light intensity increases the rate of photosynthesis.
• At low temperatures, the rate of photosynthesis is limited by the number of molecular collisions between enzymes and substrates.
• Chlorophyll absorbs the light energy required to convert carbon dioxide and water into glucose.
• Carbon dioxide concentration affects the rate of photosynthesis.
• At high temperatures, enzymes are denatured.
• A similar graph will be obtained if oxygen production is plotted against light intensity.
• If the concentration of carbon dioxide is increased, the rate of photosynthesis will increase.
• Leaves with more chlorophyll are better able to absorb the light required for photosynthesis.
• As with any other enzyme-controlled reaction, the rate of photosynthesis is affected by temperature.
• The compensation point is the light intensity at which the rate of photosynthesis is equal to the rate of respiration.
• The chemical reactions that combine carbon dioxide and water to produce glucose are controlled by enzymes.
• Chlorophyll is green - so absorbs the red and blue parts of the electromagnetic spectrum and reflects the green part of the spectrum.