Photosynthesis Make sure you revise: What Photosynthesis is Equation for Photosynthesis Factors that effect the rate of Photosynthesis Use of glucose from Photosynthesis Healthy plant growth (nitrates ions)

Carbon dioxide + water (+ light energy) Photosynthesis Photosynthesis can be summarised by the equation: Carbon dioxide + water (+ light energy)  Glucose + Oxygen Photosynthesis is when green plants use light energy to make their own food . During photosynthesis: - light energy is absorbed by chlorophyll (a green substance found in chloroplasts of some plant cells. - light energy converts carbon dioxide and water into sugar (glucose). - oxygen is released as a by-product.

What factors affect the rate of Photosynthesis

Limiting carbon dioxide levels Increasing carbon dioxide levels increases the rate of photosynthesis up to a point. Eventually one of the other factors (temperature and light) becomes limiting If there is too little carbon dioxide the rate will slow down. Carbon dioxide maybe limited in an enclosed space eg, a greenhouse on a sunny day or in a rapidly photosynthesising rain forest

Limiting light intensity Increasing light intensity increases the rate of photosynthesis up to a point When a certain light intensity is reached the rate of photosynthesis stays constant Eventually one of the other factors becomes limiting

Limiting temperature If it is cold then enzymes do not work effectively slowing down the rate. The rate of photosynthesis increases steadily with a rise in temperature up to a certain point (35-40ºC = optimum temp) After this the enzymes are destroyed and the reaction stops completely.

Healthy plant growth Plant roots absorb mineral ions needed for healthy growth For healthy growth plants need mineral ions including Nitrates and Magnesium Mineral ions: Nitrates Magnesium Needed for: Nitrates produce amino acids which are then used to make proteins for growth Needed for chlorophyll production Symptoms shown by plants growing in conditions where mineral ions are deficient: Stunted growth Yellow leaves

Photosynthesis quiz