Photosynthesis-+Sam+Ong


 * __Photosynthesis__**

· Distinguish between autotrophs and heterotrophs in terms of nutrient requirements. Plant cells are Autotrophic (self-feeding) and animal cells are heterotrophic (feeding on something different). Autotrophic cells rely on Photosynthesis to produce sugar and oxygen for the cell, whereas, heterotrophic cells rely on organic molecules to provide them with macronutrients (fats, carbohydrates) and micronutrients (vitamins and minerals). · Identify the materials required for photosynthesis. The materials required for photosynthesis are oxygen, water, sunlight and Chloroplasts. · Identify the role of Photosynthesis in ecosystems. All organisms depend on the autotrophy of the green plants because ultimately, all heterotrophic organisms depend on the autotrophic organisms’ ability to photosynthesise. This is because when plants photosynthesise, they survive to be consumed by heterotrophic organism, which then can be consumed by the next heterotrophic organism. · State what happens in the Light Reactions of photosynthesis. Energy from sunlight is absorbed by the Chlorophyll pigments in the Chloroplasts and this energy is converted into chemical energy. A portion of this energy is used to split water molecules into hydrogen and oxygen. · State what happens in the Dark Reactions (light independent) of photosynthesis. Hydrogen that has been released from the previous reaction (above), is combined with carbon dioxide to produce sugars. This process requires energy and this needed energy is supplied from the energy absorbed from the light in the first reactions. This reaction occurs in the Stoma of Chloroplasts. · Factors affect the rate of photosynthesis. The intensity of the light affects photosynthesis as a higher intensity results in faster reactions. Higher levels of Carbon Dioxide also result in faster reactions. Temperature influences the rate of photosynthesis as a temperature that is too high damages the enzymes required, however a temperature that is too low slows down the rate. An optimum temperature is around 30C. [] [] []