S2 Energy Flow and Living Things – The Bullet Points PDF

S2 Energy Flow and Living Things – The Bullet Points 1. Photosynthesis Photosynthesis takes place in the chloroplast within a plant cell. It is carried out by all green plants to make food. The word equation for photosynthesis: Carbon Dioxide + Water ---> Glucose + Oxygen....

S2 Energy Flow and Living Things – The Bullet Points 1. Photosynthesis Photosynthesis takes place in the chloroplast within a plant cell. It is carried out by all green plants to make food. The word equation for photosynthesis: Carbon Dioxide + Water ---> Glucose + Oxygen. Light and Chlorophyll are needed for the reaction to take place. When carrying out a photosynthesis investigation, the volume of oxygen produced (or number of bubbles produced) could be measured. The factors that can limit the rate of photosynthesis if in short supply are temperature, carbon dioxide concentration and light intensity. Iodine tests for starch. The colour change in a positive result is orange blue/black When testing a leaf for starch you must follow these steps: o Place piece of leaf in boiling water for 2 minutes. This kills the leaf and disrupts the cell membrane and cell wall. o Place leaf into ethanol and leave until the leaf has discoloured. This removes the chlorophyll to allow the colour change to be seen more clearly. o Rinse the leaf in warm water. This removes the ethanol from the leaf. o Place leaf on tile and add a few drops of iodine. This tests for starch. If a plant is kept in dark, low concentration of carbon dioxide or low temperature, it will not photosynthesise well. 2. Fertilisers Farmers use fertilisers to produce more food. The elements Nitrogen, Phosphorous and Potassium (N, P, K) are found in fertilisers. Nitrogen encourages leaf growth. Phosphorous encourages root growth and Potassium encourages fruit and flower growth. Natural fertilisers like manure can also be used. 3. Ecosystems and Biodiversity A habitat is the place where an organism lives A community is all of the organisms living in a habitat Ecosystem is the biological unit made up of the habitat (non-living parts) and the living community (Living parts) Biodiversity is the variety of species in a particular area. Living things need food, water, shelter and oxygen to survive. Plants can be used for more than just food e.g oak for building materials, rubber plant for wellington boots Biodiversity in an area can be negatively affected by human impacts, such as deforestation, littering, poaching, climate change and overfishing 4. Identifying organisms A key is a set of questions about the characteristics of living things