Photosynthesis & Foods

• Photosynthesis is the most important chemical reaction in the world.

• Photosynthesis takes place mainly in the leaves of green plants.

• Chlorophyll absorbs light energy from the sun.

• Light splits up water into hydrogen and oxygen.

• Plants convert part of the sun's energy that falls on them into chemical energy.

• The factors necessary for photosynthesis are carbon dioxide, water, chlorophyll and light.

• The leaf is specially adapted for the process of photosynthesis.

• The products of photosynthesis are carbohydrates and oxygen.

• Plants store food in their leaves, stems and/or roots.

• Food nutrients can be divided into different types. The main types are proteins, fats and carbohydrates.

• Carbohydrates and fats provide energy while proteins are used for growth and for the replacement of worn-out and dead cells.

• The lack of the right types of nutrients in the daily diet may result in deficiency diseases.

• Foods containing starch turn blue-black when iodine solution is added.

• Protein gives a purple coloration with sodium hydroxide and weak copper sulphate solution. An orange-red/rust-brown precipitate indicates the presence of reducing sugar in substances when Benedict's solution is added and they are heated.