In this chapter of I/GCSE Biology, we will discuss about how plants make food.
Photosynthesis
Photosynthesis can be written as
carbon dioxide + water ----light energy--> glucose + oxygen
The equation can also be written like this:
6CO2 + 6H2O ----light energy--> C6H12O6 + 6O2
There are three main stages in photosynthesis:
❶ Light energy is absorbed by the green chlorophyll
❷ Energy used to bring about the reaction between carbon dioxide and water to produce glucose (a sugar)
❸ Oxygen produced as a waste product
Glucose
Glucose is made up of carbon, hydrogen and oxygen atoms. Glucose made by the process of photosynthesis may be used in three ways:
❶ Refer to I/GCSE Biology, It can be converted into chemicals required for growth of plant cells such as cellulose
❷ It can be converted into starch, a storage molecule, that can be converted back to glucose when the plant requires it
❸ It can be broken down during the process of respiration, releasing energy stored in the glucose molecules
Plant cell
- Cell wall – provides support for cell
- Cell membrane – allows gases and water to pass in and out of the cell freely while acting as a barrier to other, larger chemicals
- Nucleus – contains DNA which carries the genetic code for making enzymes and other proteins used in the chemical reactions of photosynthesis
- Vacuole – used by the cell to store waste materials and to regulate water levels
- Cytoplasm – where the enzymes and other proteins are made
- Mitochondria – where respiration occurs
- Chloroplasts – contain chlorophyll and the enzymes for the reactions in photosynthesis
When it comes to I/GCSE Biology, plants need other chemicals in addition to glucose. The roots take up minerals from the soil in solution. Nitrogen, in the form of nitrates is absorbed and used by plant cells to make proteins.
Great! You can read Part 2~ gogogo
