Photosynthesis Noadswood Science, 2016

Photosynthesis To recall the photosynthesis equation Tuesday, May 29, 2018 Photosynthesis To recall the photosynthesis equation

Precise Learning Photosynthesis is represented by the equation: Students should recognise the chemical symbols: CO2, H2O, O2 and C6H12O6 Students should be able to describe photosynthesis as an endothermic reaction in which energy is transferred from the environment to the chloroplasts by light. The glucose produced in photosynthesis may be: used for respiration converted into insoluble starch for storage used to produce fat or oil for storage used to produce cellulose, which strengthens the cell wall used to produce amino acids for protein synthesis. To produce proteins, plants also use nitrate ions that are absorbed from the soil.

Photosynthesis What is photosynthesis? Photosynthesis is the process that produces glucose, the plants food Photosynthesis uses energy to change carbon dioxide and water into glucose and oxygen This glucose is used for a variety of things such as making cell walls and proteins

Chloroplasts Photosynthesis takes place in chloroplasts in green plant cells – these contain the pigment chlorophyll that absorbs light energy

Equations light carbon dioxide + water  glucose + oxygen 6CO2+ 6H2O  C6H12O6 + 6O2

Glucose During photosynthesis plants convert carbon dioxide and water into glucose which is used for a variety of things Respiration > plants use glucose in respiration to release energy (this energy is used for building new cells / growth / gathering minerals from the soil etc…) Cellulose > glucose is converted into cellulose for making strong cell walls Amino acid production > glucose is combined with nitrate ions forming amino acids which join to make up proteins

Glucose Storage Glucose molecules Starch molecule Glucose can also be converted into other substances for storage Lipids > plants can convert some of the glucose they produce into lipids (stored in seeds) Starch > glucose can be stored as starch so it is ready for use when photosynthesis doesn’t occur (stored in the roots, seeds and leaves) Glucose molecules Starch molecule

Starch Experiment

Photosynthesis

Photosynthesis

Practice Questions By what process do plants break down glucose in order to transfer energy to their cells? What do plants use cellulose for? What do plants absorb from the soil to make proteins with? Why is starch better for storage than glucose?

Answers By what process do plants break down glucose in order to transfer energy to their cells – respiration What do plants use cellulose for – strengthening cell walls What do plants absorb from the soil to make proteins with – nitrate ions Why is starch better for storage than glucose – it is insoluble so doesn’t draw in water (which would cause the cells to swell up)