Biology presentation

BIOLOGY IGSE REVIEW: Photosynthesis

Introduction

Limiting factors

Practice tests

STARCH

CELLULOSE

SUCROSE

RESPIRATION

Introduction

6CO2 + 6H2O

6O2

+ C6 H12 O6

Photosynthesis is a chemical process during which light energy is used to break down water and carbon dioxide's molecules in order to convert them in simple sugars needed by the plant to survive.

LIMITING FACTORS

Limiting factors are something present in the environment in such short supply that they restrict life processes.

CONCENTRATION OF CO2:As long as CO2 concentration increases photosynthesis rate does the same until it becomes constant.

LIGHT INTENSITY:As long as light intensity increases photosynthesis rate does the same until it becomes constant.

TEMPERATURE:As long as temperature increases photosynthesis rate does the same until it starts to fall.

Practice tests

If plants carry out photosynthesis it will make simple sugars and store them as starch. If it cannot photosynthesise then it will not make starch. How do we test if there is starch inside of a plant? Well, let's see:

1. Submerge a leaf in boiling water for one minute
2. Turn off any Bunsen burner used to boil the water
3. Put the leaf into a test tube of ethanol
4. Stand the test tube in a beacker of hot water for about 10 minutes
5. Wash the leaf in cold water
6. Spread the leaf out flat on a white surface or in a petri dish and put some drops of iodine solution on it
7. If the leaf goes blue-black, starch is present; if it stays red-brown there is no starch