Photosynthesis

Points to Take care of in this Topic

* Define Photosynthesis
* know that Living Organisms need food
* know the functions of food
* learn about Jean Baptiste van Helmont experiment
* know the word equation for Photosynthesis

Food is 

• a source of Energy
• used to build new cells and Tissues for Growth

Jean Baptiste van Helmont experiment
 was made to determine the source of increase in mass of the plants , He decided that it was entirely due to water it recieves.which is not correct as plants also take in mineral salts and carbon dioxide and they use also light as a source of energy

Meaning of the word Photosynthesis 

comes from two syllables
Synthesis:or the prcoess of building complex food molecules from simpler substances
and
Photo:as sunlight is the source of energy needed for making the process (photo:means light)

Greek φῶς, phōs, "light"

and σύνθεσις, synthesis, "putting together"

Chlorophyll :
That is the green substance in the chloroplasts of plant cells which has an important role in photosynthesis as it converts the light energy from the sun into chemical energy to help in the chemical reactions


The Right Hypothesis for the source of food in the plant is that it is made from air water and soil salts
So Carbohydrate formed is containing elements
 carbon hydrogen and oxygen as in glucose 
The Carbon and oxygen could be supplied by carbon dioxide CO2 from air
and Hydorgen could come from the water H2O in the soil
Nitrogen and Sulfur needed for making proteins could come from nitrates and sulfates in the soil
Word Equation for the Process:

Products of the Photosynthesis process
Glucose and oxygen
in fact glucose is rapidly converted to sucrose to be then transported and stored then in the plant as starch.

In the word equation we write glucose for simplification.

Practical Work
Experiments to Investigate photosynthesis