Photosynthesis Literally translated means ‘to make with light’ “Undoubtedly the most important single metabolic innovation in the history of life on the planet.”

Photosynthesis occurs within the chloroplasts of plant cells. Water and carbon dioxide – are used to make sugar (glucose). Chlorophyll is the green pigment in chloroplasts that traps sunlight. Many types of pigments but most important is chlorophyll A.

Chlorophyll is found in chloroplasts of any green part of a plant. Chlorophyll sits in discs called thylakoids which are stacked up. The stacks are called grana. Each stack is connected to each other by lamella. The surrounding fluid is called stroma.

The process Two steps: 1.light phase in the thylakoids 2.light independent phase (Calvin cycle) in the stroma.

LIGHT PHASE Chlorophyll absorbs light. The energy is used to do 2 things: 1.split water into oxygen (waste) & hydrogen (picked up by NADP for next phase). 2.charge up ADP to higher energy molecule ATP. The NADP (carrying hydrogen) and ATP move to stroma for Calvin cycle.

CALVIN CYCLE (the synthesis part) Carbon dioxide is captured from air. Rearrangement of CO 2 and H takes place and glucose C 6 H 12 O 6 is formed, with the help of energy (ATP molecules are used to run this process). Most of the glucose produced is converted into insoluble starch for better storage.

The photosynthesis equation

Homework Discuss the following statement: “Without photosynthesis, animal life wouldn’t exist.” Do some research to find out which organisms, other than plants, are able to carry out photosynthesis.