PhotosynthesisReporter: Levin

Christellle S. Dela Cruz

Photosynthesis

• is a process by which light energy is converted into chemical energy of sugars and other organic compounds.

• Oxygen (O2) is a by-product of photosynthesis and is released into the atmosphere.

• equation summarizes photosynthesis:

6 CO2 + 6 H2O → 6(CH2O) + 6 O2

• from the Greek word, phōs, "light", and synthesis, “putting together”

• Stomata• Chloroplast – “Site of Photosynthesis”

o Stromao Thylakoido Granao Chlorophyll

Stomata

Tradescantia zebrina

Parts of Chloroplasts

Outer and inner membranes: protective coverings that keep chloroplast structures enclosed.

Stroma: dense fluid within the chloroplast. Site of conversion of carbon dioxide to sugar.

Thylakoid: flattened sac-like membrane structures. Site of conversion of light energy to chemical energy.

Grana: dense layered stacks of thylakoid sacs. Sites of conversion of light energy to chemical energy.

Chlorophyll: a green pigment within the chloroplast. Absorbs light energy.

Two Stages of Photosynthesis

Light reactions -Occur mostly in the thylakoid stacks of the grana. -Here, sunlight is converted to chemical energy in the form of ATP and NADPH. Chlorophyll absorbs light energy and starts a chain of steps that result in the production of ATP, NADPH, and oxygen (through the splitting of water).

Dark reactions- Occur in the stroma. Carbon dioxide is converted to sugar using ATP and NADPH through the carbon fixation or Calvin cycle. - The Calvin cycle has three main stages: carbon fixation, reduction, and regeneration. 

Importance of Photosynthesis

• It begins all food chains/webs. Thus all life is supported by this process.

• Glucose is a basic energy source for all living Organisms.

• It produces oxygen which we need.