photosynthesis

Phototsynthesis is the process whereby light enerygy for the sun is transformed into chemical energy and used to synthesis large organic molecules into inorganic substances.

Autotrophs are organisms that can sunthesis complex organic moecules such as carbohydrates, lipids, protiens and nucleic acids and vitimins, from inorganic molecules and energy source.

The first organisms on the planet where chemoautotrophs - prokaryotes that synthesised complex organic molecules using energy derived from exergonic bacteria.

Organisms that can photosynthesis are described as photoautotrophs. there source of enery is sunlight and the raw materials are inorganic molecules carbon dioxide and water. Plants, some bacteria and some protoctists are photoautotrophic . the majority of food chains have producers that are photoautotrophs.

Animals, fungi and some bacterial are heteroautotrophs. They cannot make there own food, but can digest complex organic molecues and break them down into smaller soluable ones from which they can synthesis complex molecules such as lipids, protiens and nucleic acid.

Both photoautotrophs and heteroauto trophs can release the chemical potential energy in complex organic molecules, this is respiration.

Equation for photosynthesis - 6CO2 +6H20 -->C6H12O6 + 6O2.

STRUCTURE OF A CHLOROPLAST.

• They vary in shape and size but they are usually disc shape and between 2 - 10um long.
• each chloroplast is surrounded by a double membrane - an envelope
• there is an intermembrane space, about 10-20nm wide, between the inner and outer membrane
• the outer membrane is permiable to small ions
• the inner one is less permiable and has transprt proteins enbedded init. it is folded into lamelle, each stack of lamelle is a granum
• between the grana are intergranal lamelle

there are 2 distinct regions inside the chloroplast. the stroma and the grana

• The stroma is a fluid filled matrix. the reactions of the light independent stage of photosynthesis happens in the stroma, where necessary enzymes are located. there are also starch grains, oil droplets as well as DNA and prokaryotic type ribosomes.
• The grana are stacks of flattened membrane compartments called thylakoids, these are the sights of light absorbtion and ATP synthesis during the light dependent stage.

HOW ARE CHLOROPLASTS ADAPTED FOR THERE ROLE?

• The inner membrane, with its transport proteins, controls entry and exit of substances between cytoplasm and…