Photosynthesis

PHOTOSYNTHESIS

JANET BRIGIDA A. CATIPONMHS SCIENCE TEACHERMAE-CHEMISTRY, BSU

LESSON’S OBJECTIVES To identify the structures involved in the food making

process in plants To identify the raw materials and end products of

Photosynthesis To understand the process of Food Making of Plants

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PHOTOSYNTHESIS

WHERE DOES PHOTOSYNTHESIS TAKE PLACE?

Inside the leaves of plants

The Chloroplast Thylakoid Membrane

of Chloroplast

Stroma of the Chloroplast

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PHOTOSYNTHESIS

Chlorophyll

THE CHEMICAL PROCESS

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INTERNAL STRUCTURE OF A LEAF

Guard CellCuticle

Cuticle

Mesophyll Cells

Upper Epidermis

Chloroplasts

PalisadeParenchyma

XylemPhloemLower Epidermis

Spongy Mesophyll

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PHOTOSYNTHESIS

THE CHLOROPLASTS

OUTER MEMBRANEINTERMEMBRANE SPACE INNER MEMBRANE

STROMA GRANUMTHYLAKOID LAMELLA

LUMEN

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PHOTOSYNTHESIS

INSIDE THE THYLAKOID MEMBRANE

THE FIRST STAGE OF PHOTOSYNTHESIS TAKES PLACE CALLED PHOTOSYSTEM I – LIGHT DEPENDENT REACTION.

It happens in the presence of light. It occurs inside the thylakoid membrane and converts light energy to chemical energy.Absorbed water through the roots of plants is utilized and facilitates the formation of the electrons and oxygen.The energy harvested in this stage is stored in the form of ATP ( Adenine Triphosphate) and NADPH (Nicotinamide Adenine Diphosphate Hydrogen)ATP and NADPH will be needed in the 2nd stage of Photosynthesis ( Photosystem II) called the Calvin Cycle or Dark Reaction (Light Independent Reaction.

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INSIDE THE THYLAKOID MEMBRANE

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PHOTOSYNTHESIS

IN THE STROMA THE SECOND STAGE OF PHOTOSYNTHESIS TAKES PLACE CALLED THE CALVIN CYCLE - LIGHT INDEPENDENT REACTION OR DARK REACTION.

It happens in the STROMA of Chloroplast where the Carbon Dioxide absorbed by the leaves of the plant is converted into sugar.The reaction does not require light from the sun.The reaction is divided into three main stages: carbon fixation, reduction, and regeneration of the starting molecule.In fixation, the first stage of the Calvin cycle, light-independent reactions are initiated; CO2 is fixed from an inorganic to an organic molecule.In the second stage, ATP and NADPH are used to reduce 3-PGA into G3P; then ATP and NADPH are converted to ADP and NADP+, respectively.In the last stage of the Calvin Cycle, RuBP is regenerated, which enables the system to prepare for more CO2 to be fixed.

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PHOTOSYNTHESIS

THE CALVIN CYCLE

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PHOTOSYNTHESIS

STAGES OF PHOTOSYNTHESIS

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IMPORTANT TERMS 3PGA 3-phosphoglyceric acid RuBP ribulose1,5-biphosphate. an organic

substance that is involved in photosynthesis, reacts with carbon dioxide to

form 3-PGARuBisCo a plant enzyme which catalyzes the fixing of atmospheric carbon dioxide during

photosynthesis by catalyzing the reaction between carbon dioxide and

RuBP.ATP Adenine TriphosphateNADPH Nicotinamide Adenine Diphosphate HydrogenADP Adenine DiphosphateNADP Nicotinamide Adenine DiphosphateCarbon Fixation refers to the conversion process of inorganic carbon (carbon dioxide) to organic

compounds by living organisms. Reduction Reduction phase of Calvin Cycle –uses

NADPH, ATP, and carbon dioxide (which

enters from atmosphere intochloroplast at this time) to make glucoseRegeneration With 3molecules of ATP, the remaining

five G3P molecules remain in the cycle and

are used to regenerate RuBP, which enables the system to prepare for more CO2 to be fixed.