Light dependant stage of photsynthesis

Photosynthesis

The process by which photoautotrophs harness light energy produce glucose

Photoautotroph

An organism capable of creating its own energy through photosynthesis

mesophyll cell

Photosynthesising plant cell that contains large amounts of chloroplasts

Chloroplast

Membrane bound organelle containing chlorophyll that is the site of both stages of photosynthesis

Chlorophyll

Green photosynthetic pigment in the chloroplast that captures light energy

Stoma

Small pores on a leaf’s surface that opens and closes to regulate gas exchange

Root hair cells

Absorb water from the soil

Xylem

Vascular tissue that transports water from the root hair cells to the photosynthesising cells

Inputs of photosynthesis

6CO2 + 12H2O

Outputs of photosynthesis

C6H12O6 + 6O2 + 6H2O

Light Dependant Stage

generates high energy coenzymes NADPH and ATP to power the next stage.

Location of light independent stage

Thylakoid membranes

Thylakoid membranes

Flattened sac in the chloroplast, site of the light dependant stage of photosynthesis

Granum

Stack of Thylakoids

NADPH

Coenzyme that is a proton (H+) carrier in photosynthesis

ATP

High energy molecule that provides energy when broken down

Inputs of the light dependant stage

12 H2O + 12 NADP+ + 18 ADP + Pi

Outputs of the Light Dependant stage

6O2 + 12 NADPH + 18 ATP

Steps of the light Dependant stage

• Photolysis: light energy splits water into oxygen and two H+

• Oxygen is released

• H+ ions and 2 electrons are loaded onto NADP+, forming NADPH. Movement of H+ ions through ATP synthase powers ADP + Pi to become ATP

• ATP and NADPH move on to light independent stage

ATP synthase

Enzyme that uses energy from the flow of H+ ions down its concentration gradient to catalys the reaction ADP + Pi into ATP

NADP+

Unloaded coenzyme which becomes NADPH when loaded with Hydrogen ions and electrons

Role of coenzymes in photosynthesis

NADPH transfers hydrogen ions

ATP transfers energy