energy transfer

What are the two stages of photosynthesis and what do they do

• light dependent reaction which produces O2, NADPH and ATP from water and light energy

• Light independent reaction which produces glucose from ATP, CO2 and NADPH

Where do the two stages of photosynthesis occur

• light independent reaction = thylakoid

• Light independent reaction = stroma

What are photo systems

Proteins within the thylakoid which contains chlorophyll

What are the photosystems linked by

Electron carrier proteins

What are electron carrier proteins

Proteins than can transfer electrons and form the electron transport chain

What are co enzymes

Molecules that aid enzymes with the transfer of chemical groups such as hydrogen

What is OILRIG

• oxidation is loss of electrons and hydrogen

• Reduction is the gain of electrons and hydrogen

What is a coenzyme used in photosynthesis

NADP as it transfers hydrogen from one molecule to another so it oxidises or reduces

What is photolysis

Light energy is absorbed by chlorophyll and splits water into oxygen protons and electrons

What is the equation for photolysis

H2O → ½ O2 + 2e- + 2H+

What occurs during photoionisation

• photons of light absorbed by chlorophyll and the electrons within are excited

• This means they are transferred to electron carriers at higher energy levels

• This means chlorophyll is oxidised

What occurs in chemiosmosis

• electron moves down the electron transport chain by a series of oxidation and reduction reactions and it loses energy as it travels down

• This energy is used to pump the protons into the thylakoid lumen

• This leads to a higher concentration of protons in the lumen which means they move down an electrochemical gradient into stroma via ATP synthase

  • This movement releases energy which combines with ADP and Pi to form ATP

• The electrons are then transferred to NADP with a proton to form NADPH

What is the light independent reaction known as

The Calvin cycle

What are the features of the light independent reaction

• catalysed by enzyme Rubsico

• Temperature sensitive due to the involvement of enzymes

What is the AT used for in the LIR

To release energy

What is the NADPH used for in the LIR

Donates the hydrogen to reduce GP

What is RUBP

A five carbon compound

What is GP

A three carbon compound

What happens in the Calvin cycle

• CO2 reacts with RuBP to form 2 GP which is catalysed by Rubsico

• GP reduced into triose phosphate using energy from ATP and hydrogen from NADPH

• Triose phosphate used to create a organic substances like glucose with one carbon

• Rest of the triose phosphate is used to regenerate RuBP with energy from ATP

• Cycle repeats until the heroes sugars like glucose is formed

What is glucose used for in plants

• to form disaccharides and polysaccharides like sucrose and starch for storage

• Lipids