3.2 Basics + Photosynthetic pigments

What is the equation for photosynthesis?

6CO2 + 6H20 ---> C6H12O6 + 6O2

What is photophosphorylation?

An endergonic reaction, bonding a phosphate ion to a molecule of ADP using energy from light

Where does photosynthesis take place?

The chloroplasts

What takes place in the grana?

The reactions of the light-dependant stage as the grana is where the photosynthetic pigments are found

What is the stroma?

The fluid-filled interior, bathing the thylakoids and grana

What takes place in the stroma?

The light-independent stage

What is a transducer?

Something that changes one form of energy into another

How is chloroplast transducer?

It turns energy in the photons of light into chemical energy

What is a pigment?

A molecule that absorbs specific wavelengths of light

Name the 2 classes of pigments that act as transducers

Chlorophylls and Carotenoids

Which pigments are part of the chlorophyll class?

Chlorophyll a (435, 670-680 nm) + Chlorophyll b (480, 650 nm)

Which pigments are part of the carotenoid class?

Beta-carotene (425-480 nm) + Xanthophylls (400-500 nm)

What is an absorption spectrum?

A graph showing how much light is absorbed at different wavelengths

What is an action spectrum?

A graph showing the rate of photosynthesis at different wavelengths

What is the antenna complex?

An array of protein and molecules in the thylakoid membranes, that transfer energy from light of a range of wavelengths to chlorophyll a at the reaction centre

What is the reaction centre?

It's within the antenna complex, it contains 2 molecules of chlorophyll a. When these molecules absorb light their excitation allows each one to emit a electron

What is a photosystem?

A collection of accessory pigments, which absorbs light at various wavelengths and transmits the energy to a reaction centre

Where is photosystem I (PSI) and what is it's absorption peak?

It's arranged around 2 chlorophyll a molecules with an absorption peak of 700 nm

Where is photosystem II (PSII) and what is it's absorption peak?

It's arranged around 2 chlorophyll molecules with an absorption peak of 680 nm