The chloroplast and chlorophyll

Carissa Fletcher

The chloroplast• Draw and label a diagram showing the structure of a chloroplast as

seen in electron micrographs.

Key terms

Granum – A stacked membranous structure within a chloroplast that contains the chlorophyll and is the site of the light reactions of photosynthesis.

Thylakoid - A thylakoid is a membrane-bound compartment inside

chloroplasts and cyanobacteria. They are the site of the light-dependent reactions of photosynthesis.

Lamella – is used to describe numerous plate or disc-like structures at both a

tissue and cellular level. An example of this begin an extension of a thylakoid within a chloroplast, linking a thylakoid within one granum to one in another. They are the sites of photosystem one.

Stroma - Stroma, refers to the colourless fluid surrounding the grana within the chloroplast.

Explain the relationship between the structure of the chloroplast and

its function.Double membrane This separates the contents of the

chloroplast from the rest of the cell so there is no interference from the cytoplasm.

Chloroplasts contain approx 3000 lamellae m cluster

This increases the surface area available for the attachment of extra pigments molecules.

The shape of the lamellae is disc like. Maximum surface area for the attachment of enzymes involved in light dependent reactions.

The stroma surrounding the thylakoids is partitioned off.

This is so different chemical reactions can take place without interference.

Small space inside the thylakoids To enable a concentration gradient of protons H+

Absorption of light

- Visible light is in the form of electromagnetic radiation.

- Sunlight is a mixture of different wavelengths of visible light.

- Plants contain pigments that absorb light. The main photosynthetic pigment is CHLOROPHYLL

Paper chromatography

Sunlight as a mixture

Explain the relationship between the action spectrum and the absorption spectrum of photosynthetic pigments in green plants.