Edexcel A2 Biology- ATP and Chloroplasts

Photosynthesis

ATP

= adenosine triphosphate- the energy source for cells in any living organism.

• ATP consists of a nucleotide with 3 phosphate groups attached.
• When energy is needed, the 3rd phosphate bond can be broken by hydrolysis. This is catalysed by a enzyme called ATPase.
• ADP and an inorganic phosphate group (Pi) are formed.

The breakdown of ATP into ADP and Pi is reversible. ATP can be synthesised from ADP and Pi in a reaction which needs an input of energy.

The energy needed to drive the synthesis of ATP comes from catabolic reactions or redox reactions. This provides an immediate supply of energy, so that it is ready for use when needed.

Making ATP

2 main ways to make ATP:

1. using energy released from catabolic reactions that take place e.g. in cellular respiration.

2. the removal of…