A level Biology B · Edexcel 9BI0 · Topic 5A
ATP
Key points
- ATP (adenosine triphosphate) is a nucleotide: adenine, ribose and three phosphate groups.
- ATP hydrolase splits ATP into ADP and inorganic phosphate (P), releasing energy in small, usable amounts.
- ATP synthase joins ADP and P in a condensation reaction, using energy from respiration or photosynthesis.
- ATP can transfer phosphate to other molecules (phosphorylation), making them more reactive.
- ATP is used for active transport, muscle contraction, protein synthesis, DNA replication and cell division.
- It is a good energy carrier because it is small, soluble, releases energy in one simple step and is quickly remade; it cannot be stored in large amounts.
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ATP (adenosine triphosphate) is the immediate source of energy for almost every process in a cell. Energy released in respiration is not used directly; it is first stored in ATP, which then releases it in small, controlled amounts wherever…
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