Nucleotides and ATP

Nucleotides

• Inludes: a pentose sugar, nitrogenous base and a phosphate group

• In RNA - pentose sugar is ribose
• In DNA - pentose sugar is deoxyribose (one less oxygen atom)

• Phosphate group comes from the inorganic phosphates found in the cytoplasm

• Nitrogenous bases include: Adenosine, Guanine, Cytosine and Thymine in DNA
• In RNA, Thymine is replaced with Uracil

Purines and Pyrimidines

Purines:

Have two nitrogenous rings.

Bases: A, G

Pyrimidines:

Have one nitrogenous ring

CTU

ATP

• Three phosphate groups - provides the energy

• When energy is needed, hydrolysis reaction removes the third phosphate bond  with the use of the enzyme ATPase, , leaving ADP.

• Inorganic phosphates free in the cytoplasm are then used to join by condensation reaction and form ATP. Energy is needed to drive this redox reaction.