Nucleotides

Question 1

What kind of a molecule is ATP?

What are its constituent molecules?

Name the kinds of bonds involved

Answer 1

Adenosine triphosphate is a nucleotide: Adenine (nitrogenous base) + Ribose (sugar) + 3 Phosphates

Between the sugar and phosphate group we have an ester bond

Between the phosphates we have high energy anhydride bonds

Question 2

What is ATP’s role?

How is this role stored and used?

Answer 2

ATP is an energy source

Energy is stored in ATPas the phosphate groups are negatively charged, so energy is required to bring them together to form a covalent bond: This energy is stored in the P-O bond.

Energy is released by the hydrolysis of the high energy anhydride bonds (the bonds between the phosphates). Hydrolysis breaks the P-O bond releasing energy and forming a lower energy O-H bond.

• Can be hydrolysed to ADP + Pi
• Or hydrolysed to AMP + PPi(pyrophosphate)

Question 3

Which reactions produce/consume ATP?

Answer 3

Exergonic reactions produce ATP

Endergonic reactions consume ATP

Question 4

Name the 5 bases. Which ones are in DNA/RNA?

Answer 4

DNA:

• Adenine
• Thymine
• Guanine
• Cytosine

RNA

• Adenine
• Uracil
• Guanine
• Cytosine

Question 5

What is DNA/RNA a polymer of?

What are the bonds linking them?

Answer 5

Polymers of nucleotides: polynucleotides

Linked by phosphodiester bonds