2.3.1 Nucleotides & Phosphodiester Bonds

Question 1

What is an RNA nucleotide made of?

Answer 1

• Ribose sugar (OH group on 2’) (more susceptible to hydrolysis, so RNA molecule is transport molecule with shorter lifespan, and DNA molecule is storage molecule)
• Phosphate group
• Nitrogenous base (adenine, guanine, cytosine, uracil)

Question 1

What is a DNA nucleotide made of?

Answer 1

Pentose sugar (deoxyribose with H at 2’)
Nitrogenous base (adenine, guanine, cytosine, thymine)
Phosphate group

Question 2

What is a purine?

Answer 2

• Bases with a double ring structure
• Adenine and Guanine

Question 3

What is a pyrimidine?

Answer 3

• Bases with a single ring structure
• Cytosine, Thymine and Uracil

Question 4

What is the phosphodiester bond?

Answer 4

Condensation reaction between phosphate group and pentose sugar of adjacent nucleotides. COVALENTLY BONDED.

Links 5C on one deoxyribose sugar to the phosphate group of the same nucleotide, to the 3C of the deoxyribose sugar of the next DNA nucleotide

Forms sugar phosphate backbone of DNA molecule