Nucleic Acids

Question 1

What are Nucleotides made up of?

Answer 1

• Phosphate group bonded to 5’ carbon of sugar
• 5-carbon sugar
• Nitrogenous base bonded to 1’ carbon of sugar

Question 2

What are the different sugars a nucleotide can have?

Answer 2

• Ribose in RNA has OH on 2’ carbon

- Deoxyribose in DNA has an H on 2’ carbon

Question 3

Description of phosphates

Answer 3

• normally joined to C5 hydroxyl of the ribose or deoxyribose
• mono-, di-, and triphosphates are common
• triphosphate bonds are rich in energy and breaking them releases lots of energy

Question 4

What are the nitrogenous bases, which ones are pyrimidines/ purines, and pair them properly

Answer 4

Pyrimidines:
Cytosine (C), Thymine (T, DNA), Uracil (U, RNA)
Purines:
Guanine (G), Adenine (A)
Note: Purines are larger than pyrimidines
- A + T, U
- C + G

Question 5

Structure of the sugar-phosphate backbone of RNA/DNA

Answer 5

• 3’ and 5’ carbons joined by phosphodiester linkages
• 5’ end and 3’ end
• New nucleotides are added to the unlinked 3’ carbon

Question 6

Structure of the double helix

Answer 6

• the strands are antiparallel

- Hydrogen bonds form between the nucleotide pairs

Question 7

How does RNA bond to itself?

Answer 7

Forms a hairpin:

• the stem consists of a double-stranded region forming a double helix
• Single stranded region forms a loop