Nucleic Acids

Question 1

Components of a Nucleotide

Answer 1

• Pentose sugar
  Deoxyribose in DNA and Ribose in RNA
• Phosphate Group
• Nitrogen containing organic base
  > C Cytosine
  > A Adenine
  > G Guanine
  > T Thymine (not found in RNA)
  > U Uracil (only in RNA, replacing thymine)

Question 2

How are the phosphate, pentose and nitrogen bases joined?

Answer 2

Condensation reactions

Question 3

Bond formed between the nucleotides

Answer 3

Phosphodiester bond - between the sugar and phosphate group

Question 4

Phosphodiester bonds

Answer 4

The phosphate group of one nucleotide forms a covalent bond with the sugar of another.

Many nucleotides can join in this way to create a chain of phosphates and sugars known as the sugar-phosphate backbone.

Phosphodiester bonds can be broken via hydrolysis reactions, releasing the nucleotide monomers.

Question 5

What does DNA contain?

Answer 5

Deoxyribonucleic acid (DNA) is a type of nucleic acid that contains the instructions needed to make proteins.

Question 6

Components of a DNA nucleotide

Answer 6

Each DNA nucleotide is made up of three components:

1. Deoxyribose - A pentose sugar.
2. A, T, G, or C base - Adenine, thymine, guanine, or cytosine.
3. A phosphate group

Question 7

What are the features that allow DNA to pass genetic information from one generation to another?

Answer 7

1. Sugar-phosphate backbone - This protects coding bases on the inside of the helix.
2. Double stranded - This allows strands to act as templates in DNA replication.
3. Large molecule - It stores lots of information.
4. Double helix - This makes the molecule compact.
5. Complementary base pairing - This allows accurate DNA replication.
6. Weak hydrogen bonds - This allows strands to separate in DNA replication.

Question 8

Differences between purines and pyrimidines:

Answer 8

• Purines - These are larger bases that contain two carbon ring structures (A and G).
• Pyrimidines - These are smaller bases that contain one carbon ring structure (T and C).