1.7 - DNA

Question 1

What are the 2 types of bonds that hold the nucleotides in a double helix of DNA?

Answer 1

1. Covalent bonds - strong, hold together phosphate of the nucleotide to a deoxyribose sugar in the next nucleotide
2. Hydrogen bonds - somewhat weak, hold together the bases of 2 nucleotides in the center of the DNA molecule to hold the 2 chains of nucleotides together

Question 2

What are the normal DNA base pairing rules?

Answer 2

• A (purine) and T (pyramidine)
• G (purine) and C (pyramidine)

Question 3

How does so much DNA fit inside of the nucleus of a cell?

Answer 3

DNA molecules are coiled around histones to form nucleosomes which coil around each other and form chromatin. The chromatin is then folded into loops to make the chromosomes