2.3.3 DNA Structure

Question 1

Structure of DNA nucleotide

Answer 1

Question 2

Structure of DNA molecule

Answer 2

• 2 polynucleotide strands
• Antiparallel (one strand is 5’ to 3’ strand and the other is 3’ to 5’)
• Phosphodiester bond
• 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
• Nitrogenous base projects to middle
• Hydrogen bonding forms between them
• Adenine forms 2 hydrogen bonds with Thymine
• Guanine forms 3 hydrogen bonds with Cytosine
• (Complementary base pairing)
• Double helix shape