Unit 1.1 Structure of DNA

Question 1

What bonds exist between the phosphate of one nucleotide and the sugar of the next?

Answer 1

Strong Covalent Bonds

Question 2

What bonds exist between complementary base pairs?

Answer 2

Weak hydrogen bonds

Question 3

What are the complementary base pairs

Answer 3

Adenine- Thymine

Guanine - Cytosine

Question 4

What is the structure of DNA

Answer 4

• There is a sugar phosphate backbone
• A nucleotide (containing a phosphate, deoxyribose sugar and base)
• These are organised in a double stranded helix
• The strands run anti parallel

Question 5

What packs DNA tightly together?

Answer 5

Proteins called Histones

Question 6

What is the difference between eukaryotes and prokaryotes?

Answer 6

• Prokaryotes don’t have a nucleus whereas eukaryotes have a nucleus
• Prokaryotes DNA is organised in circular chromosomes whereas eukaryotes DNA is organised in linear chromosomes
• Prokaryotes contain a plasmid in their cytoplasm whereas eukaryotes have no plasmids
• Eukaryotes also have circular DNA in their chloroplasts and mitochondria