DNA structure

• what structure does DNA have?

  double helix
• how many strands is the helix made for?

  2
• what are the strands made from?

  polynecleotides
• what is a benefit of the DNA structure?

  can be coiled up very tightly meaning lots of genetic information can be fit into a small space in the cell nucleus.
• what is the structure of the DNA nucleotide?

  made from a phosphate group, deoxyribose sugar and a nitrogen-containing organic base.
• what might differ in the DNA nucleotide structure?

  the base on each nucleotide.
• what are the 4 possible bases?

  adenine, thymine, cytosine, guanine
• what is complementary base pairing?

  when 2 polynucleotide strands join together by hydrogen bonds between the bases (adenine and thymine, guanine and cytosine)
• what does complementary base pairing ensure?

  ensures there is always equal amounts of of each base pairing.

  2 hydrogen bonds form between A and T

  3 hydrogen bonds form between C and G
• How do the 2 polynucleotide strands run?

  they run anti-parallel to eachother. they then twist to form a DNA double helix.