Miller & Levine 12.2 The Structure of DNA

The nucleotide does NOT contain

• a 5-carbon sugar.

• an amino acid.

• a nitrogen base.

• a phosphate group.

According to Chargaff's rule of base paring, which of the following is true about DNA?

• A = T, and G = C

• A = C, and T = G

• A = G, and T = C

• A = T = C = G

The bonds that hold the two strands of DNA together come from

• the attraction of phosphate groups for each other.

• strong bonds between nitrogenous bases and the sugar-phosphate backbone.

• weak hydrogen bonds between nitrogenous bases.

• carbon-to-carbon bonds in the surgar portion of the nucleotides.

The four bases of the DNA nucleotides are (see image for clues - look at the letters)

What is the shape of the double-helix?

• Rectangle

• Zig Zag

• Ladder

• Twisted Ladder

In what direction do the two stands of DNA run?