2.6 Structure Of DNA And RNA

Question 1

What type of bonds join nucleotides together?

Answer 1

Covalent bonds join phosphates to sugars in nucleotide and along the side backbone. Hydrogen bonds join the bases together across the double stranded DNA

Question 2

How do DNA and RNA differ?

Answer 2

Number of strands (2vs1), base composition (RNA had U instead of T) and type of pentose sugar (DNA has deoxyribose, RNA has ribose)

Question 3

What are the nitrogenous bases?

Answer 3

Pyrimidines (smaller): cytosine, uracil, thymine

Purines (larger): guanine, alanine

Question 4

How are DNA strands drawn?

Answer 4

They are antiparallel (5to3 and 3to5). Complementary base pairing. Hydrogen bonds drawn as dotted lines.

Question 5

What is the function of a nucleosome?

Answer 5

Nucleosomes are only in euk cells. They have a core of 8 histones. DNA is wrapped around the nucleosomes (supercoiling)

Question 6

What did Hershey and Chase prove?

Answer 6

DNA is the genetic material of viruses.

Question 7

What did Crick and Watson create?

Answer 7

They created the 3D model of the double helix DNA

Question 8

What did Rosalind Franklin investigate?

Answer 8

Franklin studied DNA by X-Ray diffraction to calculate dimensions of the DNA helix. Watson and Crick stole her work to build their model and then won a Nobel Prize. Franklin was never recognized since she died before she could have been given a Nobel Prize.

Question 9

What is a nucleotide?

Answer 9

Building block of nucleic acids. Contains pentose sugar (ribose or deoxyribose), -phosphate group, and nitrogenous base (A,T,G,C, or U)