DNA structure

Question 1

Nucelotides consist of

Answer 1

1. nitrogenous base
2. pentose sugar
3. one of more phosphate groups

Question 2

Nuceloside

Answer 2

nitrogenous base+sugar

Question 3

What are the two families of nitrogenous bases?

Answer 3

1. Pyrimidine
2. Purines

Question 4

Phosphodiester linkage

Answer 4

sugar-phosphate backbone and nitrogenous base (appendages)

Question 5

Rosalind Franklin

Answer 5

proposed 2 strands with sugar-phosphate backbone and bases on interior

Question 6

Watson and Crick

Answer 6

built models of a double helix to conform to the X- rays and chemistry of DNA

Question 7

Structure of DNA molecules

Answer 7

1. Double helix: 2 polynucleotides spiraling around imaginary axis
2. Antiparallel: backbone runs in opposite 5’ to 3’ directions
3. Complementary base pairing: H bonds A-T, C-G

Question 8

Double helix similarity with screw

Answer 8

right-handed chirality; twist moves away from helix
helical pitch; van der waal interactions; hydrogen bonds

Question 9

Structure of RNA molecules

Answer 9

Single-stranded; variable in form (mRNA;tRNA; rRNA; sRNA); complementary base pairing C-G, A-U

Question 10

5’ end

Answer 10

phosphate group

Question 11

3’ end

Answer 11

sugar

Question 12

DNA is more than just a macromolecule

Answer 12

“molecules of inheritance” and “life’s operating instructions”
heredity, traits
genetic material contains genes

Question 13

Frederick Griffith

Answer 13

Discovered DNA can confer to new traits
Discovered bacterial transformation; transmitted cell to cell

Question 14

Alfred Hershey and Martha Chase

Answer 14

Discovered DNA is component of bacteriophage that enters cells (genetic material)

Question 15

Erwin Chargraff

Answer 15

Discovered DNA composition varies from one species to the next - diversity made DNA more credible candidate for genetic material

Question 16

Chargraff’s rules

Answer 16

1. the base composition of DNA varies between species
2. In any species the number of A and T bases is equal and the number of C and G bases is equal