Nucleic acids

Question 1

describe the structure of a DNA nucleotide

Answer 1

-deoxyribose sugar
-bases ( adenine, thymine, cytosine, guanine,)
-phosphate group

Question 2

describe the structure of a DNA molecule

Answer 2

• 2 DNA polynucleotides joined by hydrogen bonds between bases
  -with the 5’ end of one strand opposite the 3’end of another strand
  -anti parallel
  -double helix

Question 3

describe the structure of a RNA nucleotide

Answer 3

-ribose sugar
-bases (uracil, adenine, guanine, cytosine)
-phosphate group

Question 4

describe the structure of a RNA molecule

Answer 4

-single stranded
-shorter than DNA
-less stable

Question 5

how is a dinucleotide formed

Answer 5

-condensation reaction
-phosphodiester bond
-3- carbon of one nucleotide and the phosphate of another nucleotide

Question 6

who discovered the structure of DNA being 2 strands joined by H bonds

Answer 6

James watson
francis crick

Question 7

why is DNA more stable than RNA

Answer 7

• phosphodiester backbone protects the reactive bases
• cytosine and guanine has 3 H bonds between them–> the more C-G pairings the more stable the molecule
• no reactive OH group on the ribose sugar

Question 8

function of DNA

Answer 8

-passes genetic material between cells and generations
-3.2B base pairs in the DNA of a mammalian cell–> infinite base pairings–>provides diversity within organisms

Question 9

how is DNA adapted to its function

Answer 9

-very stable so passes from generation to generation without lots of changes
-most mutations are repaired–> persistent mutations are rare

Question 10

why did scientists doubt DNA had genetic code

Answer 10

its simplicity, they thought proteins were the more likely molecule to carry genetic code