Nucleic Acids Flashcards
What are nucleic acids? What are the nucleotides connected by?
Linear polymers made by connecting nucleotides via phosphodiester bonds (5’OH of one group + 3’OH of another group)
Draw the pentose sugars for RNA (ribose) and DNA (deoxyribose) - B furanose form
refer to notes
Draw cytosine
refer to notes
Draw thymine
refer to notes
Draw uracil
refer to notes
Draw adenine
refer to notes
Draw guanine
refer to notes
What do tautomeric shifts do?
shift the H atom and double bond
Enol form
everything is the same except -OH instead of =O
Keto form
regular structure
Imino form
everything is the same except =NH instead of -NH2
Amino form
regular structure
What is a nucleoside composed of?
base and sugar
What is a nucleotide composed of?
base and sugar and phosphate
Why is DNA more resistant than RNA to alkene hydrolysis?
Because the 2’OH group of RNA acts as a nucleophile in an intramolecular disp. breaking the phosphate bond
Chargaffs
%A = %T and %G=%C [A+G] = [C + T]
Double helix features
- right handed
- bases are hydrophobic (inside) and sugar phosphate backbone is hydrophilic (outside) = hydrophilic
- perp to axis
- 2 strands are antiparallel
- bp are 3.4 A apart
- comp bp are held together by H bonds
What links the base to the pentose in nucleotides?
Glycosidic bond
Calculating net charge on a nucleotide - both ends OH groups
(-1 x all bp) - 1
Calculating net charge on a nucleotide - one end P one end OH
(-1 x all bp) +1
Calculating net charge on a nucleotide - both ends P groups
(-1 x all bp) +three
