DNA structure Flashcards
define a gene
a sequence of bases on a DNA molecule that codes for a sequence of amino acids in a polypeptide chain
(small section of DNA that codes for protein)
what monomer is the polymer DNA made of
nucleotides
how are nucleotides joined
condensation reactions
between sugar of one and phosphate of another
what are the bonds called that form between a sugar of one nucleotide and phosphate of another
phosphodiester bonds
what are the four complementary base pairs called
adenine
thymine
cytosine
guanine
how is the sugar-phosphate backbone formed and where are the hydrophilic and phobic sides
phosphodiester bonds form backbone between phosphate and sugar
hydrophobic base on the inside
hydrophilic phosphate on the outside
what is a nucleotide made of
phosphate group
5 carbon sugar
nitrogenous base
what sugar is DNA made of
deoxyribose sugar
what bases are complementary
adenine and thymine
cytosine and guanine
(apples in the tree cars in the garage)
what bonds form between the base pairs
hydrogen bonds
how many hydrogen bonds form between the base pairs
A and T form 2 hydrogen bonds
C and G form 3 hydrogen bonds
what are the ring structure of the base pairs
adenine and guanine form a 2 ring structure
thymine and cytosine form a 1 ring structure
why do the complementary bases pair up
so a 3 ring structure can be formed in each rung of DNA
A + T = 3
C = G = 3
how to work out base pair percentages
complementary base pairs have equal percentages
e.g
if 36% of bases are A what is the percent of G
36+ 36 = 72%
100-72 = 28%
28/2= 14%
A= 36%
T= 36%
C= 14%
G= 14%
