nucleic acids Flashcards
what are the two types of nucleic acids?
.DNA
.RNA
What does DNA do?
.stores genetic information
what does RNA do?
it transfers genetic information from DNA to ribosomes
what are the monomers of DNA and RNA
nucleotides
what is the structure of nucleotide
.a pentose sugar
.phosphate
. base ( U,A,T,G,C)
describe structure of DNA nucleotide
.pentose sugar is deoxyribose
.phosphate
.bases include
adenine & thymine and guanine & cytosine
describe structure of RNA nucleotide
.ribose sugar
.phosphate
.nitrogenous bases adenine & uracil and guanin & cytosine
describe structure of a polynucleotide
. a polymer of nucleotide monomers
.nucleotides join by a condensation reaction between phosphate and sugar
. this is called a sugar-phosphate backbone
describe structure of DNA
. antiparallel polynucleotide strands from double helix
. two polynucleotide chains join together by the hydrogen bonds between complementary bases
.2 hydrogen bonds between A-T and 3 hydrogen bonds C-G.
. phosphate, nitrogenous bases and deoxyribose sugar
. sugar- phosphate backbone
describe structure of RNA
.single polynucleotide chain
.shorter than DNA polynucleotides, uracil instead of thymine
why did scientists doubt that DNA was the carrier of genetic material?
. DNA was discovered in 1800
.they doubted that because it had a relatively simple chemical composition.
how does DNA replicate
by semi-conservative replication
explain semi-conservative replication
1) the enzyme DNA helicase unwinds DNA and breaks hydrogen bonds between bases between two polynucleotide chains
2) both original strands act as template, free flowing nucleotides are attracted to their complementary base pairing
3)condensation reactions join nucleotides, this is catalysed by DNA polymerase
4)each new DNA molecule contains one original and one new strand
