cc5 - nucleic acids Flashcards
monomers of nucleic acids
nucleotides
3 components of nucleotides
pentose sugar
organic base
phosphate group
2 types of organic base
purine
pyrimidine
purine
class of organic bases
double ring structure
includes adenine (A) + guanine (G)
pyrimidine
class of organic bases
single ring structure
includes cytosine (C), thymine (T) + uracil (U)
structure of DNA nucleotide
deoxyribose
organic base (A, T, C, or G)
phosphate group
structure of RNA nucleotide
ribose
organic base (A, U, C, or G)
phosphate group
structure of ATP nucleotide
ribose
adenine
3 phosphate groups
endergonic reaction
non spontaneous reaction that requires input of energy
e.g: ATP formation
exergonic reaction
spontaneous reaction that overall releases energy
e.g: ATP hydrolysis
role of ATP
universal energy currency
hydrolysed to release energy
ATP + water = ADP + Pi + energy
complementary base pairing
how H bonds form between complementary purine + pyrimidine bases
two bonds between A and T (or U)
three bonds between G and C
structure of DNA
double stranded polymer of nucleotides twisted to form double helix
nucleotides joined by phosphodiester bonds
H bonds form between complemtary base pairs, A and T, C and G
anti parallel strands
why strands of DNA double helix described as antiparallel
complementary strands run parallel but in opposite direction
5’ to 3’ and 3’ and 5’
structure of RNA
single stranded polymer of nucleotides
nucleotides joined by phosphodiester bonds
H bonds form between complementary base pairs
A and U, C and G
compare DNA + RNA
DNA:
double stranded
long chain of nucleotides
contains deoxyribose sugar
contains bases A T C G
storage of genetic information
phosphodiester bonds join nucleotides
RNA:
single stranded
shorter chain of nucleotides
contains ribose sugar
contains bases A U C G
role in protein synthesis
phosphodiester bonds join nucleotides
3 types of RNA found in cells
transfer RNA (tRNA)
messenger RNA (mRNA)
ribosomal RNA (rRNA)
function of tRNA
carries specific amino acids to ribosomes
structure of tRNA
80 nucleotides
single helix
clover leaf shape
anticodon on one end, amino acid binding site on other
function of mRNA
carries genetic information form nucleus to ribosomes for protein synthesis
structure of mRNA
2000 nucleotides
single helix
unstable
function of rRNA
associated with proteins in cytoplasm to form ribosomes
structure of rRNA
1800 to 500p nucleotides
two subunits: one large, one small
semi-conservative replication
replication of DNA to produce 2 new DNA molecules which both contain one new strand + one old strand from of DNA molecule
role of DNA helicase in semi-conservative replication
catalyses unzipping of double stranded DNA into 2 single strands, each of which acts as a template
