RNA biochemistry and molecular biology Flashcards
what are the 2 classes of RNA?
informational and functional
describe mRNA and list what RNA class it is;
copied from protein coding-genes; it is the short lived intermediary between DNA and protein. It is the only type of RNA that undergoes translation. Messenger for protein production
informational
what are functional RNAs?
do not encode proteins instead the RNAs themselves perform functional roles in the cell
what are transfer RNAs?
encoded in dozens of forms and are covalently joined with an amino acid, which they bring into the ribosome for inclusion into a growing protein chain. Translation of RNA codon to amino acid
what are ribosomal RNAs?
folds and assembles along with numerous proteins to form ribosomes
what are small nuclear RNAs?
found in the nucleus of eukaryotes and plays a role in mRNA splicing
what are micro and small interfering RNAs?
active in plant and animal cells and are involved in posttranscriptional regulation of mRNA
what is CRISPER RNA?
found in bacterial cells and plays a role in defending the host from attack by bacteriophage
what are ribozymes?
: certain RNAs in eukaryotic cells have catalytic activity
what is the structure of RNA?
ribonucleotides joined by phosphodiester bonds
(base, sugar and phosphate)
why do RNA polynucleotides fold?
due to internal hydrogen bond formation and base-pairing
what are the characteristics of chemical modified RNA?
Chemical modifications are usually permanent but not regulatory and conserved among species
what are the 2 most prominent modifications of tRNA?
dihydrouridine and pseudouridine
what happens if adenine is not modified at position 37?
encephalopathy and myoclonic epilepsy
how can RNA fold to form double helicies?
if 2 stretches of RNA nucleotides are perfectly complementary - tend to be short
do RNA base pairs follow watson crick rules?
no
what is primary structure of RNA?
RNA sequence 5’ to 3’
what is secondary structure of RNA?
short double helical regions
what is tertiary structure of RNA?
arrangement of the double-helices and single-stranded regions in the final configuration of RNA. form when 2 different parts of an RNA molecule interact with one another
what is a hairpin?
if complementary sequences are close to one another
wh\t is coaxial stacking?
occurs when the end base-pair in one double helix interacts with the end base pair in a different double helix
Form A-type helices
what makes RNA unstable?
ribose
what is the reaction through which hydrolysis takes place?
SN2 displacement reaction
what is the result of hydrolysis?
an equimolar mixture of 2’ and 2’ NMPs
