RNA Flashcards
what is the central dogma
explanation of the flow of genetic information within a biological system
which is more unstable and more prone to degradation, RNA or DNA
RNA because of the presence of the -OH group in
ribose sugar
where is RNA found
nucleus, mitochondria and cytoplasm
how many structures does RNA have
- primary, secondary, tertiary and quaternary
what subunits is bacterial enzymes composed of
two α, one β, one β’, one ⍵, one σ
what is a holoenzyme
biochemically active compound formed by the combination of an enzyme with a coenzyme.
give an example of a coenzyme and an enzyme forming a holoenzyme in bacteria
sigma factor and core enzyme
what are the 4 functions of RNA
- Storage/transfer of genetic information
- Structural
- Catalytic
- Regulatory
give three examples of single stranded RNA viruses
ebola, influenza and rhinovirus
what is an example of double stranded RNA viruses
Rotaviruses, which cause severe gastroenteritis
RNA in ribosome has …………..activity
peptidyltransferase
what are small RNA enzymes called
ribozymes
what are the regulatory roles of RNA
- defense
- in normal development
- gene therapy
what do microRNAs do
regulate the expression of genes, possibly via binding to specific nucleotide sequences
which RNA has frequent turnover
mRNA
mRNA has long generation time. true or false
false, it is short
which parts code for genes and dont, introns and exons
introns dont code while exons do
why does eukaryotic mRNA have longer half-life than a prokaryotic mRNA
because it undergoes additional steps
how longer does eukaryotic mRNA last than that of e coli
that of e coli lasts a few seconds while eukaryotic lasts several hours
what are pre-RNAs first coated with
RNA-stabilizing proteins which protect from degradation while being processed
what does pre-mRNA receive before being translated
(i) a 5′ cap and
(ii) a 3′ poly (A) tail before
(iii) introns are removed
what is the name of the 5’ cap
7-methylguanosine cap
what are the functions of the 5’ cap
protects from degradation and initiation factors recognize the cap to help initiate translation by ribosomes
what cleaves off the rest of the pre-mRNA off the rest of the growing transcript before RNA Polymerase II has stopped transcribing
endonuclease -containing protein complex
how does endonuclease-containing protein complex work
binds to an AAUAAA sequence upstream of the cleavage site and to a GU -rich sequence downstream of the cut site
what catalyzes the addition of up to 200 A nucleotides to the 3′ end of the just-cleaved pre-mRNA
Poly (A) Polymerase (PAP)
what does the poly A tail do
- protects the mRNA from degradation,
- aids in the export of the mature mRNA to the cytoplasm,
- involved in binding proteins involved in initiating translation
what is a spliceosome
large and complex molecular machine found primarily within the nucleus of eukaryotic cells
what does a spliceosome do
removes introns from a transcribed pre-mRNA
tRNA is double stranded, true or false
false, it is single stranded
what are the two structural motifs that allow tRNA to function
1) 3’ terminus (which forms a covalent bond with a specific amino acid)
2) anticodon loop (contains three-base-pair sequence
complimentary to the DNA triplet code for an amino acid)
what is the most abundant form of RNA
ribosomal RNA
what does S stand for in 80S
stands for svedbergs, a unit used to measure how fast molecules move in a centrifuge
what does snRNA stand for
Small nuclear RNAs
what is the primary function of snRNAs
process pre-mRNA
what are snoRNAs and what is their function
Small nucleolar RNA, which guide chemical modifications of other RNAs
what binds with the PIWI subfamily proteins that are involved in maintaining genome stability in germline cells
Piwi-interacting RNAs
what is another function of Piwi-interacting RNAs
play a role in gametogenesis
what RNA species mediate post-transcriptional gene
silencing
micro-RNA (it regulates translation)
what is lncRNA in full
Long noncoding RNAs
some ……. are capable of regulating cancer-associated genes in ways that facilitate tumor development
micro-RNA
dysregulation of mirco-RNA metabolism can lead to what
linked to various neurodegenerative diseases, including Alzheimer disease
what type of RNA binds to specialized proteins known as caspases, which are involved in apoptosis (programmed cell death) hence inhibiting cell death leading to cancer
tRNA
what do tRNA-derived fragments (tRFs) play a role in
suspected to play a role in cancer
what has increase in MALAT1 (metastasis associated lung adenocarcinoma transcript 1) been associated with
proliferation and metastasis (spread) of tumour cells
what does sequestering of RNA binding proteins (RBPs) by RNAs containing repeat sequences lead to
formation of foci or aggregates in neural tissues leading to amyotrophic lateral sclerosis (ALS) and myotonic dystrophy
true or false, RNA has small grooves which makes it hard for enzymes to attack
false, that is for DNA. RNA is easily attacked by enzymes because of its large grooves
