Genetics exam 3

Which statement about RNA is not true?

RNA is a more stable molecule than DNA.

Which sequences are important to predict the protein sequence from the DNA sequence?

stop codon, start codon, transcription start site

Which sequences are present in both the pre-mRNA and the mature mRNA?

exons, 3’ UTR, 5’ UTR

RNA editing is carried out by

guide RNAs

tRNA structure

cloverleaf

the structure of the ribosome has

large and small ribosome subunits

bacterial ribosome size

70s

eukaryotic ribosome size

80s

ribosomal RNA is processed after

transcription

mRNA

encodes proteins

tRNA

acts as adaptor between mRNA and amino acid

rRNA

forms the ribosome

snRNA

functions in various nuclear processes (splicing)

siRNA

silences gene expression

miRNA

regulates gene expression

piRNA

suppresses transcription of transposable elements in reproductive cells

snoRNA

only in eukaryotes, processing and assembly of rRNAc

crRNA

only in prokaryotes, assists destruction of foreign DNA

who demonstrated that ribosomes do NOT carry genetic info

brenner, jacob, and meselson

Which region would not be present in the final RNA transcript?

promoter

core enzyme in bacterial RNA polymerase

two copies of alpha, single copy of beta, single copy of beta prime, single copy of omega

holoenzyme in RNA polymerase

contains all the subunits required for transcription initiation and elongation, including the core enzyme and sigma factor.

the sigma factor

causes DNA to unwind and allows RNA polymerase to bind to the promoter region.

What is the outcome of RNA editing?

The protein translated from the edited mRNA has a sequence different from its gene.

pre-mRNA has

introns, exons, and tail and/or cap

multiple 3’ cleavage sites

premRNA is transcribed into slightly shorter or longer mRNAs depending on the place it cuts, increasing diversity of mRNA products

transplicing

This process joins exons from different mRNA molecules, which creates an amino acid sequence that does not correspond to a single gene

RNA editing

alters nucleotides within a single RNA molecule, can change codons, does NOT join RNAs together

Which RNA sequences can potentially fold to form double‑stranded RNA via a hairpin loop?

5⁢′−.....AGUCC.......GGACU......-3⁢′