RNA, transcription and translation Flashcards
The four main types of RNA
mRNA, tRNA, rRNA, small RNAs
RNA that encodes amino acid sequence of one or more polypeptides specified by a gene or a set of genes
mRNA
RNA in ribosomes
rRNA
RNA that reads information encoded in the mRNA and transfer the appropriate amino acid to a growing polypeptide chain during protein synthesis
tRNA
The entire chromosome is transcribed to RNA. T/F
F
Only particular genes or groups of genes are transcribed at any one time, and some portions of the DNA genome are never transcribed.
The sum of all the RNA molecules produced in a cell under a given set of conditions
Transcriptome
Transcription requires a primer. T/F
F
RNA polymerase can directly initiate synthesis once it binds to a promoter
Which ions does RNA polymerase require for transcription?
Mg, Zn
RNA polymerase is most active when?
When bound to a double-stranded DNA
Which enzymes synthesize RNA?
RNA polymerase
The two strands of DNA is known as what during transcription?
Template strand and nontemplate strand (coding strand)
Which DNA strand is complementary to the RNA strand?
Template strand/ antisense/ negative strand
Which DNA strand is identical to the RNA strand, except U is in place of T?
Coding strand/nontemplate strand/ sense/ positive strand
RNA polymerases have a separate proofreading 3’ to 5’ exonuclease active site. T/F
F
Transcription is less accurate than DNA replication.
RNA synthesis is initiated at which specific sequences?
Promoters
Which polymerase synthesizes the precursors for rRNA?
RNA polymerase I (Pol I)
Which polymerase synthesizes tRNA?
RNA polymerase III (Pol III)
Which polymerase synthesizes mRNA?
RNA polymerase II (Pol II)
The RNA strand produced from a DNA template
Primary RNA transcript
Noncoding tracts on the RNA that break up the coding regions of the transcript
Introns
The coding segments of RNA
Exons
What is splicing?
The process where introns are removed from the primary transcript and the exons are joined to form a continuous sequence that specifies a functional polypeptide
Most eukaryotic mRNAs are capped at which end?
5’
What molecule is the 5’cap?
7-methylguanosine
The methyl groups of 7-methylguanosine are donated by which molecule?
S-adenosylmethionine (sAM)
Introns and exons of the DNA are transcribed into RNA. T/F
T
Which group of introns are self-splicing?
Groups I, II
What does self-splicing mean?
No protein enzymes are involved in the removal of introns and the joining of exons
Which is the largest class of introns?
Spliceosomal introns
Which protein catalyzes the removal of spliceosomal introns?
Spliceosome
The spliceosome is a protein complex made up of specialized RNA-protein complexes known as what?
Small nuclear ribonucleoproteins (snRNPs)
Each snRNP is made up of eukaryotic RNAs, 100 to 200 nucleotides long, known as what?
Small nuclear RNAs (snRNAs)
Eukaryotic mRNAs have which distinctive 3’ end structure?
poly(A) tail
The process by which mRNA is utilized as a template to direct the synthesis of a polypeptide
Translation
The triplet sequence of nucleotides on the mRNA molecule
Codon
the complementary triplet on the tRNA molecule
Anticodon
The stem-loop structure on a tRNA
Anticodon loop
Stop codons
UAA, UAG, UGA