Reading Quiz - Open Stax 15.4-15.5 Translation

Match the following definitions with their correct term relating to translation

7-methylguanosine cap

aminoacyl tRNA synthetase

anticodon

exon

initiator tRNA

nonsense codon

Octamer box

reading frame

RNA editing

Shine-Dalgarno sequence

signal sequence

small nuclear RNA

v modification added to the 5' end of pre-mRNAs to protect mRNA from degradation and assist translation

enzyme that “charges” tRNA molecules by catalyzing a bond between the tRNA and a corresponding amino acid

v three-nucleotide sequence in a tRNA molecule that corresponds to an mRNA codon

v sequence present in protein-coding mRNA after completion of pre-mRNA splicing

v in prokaryotes, called tRNAMetftRNAfMet; in eukaryotes, called tRNAi; a tRNA that interacts with a start codon, binds directly to the ribosome P site, and links to a special methio...

v one of the three mRNA codons that specifies termination of translation

V (ATTTGCAT) nonessential eukaryotic promoter sequence that binds cellular factors to increase the efficiency of transcription; may be present several times in a promoter

V sequence of triplet codons in mRNA that specify a particular protein; a ribosome shift of one or two nucleotides in either direction completely abolishes synthesis of that protein

v direct alteration of one or more nucleotides in an mRNA that has already been synthesized

v (AGGAGG); initiates prokaryotic translation by interacting with rRNA molecules comprising the 30S ribosome

V short tail of amino acids that directs a protein to a specific cellular compartment

V molecules synthesized by RNA polymerase Ill that have a variety of functions, including splicing pre-mRNAs and regulating transcription factors

How do enhancers and promoters differ?

 

 

Enhancers bind transcription factors to silence gene expression, while promoters activate transcription.

 

Enhancers increase the efficiency of gene expression but are not essential for transcription. Promoter recognition is essential to transcription initiation.

 

Promoters bind transcription factors to increase the efficiency of transcription. Enhancers bind RNA polymerases to initiate transcription.

 

There is no difference. Both are transcription factor-binding sequences in DNA.

Enhancers increase the efficiency of gene expression but are not essential for transcription. Promoter recognition is essential to transcription initiation.

What processing step enhances the stability of pre-tRNAs and pre-rRNAs?

 

methylation

 

nucleotide modification

 

cleavage

 

splicing

 

methylation

What is the predicted size of the corresponding mature mRNA in base pairs (bp), excluding the 5’ cap and 3’ poly-A tail?

 

220bp

 

295bp

 

140bp

 

435bp

295bp

The RNA components of ribosomes are synthesized in the ________.

cytoplasm

nucleus

 

nucleolus

 

endoplasmic reticulum

nucleolus

In any given species, there are at least how many types of aminoacyl tRNA synthetases?

 

20

 

40

 

100

 

200

20

A scientist introduces a mutation that makes the 60S ribosomal subunit nonfunctional in a human cell line. What would be the predicted effect on translation?

 

Translation stalls after the initiation AUG codon is identified.

 

The ribosome cannot catalyze the formation of peptide bonds between the tRNAs in the A and P sites.

 

The ribosome cannot interact with mRNAs.

 

tRNAs cannot exit the E site of the ribosome.

 

Translation stalls after the initiation AUG codon is identified.

Which pre-mRNA processing step is important for initiating translation?

 

poly-A tail

 

RNA editing

 

splicing

 

7-methylguanosine cap

7-methylguanosine cap