Bio Ch 17

What would be the consequence of a defective aminoacyl-tRNA synthetase enzyme that could bind to three different amino acids?

Proteins would be made with the wrong amino acid at some positions.

For a particular gene, both strands of DNA may be transcribed into mRNA.

False

What is an anticodon?

The part of a tRNA that binds to a codon in the mRNA.

Termination of transcription in bacteria occurs when ________.

a hairpin secondary structure forms in the RNA transcript, and it separates from the RNA polymerase

Which of the following statements about transcription is false?

mRNAs must fold into a cloverleaf structure in order for translation to occur.

A mutant bacterial cell has a defective aminoacyl-tRNA synthetase that attaches a lysine to tRNAs with the anticodon AAA instead of the normal phenylalanine. The consequence of this for the cell will be that _____.

proteins in the cell will include lysine instead of phenylalanine at amino acid positions specified by the codon UUU

Which of the following is NOT used in protein synthesis?

snRNP

Which choice describes the cycle of events for each new amino acid during translation elongation?

Charged tRNA enters A site; peptide bond is formed; ribosome translocates.

Ribosomes can attach to prokaryotic messenger RNA ________.

before transcription is complete

There are 61 mRNA codons that specify an amino acid, but only 45 tRNAs. This is best explained by the fact that ________.

the rules for base pairing between the third base of a codon and tRNA are flexible