Question 1

Which is true regarding the binding of an amino acid to a tRNA?
a.Amino acids bind to the 5' end of the tRNA.
b.The binding of amino acids requires GTP.
c.There is one aminoacyl trans-tRNA synthetase that binds all amino acids to all tRNAs.
d.When tRNAs release an amino acid,it is called tRNA charging.
e.None of the above is true.

None of the above is true.

Accepted Answer

Amino acids bind to the 3' end of the tRNA, the binding requires ATP, each amino acid has its own specific aminoacyl-tRNA synthetase, and tRNA charging refers to the attachment of an amino acid to tRNA, not its release.

Question 2

What cellular structure helps properly fold some proteins?&#10;a.ribosomes&#10;b.ribozymes&#10;c.signal sequences&#10;d.molecular chaperones

Accepted Answer

Molecular chaperones are cellular structures that help proteins properly fold into their functional shapes. They do this by binding to the protein, preventing it from aggregating, and providing a protected environment for the folding process to occur. Ribosomes assemble amino acids into proteins, ribozymes are RNA molecules that catalyze chemical reactions, and signal sequences are short amino acid sequences that direct newly synthesized proteins to specific destinations within or outside the cell.

Question 3

The formation of peptide bonds during elongation is catalyzed by an enzyme called the ribozyme.The ribozyme is made of what macromolecule?
a.protein in the large subunit of the ribosome
b.protein in the small subunit of the ribosome
c.rRNA in the large subunit of the ribosome
d.rRNA in the small subunit of the ribosome
e.tRNA

Accepted Answer

The ribozyme that catalyzes the formation of peptide bonds during elongation is a part of the large subunit of the ribosome, which is made up of rRNA molecules. Therefore, choice C is the correct answer as it states rRNA in the large subunit of the ribosome. The other choices are incorrect as they either refer to protein components of the ribosome or tRNA, which is not involved in the catalysis of peptide bonds.

Question 4

Any given DNA sequence has ______ possible reading frames,and the correct one is set by an___________________.
a.2; termination codon
b.4; initiation codon
c.3; initiation codon
d.3; termination codon
e.2; initiation codon

Accepted Answer

Any given DNA sequence has 3 possible reading frames, set by the initiation codon. The correct reading frame is chosen based on the location of the initiation codon. There is only one termination codon, which signals the end of the reading frame.

Question 5

The wobble rules account for non-Watson and Crick nucleotide pairing at which position of the codon and anticodon,respectively?
a.first and third
b.first and second
c.second and second
d.third and first
e.third and second

Accepted Answer

The wobble rules allow for flexibility in base pairing at the third position of the codon and the first position of the anticodon, enabling some tRNAs to recognize multiple codons.

Question 6

If instead of 20 amino acids there were 200 amino acids,then how many nucleotides would you predict to be in a codon?&#10;a.2&#10;b.3&#10;c.4&#10;d.5&#10;e.6

Accepted Answer

With 200 amino acids, a codon would need to encode more possibilities. A 3-nucleotide codon can encode 64 combinations (4^3), which is insufficient. A 4-nucleotide codon can encode 256 combinations (4^4), which is sufficient to cover 200 amino acids.

Deck 11: From DNA to Proteins: Translation