Question

Where is the amino acid covalently attached on a charged tRNA?

Question 29 options:

	at the 3' end
	on the T arm
	on the anticodon loop
	on the D arm
	at the 5' end

Question 28 (1 point)

The substrate for the maintenance methyl-transferase in eukaryotic cells is most similar to which of the following?

Question 28 options:

	a double-stranded break
	DNA just after replication in E.coli
	a tRNA
	DNA just after replication in S.cerevisiae (yeast)
	a restriction endonuclease site

Question 27 (1 point)

The Trp operon in Escherichia coli encodes the components necessary for tryptophan biosynthesis. In the presence of tryptophan in the bacterium,

Question 27 options:

	the operon genes are expressed.
	the expression of the tryptophan repressor is shut off.
	All of these choices.
	the tryptophan repressor is bound to the tryptophan operator.
	the tryptophan repressor is bound to bacterial RNA polymerase.

Answer 1

29. The amino acid carried by the tRNA is covalently attached to the nucleotide at the 3' end of the tRNA, known as the tRNA's acceptor arm.

28. The substrate for the maintenance methyl-transferase in eukaryotic cells is most similar to a restriction endonuclease site. Restriction enzymes Mspl and Hpall cut a site containing CpG.

27. The Trp operon in Escherichia coli encodes the components necessary for tryptophan biosynthesis. In the presence of tryptophan in the bacterium, the tryptophan repressor is bound to the tryptophan operator. Binding of the tryptophan repressor complex at the operator physically prevents the RNA polymerase from binding and transcribing the downstream genes.