In the triplet-binding assay of Nirenberg and Leder, an RNA triplet composed of three bases was able to cause the a. translation of a polypeptide. b. binding of a tRNA carrying the appropriate amino acid. c. termination of translation. d. release of the amino acid from the tRNA.

In chain termination sequencing, which of the following terminates the chain?       a.  The lack of a base at the 1' carbon       b.  The lack of OH at the 2' carbon       c.  The lack of OH at the 3' carbon       d.  The lack of phosphate at the 5' carbon

You need to determine if a specific mRNA is modified. What method will you choose to determine this and why?

Which of the following is NOT true of DNA Methylation.     A.   DNA methylation is typically correlated to gene repression.       B.   On a given gene, histone modifications or DNA methylation could be used, but not both at the same gene.       C.  DNA methylation can be used in mismatch repair to identify the parent strand after DNA replication.       D.  DNA methylation typically occurs on dCTP nucleotides in eukaryotes.       E.  DNA methylation can be inherited through mitosis.

A sample of E.coli cells is transformed with a plasmid containing a transcriptional fusion including the promoter of an E.coli housekeeping gene and the LacZ gene. The transformed cells are plated out on selective medium containing X-gal. Which of the following best describes the likely results. a. Colonies will only be blue if lactose is also included in the growth medium. b. Colonies will only be blue if lactose and glucose are included in the growth medium c. Most of the colonies should turn blue. d. Presence of any white colonies may indicate deletion or mutation of the promoter. e. Both c. and d. are correct

You will learn more about genetic engineering in Chapter10, but for now, put on your genetic engineer’s cap andtry to solve this problem. E. coli is widely used in laboratories to produce proteins from other organisms.a. You have isolated a yeast gene that encodes a metabolic enzyme and want to produce this enzyme in E. coli.You suspect that the yeast promoter will not work inE. coli. Why?b. After replacing the yeast promoter with an E. colipromoter, you are pleased to detect RNA from the yeastgene but are confused because the RNA is almost twicethe length of the mRNA from this gene isolated fromyeast. Explain why this result might have occurred.

You design a guide RNA to target your gene of interest, which you will express attached to a scaffold RNA. You transform cells with Cas9, the guide+scaffold RNA, and an HDR template. The HDR template codes for the insertion of a premature stop codon located 10 bp upstream of the Cas9 cut site, a base pair substitution 15 bp upstream of the Cas9 cut site, and a base pair substitution in the PAM sequence. Question: Is this scenario “possible” or “not possible”? Cas9 cuts the target site, the stop codon and the two base pair substitutions are introduced.

With regard to a promoter, a transcriptional start site is a. located at the −35 sequence and is recognized by σ factor. b. located at the −35 sequence and is where the first base is used as a template for transcription. c. located at the +1 site and is recognized by σ factor. d. located at the +1 site and is where the first base is used as a template for transcription.