A partial diploid in E. coli is created so that LacI is no longer expressed from the genome and is instead expressed from a plasmid. When this E. coli strain is grown in the presence of lactose and glucose, we should expect that the lac operon will be:   Question 14 options:   Constitutively expressed due to LacI being expressed from a plasmid   Induced due to functional Catabolite Activator Protein (CAP)   Repressed due to functional LacI   Induced due to non-functional LacI   Expressed at low levels due to non-functional Catabolite Activator Protein (CAP)

In selecting target cells to receive a transferred gene in gene therapy, what factors do you think would have to be taken into account?

INTERPRET DATA Develop a simple hypothesis that would explain the behavior of each of the following types of mutants in E. coli. Mutant a: The map position of this mutation is in the trp operon. The mutant cells are constitutive; that is, they produce all the enzymes coded for by the trp operon, even if large amounts of tryptophan are present in the growth medium. Mutant b: The map position of this mutation is in the trp operon. The mutant cells do not produce any enzymes coded for by the trp operon under any conditions. Mutant c: The map position of this mutation is some distance from the trp operon. The mutant cells are constitutive; that is, they produce all the enzymes coded for by the trp operon, even if the growth medium contains large amounts of tryptophan.

IS. Alternative splicing has been estimated to occur in more than 95% of multi-exon genes. Which of the following is not an evolutionary advantage of alternative splicing? Alternative splicing increases diversity without increasing genome size Different gene isoforms can be expressed in different tissues Alternative splicing creates shorter mRNA transcripts Different gene isoforms can be expressed during different stages of development.

Cloning Genes Is a Multistep Process In cloning human DNA, why is it necessary to insert the DNA into a vector such as a bacterial plasmid?

Put the following processes in order of their occurrence during expression of a eukaryotic gene: a. mRNA processing c. transcription b. translation d. RNA leaves nucleus

Discuss Concepts In a mutant strain of E. coli, the CAP protein is unable to combine with its target region of the lac operon. How would you expect the mutation to affect transcription when cells of this strain are subjected to the following conditions? Lactose and glucose are both available. Lactose is available but glucose is not. Both lactose and glucose are unavailable.

The search for the BRCA1 breast cancer gene discussed in this chapter was widely publicized in the media (for example, Newsweek, December 6, 1993). Describe the steps taken by Mary-Claire King and her colleagues to clone this gene. How long did this process take?

Although it is well known that X-rays cause mutations, they are routinely used to diagnose medical problems, including potential tumors, broken bones, and dental cavities. Why is this done? What precautions need to be taken?

Through alternative splicing, eukaryotes (a) reinforce gene inactivation (b) prevent transcription of heterochromatin (c) produce related but different proteins in different tissues (d) amplify genes to meet the requirement of high levels of a gene product (e) bind transcription factors to enhancers to activate transcription