The promoter of the araBAD operon from E. coli is activated in the presence of arabinose and the absence of glucose and directs expression of genes encoding enzymes required for arabinose metabolism. Unlike the cases of lac and gal genes, where a repressor and an activator work together, here two activators work together: AraC and CAP

+ arabinose	AraC binds that sugar and adopts a configuration that allows it to bind DNA as a dimer to the adjacent half-sites, araI1 and araI2
– arabinose	the AraC dimer adopts a different conformation and binds to araO2 and araI1, there is no monomer at site araI2, and so the protein cannot activate the araBAD promoter (araPBAD). This promoter is also controlled by CAP.

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#Question id: 15006

#Unit 8. Inheritance Biology

Which of the following is not a mechanism for sex determination?

TLS Online TPP Program

#Question id: 15007

#Unit 8. Inheritance Biology

You set up a cross between true breeding wild type male fruit flies and true breeding female flies with a yellow body color. You notice in the F1 generation that half the flies, specifically all the males, have yellow body color while the females are wild type (gray). Which of the following explanations is the most likely?

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#Question id: 15008

#Unit 8. Inheritance Biology

You have a white eyed, male fruit fly with vestigial wings and a wild type female known to be heterozygous for both traits. You know that vestigial is located on an autosome. What is the probability that a mating between these two flies will generate a female offspring with vestigial wings and white eyes?

TLS Online TPP Program

#Question id: 15009

#Unit 8. Inheritance Biology

A mutation in which most of the protein coding sequence of the gene is removed is most likely to be which type of allele?

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#Question id: 15010

#Unit 8. Inheritance Biology

The phenomenon where half the "normal" level of functional protein is not enough to generate a normal phenotype is called haploinsufficiency. Which of the following situations demonstrates haploinsufficiency?

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#Question id: 15011

#Unit 8. Inheritance Biology

Which of the following statements about a lethal allele is NOT correct?