You are studying a new strain of E. coli that can utilize the disaccharide melibiose very efficiently. You find that utilization depends on the enzyme melibiase, which is encoded by the gene Mel1. Mel1 is not expressed unless melibiose is present in the growth medium.

You next construct a MelA– MelB– double mutant, which gives the following behavior:

 

Which of your two models is consistent with this new data?

a) the MelA- MelB- double mutant is identical to the MelB- mutant

b) MelA- is epistatic to MelB-

c) MelB- is epistatic to MelA-

d) the MelA- MelB- double mutant is identical to the MelA- mutant

Which of the following is the correct prediction about the double mutants?

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#Question id: 8956

#SCPH28 | Zoology

Protostome characteristics generally include which of the following?

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#Question id: 8957

#SCPH28 | Zoology

A student encounters an animal embryo at the eight-cell stage. The four smaller cells that comprise one hemisphere of the embryo seem to be rotated 45 degrees and lie in the grooves between larger, underlying cells (spiral cleavage). This embryo may potentially develop into a(n)

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#Question id: 8958

#SCPH28 | Zoology

A student encounters an animal embryo at the eight-cell stage. The four smaller cells that comprise one hemisphere of the embryo seem to be rotated 45 degrees and lie in the grooves between larger, underlying cells (spiral cleavage). If we were to separate these eight cells and attempt to culture them individually, then what is most

likely to happen?

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#Question id: 9050

#SCPH06 I Botany

If an ecologist were studying the regional interactions among multiple populations of different species and how they influence the exchange of materials between their various environments, then this would be an example of which kind of research?

TLS Online TPP Program

#Question id: 9050

#SCPH28 | Zoology

If an ecologist were studying the regional interactions among multiple populations of different species and how they influence the exchange of materials between their various environments, then this would be an example of which kind of research?

TLS Online TPP Program

#Question id: 9051

#SCPH06 I Botany

What would happen to the seasons if Earth were tilted 35 degrees off its orbital plane instead of the usual 23.5 degrees?