Question at position 7 Cells of which bacterial genotype would be able to utilize lactose as an energy source?I+O+Z+Y- /F’ (ISO+Z-Y+)ISO+Z+Y+I+O+Z-Y+I+OCZ+Y- /F’ (I+O+Z-Y+)Clear my selection

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Question at position 7 Cells of which bacterial genotype would be able to utilize lactose as an energy source?I+O+Z+Y- /F’ (ISO+Z-Y+)ISO+Z+Y+I+O+Z-Y+I+OCZ+Y- /F’ (I+O+Z-Y+)Clear my selection

BlackTom AI · Accepted Answer

The question asks which bacterial genotype would be able to utilize lactose as an energy source. In this context, the Z and Y genes are typically the lactose utilization genes (Z often corresponds to beta-galactosidase activity and Y to lactose permease). Therefore, a genotype must have functional (plus) alleles for both Z and Y to metabolize lactose effectively.

Option 1: I+O+Z+Y- /F’ (ISO+Z-Y+)
- This genotype has Z+ but Y- (lactose permease is nonfunctional). Even with beta-galactosidase present, the cell cannot import lactose efficiently without permease, so lactose utilization would be impaired. This option is unlikely to support lactose metabolism.

Option 2: ISO+Z+Y+
- This genotype has both Z+ and Y+ (functional beta-galactosidase and functional lactose permease). With both components available, lactose can be transported into the cell and metabolized, making this a plausible lactose-using genotype.

Option 3: I+O+Z-Y+
- Here Z is -, so beta-galactosidase is nonfunctional while Y+ is present. Even if lactose could be transported, the lack of functional beta-galactosidase prevents lactose breakdown, so lactose utilization would be compromised.

Option 4: I+OCZ+Y- /F’ (I+O+Z-Y+)
- This option shows Y- (lactose permease nonfunctional) despite Z+ present. Without permease, lactose uptake is inefficient or impossible, preventing utilization despite any beta-galactosidase activity. This makes lactose metabolism unlikely.

In summary, the key requirement is simultaneous functionality of both Z and Y genes to enable lactose utilization. Among the options, only Option 2 supplies Z+ and Y+ together, making it the genotype capable of utilizing lactose as an energy source.

Question at position 7 Cells of which bacterial genotype would be able to utilize lactose as an energy source?I+O+Z+Y- /F’ (ISO+Z-Y+)ISO+Z+Y+I+O+Z-Y+I+OCZ+Y- /F’ (I+O+Z-Y+)Clear my selection

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类似问题

When glucose is present, and lactose is absent in the bacteria cell’s environment, which of the following is INCORRECT with respect to the lac operon?

Question at position 18 Cells of which bacterial genotype would be able to utilize lactose as an energy source?I+O+Z+Y- / (I+O+Z-Y+)I+O+Z-Y+ISO+Z+Y+I+OCZ+Y- / (I+O+Z-Y-)Clear my selection

Question31 Which of these are constitutive mutants of the lac system and as such would cause the constant expression of the Z, Y, and A genes associated with the lac operon? Select up to two alternatives: Oc Y+ I− Z+ ResetMaximum marks: 1 Unflag question undefined

Bacteria require both lactose and glucose to be present to synthesise protein linked to a lac operon.

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