Respuesta :
Answer:
A) LacZ and LacY are genes that code for beta-galactosidase and permease, respectively.
Explanation:
The lac operon is also commonly referred to as the lactose operon. The lac operon is a system found in bacteria, E. coli which helps regulating the genes responsible for lactose metabolism.
a) True. The three structural genes involved in lactose metabolism are: lacZ (Beta-galactosidase), lacY (Lactose permease), and lacA (Transacetylase)
b) False. LacI is a gene that codes for the lac repressor protein, not allolactose.
c) False. In the presence of lactose, the lac operon is active rather than inactive.
Lac operon is an example of inducible operon and it is usually turned off in the absence of lactose but can be turned on in the presence of lactose.
d) False. The lac operon is not constitutively expressed . It's regulation is based on the presence or absence of inducer.
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Therefore, option (a) the correct statement.
Final answer:
The accurate statement is that LacZ and LacY code for beta-galactosidase and permease. The lac operon is activated in the presence of lactose, contrary to one of the incorrect options provided. The correct answer is (option A).
Explanation:
The correct statement about the lac operon is: A) LacZ and LacY are genes that code for beta-galactosidase and permease, respectively. The lac operon is a group of genes responsible for the metabolism of lactose in bacteria such as E. coli. The lacI gene encodes a repressor that can bind to the operator sequence and inhibit the transcription of the operon. However, in the presence of lactose, an isomer of lactose called allolactose binds to the repressor making it unable to bind to the operator, leading to the expression of the operon. Thus, the operon is not inactive in the presence of lactose, rather lactose is required for the operon's activation.
