Answer:
Soo... Is that the answer you chose?
Explanation:
I think is correct.
The lac operon, which stands for Lactose operon is known as an inducible system. It is the an operon required for the transport and metabolism of lactose some enteric bacteria (Echerichia coli for example). The Lac operon is only activated in the presence of a key molecule. The key molecule is lactose.
From the given options the following best describes the Lac operon:
D. The repressor is freed from the operator when lactose is present.
Answer: alleles
Explanation:
"An allele is a variant form of a gene. Genes come in different varieties, called alleles. Somatic cells contain two alleles for every gene, with one allele provided by each parent of an organism."- Nature .com
Answer:
A. whether the glycoproteins or capsid proteins on its surface recognize those of the host cells.
Explanation:
Virus has different surface proteins that are recognized by the receptors present on its host cell. The range of a virus is determined by the recognition of these proteins by the host cell.
The interaction between the receptor on the host cell and surface proteins on the viral capsid is important for viral genome entry in the host cell and to determine the range of the host cells.
If the surface protein of the virus is not able to bind to the receptor on any cell then the virus can not infect the cell. For example, the HIV virus infects only those cell which have CD4 receptors. So the right answer is A.
