Answer:
C. Responsiveness and timing
Explanation:
I just know it, I really don't know how to explain
Answer:
The second statement is correct: "The "host range" for a virus is determined by the presence or absence of particular components on the surface of a host cell that are required for the virus to attach."
Explanation:
The virus attaching itself to the host cell is the first step for it to successfully infect the host. Viruses are smaller in size than bacteria, so the first statement is incorrect. The third statement is incorrect because viruses do not have the necessary machinery to carry out protein synthesis or to generate ATP, this precisely why they seek out a host to begin with. The fourth statement is false because the virus will either have DNA or RNA, but both at the same time.
Hope that answers the question, have a great day!
What is the choices for the blank?
Answer:
a. + glucose, + lactose = On
b. - glucose, - lactose = Off
c. + glucose, - lactose = Off
d. - glucose, + lactose = On
Explanation:
Lac operon has both types of control, repressible and inducible.
Whenever glucose level is low in the cell, an enzyme known as adenylyl cyclase raises the level of cAMP which forms a dimer with CRP protein and they both act as activator of lac operon and cause expression.
Apart from this, when lactose is present in the cell, β-galactosidase enzyme metabolizes lactose to form allolactose which causes allosteric repulsion in the lac repressor and causes its removal from the operator. As soon as repressor is removed lac operon gets activated.
In wild type lac operons, the expression of lac operon occurs when glucose level is low in the cell and lactose is present but in this mutant presence or absence of glucose will not make a difference because CRP will bind Plac promoter independent of cAMP level i.e. activator CRP will work even in high glucose concentration. If lactose is present then lac operon will always express so in option 'a & d' lac operon will express but in option 'b & c' it will not express.
The best and most correct answer among the choices provided by your question is the second choice.
<span>
Introns are functional proteins that would contain the information contained within which of the following regions of DNA.</span>
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