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.
Answer:
The correct answer is option C.
Explanation:
The slugs prefer pink flowers over the white ones. Thus, if the slugs are withdrawn from the population, the pink flowers are no more consumed and their number enhances. In a similar manner, the bees like to pollinate more pink flowers in comparison to the white ones.
Thus, again, the pink flowers are getting pollinated in huge concentrations. Thus, the fruits and seeds are set and they produce another generation of pink flowers. Ultimately, there would be more pink flowers in the region in comparison to the white ones as the slugs that used to consume them, are also withdrawn.
Earlier, both the numbers of pink and white flowers would remain steady as even though only some of the bees were pollinating white flowers, they were not getting consumed by the slugs. This had maintained a balance between the number of pink and white flowers. Thus, the number of pink flowers would increase with time if the slugs are removed.
The answer is "PET scan" or "PET-CT".
PET scan or positron emission tomography uses the technology behind conventional CT scans but performs to quantify the function in specific parts of organs (i.e. brain). The patient will be given a positron emitting substance most commonly fluorodeoxyglucose or FDG via intravenous injection. After which, the patient will go to the PET machine and the PET machine will measure the positron emitted throughout the body. Positron is well correlated to the function of a specific part of an organ.
You could make sure before you leave an area to get all seeds off your cloths before heading to somewhere where the plant doesn't grow.
