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.
Covalent bond because a covalent bond is when it only shares electrons and it doesn't give or lose.
Carbon Dioxide is the main cause, but other effectors include nitrous oxide and <span>methane.
Hope this helps!</span>
Answer:
I think it's " P waves from earthquakes can travel through both solids and liquids so they tell us what is inside the earth. "
Explanation:
Answer:
In order for a metamorphic rock to become a sedimentary rock, the rock must undergo erosion. Once the rock has eroded, it will produce rock fragments or sediments which accumulate to form a sedimentary rock. ... In turn, when igneous and sedimentary rocks are exposed to heat and pressure, the rocks become metamorphic.
Explanation:
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