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:
B
Explanation:
Hope this helps! Have a great rest of your day! ;)
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Answer:
The heat from the strawberries transfers to the freezer and causes the strawberries to freeze.
Explanation:
When Eric-palces some room temperature strawberries into the freezer, he is changing the temeprature of the strawberries. When the strawberries are in the room tempertaure, they are absorbing certain amount of heat.
When they are placed in the freezer they are releasing the heat to the environment and this leads to condition called as phase change. Due to this phenomenon, the heat from the strawberries transfers to the freezer and causes the strawberries to freeze.
The condition called dysuria is characterized by painful or difficult urination, it can be due to pathologic or benign causes.
Answer:
<u><em>C.)</em></u> <em>Crest to trough</em>
