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:
D. Lung cells
Explanation:
There are many organizations of living things and parts of living things. From simplest to complex the levels are: cells, tissue, organ, system, organism. So, if you have lung tissue then the only simpler organization is cells. These are simpler because cells are what make up tissue, just as tissue makes up organs. Through the levels, the more simple something is then the smaller it is, relatively.
I would say internal stimulus of hunger but Idk
It begins with cells, tissues, organs, organ system to organism. There are 11 organ systems that work collectively for an organism to function. Each organ is responsible for a different function and has its own structure. The organism system that consist of the body's outer covering is the integumentary system. It consist of skin, hair, nails, and endocrine glands; they are the protectors of the body. The environment such as UV rays are harmful and the skin, hair, nails, etc protect the body as needed.
