A. can cats learn to sit down on command
Answer:
Explanation:
The bacteriostatic antibiotics can be defined as those antibiotics, which prevents the growth of bacteria. These keeps the growth of bacteria in the stationary phase so that bacteria cannot cause harm to the host.
The bactericidal antibiotics can be defined as those antibiotics, which kills the bacteria.
The example of bacteriostatic antibiotic is Tetracycline that it inhibit the bacteria ribosome production of proteins. This way bacterial growth and reproduction will get restricted.
The example of bacteriocidal antibiotic is polymyxin B. It causes injuries to the plasma membrane of the bacteria which can be lethal for bacteria.
Answer:
(C) 10 times more acidic than distilled water.
Explanation:
The pH scale is logarithmic, meaning a pH difference of one is a difference of 10 times.
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.
