Question

Most effective pesticides are
A) Carbamates
B) Organochlorine
C) Organophosphate
D) All of the above

Answer 1

Hint: Pesticides are those molecules which can be derived from organic or synthetic sources which will be effective against different enzymatic reactions either by disrupting its structure or acting as an antagonist thereby reducing the function of the enzyme which might result in death of an organism.

Complete answer:
The given chemicals act as pesticides with different modes of action. Carbamates are the derivatives of carbamic acids which consist of organic functional groups bound by replacing hydrogen atoms such as ester ethyl carbamate, they target acetylcholinesterase in insects and disrupt them, thereby causing death of an insect.

Organochlorine pesticides are those compounds which consist of chlorine atoms which is conveniently bound to hydrocarbon specifically alkanes. One of the popular members of this group is DDT, this is effective on the peripheral nervous system of the insect. They induce membrane depolarisation by preventing gate closure active activation of the sodium channel in the axon region of the neuron. This causes sodium leaks through the membrane and induces destabilisation of the perennial across the membrane. Thereby Killing the pests.

Organophosphate pesticides are those ester molecules which consist of phosphate groups along with aromatic or alkyl groups, they are also known as phosphoric esters. These molecules are nerve signal inhibitors where they destabilise acetylcholinesterase enzyme, which is required to breakdown the neurotransmitter acetylcholine which relay downstream signals at the postsynaptic receptors, disrupting these members result in blockage of the signal and accumulation of acetylcholine at one particular region thereby disrupting the normal function of the neuron. Therefore, all the above molecules are effective pesticides in their own mode of action.

Hence, the correct answer is option D.

Note:While answering this question, effective refers to the mode of action on insects not on humans or on other organisms and not even on the environment. All the above pesticides are not eco friendly.