Question

An auxotroph is
A)A plant capable of synthesizing its own carbohydrates.
B)Plants showing quick bending response to sunlight
C)A mutant lost the ability to synthesise one or more nutrients
D)An organism dependent on another for nutrient requirements

Answer 1

Hint: Met mutants are Met auxotrophs, which means they are unable to expand in non-Met-containing media.In genetics, auxotrophic strains have multiple applications. Auxotrophic strains are mostly used by researchers as hosts for plasmid transformation.

Complete answer:
An auxotroph is any microorganism that, typically as a consequence of mutation, has lost the ability to synthesise an organic compound needed for its development.

Prototrophic cells (also known as 'wild type') are self-sufficient producers of all necessary metabolites (e.g. amino acids, lipids, cofactors), while auxotrophs require the metabolite they are unable to produce to be on medium. For example, saying a cell is auxotrophic methionine means that it would have to be on a methionine-containing medium or else it would not be able to replicate. This is because it is unable to generate its own methionine (methionine auxotroph) in this case.However, with or without methionine, a prototroph or a methionine prototrophic cell will be able to act and replicate on a medium.

In genetics, if it bears a mutation that makes it unable to synthesise an essential compound, a strain is said to be auxotrophic. For example, a yeast mutant with an inactivated uracil synthesis pathway gene is a uracil auxotroph (for example, the uracil auxotroph is the resulting strain when the yeast gene Orotidine 5'-phosphate decarboxylase is inactivated). Such a strain is incapable of synthesising uracil and can only expand if it is possible to extract uracil from the environment.

Hence, the correct answer is option (C)

Note: For large classes of compounds needed for development, many living organisms, including humans, are auxotrophic and have to obtain these compounds through diet.