Correct Answer – Option 4 - enzymes

DNA replication occurs with the help of enzymes.

A Scalpel is too large to cut a DNA. Hence, option 1 is incorrect.

Electrophoresis is also not a method that can be used for cutting the DNA. Hence, option 2 is incorrect

Hormones cannot cut the DNA. Hence, option 3 is incorrect.

Correct Answer – Option 1 – may result in the production of a defective protein

A gene mutation is a permanent change in the DNA sequence that makes up a gene. Mutations range in size from a single DNA building block (DNA base) to a large segment of a chromosome.

Gene mutation in a human skin cell cannot alter the sequence of sugars in insulin, cannot decrease mutation rate in offspring and cannot alter the rate of all the metabolic processes in humans. Hence, the options 2,3 and 4 are incorrect.

Correct Answer – Option 3

Variation in offspring's occurs due to cross over. This is quite evident in the figure shown above representing "After"

Correct Answer – Option 4 – The inserted DNA may direct the synthesis of human proteins

The human gene is inserted into a bacterial cell making it a part of the gene of the bacteria. The bacteria will not destroy itself hence cannot destroy the human gene. Hence, option 1 is incorrect.

Embryo cannot be formed by asexual reproduction, which is the mode of reproduction of bacteria. Hence, option 2 is incorrect.

The inserted human DNA does not have full control of the functioning of the cell. Hence, it cannot change the harmful bacteria to harmless one. However it may direct the synthesis of human protein. Hence, option 3 is incorrect and option 4 is the correct answer.

Correct Answer – Option 3

Increase in temperature is does not refer to behavior of the fruit fly or intensity of light, hence, options 1 and 2 are incorrect.

Mutation is an activity taking place with respect to the cell structure and is not governed by temperature however is influenced by the environment, hence, option 3 is the most appropriate answer.

Option 3 - Enzymes

Enzymes are biomolecules that catalyze. Enzymes bind temporarily to one or more of the reactants of the reaction they catalyze. In doing so, they lower the amount of activation energy needed and thus speed up the reaction

Option 1 – A

Mutation is a permanent change in the DNA sequence of a gene. Mutations in a gene's DNA sequence can alter the amino acid sequence of the protein encoded by the gene. The DNA sequence is interpreted in groups of three nucleotide bases, called codons. Each codon specifies a single amino acid in a protein.

Option 3 – Mitotic Cell Division

Mitosis is nuclear division plus cytokinesis, and produces two identical daughter cells during prophase, prometaphase, metaphase, anaphase, and telophase.

Option 3 – Genetic Engineering

Is a term that applies to the direct manipulation of an organism's genes. Genetic engineering uses the techniques of cloning and transformation to alter the structure and characteristics of genes directly.  Some examples are in improving crop technology, the manufacture of synthetic human insulin through the use of modified bacteria etc.

Incorrect Answers

Option 1 – Natural Selection: Natural selection is a process that results in the adaptation of an organism to its environment by means of selectively reproducing changes in its genotype, or genetic constitution. It is an environment determines which members of a species survive to reproduce and so pass on their genes to the next generation (survival of the fittest). The environmental effects lead to varying degrees of reproductive success among individuals of a population of organisms with different hereditary characters, or traits. The characters that inhibit reproductive success decrease in frequency from generation to generation. The resulting increase in the proportion of reproductively successful individuals usually enhances the adaptation of the population to its environment.


Option 2 - Asexual Production: Asexual reproduction is reproduction which does not involve meiosis, ploidy reduction, or fertilization. Only one parent is involved in asexual reproduction. Asexual reproduction may provide a secondary means of multiplying in organisms that ordinarily reproduce sexually.

Option 4 – Habitat modification: Habitat modification alters the structure of tropical host parasite food webs. It is the process by which a natural habitat is modified intentionally or unintentionally.