Human Reproduction — BIOLOGY STD 12 Science — Question

Gene therapy is an attempt to correct a genetic defect by providing a normal gene into the individual. By this the normal function can be restored. An alternate method would be to provide the gene product (protein/ enzyme) known as enzyme replacement therapy, which would also restore the function. Which in your opinion is a better option? Give reason for your answer.

Transplantation to save certain patients often fails due to rejection by the patient. What is transplantation? Which type of immune response is responsible for such rejections?

Vivipary automatically limits the number of offsprings in a litter. How?

With an example explain lattitude gradient, as a pattern of biodiversity.

Answer the following questions:
What are biopesticides? Give any two examples of their application.

Name the host plant and its part that Meloidegyne incognita infects. Explain the role of Agrobacterium in the production of dsRNA in the host plant.

During reproduction, the chromosome number (2n) reduces to half (n) in the gametes and again resume the original number (2n) in the offspring, what are the processes through which these events take place?

Write a short note on viability of seeds.###How long do the seeds remain alive after they are dispersed?

DNA separated from one cell, when introduced into another cell is able to bestow some of the properties of former to the latter. What is this change called in technical terms? Describe the experimental evidences which led to the discovery of the above phenomenon.

The diversity of plants and animals is not uniform throughout the world but shows a rather uneven distribution. Explain with example.