Science (English Medium) Class 12 - CBSE Question Bank Solutions for Biology

Draw a diagram of the microscopic structure of human sperm. Label the following parts in it and write their functions:

1. Acrosome
2. Nucleus
3. Middle piece

Why a transgenic animals so called?

Explain the role of transgenic animals in (i) Vaccine safety and (ii) Biological products with the help of an example each.

Draw a schematic sketch of pBR 322 plasmid and label the following in it:

(a) Any two restriction sites.

(b) Ori and rop genes.

(c) An antibiotic resistant gene.

The following is the illustration of the sequence of ovarian events (a − i) in a human female

(i) Identify the figure that illustrates ovulation and mention the stage of oogenesis it represents.

(ii) Name the ovarian hormone and the pituitary hormone that have caused the above mentioned event.

(iii) Explain the changes that occur in the uterus simultaneously in anticipation.

(iv) Write the difference between ‘c’ and ‘h’.

(v) Draw a labeled sketch of the structure of a human ovum prior to fertilization.

Explain the function of “anaerobic sludge digester” in a sewage treatment plant.

Distinguish between the roles of flocs and anaerobic sludge digesters in sewage treatments.

How are productivity, gross productivity, net primary productivity and secondary productivity interrelated ?

Explain the development of a secondary oocyte (ovum)  in a human female from the embryonic stage upto its ovulation. Name the hormones involved in this process.

How have transgenic animals proved to be beneficial in production of biological products?

How have transgenic animals proved to be beneficial in chemical safety testing?

Explain the process of sewage water treatment before it can be discharged into natural water bodies.

Male and female gametes are ______.

The process of release of the ovum from a mature follicle is called ______.

Ovulation is induced by a hormone called ______.

The fusion of the male and the female gametes is called ______.

Briefly describe the process of spermatogenesis.

Name the hormones involved in regulation of spermatogenesis.

Define spermiogenesis.

Define spermiation.