Science (English Medium) इयत्ता १२ - CBSE Question Bank Solutions

Write two major functions of testis.

Describe the structure of a seminiferous tubule.

What are the major components of seminal plasma?

What are the major functions of male accessory ducts and glands?

Identify True/False statement. Correct false statement to make it true.

Androgens are produced by Sertoli cells.

Identify True/False statement. Correct false statement to make it true.

Spermatozoa get nutrition from Sertoli cells.

Identify True/False statement. Correct the false statement to make it true.

Leydig cells are found in the ovary.

Identify True/False statement. Correct false statement to make it true.

Leydig cells synthesise androgens.

Two heterozygous parents are crossed. If the two loci are linked, what would be the distribution of phenotypic features in the F₁ generation for a dihybrid cross?

Group the following as nitrogenous bases and nucleosides:

Adenine, Cytidine, Thymine, Guanosine, Uracil and Cytosine.

If a double stranded DNA has 20 per cent of cytosine, calculate the per cent of adenine in the DNA.

Which property of DNA double helix led Watson and Crick to hypothesise semi-conservative mode of DNA replication? Explain.

Bacteria cannot be seen with the naked eyes, but these can be seen with the help of a microscope. If you have to carry a sample from your home to your biology laboratory to demonstrate the presence of microbes with the help of a microscope, which sample would you carry and why?

Give examples to prove that microbes release gases during metabolism.

In which food would you find lactic acid bacteria? Mention some of their useful applications.

Name some traditional Indian foods made of wheat, rice and Bengal gram (or their products) which involve use of microbes.

Find out the role of microbes in the following:

Single cell protein (SCP)

What would be the molar concentration of human DNA in a human cell?

Distinguish between plasmid DNA and chromosomal DNA.

Distinguish between RNA and DNA.