Zoology

Yes, definitely you can apply for M.Sc. In Biotechnology after completing graduation in Zoology. Those who have
completed graduation in any biological subjects are eligible to apply for the exam. The degree must be passed from a recognised educational institution with a minimum of 50% marks. Most of the Universities offer admission to the course on the basis of entrance test. The candidate should perform well in the entrance test to get admission to the course. Certain colleges offer admission on the bases of the marks of the qualifying degree exam. Banaras Hindu University, Birsa Agriculture University, Calicut University, etc. Are some of the Universities that offer M.Sc. In Biotechnology. The candidate can also pursue the course from Jawaharlal Nehru University, Madurai Kamaraj University, etc.

Zoology or animal biology is the branch of biology that studies the animal kingdom, including the structure, embryology, evolution, classification, habits, and distribution of all animals, both living and extinct, and how they interact with their ecosystems. Whereas Microbiology is the study of microscopic organisms, such as bacteria, viruses, archaea, fungi and protozoa. This discipline includes fundamental research on the biochemistry, physiology, cell biology, ecology, evolution and clinical aspects of microorganisms, including the host response to these agents.
Microbiology has a very broad scope in India as well as abroad. If you have done microbiology, you have dairy industry knowledge , you have forensic knowledge , you have opportunity to be in education field , you have broad opportunities in food industry , medical industry like various biological production unit as well as Vaccine Production , you have broad scope in R & D field , You have better scope with Government.
Every industry has their Microbiologist who regularly performs tests on different products as well as effluents. If you choose Microbiology you can perform various medical tests which are performed in Laboratory. Thus, I would conclude that all the options I listed are open to the person with Microbiology degree, other than that, Bollywood also have some microbiologists such as the Queen of Hearts, Madhuri Dixit.