For MSc Entrances you have to follow a syllabi which is based on the examination you are appearing for. As most of the Central universities don't have any rigorous syllabi for the examination so you have to focus on the some of the important crux subjects. This are:

1.cell cycle

2.transport through plasma membrane

3.Simple idea of vesicles trafficking ER

4.E coli division related questions

Genetics and mol BIOLOGY

1.GTCA structures

2.A B Z type of DNA

3.syndromes and aberrations

4.lac operon analytical approach

Ecology

1.Succession

2.Pyramids

Physiology

1.endocrone system

2.digestion

3.rthyms

Biochemistry complete

Apart from this you should also focus on the previous year problem solving which will provide you a more important basis of preparation. If you have sufficient time then you can follow your UG syllabus rigorously.

To know more about Zoology as a career visit the link below:

https://www.careers360.com/courses/zoology-course

I hope this answer helps. All the very best for your future endeavors!