CSS past paper

CSS Zoology Past Paper 2025

CSS Zoology 2025 carries 100 marks over 3 hours. It has 7 questions.

Years

How to attempt: Attempt ONLY FOUR questions from PART-II. ALL questions carry EQUAL marks.

Question 1 (Part I) is the paper's MCQs, which are not reproduced here.

Q. 2
Differentiate between enzymes, co-enzymes, and co-factors in a biological cell. Describe with a flow chart which enzymes/co-enzymes take part in glycolysis and Kreb’s Cycle.
(20)
Q. 3
Explain the transcription and processing of mRNA in the nucleus. Describe in detail the roles of mRNA, tRNA, and rRNA in polypeptide synthesis.
(20)
Q. 4
Explain with diagrams the structure, synthesis, and functions of thyroid hormones. Describe hypo-and-hyper-thyroidism in detail.
(20)
Q. 5
Differentiate between blood, plasma, and serum. Explain the various types and sub-types of blood cells in mammals. What is immunity? Explain the roles of different types of lymphocytes in immunity.
(20)
Q. 6
Discuss the economic and medical importance of ticks and mites of order Acari to human well-being.
(20)
Q. 7
What are the advantages of migration of birds? What are the major migratory routes of birds? How birds navigate?
(20)
Q. 8
Write short notes on any TWO of the following: (10 each)
(20)
- (a)
  Mechanism of action of protein hormones
  (10)
- (b)
  Leishmaniasis in human
  (10)
- (c)
  Types of feathers in birds
  (10)

Part-II is to be attempted on the separate Answer Book.
Attempt ONLY FOUR questions from PART-II. ALL questions carry EQUAL marks.
All the parts (if any) of each Question must be attempted at one place instead of at different places.
Write Q. No. in the Answer Book in accordance with Q. No. in the Q.Paper.
No Page/Space be left blank between the answers. All the blank pages of Answer Book must be crossed.
Extra attempt of any question or any part of the question will not be considered.