Medicneet Logo
NEET 2023 Phase 1 · BiologyPrevious Year Question

The phenomenon of pleiotropism refers to

Answer: (C) a single gene affecting multiple phenotypic expression.. Answer: (C) a single gene affecting multiple phenotypic expression.

  1. A.presence of several alleles of a single gene controlling a single crossover.
  2. B.presences of two alleles, each of the two genes controlling a single trait.
  3. C.a single gene affecting multiple phenotypic expression.✓
  4. D.more than two genes affecting a single character.

Correct Answer

(C) a single gene affecting multiple phenotypic expression.

Solution & Explanation

Answer: (C) a single gene affecting multiple phenotypic expression. Solution: Pleiotropy (pleiotropism) is the phenomenon where a single gene exhibits multiple phenotypic expressions, usually by acting on several steps of a metabolic pathway. NCERT gives phenylketonuria as an example. The other options describe multiple alleles, dihybrid traits, or polygenic inheritance, not pleiotropy. NCERT Reference: NCERT Class XII, Ch 4, p.69, lines 25-27: "There are however instances where a single gene can exhibit multiple phenotypic expression. Such a gene is called a pleiotropic gene."

🎯
43,000+ questions in हिंदी & English · one-tap toggle
Practice NEET 2023 Phase 1 Biology — free, with instant solutions
43,000+ NEET questions solved step-by-step, chapter-wise, in the MedicNEET app.
📚Practice all NEET Biology PYQs chapter-wise →💡Don't get it? Learn the Principles of Inheritance and Variation concepts →
← Biology Q22Biology Q24 →

More NEET PYQ solutions

BiolWhich one of the following is an example of ex-situ conservation?BiolWhich of the following is an example of a zygomorphic flower? (NEET 2025)BiolWhich of the following is an example of actinomorphic flower? (NEET 2024)BiolIn the seeds of cereals, the outer covering of endosperm separates the embryo by a protein-rich layer called : (NEET 2025)BiolGiven below are two statements: Statement I : In a floral formula the symbol [percentage/division-type symbol] stands for zygomorphic nature of the flower, and G with a bar above it stands for inferior ovary. Statement II : In a floral formula the symbol [same symbol] stands for actinomorphic nature of the flower and G with a bar below it stands for superior ovary. In the light of the above statements, choose the correct answer from the options given below: (NEET 2025)BiolMatch List I with List II: List I — A. Scutellum; B. Non-albuminous seed; C. Epiblast; D. Perisperm. List II — I. Persistent nucellus; II. Cotyledon of Monocot seed; III. Groundnut; IV. Rudimentary cotyledon. Choose the option with all correct matches. (NEET 2025)BiolGiven below are the stages in the life cycle of pteridophytes. Arrange the following stages in the correct sequence. A. Prothallus stage B. Meiosis in spore mother cells C. Fertilisation D. Formation of archegonia and antheridia in gametophyte. E. Transfer of antherozoids to the archegonia in presence of water. Choose the correct answer from the options given below:BiolThe correct sequence of events in the life cycle of bryophytes is A. Fusion of antherozoid with egg. B. Attachment of gametophyte to substratum. C. Reduction division, to produce haploid spores. D. Formation of sporophyte. E. Release of antherozoids into water. Choose the correct answer from the options given below:
More: All NEET 2023 Phase 1 Biology PYQs · NEET Biology PYQs · All NEET PYQs · Previous year papers