Punnett Square & F₂ Generation — NEET Biology
✅ Asked in NEET 2021The production of gametes by the parents, formation of zygotes, the F₁ and F₂ plants, can be understood from a diagram called: (NEET 2021)
The production of gametes by the parents, formation of zygotes, the F₁ and F₂ plants, can be understood from a diagram called: (NEET 2021)
Answer & NCERT explanation
Correct answer: D — Punnett square
A Punnett square is a diagrammatic representation used to predict the genotypes and phenotypes of offspring from a genetic cross. It shows gamete formation by parents, zygote formation, and the resulting F₁ and F₂ generations. This tool was developed by Reginald Punnett and is fundamental to understanding Mendelian genetics as explained in NCERT Chapter 5.
Read more NCERT concept on the PYQ
The Punnett Square shows the parental tall TT (male) and dwarf tt (female) plants, the gametes produced by them and, the F₁ Tt progeny. The F₁ plants of genotype Tt are self-pollinated. The symbols ♀ and ♂ are used to denote the female (eggs) and male (pollen) of the F₂ generation, respectively. The F₁ plant of the genotype Tt when self-pollinated, produces gametes of the genotype T and t in equal proportion. When fertilisation takes place, the pollen grains of genotype T have a 50 per cent chance to pollinate eggs of the genotype T, as well as of genotype t. Also pollen grains of genotype t have a 50 per cent chance of pollinating eggs of genotype T, as well as of
The Punnett Square predicts offspring genotypes when F₁ heterozygotes (Tt) self-pollinate. Each gamete has 50% chance of carrying T or t allele, so F₂ shows 1 TT : 2 Tt : 1 tt ratio (genotypic) and 3 tall : 1 dwarf (phenotypic). Students often confuse F₁ and F₂ generations or miscalculate gamete probabilities. Remember: equal proportions of gametes from heterozygote produce a 3:1 phenotypic ratio in F₂. This foundational concept tests understanding of segregation and probability in crosses—essential for predicting inheritance patterns in NEET genetics problems.
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Which chapter is this from?
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