Question

The production of gametes by the parents, the formation of zygotes, and the F₁ and F₂ plants, can be understood from a diagram called :

• A. Net square
• B. Bullet square
• C. Punch square
• D. Punnett square

Answer 1

The Correct Option is D

The question is about understanding a diagram used in genetics to predict the genotypes of offspring from a particular cross or breeding experiment.

The correct answer to the question is the Punnett square.

The Punnett square is a square diagram that is used in genetics to predict the genotypes of a particular cross or breeding experiment. This tool allows us to visualize the way alleles of genes segregate and combine during sexual reproduction.

• Step 1: Understanding How Gametes Combine - During sexual reproduction, each parent contributes one allele for a trait, randomly, from their pair of alleles. The Punnett square helps visualize this combination process by showing all possible combinations of parental alleles.
• Step 2: Formation of Zygotes - The combinations shown in the Punnett square are the potential genotypes of the offspring or zygotes resulting from this cross.
• Step 3: Analyze the Resulting Generations - By examining the Punnett square, one can predict the genotypes and phenotypes of the F₁ (first filial) and F₂ (second filial) generations.

Here is an example diagram of a Punnett square for a monohybrid cross between two heterozygous parents:

In this diagram, each box represents a possible genotype for the offspring. For example, if looking at a trait governed by two alleles 'A' (dominant) and 'a' (recessive), a Punnett square of a cross between Aa x Aa yields offspring with genotypes in the ratio 1:2:1 (1 AA, 2 Aa, 1 aa), which also explains the phenotypic ratio for the trait if 'A' is dominant over 'a'.

This explanation makes it clear why the correct answer is the Punnett square and helps you understand how to interpret genetic information through this diagrammatic approach.