This section focuses on numerical, probability-based, and cross-calculation problems related to Mendelian genetics and heredity. It is designed for Class 11–12 students, NEET aspirants, and undergraduate learners to strengthen their ability to apply inheritance laws using logical and mathematical reasoning.
In this section, you will practice:
Numerical problems based on monohybrid and dihybrid crosses
Calculation of genotype and phenotype ratios
Probability-based questions in inheritance patterns
Test cross and back cross numerical problems
Data-based questions on Mendelian ratios and deviations
NCERT-aligned numerical questions and exam-oriented practice sets
The content is structured to improve step-by-step problem solving, enhance accuracy in ratio and probability calculations, and help students confidently handle numerical and cross-based questions in school examinations, NEET, and undergraduate assessments.
Develop speed, precision, and confidence in solving numerical applications related to Mendelian genetics and heredity through systematic practice.
Q. If a plant with genotype AaBb is crossed with another AaBb plant, what fraction of the offspring will be homozygous recessive for both traits?
A.
1/16
B.
1/4
C.
3/16
D.
9/16
Solution
The fraction of offspring that are homozygous recessive (aabb) from the cross AaBb x AaBb is 1/16.
Q. If a trait is controlled by a single gene with two alleles, what is the maximum number of different genotypes possible in a population?
A.
1
B.
2
C.
3
D.
4
Solution
For a single gene with two alleles, the maximum number of different genotypes possible is 3: homozygous dominant, heterozygous, and homozygous recessive.
Q. In a cross between two pea plants, one with round seeds (R) and one with wrinkled seeds (r), what is the phenotype of the F1 generation if round is dominant?
A.
Round
B.
Wrinkled
C.
Both
D.
Neither
Solution
The phenotype of the F1 generation will be round seeds since round (R) is dominant over wrinkled (r).
Q. In a test cross, an individual with an unknown genotype is crossed with a homozygous recessive individual. What is the purpose of this cross?
A.
To determine the dominant allele
B.
To determine the recessive allele
C.
To determine the genotype of the unknown
D.
To determine the phenotype of the offspring
Solution
The purpose of a test cross is to determine the genotype of an individual with a dominant phenotype by crossing it with a homozygous recessive individual.
Correct Answer:
C
— To determine the genotype of the unknown
