Question

A cross done between a homozygous recessive and a heterozygous plant is called as
A. Monohybrid cross
B. Dihybrid cross
C. Test cross
D. Back cross

Answer 1

Hint: Gregor Mendel (1822 - 1884) , he is responsible for the law of governing inheritance of traits. Punnett square used to help solve genetics problems. Trait is any type of characteristics that can be passed from parent to offspring. Heredity is the passing of traits from parent to offspring. Genetics is the study of heredity.

Complete Answer:
- Genetic cross is a purposeful mating of two individuals leading in the combination of genetic materials in the offspring.
- Types of genetic crosses are monohybrid cross, dihybrid cross, test cross, back cross. Punnett squares allow geneticists to predict the possible genotype and phenotypes of spring.
- Monohybrid cross is the cross that examines the inheritance of only one specific trait.
- Dihybrid cross is the cross that examines the inheritance of only two different traits.

- Back cross is the mating of hybrid organisms (offspring of genetically unlike parents) with one of its parents or with an organism genetically alike to parent. Test cross is a cross between homozygous plants with recessive traits and a heterozygous plant. Test cross is a valuable tool in judging the genotype of the organisms in question. Mendel and his goal were to discover if the genotype in a homozygous (AA) or heterozygous dominant (Aa) plant.

Thus, the option (C) is correct.

Note: Test cross is a simple and easy method of discovering the true breed. Genotype is a gene combination for a trait (example RR, Rr, rr). Phenotype is the physical features resulting from a genotype. Example for monohybrid cross is flower colour. Example for Dihybrid cross is flower colour and plant height.