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Test Cross MCQ - NEET Practice Questions with Answers

Edited By admin | Updated on Sep 18, 2023 18:34 AM | #NEET

Quick Facts

  • Test Cross is considered one of the most asked concept.

  • 17 Questions around this concept.

Solve by difficulty

The genotype of a plant showing the dominant phenotype can be determined by:

Test cross in plants or in Drosophila involves crossing

Match the terms in Column I with their description in Column II and choose the correct option:

Column I

Column II

(a)    Dominance

(i)    Many genes govern a single character

(b)    Codominance

(ii)    In a heterozygous organism only one
allele expresses itself

(c)    Pleiotropy

(iii)    In a heterozygous organism both alleles
express themselves fully

(d)    Polygenic inheritance

(iv)    A single gene influences
many characters

Codes:

(a)    (b)    (c)    (d)

 

A cross in which an organism showing a dominant phenotype is crossed with the recessive parent to know its genotype is called :

Concepts Covered - 1

Test Cross
  • From what we have learnt,  it is clear that though the genotypic ratios can be calculated using mathematical probability, but simply looking at the phenotype of a dominant trait, it is not possible to know the genotypic composition. 
  • Therefore, a test cross is performed between phenotypically dominant plant (whose genotype is unknown) and a recessive plant (whose genotype is obviously homozygous recessive).
  • Result:
    • If the dominant-expressing organism is a homozygote, then all F1 offspring will be heterozygotes expressing the dominant trait.
    • If the dominant expressing organism is a heterozygote, the F1 offspring will exhibit a 1:1 ratio of heterozygous and recessive homozygotes.

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Test Cross

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