MEDIUM
12th CBSE
IMPORTANT
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How does a test cross help in identifying the genotype of the organism? Explain.

Important Questions on Principles of Inheritance and Variations

MEDIUM
12th CBSE
IMPORTANT
TRUEMAN'S ELEMENTARY Biology VOL. II For XII Class of 10+2>Chapter 5 - Principles of Inheritance and Variations>TEST QUESTIONS>Q 8
When a tall pea plant was self bred, it produced one-fourth of the progeny as dwarf. Explain with the help of a cross.
MEDIUM
12th CBSE
IMPORTANT
TRUEMAN'S ELEMENTARY Biology VOL. II For XII Class of 10+2>Chapter 5 - Principles of Inheritance and Variations>TEST QUESTIONS>Q 9
Why are F2 Phenotypic and genotypic ratios are the same in a cross between red-flowered snapdragon and white-flowered snapdragon plants? Explain with the help of a cross.
MEDIUM
12th CBSE
IMPORTANT
TRUEMAN'S ELEMENTARY Biology VOL. II For XII Class of 10+2>Chapter 5 - Principles of Inheritance and Variations>TEST QUESTIONS>Q 10
A relevant portion of β- chain of haemoglobin of a normal human is
Val - His - Leu - Thr - Pro - Glu - Glu
  1      2      3       4       5       6     7
The codon for this sixth amino acid is GAG. It mutates to GAA due to mutation 'A' and GUG due to mutation 'B'. Haemoglobin structure did not change as a result of mutation 'A' but mutation 'B' led to sickle cell shaped RBCs. Explain giving reasons how could mutation 'B' changed the haemoglobin structure and not mutation 'A'.
MEDIUM
12th CBSE
IMPORTANT
TRUEMAN'S ELEMENTARY Biology VOL. II For XII Class of 10+2>Chapter 5 - Principles of Inheritance and Variations>TEST QUESTIONS>Q 11
A cross between a red flower-bearing plant and a white flower-bearing plant of Antirrhinum produced all plant having pink flowers. Work out a cross to explain how this is possible.
MEDIUM
12th CBSE
IMPORTANT
TRUEMAN'S ELEMENTARY Biology VOL. II For XII Class of 10+2>Chapter 5 - Principles of Inheritance and Variations>TEST QUESTIONS>Q 12
In a typical monohybrid cross, the F2 generation is written as 3:1 for phenotype but expressed as 1:2:1 for genotype. Explain with the help of an example.
MEDIUM
12th CBSE
IMPORTANT
TRUEMAN'S ELEMENTARY Biology VOL. II For XII Class of 10+2>Chapter 5 - Principles of Inheritance and Variations>TEST QUESTIONS>Q 13
Work out a cross to find the genotype of a tall pea plant. Name the type of cross.
MEDIUM
12th CBSE
IMPORTANT
TRUEMAN'S ELEMENTARY Biology VOL. II For XII Class of 10+2>Chapter 5 - Principles of Inheritance and Variations>TEST QUESTIONS>Q 14
How does gene I control, ABO blood groups in humans? Write the effect of the gene on the structure of red blood cells
MEDIUM
12th CBSE
IMPORTANT
TRUEMAN'S ELEMENTARY Biology VOL. II For XII Class of 10+2>Chapter 5 - Principles of Inheritance and Variations>TEST QUESTIONS>Q 15

Write the type of sex determination mechanism of the following cross. Give an example of this type.

Female XX and male XO