Principles of Inheritance and Variation Practice Questions
NEET · Biology · 986 free MCQs with instant results and detailed explanations.
986
Total
207
Easy
436
Medium
343
Hard
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Topics in Principles of Inheritance and Variation
Mutation
175
Sex Determination
171
Linkage and Recombination
168
Genetic Disorders
175
Chromosome Theory
170
Mendelian Genetics
127
Sample Questions from Principles of Inheritance and Variation
Here are 10 sample questions. Start a quiz to get randomized questions with scoring.
Q1
Easy
In a dihybrid cross, what is the expected phenotypic ratio for the offspring?
A.
1:1
B.
3:1
C.
9:3:3:1
D.
1:2:1
Show Answer & Explanation
Correct Answer: C
A dihybrid cross results in a phenotypic ratio of 9:3:3:1, indicating the combination of two traits with independent assortment.
Q2
Easy
If a pea plant with the genotype Tt is crossed with tt, what is the probability of obtaining a tall plant?
A.
0%
B.
25%
C.
50%
D.
75%
Show Answer & Explanation
Correct Answer: C
The cross Tt x tt produces a 1:1 ratio of tall (Tt) to short (tt) plants, resulting in a 50% chance of obtaining a tall plant.
Q3
Easy
Which of the following traits is controlled by multiple alleles?
A.
Height in pea plants
B.
Skin color in humans
C.
Seed shape in pea plants
D.
Eye color in Drosophila
Show Answer & Explanation
Correct Answer: B
Skin color in humans is influenced by multiple alleles, contributing to the variation seen in human pigmentation.
Q4
Medium
In a monohybrid cross between two heterozygous parents (Tt), what is the phenotypic ratio of the offspring?
A.
1:2:1
B.
3:1
C.
9:3:3:1
D.
1:1
Show Answer & Explanation
Correct Answer: B
The phenotypic ratio of a monohybrid cross between two heterozygous parents is 3:1, where 3 represent the dominant phenotype and 1 the recessive phenotype.
Q5
Medium
If a plant with the genotype AaBb is crossed with another plant of genotype Aabb, what proportion of the offspring will have the genotype AaBb?
A.
1/4
B.
1/2
C.
1/8
D.
3/8
Show Answer & Explanation
Correct Answer: A
The genotype AaBb will appear in 1 out of 4 offspring from this cross, according to the segregation of alleles.
Q6
Medium
What is the expected genotypic ratio in the offspring of a dihybrid cross of two heterozygous individuals (AaBb x AaBb)?
A.
1:1:1:1
B.
9:3:3:1
C.
1:2:1
D.
3:1
Show Answer & Explanation
Correct Answer: B
A dihybrid cross between two heterozygous parents results in a genotypic ratio of 9:3:3:1, representing the combinations of two traits.
Q7
Medium
In a test cross involving a pea plant with a dominant phenotype, what can be inferred if all offspring display the dominant phenotype?
A.
The parent is homozygous dominant.
B.
The parent is heterozygous.
C.
The parent is homozygous recessive.
D.
The result is inconclusive.
Show Answer & Explanation
Correct Answer: A
If all offspring display the dominant phenotype in a test cross, the parent must be homozygous dominant (TT).
Q8
Hard
In a certain plant, the allele for tallness (T) is dominant over the allele for shortness (t). What is the expected phenotypic ratio of the offspring from a cross between Tt and tt?
A.
1:1
B.
3:1
C.
2:1
D.
1:2
Show Answer & Explanation
Correct Answer: A
The cross Tt x tt gives offspring with phenotypes Tt (tall) and tt (short). The ratio of tall to short plants is 1:1.
Q9
Hard
In a dihybrid cross between two pea plants heterozygous for both traits (AaBb x AaBb), what is the expected phenotypic ratio of the offspring?
A.
9:3:3:1
B.
1:1:1:1
C.
3:1
D.
1:2:1
Show Answer & Explanation
Correct Answer: A
A dihybrid cross AaBb x AaBb results in a phenotypic ratio of 9:3:3:1 for dominant and recessive traits.
Q10
Hard
If a plant with the genotype AaBb produces gametes, what percentage of its gametes will be heterozygous for both traits?
A.
50%
B.
25%
C.
100%
D.
0%
Show Answer & Explanation
Correct Answer: B
The plant can produce four types of gametes: AB, Ab, aB, and ab. Only the Ab and aB gametes are heterozygous for both traits, making 2 out of 8 total (25%).
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Principles of Inheritance and Variation — NEET Biology Practice Questions Online
This page contains 986 practice MCQs for the chapter Principles of Inheritance and Variation in NEET Biology. The questions are organized by difficulty — 207 easy, 436 medium, 343 hard — so you can choose the right level for your preparation.
Every question includes a detailed explanation to help you understand the concept, not just memorize answers. Take a timed quiz to simulate exam conditions, or practice at your own pace with no time limit. This chapter covers 6 topics, giving you comprehensive coverage of the entire chapter.