Principles of Inheritance and Variation is one of the highest-scoring chapters in NEET Biology. This set covers Mendel's laws and ratios, the test cross, incomplete dominance and codominance, multiple alleles, sex determination, linkage, pedigree patterns and chromosomal and Mendelian disorders, all based on the NCERT Class 12 text.
How to practise: read each question and tap the option you think is correct. You will see right away whether you got it, along with a short explanation, and your score is tracked at the bottom of the screen. This set has 15 questions.
Topics covered in this set
- Mendel's laws, monohybrid and dihybrid crosses
- Test cross
- Incomplete dominance, codominance and multiple alleles
- Sex determination in humans, insects and birds
- Linkage and recombination
- Mendelian and chromosomal disorders
NEET Biology MCQs with answers and explanations
Q1. What is the phenotypic ratio in the F2 generation of a monohybrid cross with complete dominance?
a) 9:3:3:1
b) 3:1
c) 1:2:1
d) 1:1
Q2. What is the phenotypic ratio in the F2 generation of Mendel's dihybrid cross?
a) 1:2:1
b) 3:1
c) 1:1:1:1
d) 9:3:3:1
Q3. A test cross is a cross between an organism with a dominant phenotype and:
a) A homozygous dominant parent
b) A heterozygous parent
c) Its own F1
d) A homozygous recessive parent
Q4. In snapdragon (Antirrhinum), crossing red and white flowered plants gives pink F1. What is the F2 phenotypic ratio?
a) 9:7
b) 1:1
c) 3:1
d) 1:2:1
Q5. A person with genotype IᴬIᴮ has blood group AB. This is an example of:
a) Incomplete dominance
b) Codominance
c) Polygenic inheritance
d) Epistasis
Q6. How many genotypes are possible for the human ABO blood group?
a) 4
b) 3
c) 9
d) 6
Q7. Which organism shows the XO type of sex determination?
a) Drosophila
b) Humans
c) Grasshopper
d) Birds
Q8. In birds, which sex is heterogametic?
a) Female
b) Male
c) Both
d) Neither
Q9. A carrier woman for haemophilia marries a normal man. What fraction of their sons is expected to be haemophilic?
a) 25%
b) 0%
c) 100%
d) 50%
Q10. What is the cause of sickle-cell anaemia?
a) Substitution of glutamic acid by valine at the sixth position of the β-globin chain
b) Lack of an enzyme
c) Deletion of the β-globin gene
d) Trisomy of chromosome 11
Q11. Phenylketonuria is inherited as:
a) Autosomal recessive
b) Y-linked
c) X-linked recessive
d) Autosomal dominant
Q12. What is the chromosomal cause of Down's syndrome?
a) Trisomy of chromosome 21
b) Trisomy of chromosome 18
c) XXY condition
d) Monosomy of the X chromosome
Q13. What is the karyotype of Turner's syndrome?
a) 47, +21
b) 47, XXX
c) 45, XO
d) 47, XXY
Q14. Who coined the term linkage and studied it in Drosophila?
a) Sutton and Boveri
b) Hugo de Vries
c) Gregor Mendel
d) T. H. Morgan
Q15. Which trait shows polygenic inheritance in humans?
a) Haemophilia
b) Skin colour
c) ABO blood group
d) Sickle-cell anaemia
Quick revision notes
- Monohybrid F2: 3:1 (genotype 1:2:1); dihybrid F2: 9:3:3:1.
- Incomplete dominance: 1:2:1 for both phenotype and genotype.
- ABO: codominance and multiple alleles, 6 genotypes, 4 phenotypes.
- XO grasshopper; ZW female birds; XY humans and Drosophila.
- Down 47,+21; Turner 45,XO; Klinefelter 47,XXY.
Frequently asked questions
Are these NEET previous year questions?
No. They are original practice questions based on the NCERT Class 12 chapter Principles of Inheritance and Variation.
How should I solve pedigree questions?
First decide whether the trait is dominant or recessive, then whether it is X-linked by checking whether affected mothers have affected sons and whether fathers pass it to sons.
Which NCERT chapters should I revise with this set?
Principles of Inheritance and Variation, followed by Molecular Basis of Inheritance.
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