The Inheritance and Variation MCQ with Answers is a valuable practice resource designed to simplify the complex concepts of genetics, this MCQ on Principle of Inheritance and Variation quiz allows you to assess your understanding of inheritance and genetic variations.
Principle of Inheritance and Variation MCQ provides immediate answers along with detailed explanations of the concepts. This way, you can learn from your mistakes and strengthen your knowledge base effectively. So, don't hesitate to give it a try, learn from the explanations provided, and establish a solid foundation for success in NEET Biology.
These MCQs are prepared based on the latest exam pattern. By solving these NCERT Class 12 Biology Principles of Inheritance and Variation MCQ with answers, students can gauge their preparation level effectively.
Principle of Inheritance and Variation MCQ
1. The phenomenon of pleiotropism refers to:
a) The inheritance of two or more traits from a single gene
b) The interaction of multiple genes to produce a single trait
c) The expression of multiple traits from a single gene
d) The variation in traits due to environmental factors
Answer: c) The expression of multiple traits from a single gene
2. Which of the following statements are correct about Klinefelter's Syndrome?
a) It is caused by the presence of an additional X chromosome in males (XXY).
b) Individuals with Klinefelter's Syndrome are typically sterile.
c) Symptoms may include reduced facial and body hair, gynecomastia, and infertility.
d) All of the above.
Answer: d) All of the above.
3. What is the main difference between inheritance and variation?
a) Inheritance refers to the passing of traits from parents to offspring, while variation refers to the differences in traits among individuals of the same species.
b) Inheritance refers to changes in traits over time, while variation refers to the stable transmission of traits from one generation to the next.
c) Inheritance refers to environmental factors influencing traits, while variation refers to genetic factors.
d) Inheritance and variation are synonymous terms.
Answer: a) Inheritance refers to the passing of traits from parents to offspring, while variation refers to the differences in traits among individuals of the same species.
4. What is the first law of inheritance?
a) Law of dominance
b) Law of segregation
c) Law of independent assortment
d) Law of inheritance
Answer: b) Law of segregation
5. A heterozygous pea plant with violet flowers was crossed with a homozygous pea plant with white flowers. Violet is dominant over white. Which one of the following represents the expected combinations among 40 progenies formed?
a) 20 violet : 20 white
b) 30 violet : 10 white
c) 10 violet : 30 white
d) 40 violet : 0 white
Answer: b) 30 violet : 10 white
6. Select the correct statements about sickle cell anemia:
a) It is caused by a mutation in the hemoglobin gene.
b) Individuals with sickle cell anemia may experience pain, anemia, and organ damage.
c) It is an autosomal recessive genetic disorder.
d) All of the above.
Answer: d) All of the above.
7. Select the correct statement/s with respect to the mechanism of sex determination in Grasshopper.
a) Males are heterogametic (XY) and females are homogametic (XX).
b) Males are homogametic (XX) and females are heterogametic (XY).
c) Sex determination is influenced by environmental factors.
d) Grasshoppers do not exhibit genetic sex determination.
Answer: a) Males are heterogametic (XY) and females are homogametic (XX).
8. Color blindness is an _______ linked recessive trait.
a) X-linked
b) Y-linked
c) Autosomal
d) Dominant
Answer: a) X-linked
9. Why is hemophilia a disease that is more commonly seen in males?
a) Because the gene responsible for hemophilia is located on the Y chromosome.
b) Because males have two copies of the gene responsible for hemophilia.
c) Because females have two X chromosomes and males have only one.
d) Because females are more resistant to the symptoms of hemophilia.
Answer: c) Because females have two X chromosomes and males have only one.
10. Which of the following statements about aneuploidy is false?
a) Aneuploidy involves an abnormal number of chromosomes.
b) Aneuploidy can result from errors in meiosis.
c) Aneuploidy always results in death before birth.
d) Aneuploidy can lead to developmental disorders.
Answer: c) Aneuploidy always results in death before birth.
11. Which of the following types of mutations occurs the most frequently?
a) Point mutations
b) Insertion mutations
c) Deletion mutations
d) Silent mutations
Answer: a) Point mutations
12. ZZ/ZW type of sex determination is seen in:
a) Mammals
b) Birds
c) Reptiles
d) Insects
Answer: b) Birds
13. A cross between two tall plants resulted in offspring having a few dwarf plants. What would be the genotypes of both parents?
a) TT and tt
b) Tt and Tt
c) TT and TT
d) tt and tt
Answer: b) Tt and Tt
14. In a monohybrid cross between two heterozygous individuals, the percentage of pure homozygous individuals obtained in the F1 generation will be:
a) 0%
b) 25%
c) 50%
d) 75%
Answer: c) 50%
15. Which of the following is incorrect regarding ZW–ZZ type of sex determination?
a) Females are heterogametic (ZW) and males are homogametic (ZZ)
b) Found in some species of reptiles and fish
c) The female determines the sex of the offspring
d) Found in mammals
Answer: d) Found in mammals
16. ABO blood grouping in human beings cites the example of:
a) Multiple alleles and co-dominance
b) Incomplete dominance
c) Pleiotropy
d) Polygenic inheritance
Answer: a) Multiple alleles and co-dominance
17. Which three scientists independently rediscovered Mendel’s work?
a) Watson, Crick, Franklin
b) Hershey, Chase, Griffith
c) Avery, MacLeod, McCarty
d) de Vries, Correns, von Tschermak
Answer: d) de Vries, Correns, von Tschermak
18. Chromosomal theory of inheritance was given by:
a) Thomas Hunt Morgan
b) Gregor Mendel
c) Alfred Hershey
d) Frederick Griffith
Answer: a) Thomas Hunt Morgan
19. Genes located very close to one another on the same chromosome tend to be transmitted together and are called:
a) Linked genes
b) Homologous genes
c) Independent genes
d) Recombinant genes
Answer: a) Linked genes
20. This abnormality occurs due to monosomy (2n – 1); the individual has 2n = 45 chromosomes with a 44 + XO genotype.
a) Turner syndrome
b) Down syndrome
c) Klinefelter syndrome
d) Edwards syndrome
Answer: a) Turner syndrome
Principle of Inheritance and Variation MCQ Question NO. and Explanations:
1. The phenomenon of pleiotropism refers to:
Answer: c) The expression of multiple traits from a single gene
Explanation: Pleiotropism occurs when a single gene affects multiple, seemingly unrelated phenotypic traits. This can happen because genes often have multiple effects on an organism's development or physiology.
2. Which of the following statements are correct about Klinefelter's Syndrome?
Answer: d) All of the above.
Explanation: Klinefelter's Syndrome is a genetic disorder characterized by the presence of an extra X chromosome in males (XXY). Individuals with this syndrome may experience symptoms such as reduced facial and body hair, gynecomastia (enlarged breasts), and infertility.
3. What is the main difference between inheritance and variation?
Answer: a) Inheritance refers to the passing of traits from parents to offspring, while variation refers to the differences in traits among individuals of the same species.
Explanation: Inheritance refers to the transmission of genetic traits from parents to offspring, while variation refers to the differences in traits that exist among individuals of the same species due to genetic and environmental factors.
4. What is the first law of inheritance?
Answer: b) Law of segregation
Explanation: The first law of inheritance, also known as the Law of Segregation, states that alleles for a trait segregate during gamete formation, so that each gamete receives only one allele for each gene.
5. A heterozygous pea plant with violet flowers was crossed with a homozygous pea plant with white flowers. Violet is dominant over white. Which one of the following represents the expected combinations among 40 progenies formed?
Answer: b) 30 violet : 10 white
Explanation: In this cross, the genotype of the heterozygous parent is Vv (where V represents the violet allele and v represents the white allele), and the genotype of the homozygous parent is vv. Therefore, according to Mendel's principles, the expected phenotypic ratio among the progenies would be 3 violet : 1 white.
6. Select the correct statements about sickle cell anemia:
Answer: d) All of the above.
Explanation: Sickle cell anemia is caused by a mutation in the hemoglobin gene, resulting in the production of abnormal hemoglobin molecules. Individuals with sickle cell anemia may experience symptoms such as pain, anemia, and organ damage. It is inherited as an autosomal recessive genetic disorder.
7. Select the correct statement/s with respect to the mechanism of sex determination in Grasshopper.
Answer: a) Males are heterogametic (XY) and females are homogametic (XX).
Explanation: In grasshoppers, males have heteromorphic sex chromosomes (XY), where the Y chromosome determines maleness. Females have homomorphic sex chromosomes (XX).
8. Color blindness is an _______ linked recessive trait.
Answer: a) X-linked
Explanation: Color blindness is typically inherited as an X-linked recessive trait, meaning that the gene responsible for color vision is located on the X chromosome. As a result, males are more commonly affected by color blindness than females.
9. Why is hemophilia a disease that is more commonly seen in males?
Answer: c) Because females have two X chromosomes and males have only one.
Explanation: Hemophilia is an X-linked recessive disorder, meaning that the gene for hemophilia is located on the X chromosome. Since males have only one X chromosome, they are more likely to express the disorder if they inherit the affected gene.
10. Which of the following statements about aneuploidy is false?
Answer: c) Aneuploidy always results in death before birth.
Explanation: Aneuploidy is a condition characterized by an abnormal number of chromosomes. While some forms of aneuploidy can be lethal, not all instances result in death before birth. Some individuals with aneuploidy can survive and may exhibit developmental disorders.
11. Which of the following types of mutations occurs the most frequently?
Answer: a) Point mutations
Explanation: Point mutations, involving changes in a single nucleotide base, occur most frequently among different types of mutations. They can include substitutions, insertions, or deletions of a single nucleotide.
12. ZZ/ZW type of sex determination is seen in:
Answer: b) Birds
Explanation: Birds typically exhibit ZZ/ZW sex determination, where males have two similar sex chromosomes (ZZ) and females have two different sex chromosomes (ZW). This is in contrast to mammals, where males are XY and females are XX.
13. A cross between two tall plants resulted in offspring having a few dwarf plants. What would be the genotypes of both parents?
Answer: b) Tt and Tt
Explanation: In this scenario, both parents must be heterozygous (Tt) for the tall trait to produce dwarf offspring. If one parent was homozygous tall (TT) and the other homozygous dwarf (tt), all offspring would be tall.
14. In a monohybrid cross between two heterozygous individuals, the percentage of pure homozygous individuals obtained in the F1 generation will be:
Answer: c) 50%
Explanation: In a monohybrid cross between heterozygous individuals (Tt x Tt), 50% of the offspring will be heterozygous (Tt), 25% will be homozygous dominant (TT), and 25% will be homozygous recessive (tt).
15. Which of the following is incorrect regarding ZW–ZZ type of sex determination?
Answer: d) Found in mammals
Explanation: The ZW-ZZ sex determination system is found in certain groups of animals, such as birds, some fish, and some insects. It is not found in mammals, where sex determination is typically based on the presence of XY chromosomes.
16. ABO blood grouping in human beings cites the example of:
Answer: a) Multiple alleles and co-dominance
Explanation: ABO blood grouping in humans is determined by multiple alleles (IA, IB, i) and exhibits co-dominance, where both alleles are fully expressed in heterozygous individuals.
17. Which three scientists independently rediscovered Mendel’s work?
Answer: d) de Vries, Correns, von Tschermak
Explanation: Hugo de Vries, Carl Correns, and Erich von Tschermak are credited with independently rediscovering Gregor Mendel's laws of inheritance in the early 20th century.
18. Chromosomal theory of inheritance was given by:
Answer: a) Thomas Hunt Morgan
Explanation: Thomas Hunt Morgan proposed the chromosomal theory of inheritance, which states that genes are located on chromosomes and that the behavior of chromosomes during meiosis and fertilization accounts for inheritance patterns.
19. Genes located very close to one another on the same chromosome tend to be transmitted together and are called:
Answer: a) Linked genes
Explanation: Genes located close together on the same chromosome tend to be inherited together as a result of genetic linkage. This phenomenon is called linkage, and such genes are referred to as linked genes.
20. This abnormality occurs due to monosomy (2n – 1); the individual has 2n = 45 chromosomes with a 44 + XO genotype.
Answer: a) Turner syndrome
Explanation: Turner syndrome is a genetic disorder that occurs in females and is characterized by the presence of only one X chromosome (XO) instead of the typical two (XX). This condition arises due to monosomy, where one chromosome is missing.
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