Genetics MCQ For NEET Biology With Explanation, Practice Now

What is Genetics?

Genetics is the branch of biology that studies how traits are passed from one generation to another. It explains how genes work, how DNA and RNA function, and how mutations lead to variations. This subject is important for understanding evolution, genetic diseases, and biotechnology applications.

Genetics Important MCQs with Explanations

Practicing MCQs on genetics helps in better understanding of inheritance, mutations, and genetic disorders. These questions test the concepts covered in the NEET syllabus and improve problem-solving skills for the exam.

Q1. What is the degree by which progeny differ from their parents?

1. Mutation 
2. Inheritance
3. Variation
4. Mendelism

Answer: (3) Variation

Explanation: Variation refers to the degree by which progeny differ from their parents. It arises due to genetic recombination, mutation, and environmental influences, leading to differences in traits among individuals.

 Q2. Assertion (A): Mendel used true-breeding pea lines for artificial pollination experiments for his genetic studies.

Reason (R): For several generations, a true-breeding line shows the stable trait inheritance and expression.

1.  Both Assertion and Reason are true and Reason is the correct explanation of Assertion.
2. Both Assertion and Reason are true but Reason is not the correct explanation of Assertion.
3. Assertion is true but Reason is false.
4. Assertion is false but Reason is true.

Answer: (1) Both Assertion and Reason are true and Reason is the correct explanation of Assertion.

Explanation: Mendel used true-breeding pea lines because they consistently exhibited stable trait inheritance over generations. This ensured reliable experimental results, making Reason the correct explanation for the Assertion.

 Q3. Incorrect statement among the following is:

1. Mendel was first to consider results of hybridization in terms of single traits.
2. Mendel compared his experimental proportions with mathematical models.
3. Mendel’s experiments laid the foundation for modern genetics.
4. Mendel was the first person to perform hybridization experiments.

Answer: (4) Mendel was the first person to perform hybridization experiments.

Explanation: While Mendel was the first to analyze hybridization using mathematical models and single traits, hybridization experiments had been performed before him. Therefore, the statement that Mendel was the first to perform hybridization experiments is incorrect.

 Q4. A monohybrid cross is the one in which:

1. only a single plant in involved for the experiment.
2. a single pair of contrasting characters is considered for the genetic results.
3. a hybrid is crossed to a homozygous.
4. none of these.

Answer: (2) a single pair of contrasting characters is considered for the genetic results.

Explanation: A monohybrid cross considers only one pair of contrasting traits (e.g., tall vs. short plants) to study inheritance patterns, following Mendel’s first law of inheritance.

 Q5. A cross is made between the two organisms both of which have a genetic make up of Bb for a particular trait, and two offsprings are produced. The first offspring exhibit the dominant trait. What is the probability that the second offspring will exhibit the recessive trait?

1. 100
2. 1/4
3. Zero
4. ¾

Answer: (2) 1/4

Explanation: A cross between Bb × Bb results in offspring with a 3:1 phenotypic ratio, meaning 1/4 of the offspring will show the recessive trait (bb). Since each offspring’s probability is independent, the second offspring has a 1/4 chance of exhibiting the recessive trait.

 Q6. Originally, genetic inheritance was thought to be a

function of the blending of traits from the two parents.

Which exception to Mendel’s rules is an example of

blending?

1.  Polygenic inheritance
2.  Incomplete dominance
3. Codominance
4. Pleiotropism

Answer: (2) Incomplete dominance

Explanation: Incomplete dominance is an exception to Mendel’s rules where heterozygous offspring exhibit a blend of parental traits (e.g., red and white flowers producing pink flowers), deviating from the typical dominant-recessive inheritance.

 Q7. Mendel’s law of independent assortment holds good for genes situated on the -

1. Non homologous chromosomes
2. Homologous chromosomes
3. Extra nuclear genetic element
4.  Same chromosome

Answer: (2) Homologous chromosomes

Explanation: Mendel’s law of independent assortment states that genes on non-homologous chromosomes assort independently during gamete formation, ensuring genetic variation in offspring.

 Q8. Chromosomal theory of inheritance is a combination of:

1. knowledge of chromosomal segregation with Mendelian principle.
2. knowledge of dihybrid cross with motion of chromosome.
3. knowledge of Law of dominance with chromosomal appearance.
4. knowledge of classical genetics with modern molecular biology.

Answer: (1) knowledge of chromosomal segregation with Mendelian principle.

Explanation: The chromosomal theory of inheritance integrates Mendelian principles with the understanding of chromosomal segregation, explaining how genes are inherited through chromosomes.

 Q9. The theory that genetic material in living organisms is contained within chromosomes is known as:

1. the organic chromosomal theory.
2. the chromosomal theory of inheritance.
3. Mendel’s first law.
4. Mendel’s second law.

Answer: (2) the chromosomal theory of inheritance.

Explanation: The chromosomal theory of inheritance states that genetic material is carried on chromosomes, providing a structural basis for Mendel’s observations and explaining gene transmission from parents to offspring.

 Q10. Linkage and recombination frequencies have been used to generate:

1. solutions for global warming.
2. genetic maps.
3. genetic networks.
4. mutation maps.

Answer: (2) genetic maps.

Explanation: Genetic maps are created using linkage and recombination frequencies, which help in determining the relative positions of genes on a chromosome, aiding in genome studies.

 Q11. Assertion (A): Alfred Sturtevant developed the concept of genetic mapping.

Reason (R): The farther apart two genes are on a chromosome, the more likely a crossover event will occur between them during meiosis.

1.  Both Assertion and Reason are true and Reason is the correct explanation of Assertion.
2. Both Assertion and Reason are true but Reason is not the correct explanation of Assertion.
3. Assertion is true but Reason is false.
4. Assertion is false but Reason is true.

Answer: (2) Both Assertion and Reason are true but Reason is not the correct explanation of Assertion.

Explanation: Alfred Sturtevant introduced genetic mapping, but while gene distance affects recombination frequency, this does not directly explain the concept of genetic mapping itself. Therefore, the assertion and reason are true, but the reason does not fully explain the assertion.

 Q12. What concept do the following sentences explain?

(i) During spermatogenesis, two types of gametes are produced. 50 per cent of the sperm produced carry the X-chromosome and the rest 50 per cent has Y-chromosome.

(ii) Females produce only one type of ovum with an X-chromosome.

(iii) Genetic makeup of the sperm determines the sex of the child.

1. Sex Determination in Grasshopper
2. Sex Determination in Honey bees
3. Sex Determination in Birds
4. Sex Determination in Humans and Drosophila

Answer: (4) Sex Determination in Humans and Drosophila

Explanation: The sex determination system in humans and Drosophila is based on the XY mechanism, where males produce two types of gametes (X and Y sperm), and females always produce X-bearing ova. The sperm determines the sex of the offspring.

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