RBSE Solutions For Class 12 Biology Chapter 37: Mutation | Textbook Important Questions & Answers

RBSE Class 12 Biology Chapter 37- Mutation. In this chapter, students can learn in detail about mutation, types of mutation, factors affecting the rate of mutation, structural changes in chromosomes, genetic code, main features of the human genome, DNA fingerprinting, cloning, types of cloning, applications of cloning and mechanisms of cloning. It also deals with gene mutations, chromosomal mutation, features of gene mutation, numerical changes in chromosomes, deletion, translocation, Human genome project and a lot more.

These important questions help students to perform exceptionally well in their exams. By practising these important questions, students can analyze their preparation, get a thorough knowledge about all the important terminologies and perform their best in the examinations.

RBSE Solutions for Class 12 are the best study material for both class assignments and other board examinations. By practising these important questions, students can gain deep knowledge about the topics explained in this chapter and also help them to be well prepared for their upcoming examinations.

RBSE Class 12 Biology Chapter 37 Important Questions

RBSE Biology Chapter 37: MCQ Type Questions

Q.1. What is a mutation?

(a) Any kind of variations

(b) The changes in the cytoplasm of the cell

(c) Permanent and Hereditary changes in the DNA

(d) The changes in the genetic material of the DNA

Sol: (c) Permanent and Hereditary changes in the DNA.

Q.2. How many numbers of nucleotides pairs are found in humans?

(a) 3 lakhs

(b) 30 lakhs

(c) 3 Crores

(d) 3 Billions

Sol: (d) 3 Billions.

Q.3. What is a genome?

(a) The diploid set of chromosomes

(b) The number of chromosomes found in the zygote

(c) The total number of chromosomes in an organism.

(d) Sum of a haploid set of chromosomes and extrachromosomal material of the cell

Sol: (d) Sum of a haploid set of chromosomes and extrachromosomal material of the cell.

Q.4. What is the basis of DNA fingerprinting?

(a) Self copy of a DNA

(b) Fingerprint of DNA

(c) DNA fingerprints of two individuals are not the same.

(d) None of the above

Sol: (c) DNA fingerprints of two individuals are not the same.

Q.5. Which of the following techniques is used to produce Dolly?

(a) From cloning

(b) From tissue culture

(c) From normal hybridization

(d) From normal sexual reproduction

Sol: (a) From cloning.

Q.6. If adenine is replaced from guanine then the mutation is _________.

(a) Transcription

(b) Transition

(c) Transversion

(d) Frameshift mutation

Sol: (b) Transition.

Q.7. Genetic code includes _________.

(a) 2 Bases and 64 Codons

(b) 2 Bases and 32 Codons

(c) 3 Nucleotide bases and 64 codons

(d) 3 Nucleotide bases and 18 codons

Sol: (c) 3 Nucleotide bases and 64 codons

Q.8. Polyploidy can be produced by _________.

(a) X Rays

(b) Colchicines

(c) Gamma Rays

(d) None of the above

Sol: (b) Colchicines.

Q.9. How many types of numerical changes are there in chromosomes?

(a) Two

(b) Three

(c) Four

(d) None of the above

Sol: (a) Two.

Q.10. In which year was the human genome project (HGP) started?

(a) 1991

(b) 1999

(c) 1980

(d) 1990

Sol: (d) 1990

RBSE Biology Chapter 37: Short and Long Answer Type Questions.

Q.1.Which international agencies initiated the human genome project (HGP)?

Sol: The human genome project (HGP) was started by the National Institute of Health and Department of Energy, America in the year 1990.

Q.2.What is VNTR?

Sol: VNTR refers to the Variable Number of Tandem Repeat. They are the smaller segments of the nucleotides which are repetitive.

Q.3. What is nondisjunction?

Sol: The failure of a pair of homologous chromosomes to separate in meiosis – I, failure of sister chromatids to separate during the meiosis – II are called the non-disjunction.

Q.4. What is called the stage in which the number of chromosomes changes?

Sol: The stage through which the changes in a chromosomes number occurs is called polyploidy.

Q.5. What is mutagen?

Sol: The factors which produce mutations are called the mutagens.

Mutagens can be classified into 3 types based on their origin. They are as follows:

  1. Physical mutagens: These include X-rays, gamma rays, alpha particles and ultraviolet radiations
  2. Chemical mutagens: These include elements such as arsenic, nickel, chromium and some organic compounds like benzene.
  3. Biological mutagens: These include biological mutagens involve transposons and viruses and other bacteria such as Helicobacter pylori.

Q.6.What is the probe?

Sol: The probe is a fragment of DNA or RNA of variable length which can be radioactively or fluorescently labelled.

Q.7. Which scientist discovered the Honolulu technique and where?

Sol: The Honolulu technique was developed by Teruhiko Wakayama and Ryuzo Vanagimachi at the University of Hawaii in the year 1998. This technique is mainly used for the production of an animal clone.

Q.8. What are Genes?

Sol: Genes are functional units of heredity as they are made of DNA. It is a subdivision of DNA and is mainly passed down from parents to their children. Genes are generally organized and packaged in components called chromosomes. A gene is located on a chromosome and is coded with heredity information.

Q.9. What is the genetic code?

Sol: The genetic code is a dictionary that corresponds with the sequence of nucleotides and sequence of the Amino Acids.

Q.10. What is a mutation? What are the causes of mutation?

Sol: The phenomenon of change occurring within the DNA sequence is called a mutation. The mutation is caused by both the internal and external factors including UV rays, smoking, etc. The other factors, which causes the mutation are the DNA variation in an organism and it is the recombination.

Q.11.What is gene mutation?

Sol: The gene mutation can be defined as the mismatch combination of nitrogenous bases which occurs in a daughter DNA.

Q.12.What are deletion and duplication?

Sol: Deletion

It is referred to a common kind of chromosomal aberration. The deletion is the loss of the chromosomal segment. The terminal deletion refers to the loss of a segment from one or the other end of the chromosome. Intercalary of the interstitial deletion involves an intercalary segment of the chromosome with the reunion of the terminal segments.


In some rare cases, a few genes are present more than once in a chromosome. i.e. one segment repeats twice in a chromosome. This is called duplication.

Q.13. What are the internal and external causes of mutations?

Sol: The internal causes of mutation are:

The mutations occur when the DNA fails to copy accurately. During cell division, the DNA makes a copy of its own. Sometimes, the copy of the DNA is not perfect and this slight difference from the original DNA is called a mutation.

The external causes of mutation are:

When the DNA is exposed to certain radiations or chemicals, it results in the breakdown of the DNA. The ultraviolet radiations cause the thymine dimers to break resulting in a mutated DNA.

Q.14. What is Translation? Name any disease caused due to the change in a single base pair of the gene.

Sol: Translation is the process of conversion of nucleic acid information into amino acids. Sickle cell anaemia is the disease caused due to the change in a single base pair of the gene.

Q.15.What is the point mutation?

Sol: Point mutation is the mutation that affects a single nucleotide or nucleic acid. It commonly occurs when one base is substituted for the other. It may also result due to insertion and deletion of a single base pair.

Q.16. Give any two examples of point mutation.

Sol: Examples of point mutation are:

Cystic fibrosis, which is caused due to the deletion of three nucleotides in the CFTR gene. In this, amino acid phenylalanine is lost which causes misfolding of the protein.

Sickle cell anaemia, which is caused by a single point mutation in the beta haemoglobin gene. This results in the conversion of GAG codon into GUG that encodes amino acid valine.

Q.17. Draw a neat labelled diagram of the genetic code and the mutation.

Genetic code and the Mutation

Q.18. What is the genome?

Sol: A genome is the complete set of genetic information of an organism. It contains all the instructions for creating and maintaining life. Every living organism consists of its own genome.

A human genome consists of nuclear and mitochondrial DNA. There are 20,000 genes in the human body, which make up 1-5% of our genome. The DNA between the genes is involved in gene regulation.

Q.19.What is euploidy?

Sol: Euploidy is also called polyploidy. The total set of a number of chromosomes in a cell or an organism is called monoploidy. The gaining of one or more complete sets of chromosomes is called euploidy or polyploidy. There are two different types of polyploidy:

  1. Autopolyploidy.
  2. Allopolyploidy.

Q.20. What is the silent mutation and missense mutation?


Silent mutation

A variation or changes caused within the nucleotide bases sequences, which constitutes DNA, without a subsequent change in the amino acids or the function of the overall protein.

Missense mutation

The type of point mutation, which commonly occurs when two amino acids of different groups are placed within the produced protein, other than its original is called the missense mutation.

Q.21. What is the significance of DNA Cloning?

Sol: Importance of DNA Cloning

The DNA molecules produced through the cloning techniques are used for many purposes which include:

  1. DNA cloning can be used to make proteins such as insulin with biomedical techniques.
  2. It is used to develop recombinant versions of the non-functional gene to understand the functioning of the normal gene. This is applied in gene therapies also.
  3. It helps to analyse the effect of the mutation on a particular gene.
  4. Dolly, a female sheep, was the first mammal to be cloned from adult somatic cells by the process of nuclear transfer.
  5. Cat, deer, ox, mule, dog, rabbit and rat are the animals that have been cloned.

Q.22.What is DNA Cloning? What is the purpose of DNA Cloning?

Sol: DNA cloning is a molecular biology technique which is used for the creation of exact copies or clones of a particular gene or DNA. DNA cloning is used to create a large number of copies of genes or a DNA segment.

Q.23.What are the goals of the human genome project?

Sol: The goals of the human genome project include:

  1. Sequencing the entire genome.
  2. Optimization of the data analysis.
  3. Identification of the complete human genome.
  4. Creating genome sequence databases to store the data.
  5. Taking care of the legal, ethical and social issues that the project may pose.

Q.24.What is a chromosomal aberration?

Sol: The arrangement of a gene is changed due to the changes in the structure of a chromosome, which is called the chromosomal aberration. The different methods of the chromosomal aberration are :

  1. Deletion
  2. Duplication
  3. Inversion
  4. Translocation

Q.25. Brief out the different types of gene mutation?

Sol: The gene mutation can be defined as the mismatch combination of nitrogenous bases which occurs in a daughter DNA.

Types of gene mutation

Gene mutation is of following types:


In this type of gene mutation, one purine base is replaced by another purine base or one pyrimidine by another pyrimidine base.



In this type of gene mutation, one purine base is replaced by another pyrimidine base or in the same way the pyrimidine base is replaced by other purine bases.


Frame shift

In this gene mutation, the frame of reading of complete genes and codes of genes is changed due to loss or gaining of the one nucleotide.



Due to the replacement of the nucleotide (base), the changes in the genetic code results in the addition to other amino acids. Sickle cell haemoglobin like disease can be caused by the changed protein.


If the genetic code changes in the halfway, it becomes a stop codon and there is no more protein formation.


Here, the protein synthesis stops because UAA is a nonsense code.


In this type of gene mutation, there are no changes in any of the phenotypes by the changes in the nucleotide.

Q.26. What are the factors affecting or inducing Gene mutations?

Sol: The substances or the factors which cause mutation in any cell are called the mutagens. Mutagens can be of the following types:

  1. Normal ultraviolet rays.
  2. Alpha (ɑ) Beta (β) Gamma (𝛄) rays emitted from radioactive substances.
  3. Neutrons and protons
  4. Chemical mutagens, such as mustard gas and the gases of actinomycin D.
  5. Increased temperature increases the rate of the mutations.

Q.27. What are mutations? Draw a neat labelled diagram of the external effects of mutations.

Sol: Mutation is the change that occurs in our DNA sequence due to environmental factors such as UV light, or due to the mistakes caused when the DNA is copied.

External effects of mutations

When the DNA is exposed to certain chemicals and other radiations, it results in the breakdown of DNA. The ultraviolet radiations cause the thymine dimers to break resulting in a mutated DNA.

The below diagram explains the effects of mutations by the external factors.

External effects of Mutations

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