Molecular Basis of Inheritance Questions and Answers AP Inter 2nd Year Zoology Chapter 4

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Reviewing AP Inter 2nd Year Zoology Study Material Chapter 4 Molecular Basis of Inheritance Questions and Answers can help students prepare confidently for exams.

AP Inter 2nd Year Zoology 4th Lesson Molecular Basis of Inheritance Questions and Answers

IV. Very Short Answer Questions

Question 1.
What are VNTRs?
Answer:

  1. VNTRs (Variable Number of Tandem Repeats) are DNA sequences that act as important genetic markers.
  2. The number of VNTR repeats differs among individuals, making them useful in DNA fingerprinting.

Question 2.
List out any two applications of DNA fingerprinting technology.
Answer:
Applications of DNA Fingerprinting:

  1. Forensic investigations
  2. Medico-legal cases
  3. Pedigree analysis

Question 3.
What is DNA polymorphism?
Answer:

  1. DNA polymorphism refers to genetic variation caused by mutations.
  2. When an inheritable mutation occurs frequently within a population, it is termed DNA polymorphism.

Molecular Basis of Inheritance Questions and Answers AP Inter 2nd Year Zoology Chapter 4

V. Short Answer Questions

Question 1.
Write the salient features of the Human Genome Project (HGP).
Answer:
Important Features of the Human Genome Project:

  1. The human genome is composed of chromosomes containing nearly three billion nucleotide base pairs.
  2. An average human gene contains about 3000 base pairs, although gene sizes vary greatly. The largest known gene codes for dystrophin.
  3. The total number of genes in humans is estimated to be around 30,000, and about 99.9% of
    nucleotide sequences are identical among all humans.
  4. The functions of nearly 50% of the identified genes are still unknown.
  5. Less than 2% of the genome is involved in coding proteins.
  6. A major portion of the genome consists of repetitive DNA sequences.
  7. These repetitive sequences may not have direct coding functions but are important for understanding chromosome evolution and dynamics.
  8. Chromosome 1 contains the highest number of genes (2968), whereas the Y chromosome contains the fewest (231).
  9. Around 1.4 million SNPs (Single Nucleotide Polymorphisms) occur in humans and help in disease mapping and evolutionary studies.

Question 2.
Describe the steps involved in DNA fingerprinting technology.
Answer:
DNA Fingerprinting-Procedure:

  1. Collection of DNA: DNA is isolated from sources such as blood, saliva, semen, hair roots, or tissues. If needed, DNA is amplified using cloning techniques or PCR.
  2. Fragmentation of DNA: DNA is cut into smaller fragments at specific locations using restriction endonucleases.
  3. Separation of DNA Fragments: The DNA fragments are separated by agarose gel electrophoresis. Smaller fragments move faster and travel farther through the gel.
  4. Denaturation: The double-stranded DNA is converted into single strands using heat or alkaline chemicals.
  5. Blotting: DNA fragments are transferred from the gel onto a nylon membrane. This transfer process is known as Southern blotting.
  6. Hybridization with DNA Probes: Radioactively labelled DNA probes complementary to the target sequences are added. These probes bind to matching DNA fragments.
  7. Probe Hybridization: After binding occurs, excess probes are removed, leaving only DNA- probe hybrids on the membrane.
  8. Autoradiography and DNA Fingerprint Formation: The membrane exposed to photographic film. Radioactive signals produce characteristic bands that form the individual’s DNA fingerprint.

VI. Long Answer Questions

Question 1.
Why is the Human Genome Project called a mega project?
Answer:
The Human Genome Project (HGP) is regarded as a mega project because of its enormous scope, high expenditure, long duration, and the vast amount of genetic information it generated. It demanded worldwide cooperation, significant financial support, and sophisticated computational technologies.

The following points explain why it is considered a mega project:
1. Huge Number of Base Pairs: The human genome consists of nearly 3 × 109 base pairs, making it extremely large and complex. Identifying and sequencing every base pair across all chromosomes was an enormous scientific challenge unlike any previous genetic research.

2. Enormous Financial Investment: The project required substantial funding. If sequencing a single base pair cost about $3, the estimated expenditure for the entire project would have been approximately $9 billion. Such an extraordinary financial commitment makes it a true mega project.

3. Extended Time Period: Completing a project of this scale required careful planning and many years of work. Initiated in 1990, the Human Genome Project was successfully completed in 2003, taking nearly 13 years.

4. Massive Data Generation and Bioinformatics: The project produced an enormous volume of genetic data. If this information were printed, assuming each book contained 1,000 pages with 1,000 letters per page, nearly 3,300 books would be needed to store the genetic information from a single human cell. Managing, storing, and analyzing such data required advanced computer systems, leading to the development of the field of Bioinformatics.

5. Global and Multidisciplinary Collaboration: A project of this magnitude could not be accomplished by a single nation or institution. It involved international cooperation under the coordination of the U.S. Department of Energy and the National Institutes of Health (NIH), with major contributions from the United Kingdom, Japan, France, Germany, and China. Scientists from diverse fields, including biology, computer science, engineering, and mathematics, worked together to achieve its objectives.

6. Significant Scientific and Medical Impact: The Human Genome Project revolutionized biological and medical research. It enabled scientists to identify the genetic basis of numerous diseases, improved preventive healthcare, and supported the development of personalized medicine and pharmacogenomics, greatly benefiting human health and scientific advancement.

Molecular Basis of Inheritance Questions and Answers AP Inter 2nd Year Zoology Chapter 4

Question 2.
Write an essay on DNA Fingerprinting.
Answer:
1. DNA Fingerprinting: DNA fingerprinting is a technique used to identify individuals based on the unique pattern of their DNA. Since every person (except identical twins) possesses a distinct DNA profile, this method is highly reliable for identification.

  • DNA fingerprinting is also referred to as DNA typing or genetic fingerprinting.
  • It is extensively used in forensic investigations, paternity and maternity testing, and individual identification.
  • DNA samples can be collected from blood, saliva, semen, hair roots, tissues, bones, or other biological materials.
  • Although more than 99% of the nearly 3 billion base pairs in human DNA are identical, the remaining variations make each individual unique.
  • Except for identical twins, no two individuals possess the same DNA sequence.
  • These variable DNA regions are known as Restriction Fragment Length Polymorphisms (RFLPs) or Variable Number Tandem Repeats (VNTRs).
  • The pattern of VNTRs differs from one individual to another, making them useful for identification.
  • The DNA fingerprinting technique was developed by Sir Alec Jeffreys while studying the myoglobin gene.

2. Procedure of DNA Fingerprinting. DNA fingerprinting involves the following steps:

Isolation of DNA: DNA is extracted from biological samples such as blood, saliva, semen, hair roots, or tissues. If required, the extracted DNA is amplified using cloning or DNA amplification techniques.

Digestion of DNA: The isolated DNA is cut into smaller fragments at specific recognition sites using restriction endonuclease enzymes.

Separation of DNA Fragments by Gel Electrophoresis: The DNA fragments are loaded onto an agarose gel and subjected to an electric field. Smaller DNA fragments migrate faster and travel farther through the gel than larger fragments.

Denaturation of DNA: The double-stranded DNA is separated into single strands using alkaline chemicals or by heating.

Southern Blotting: The separated DNA fragments are transferred from the gel onto a nylon membrane by placing the membrane over the gel and allowing absorbent paper to draw the DNA onto it. This transfer process is known as Southern blotting.

Identification Using DNA Probes: Radioactively labelled DNA probes, which are complementary to specific DNA sequences, are added. These probes bind to the matching DNA fragments through hydrogen bonding.

3. Hybridisation with DNA Probe: After hybridisation, the excess probes are washed away. The nylon membrane containing the DNA-probe hybrids is then covered with photographic (X-ray) film.

4. Development of the DNA Fingerprint: The radioactive probes expose the photographic film, producing dark bands that correspond to specific DNA fragments. The unique arrangement of these bands forms the DNA fingerprint of an individual.

5. Applications of DNA Fingerprinting :

  • Forensic Science: Used to identify criminals and establish the identity of suspects.
  • Medico-Legal Cases: Helps determine biological relationships such as paternity and maternity.
  • Anthropological Research: Assists in studying human evolution, ancestry, and migration patterns.
  • Pedigree Analysis: Used to trace inheritance patterns across generations.
  • Taxonomy: Helps in studying phylogenetic relationships among organisms.
  • Wildlife Conservation: Assists in maintaining genetic records and conserving endangered species.

I. Multiple Choice Questions

Question 1.
Which chromosome in the human genome has the highest number of genes?
1. Chromosome 1
2. Chromosome 10
3. Chromosome X
4. Chromosome Y
Answer:
1. Chromosome 1

Question 2.
Expressed Sequence Tags (ESTs) refer to.
1. Novel DNA sequences
2. Genes expressed as RNA
3. Variable Number of Tandem Repeats
4. DNA polymorphism
Answer:
2. Genes expressed as RNA

Question 3.
DNA polymorphism forms the basis of
1. Genetic mapping
2. DNA fingerprinting
3. Both genetic mapping and DNA fingerprinting
4. Translation
Answer:
3. Both genetic mapping and DNA fingerprinting

Molecular Basis of Inheritance Questions and Answers AP Inter 2nd Year Zoology Chapter 4

Question 4.
Match the following List – I with List-II with reference to salient features of Human Genome.

List-IList – II
a) Chromosome Yi) 1.4 million locations
b) Single-base DNA differencesii) 3000 bases
c) Average geneiii) 231 genes
d) Codes for proteinsiv) Less than 2% of the genome

Choose the correct answer from the options given below.
1. a-ii, b-iii, c-i, d-iv
2. a-ii, b-i, c-iv, d-ii
3. a-iii, b-i, c-ii, d-iv
4. a-i, b-iv, c-ii, d-iii
Answer:
3. a-iii, b-i, c-ii, d-iv

Question 5.
The largest known human gene is located on
1. Chromosome 1
2. Chromosome X
3. Chromosome 2
4. Chromosome 21
Answer:
2. Chromosome X

Question 6.
Given below are two statements. One labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): Mutations in non – coding DNA sequences keep on accumulating generation after generation and form one of the basis of variability/ polymorphism.
Reason (R): Mutations in non – coding DNA sequences may not have any immediate effect/impact in an individual’s reproductive ability.
In the light of above statements, choose the most appropriate answer from the options
given below.
1. Both A and R are correct, and R is the correct explanation of A.
2. Both A and R are correct, but R is not the correct explanation of A.
3. A is not correct, but R is correct.
4. A is correct, but R is not correct.
Answer:
1. Both A and R are correct, and R is the correct explanation of A.

Question 7.
Given below are two statements.
Statement I: DNA fingerprinting is the basis of paternity testing in case of disputes.
Statement II: DNA polymorphisms are inheritable from parents to children.
In the light of above statements, choose the most appropriate answer from the options given below.
1. Both statement I and statement II are true.
2. Statement I is false, but statement II is true.
3. Statement I is true, but statement II is false.
4. Both statement I and statement II are false.
Answer:
1. Both statement I and statement II are true.

Question 8.
The sequence of chromosome 1 was completed only in
1. April, 2003
2. October, 1990
3. May, 2006
4. December, 2000
Answer:
3. May, 2006

Question 9.
Which of the following is incorrect w.r.t. satellite DNA?
1. These sequences normally do not code for any proteins
2. They form a large portion of human genome.
3. These sequences show high degree of polymorphism.
4. They cannot be used as identification tool in forensic applications.
Answer:
4. They cannot be used as identification tool in forensic applications.

Question 10.
In the technique of DNA fingerprinting, hybridized DNA fragments can be detected by,
1. Gel electrophoresis
2. Restriction endonucleases
3. Western blotting
4. Autoradiography
Answer:
4. Autoradiography

Molecular Basis of Inheritance Questions and Answers AP Inter 2nd Year Zoology Chapter 4

II. Fill in the Blanks

1. In HGP, the DNA fragments were sequenced using automated DNA sequencers that worked on the principle of a method developed by …………………………. .
Answer:
Frederick Sanger

2. Scientists have identified about ………………………. million locations where single base DNA differences occur in humans.
Answer:
1.4

3. Polymorphism (variation at genetic level) arises due to …………………….. .
Answer:
Mutations.

4. In simple terms, if an inheritable mutation is observed in a population at high frequency, it is referred to as ………………….. .
Answer:
DNA polymorphism

5. ………………………… per cent of base sequence among humans is the same.
Answer:
99.9

III. One Word Answer Questions

Question 1.
How many base pairs are present in the human genome?
Answer:
Approximately 3164.7 million base pairs

Question 2.
Who did initially developed the technique of DNA fingerprinting?
Answer:
Alec Jeffreys

Molecular Basis of Inheritance Questions and Answers AP Inter 2nd Year Zoology Chapter 4

Question 3.
Name the class of satellite DNA to which VNTR belongs.
Answer:
Mini-satellite DNA

Question 4.
Which sequences make up a very large portion of the human genome?
Answer:
Repeated DNA sequences

Question 5.
Name the vectors used for cloning DNA fragments during DNA sequencing.
Answer:
BAC (Bacterial Artificial Chromosome) and YAC (Yeast Artificial Chromosome)

Objective Questions

Question 1.
Human Genome Project (HGP) was launched in
1. 1985
2. 1990
3. 1995
4. 2000
Answer:
2. 1990

Question 2.
Human Genome Project is called a
1. Mini project
2. Micro project
3. Mega project
4. Pilot project
Answer:
3. Mega project

Question 3.
The human genome contains approximately
1. 3 × 106 base pairs
2. 3 × 108 base pairs
3. 3 × 109 base pairs
4. 3 × 1012 base pairs
Answer:
3. 3 × 109 base pairs

Question 4.
One of the main goals of HGP was to identify approximately
1. 2,000 – 5,000 genes
2. 10,000 – 15,000 genes
3. 20,000 – 25,000 genes
4. 50,000 – 60,000 genes
Answer:
3. 20,000 – 25,000 genes

Question 5.
Human Genome Project was completed in
1. 1998
2. 2000
3. 2003
4. 2006
Answer:
3. 2003

Molecular Basis of Inheritance Questions and Answers AP Inter 2nd Year Zoology Chapter 4

Question 6.
HGP was coordinated mainly by
1. WHO
2. U.S. Department of Energy and NIH
3. UNESCO
4. NASA
Answer:
2. U.S. Department of Energy and NIH

Question 7.
Bioinformatics mainly deals with
1. Protein synthesis
2. Data storage, retrieval, and analysis
3. Cell division
4. Photosynthesis
Answer:
2. Data storage, retrieval, and analysis

Question 8.
Expressed Sequence Tags (ESTs) represent
1. Non-coding DNA
2. Genes expressed as RNA
3. Satellite DNA
4. Introns
Answer:
2. Genes expressed as RNA

Question 9.
Sequence annotation refers to
1. DNA digestion
2. Assigning functions to DNA sequences
3. DNA replication
4. RNA translation
Answer:
2. Assigning functions to DNA sequences

Question 10.
DNA fragments during HGP were cloned using
1. Viruses only
2. BAC and YAC vectors
3. Plasmids only
4. Cosmids only
Answer:
2. BAC and YAC vectors

Question 11.
BAC stands for
1. Bacterial Artificial Chromosome
2. Basic Artificial Chromosome
3. Biological Artificial Chromosome
4. Bacterial Active Chromosome
Answer:
1. Bacterial Artificial Chromosome

Question 12.
YAC stands for
1. Yeast Artificial Chromosome
2. Young Artificial Chromosome
3. Yeast Active Chromosome
4. Yellow Artificial Chromosome
Answer:
1. Yeast Artificial Chromosome

Molecular Basis of Inheritance Questions and Answers AP Inter 2nd Year Zoology Chapter 4

Question 13.
Automated DNA sequencing was based on the method developed by
1. Watson
2. Crick
3. Frederick Sanger
4. Mendel
Answer:
3. Frederick Sanger

Question 14.
Alignment of DNA sequences was mainly done using
1. Manual calculation
2. Computer programs
3. Microscope
4. Centrifuge
Answer:
2. Computer programs

Question 15.
The sequence of chromosome 1 was completed in
1. 2003
2. 2004
3. 2005
4. 2006
Answer:
4. 2006

Question 16.
Human genome contains
1. 3164.7 million base pairs
2. 3000 million base pairs
3. 2000 million base pairs
4. 5000 million base pairs
Answer:
1. 3164.7 million base pairs

Question 17.
Average size of a human gene is about
1. 300 bp
2. 3000 bp
3. 30,000 bp
4. 3 lakh bp
Answer:
2. 3000 bp

Question 18.
Largest known human gene is
1. Hemoglobin
2. Insulin
3. Dystrophin
4. Collagen
Answer:
3. Dystrophin

Question 19.
Almost identical nucleotide sequence among humans is
1. 90%
2. 95%
3. 98%
4. 99.9%
Answer:
4. 99.9%

Question 20.
More than …………………………. of discovered genes have unknown functions.
1. 10%
2. 25%
3. 50%
4. 90%
Answer:
3. 50%

Molecular Basis of Inheritance Questions and Answers AP Inter 2nd Year Zoology Chapter 4

Question 21.
Less than …………………………. of human genome codes for proteins.
1. 2%
2. 5%
3. 10%
4. 20%
Answer:
1. 2%

Question 22.
Most of the human genome consists of
1. Protein-coding genes
2. Repeated sequences
3. Ribosomal genes
4. tRNA genes
Answer:
2. Repeated sequences

Question 23.
The chromosome having the maximum number of genes is
1. Chromosome 21
2. Chromosome 1
3. Chromosome X
4. Chromosome Y
Answer:
2. Chromosome 1

Question 24.
The chromosome having the fewest genes is
1. Chromosome 18
2. Chromosome 10
3. Chromosome Y
4. Chromosome X
Answer:
3. Chromosome Y

Question 25.
SNP stands for
1. Single Nucleotide Polymorphism
2. Satellite Nuclear Protein
3. Sequence Number Pattern
4. Single Nuclear Protein
Answer:
1. Single Nucleotide Polymorphism

Question 26.
Scientists identified about ……………………………. million SNP locations in humans.
1. 0.5
2. 1.4
3. 2.5
4. 3.0
Answer:
2. 1.4

Question 27.
DNA fingerprinting mainly compares
1. RNA molecules
2. Protein sequences
3. DNA polymorphism
4. Lipids
Answer:
3. DNA polymorphism

Question 28.
DNA fingerprinting is based on
1. Translation
2. DNA polymorphism
3. Replication
4. Mutation only
Answer:
2. DNA polymorphism

Question 29.
Repetitive DNA is also called
1. Satellite DNA
2. Messenger DNA
3. Coding DNA
4. Template DNA
Answer:
1. Satellite DNA

Question 30.
Satellite DNA is separated by
1. PCR
2. Gel electrophoresis
3. Density gradient centrifugation
4. Chromatography
Answer:
3. Density gradient centrifugation

Question 31.
DNA fingerprinting is highly useful in
1. Blood grouping only
2. Forensic science
3. Plant breeding only
4. Tissue culture
Answer:
2. Forensic science

Question 32.
DNA fingerprinting is widely used in
1. Paternity testing
2. Weather forecasting
3. Blood circulation studies
4. Photosynthesis
Answer:
1. Paternity testing

Molecular Basis of Inheritance Questions and Answers AP Inter 2nd Year Zoology Chapter 4

Question 33.
DNA polymorphism mainly arises due to
1. Nutrition
2. Mutation
3. Pollution
4. Temperature
Answer:
2. Mutation

Question 34.
DNA polymorphism is more common in
1. Coding DNA
2. Non-coding DNA
3. rRNA only
4. tRNA only
Answer:
2. Non-coding DNA

Question 35.
DNA fingerprinting technique was developed by
1. Frederick Sanger
2. Watson
3. Alec Jeffreys
4. Mendel
Answer:
3. Alec Jeffreys

Question 36.
Alec Jeffreys used ……………………… as a probe.
1. mRNA
2. Satellite DNA
3. Plasmid DNA
4. tRNA
Answer:
2. Satellite DNA

Question 37.
VNTR stands for
1. Variable Number of Tandem Repeats
2. Variable Nucleotide Tandem Region
3. Viral Number Tandem Repeat
4. Variable Nuclear Tandem Repeat
Answer:
1. Variable Number of Tandem Repeats

Question 38.
VNTR belongs to
1. Microsatellite
2. Minisatellite
3. Macrosatellite
4. Megasatellite
Answer:
2. Minisatellite

Question 39.
DNA digestion in fingerprinting is carried out by
1. DNA polymerase
2. Restriction endonucleases
3. Ligase
4. Helicase
Answer:
2. Restriction endonucleases

Question 40.
DNA fragments are separated by
1. PCR
2. Electrophoresis
3. Centrifugation
4. Hybridization
Answer:
2. Electrophoresis

Question 41.
Transfer of DNA fragments to a membrane is called
1. Translation
2. Blotting
3. Replication
4. Annealing
Answer:
2. Blotting

Molecular Basis of Inheritance Questions and Answers AP Inter 2nd Year Zoology Chapter 4

Question 42.
Hybridized DNA fragments are detected by
1. Centrifugation
2. Electrophoresis
3. Autoradiography
4. PCR
Answer:
3. Autoradiography