Prepare for your upcoming TNPSC exam? TNPSC Biology Genetics Quiz featuring carefully selected multiple-choice questions based on important genetics concepts. This quiz covers heredity, genes, DNA, chromosomes, mutations, and genetic disorders commonly asked in TNPSC General Science and other competitive examinations. Attempt the quiz to evaluate your knowledge and strengthen your Biology preparation.
TNPSC Biology Genetics Quiz 1 – Detailed Explanations
The TNPSC Biology Genetics Quiz explanations below help you understand important genetics concepts in a simple and exam-oriented manner for Each Questions. Learn about genes, heredity, DNA, chromosomes, dominant and recessive traits, and other essential topics that frequently appear in TNPSC General Science examinations.
Q1. Who is known as the father of genetics?
Gregor Mendel is known as the Father of Genetics because his experiments on pea plants established the fundamental principles of heredity. He demonstrated how traits are inherited from one generation to the next through dominant and recessive factors, now known as genes. His discoveries laid the foundation for modern genetics and are an important topic in TNPSC Biology.
Key Points:
- Conducted experiments using pea plants.
- Introduced the laws of inheritance.
- Explained dominant and recessive traits.
- Regarded as the Father of Genetics.
Real-Life Example:
Children inheriting eye colour or blood group from their parents is an example of Mendel’s principles of heredity.
Answer: Gregor Mendel
Q2. What is a gene?
A gene is the basic unit of heredity found on chromosomes. It is a segment of DNA that carries instructions for inherited traits such as eye colour, height, and blood group. Genes pass genetic information from parents to offspring and play a vital role in growth, development, and body functions.
Key Points:
- Gene is the basic unit of heredity.
- Located on chromosomes.
- Made up of DNA.
- Controls inherited characteristics.
Real-Life Example:
A child inheriting curly hair or dimples from a parent is due to genes.
Answer: A unit of heredity
Q3. Where are genes located?
Genes are located on chromosomes inside the nucleus of a cell. A gene is a segment of DNA that contains instructions for inherited traits and helps control the growth, development, and functioning of living organisms. Since chromosomes are found within the nucleus, genes are also present there. Understanding the location of genes is an important topic in TNPSC Biology Genetics.
Key Points:
- Genes are segments of DNA.
- Genes are arranged on chromosomes.
- Chromosomes are located inside the nucleus.
- The nucleus stores the genetic information of the cell.
Real-Life Example:
Traits such as eye colour, blood group, and hair type are inherited through genes located on chromosomes in the nucleus.
Answer: Nucleus
Q4. What carries genetic information?
DNA (Deoxyribonucleic Acid) is the molecule that carries genetic information in almost all living organisms. It contains the instructions needed for growth, development, reproduction, and normal cell functions. DNA is passed from parents to offspring, making it the foundation of heredity and an essential topic in TNPSC Biology.
Key Points:
- DNA stands for Deoxyribonucleic Acid.
- DNA stores hereditary information.
- Genes are segments of DNA.
- DNA is located on chromosomes inside the nucleus.
Real-Life Example:
A child inherits characteristics such as eye colour and blood group because DNA carries genetic information from parents.
Answer: DNA
Q5. What is heredity?
Heredity is the process by which characteristics are passed from parents to their offspring through genes. These inherited traits include physical features, blood group, and certain genetic conditions. Heredity explains why children often resemble their parents and forms the foundation of genetics.
Key Points:
- Heredity is the transmission of traits from parents to offspring.
- Genes carry hereditary information.
- Inherited traits can be physical or physiological.
- Gregor Mendel explained the basic principles of heredity.
Real-Life Example:
A child inheriting eye colour or blood group from their parents is an example of heredity.
Answer: Transmission of traits
Q6. What are chromosomes made of?
Chromosomes are composed of DNA and proteins called histones. DNA stores genetic information, while proteins help package and organize DNA inside the nucleus. Together, they ensure that hereditary information is accurately stored and passed on during cell division.
Key Points:
- Chromosomes are made of DNA and proteins.
- Histone proteins help package DNA.
- Chromosomes contain genes.
- They are located inside the nucleus of the cell.
Real-Life Example:
During cell division, chromosomes ensure that each new cell receives the correct genetic information.
Answer: DNA and protein
Q7. How many chromosomes are present in human body cells?
Human body cells contain 46 chromosomes, arranged in 23 pairs. Each parent contributes 23 chromosomes to the child, resulting in a complete set of 46 chromosomes. These chromosomes carry genes responsible for inherited traits and normal body functions.
Key Points:
- Human body cells contain 46 chromosomes.
- Chromosomes are arranged in 23 pairs.
- Each parent contributes 23 chromosomes.
- The 23rd pair determines the sex of an individual.
Real-Life Example:
A child inherits 23 chromosomes from the mother and 23 from the father, making a total of 46 chromosomes.
Answer: 46
Q8. Which trait is dominant?
A dominant trait is a characteristic that is expressed even when only one copy of the dominant gene is present. It masks the expression of a recessive trait and appears in the organism’s observable characteristics. Dominant traits were first explained by Gregor Mendel through his pea plant experiments.
Key Points:
- A dominant trait is expressed with one dominant allele.
- It masks the effect of a recessive trait.
- Dominant alleles are represented by capital letters.
- Dominant traits appear in the first generation of offspring.
Real-Life Example:
If brown eye colour is dominant over blue eye colour, a person with one brown-eye allele and one blue-eye allele will have brown eyes.
Answer: Trait that is always expressed
Q9. Which trait is recessive?
A recessive trait is expressed only when an individual inherits two recessive alleles for a particular characteristic. If a dominant allele is present, the recessive trait remains hidden. Recessive traits become visible only in the absence of a dominant allele.
Key Points:
- A recessive trait requires two recessive alleles.
- It remains hidden when a dominant allele is present.
- Recessive alleles are represented by lowercase letters.
- Mendel identified recessive traits through pea plant experiments.
Real-Life Example:
Blue eye colour is a recessive trait and appears only when both parents pass on the recessive allele.
Answer: Expressed only when both genes are the same
Q10. What is the shape of DNA?
DNA has a double helix structure, which resembles a twisted ladder. This unique structure allows DNA to store, replicate, and transmit genetic information accurately from one generation to the next. The double helix model was proposed by James Watson and Francis Crick.
Key Points:
- DNA has a double helix structure.
- It consists of two complementary strands.
- DNA stores and transmits genetic information.
- The double helix model was proposed by Watson and Crick.
Real-Life Example:
During cell division, the double helix unwinds and copies itself so that each new cell receives identical genetic information.
Answer: Double helix
Q11. What is a mutation?
A mutation is a sudden change in the DNA sequence or genetic material of an organism. Mutations may occur naturally during cell division or due to environmental factors such as radiation and certain chemicals. While some mutations are harmless, others can lead to inherited disorders or changes in an organism’s characteristics.
Key Points:
- A mutation is a change in genetic material.
- It occurs in the DNA sequence.
- Mutations may be beneficial, harmful, or neutral.
- Some mutations are inherited by future generations.
Real-Life Example:
Certain inherited disorders, such as sickle cell anemia, are caused by mutations in specific genes.
Answer: Change in genetic material
Q12. What determines the sex of a child?
The sex of a child is determined by the father because the father’s sperm carries either an X chromosome or a Y chromosome, while the mother’s egg always carries an X chromosome. If an X-bearing sperm fertilizes the egg, the child is female (XX). If a Y-bearing sperm fertilizes the egg, the child is male (XY).
Key Points:
- The mother always contributes an X chromosome.
- The father contributes either an X or a Y chromosome.
- XX results in a female child.
- XY results in a male child.
Real-Life Example:
The sex of every child depends on whether the fertilizing sperm carries an X or a Y chromosome.
Answer: Father
Q13. Which chromosome pair determines sex?
In humans, the 23rd pair of chromosomes is known as the sex chromosomes. This pair determines whether an individual is male or female. Females have two X chromosomes (XX), while males have one X and one Y chromosome (XY).
Key Points:
- Humans have 23 pairs of chromosomes.
- The 23rd pair is the sex chromosome pair.
- XX represents females.
- XY represents males.
Real-Life Example:
Doctors can identify the sex chromosome pair through chromosome analysis to study genetic conditions.
Answer: 23rd pair
Q14. What is a phenotype?
A phenotype refers to the observable physical and biological characteristics of an organism. These traits result from the interaction between an individual’s genes and the environment. Examples include height, eye colour, skin colour, and blood group.
Key Points:
- Phenotype means observable characteristics.
- It is influenced by both genes and the environment.
- Physical appearance is part of the phenotype.
- Individuals with similar genes may show slight phenotypic differences due to environmental factors.
Real-Life Example:
Two siblings may inherit similar genes but differ slightly in height because of differences in nutrition and lifestyle.
Answer: Physical appearance
Q15. What is a genotype?
A genotype is the complete genetic makeup of an organism. It refers to the combination of genes or alleles inherited from the parents. The genotype influences an organism’s characteristics and, together with environmental factors, determines the phenotype.
Key Points:
- Genotype means the genetic makeup of an organism.
- It consists of inherited genes or alleles.
- Genotype influences physical traits.
- It is represented using letters such as AA, Aa, or aa.
Real-Life Example:
A person may have the genotype Aa for a particular trait, but the dominant gene determines the visible characteristic.
Answer: Genetic makeup
Q16. Which scientist discovered DNA structure?
James Watson and Francis Crick proposed the double helix structure of DNA in 1953 based on experimental evidence, including X-ray diffraction studies. Their discovery explained how genetic information is stored, copied, and passed from one generation to the next, making it one of the greatest achievements in modern biology.
Key Points:
- Watson and Crick proposed the double helix model of DNA.
- The discovery was made in 1953.
- DNA stores hereditary information.
- The double helix model explains DNA replication and inheritance.
Real-Life Example:
Modern genetic testing and DNA fingerprinting are possible because scientists understand the structure of DNA.
Answer: Watson and Crick
Q17. What is the function of DNA?
DNA is responsible for storing and transmitting genetic information in living organisms. It contains the instructions needed for cell growth, reproduction, and the synthesis of proteins. DNA ensures that hereditary characteristics are passed from parents to offspring.
Key Points:
- DNA stores genetic information.
- It controls protein synthesis.
- DNA passes hereditary traits to the next generation.
- It plays a vital role in cell growth and reproduction.
Real-Life Example:
Children inherit characteristics such as blood group and eye colour because DNA carries genetic information from their parents.
Answer: Carry genetic information
Q18. Which process produces gametes?
Meiosis is a special type of cell division that produces gametes such as sperm and egg cells. During meiosis, the chromosome number is reduced by half, ensuring that the normal chromosome number is restored after fertilization. This process is essential for sexual reproduction.
Key Points:
- Meiosis produces sperm and egg cells.
- It reduces the chromosome number by half.
- Meiosis occurs in reproductive organs.
- It helps maintain the correct chromosome number in offspring.
Real-Life Example:
In humans, meiosis produces sperm cells in males and egg cells in females, which unite during fertilization to form a new individual.
Answer: Meiosis
Q19. What is an allele?
An allele is an alternative form of the same gene that controls a specific trait. Every individual inherits one allele from each parent. Different combinations of alleles determine how a particular characteristic is expressed in an organism.
Key Points:
- Alleles are different forms of the same gene.
- One allele is inherited from each parent.
- Alleles determine inherited traits.
- They may be dominant or recessive.
Real-Life Example:
A person may inherit one allele for brown eyes from one parent and one allele for blue eyes from the other, with the dominant allele determining the eye colour.
Answer: Different form of a gene
Q20. Which disease is genetic?
Hemophilia is a hereditary genetic disorder in which the blood does not clot properly due to the absence or deficiency of certain clotting factors. It is an inherited condition that is passed from parents to their children through genes and is commonly associated with the X chromosome.
Key Points:
- Hemophilia is an inherited genetic disorder.
- It affects the blood clotting process.
- It is usually passed through the X chromosome.
- It is different from infectious diseases such as malaria, tuberculosis, and cholera.
Real-Life Example:
A person with hemophilia may experience prolonged bleeding even from a minor injury because the blood takes longer to clot.
Answer: Hemophilia
FINAL REVISION TIPS (GENETICS)
- Mendel → Father of Genetics
- Gene → Unit of heredity
- Gene located on → Chromosome
- DNA → Carries genetic information
- 23 pairs = 46 chromosomes in humans
- Dominant → Expressed, Recessive → Hidden
- DNA shape → Double helix
- XX → Female, XY → Male
- Phenotype → Visible traits, Genotype → Genetic makeup
- Meiosis → Produces gametes
- Alleles → Different forms of gene
- Genetic disease → Inherited disorder
👉 Revise keywords, not paragraphs — TNPSC asks direct concepts
Further Reading:
For a deeper understanding of Genetics, heredity, DNA, and chromosomes, refer to the NCERT Biology resources. They provide reliable and concept-based explanations that are useful for TNPSC and other competitive exams.
🔗 Authority Reference: Read NCERT Class 10 Science – Heredity and Evolution
