Heredity is the process by which traits or characteristics are passed from parents to their offspring. It is the reason why offspring resemble their parents and inherit specific features.
Key Points:
- Genes and DNA control inheritance.
- Dominant traits (e.g., brown eyes) are expressed if one allele is present.
- Recessive traits (e.g., blue eyes) are expressed only when both alleles are recessive.
- Mendel’s Laws describe how traits are inherited:
- Segregation – each parent passes one allele for a trait.
- Independent Assortment – genes for different traits are inherited separately.
Example: Eye color inheritance – brown eyes (dominant) vs blue eyes (recessive).
Practice Questions PDF
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Questions on Heredity
Showing 1–30 of 591.Briefly explain how DNA and chromosomes work together to store and transmit genetic information. 2.In a large, randomly mating population, if the allele frequencies for a particular gene remain constant from one generation to the next, what does this suggest about the evolutionary forces acting on that gene? 3.While not strictly a Class 10 topic, how would you briefly describe the concept that environmental factors can influence gene expression without changing the underlying DNA sequence, and its relevance to heredity? 4.In a family pedigree, a trait appears in every generation, and affected individuals always have at least one affected parent. It also affects males and females equally. What is the most likely mode of inheritance? 5.Many genetic disorders arise from a mutation in a gene that codes for an enzyme. How might this lead to the symptoms of the disorder? 6.If two genes A and B show 50% recombination frequency, what can be inferred about their location relative to each other? 7.Differentiate between complete dominance and incomplete dominance using an example for each. 8.How does meiosis contribute to maintaining the chromosome number across generations while also promoting genetic variation? 9.A weightlifter develops large, strong muscles through rigorous training. If this weightlifter has children, will their children automatically inherit these large muscles? Justify your answer. 10.Cystic fibrosis is an autosomal recessive genetic disorder. If two carrier parents (heterozygous) have children, what is the probability that their second child will be unaffected and not a carrier? 11.In Mendel's experiments, what did he call the first generation of offspring resulting from a cross between two true-breeding parents, and what did he call the generation resulting from self-pollinating these offspring? 12.Give two reasons why Gregor Mendel chose pea plants (Pisum sativum) for his experiments on heredity. 13.Arrange the following terms in increasing order of complexity: DNA, gene, chromosome, nucleotide. 14.While humans use the XX/XY system, some animals like birds use a ZW/ZZ system where females are ZW and males are ZZ. If a male bird mates with a female bird, which parent determines the sex of the offspring? 15.Genetic screening can identify carriers of certain genetic disorders. While beneficial, what is a potential ethical concern associated with widespread pre-natal genetic screening? 16.Apart from recombination during sexual reproduction, what is another significant source of new alleles and genetic variation in a population? 17.If a cross between two individuals results in offspring with a phenotypic ratio of approximately 3 dominant : 1 recessive for a single trait, what must be the genotypes of the parents? 18.Genes are located on chromosomes at specific positions. What is the term for this specific physical location of a gene on a chromosome? 19.Explain the difference between a homozygous and a heterozygous individual for a particular gene. 20.In humans, attached earlobes (a) are recessive to free earlobes (A). If a woman with attached earlobes marries a man who is heterozygous for free earlobes, what is the probability that their first child will have free earlobes? 21.A scientist is studying a population of butterflies where wing color is determined by a single gene. However, they observe that butterflies raised in colder temperatures have darker wing colors than those raised in warmer temperatures, even if they have the same genotype. What does this indicate? 22.Why is Gregor Mendel considered the 'Father of Genetics'? 23.How many different types of gametes can be produced by an individual with the genotype AaBb? 24.If a genetic disorder affects males and females equally, and an affected child can have unaffected parents, which of the following is the most probable mode of inheritance? 25.Consider a population of bacteria exposed to an antibiotic. Only a small fraction of the bacteria survive and multiply, leading to a resistant population. Which concept of heredity is best illustrated by this scenario? 26.In a monohybrid cross, if the F2 phenotypic ratio is 1:2:1, what type of dominance pattern is indicated? 27.How does sexual reproduction contribute more to variation in a population compared to asexual reproduction? 28.What is the primary definition of 'heredity' in biology? 29.If genes for two different traits are located very close together on the same chromosome, what can be inferred about their inheritance pattern compared to genes on different chromosomes? 30.Briefly explain how genetic information is transmitted from one generation to the next.