NCERT MCQ Solutions for Class 10 Science Chapter 8 Heredity

DNA contains the genetic blueprint of life. It provides instructions in the form of specific sequences of nitrogenous bases which guide the synthesis of proteins that perform essential functions in all living organisms.

In Mendel’s experiments with pea plants tallness was a dominant trait. This means that even if only one allele for tallness was present the plant exhibited tallness over the short trait.

Gregor Mendel is called the Father of Genetics for his groundbreaking work with pea plants. His experiments established the basic principles of heredity and introduced the concept of dominant and recessive traits.

A short pea plant according to Mendel’s observations possesses two recessive alleles (tt). The trait is expressed only when both alleles are recessive and there is no dominant allele.

The father contributes either an X or a Y chromosome. If the sperm carries an X chromosome the child will be female. If it carries a Y chromosome the child will be male.

Humans have a total of 46 chromosomes arranged in 23 pairs. Of these 22 pairs are autosomes and the 23rd pair consists of sex chromosomes that determine gender.

A gene is a sequence of DNA that holds instructions to build specific proteins. These proteins determine traits and functions in an organism and are passed from parents to offspring.

In Mendel’s study wrinkled seeds only appeared when both alleles were for the wrinkled trait. Thus wrinkled seeds were identified as recessive as they were masked by round seed alleles.

Snails are hermaphrodites and can change sex depending on environmental and physiological conditions. This ability enhances reproductive flexibility and survival in changing environments.

Mendel’s law of independent assortment explains how alleles of different genes separate independently during gamete formation leading to various combinations and genetic variation in offspring.

Mothers contribute an X chromosome to every child. Fathers contribute either an X or a Y which then determines the child’s gender. Thus the X from the mother is always passed.

Each trait is determined by a pair of alleles inherited from each parent. These alleles can be dominant or recessive and their interaction decides the trait’s expression.

Recessive traits are those that remain unexpressed in the presence of a dominant allele. They appear only when an individual inherits two recessive alleles for that trait.

The 23rd pair of chromosomes are sex chromosomes. XX results in a female child and XY results in a male child. These are distinct from the autosomal chromosome pairs.

Fertilization combines genetic material from two different parents. This recombination of genes during gamete fusion introduces variation in the resulting offspring which is crucial for evolution.

A trait is considered recessive when it is expressed only if an individual inherits two copies of the recessive allele. Presence of a dominant allele will mask it.

A Punnett square is a diagram used in genetics to predict the possible combinations of alleles and traits in offspring from a particular genetic cross.

In the first filial (F1) generation of his cross between tall and short pea plants Mendel found only tall plants indicating that tallness was a dominant trait.

A female child has two X chromosomes. One comes from the mother and one from the father. If the father contributes a Y chromosome the child will be male.

Variations are differences that arise in organisms due to recombination of genes during reproduction. They form the basis for natural selection and evolution in populations.