Test: Genetics - Some Basic Fundamentals - Class 10 MCQ

Genetics primarily focuses on understanding how traits are transmitted from parents to their offspring and the underlying rules governing this process. This field helps explain variations in characteristics within a species and lays the groundwork for comprehending heredity.

Y-linked genetic traits can only be expressed in males, as they inherit the Y chromosome exclusively from their fathers. Such traits include certain male-specific characteristics, like hypertrichosis.

X-linked inheritance refers to traits determined by genes located on the X chromosome. Conditions such as color blindness and hemophilia are classic examples of X-linked traits, affecting primarily males due to their single X chromosome.

Genetic engineering involves altering the genetic makeup of an organism, often by introducing new genes into its genome. This technique has led to the development of genetically modified organisms (GMOs), which can have benefits such as improved agricultural traits.

The garden pea (Pisum sativum) was suitable for genetic studies because it can both self-pollinate and be cross-pollinated, allowing Mendel to control breeding experiments and observe the inheritance of traits across generations.

The study of genetics in modern science aims to understand biological processes and improve various applications, such as agricultural practices through biotechnology and developing medical therapies for genetic disorders. This knowledge is essential for advancements in health and food production.

Alleles are different forms of a gene that can exist at a specific locus on a chromosome. They contribute to the diversity of traits within a species and determine how those traits are expressed in an organism.

Sickle Cell Anaemia is caused by a mutation in a single gene that alters the structure of hemoglobin, leading to the production of abnormally shaped red blood cells. This condition exemplifies how mutations can significantly impact health.

The phenotype refers to the observable characteristics or traits of an organism, which result from the interaction of its genotype and the environment. For example, the ability to roll one's tongue is a visible phenotype influenced by genetic factors.

Down's Syndrome is characterized by the presence of an extra copy of chromosome 21, leading to various developmental and intellectual disabilities. This genetic condition is an example of aneuploidy, where there is an abnormal number of chromosomes.

The Law of Segregation states that the two alleles for a trait separate during the formation of gametes, ensuring that each gamete carries only one allele for each gene. This principle is fundamental to understanding genetic inheritance.

In genetics, a mutation refers to a sudden alteration in the DNA sequence of a gene, which can lead to changes in traits or functions. Mutations can have various effects, from benign to harmful, and are a source of genetic diversity.

Tongue rolling is an example of a dominant trait. Individuals who can roll their tongues carry at least one dominant allele (R), while those who cannot roll their tongues must have two recessive alleles (rr). This illustrates how dominant traits can mask the expression of recessive traits.

Mendel's Law of Independent Assortment states that alleles for different traits are distributed to gametes independently of one another. This principle is vital for understanding genetic variation and the combinations of traits that can occur in offspring.

A homozygous dominant genotype consists of two identical dominant alleles (e.g., RR), which means the dominant trait will be expressed in the phenotype. This genotype contrasts with heterozygous genotypes, which contain one of each allele.

In a pedigree chart, a hollow circle represents a female who expresses the trait being studied. This visual representation helps track the inheritance of traits in a family over generations.

Recessive genes express their traits in the phenotype only when paired with another recessive allele. This means that for an individual to exhibit a recessive trait, they must inherit the same recessive allele from both parents.

Mendel observed a phenotypic ratio of 9:3:3:1 in his dihybrid crosses, which involved two traits. This ratio emerged when he crossed plants exhibiting two pairs of contrasting traits, demonstrating the principle of independent assortment.

Homologous chromosomes are pairs of chromosomes that have the same genes at the same loci but may carry different alleles. They consist of one chromosome from each parent and play a crucial role during meiosis and genetic recombination.

In humans, sex determination is based on the combination of sex chromosomes inherited from the parents. Males have one X and one Y chromosome (XY), while females have two X chromosomes (XX). The sperm’s contribution decides the gender of the offspring at fertilization.