Biology: CUET Mock Test - 10 - Class 12 MCQ

The law of dominance states characters encoded by discrete units. Mendel called these factors, which he believed transferred from parents during progeny during fertilization. These are now known as genes.

The principle of dominance does not state the segregation of factors. This is stated by the law of segregation or separation.

The law of segregation states that the factors separate during gamete formation. Thus a homozygous parent will produce gametes that have similar factors while the heterozygous parent would produce gametes with dissimilar alleles.

The phenotypic ratio is the ratio of different phenotypes observed in the progeny. In the F2 generation of a Mendelian cross, there are 75% plants with dominant phenotype and 25% plants with a recessive phenotype. This gives a phenotypic ratio of 3:1.

The genotypes of a progeny can be studied using Punnett square. The ratio of different genotypes is called the genotypic ratio.

In the Punnett square, the boxes are filled with the offsprings that can be produced, in principle, from the combinations of gametes of both parents. This can be used to determine the genotypic and phenotypic ratios of the progeny.

The Punnett square was discovered by a British scientist named Reginald Punnett. Its importance was recognized by Gregor Mendel, who used it to study the patterns of inheritance and thus formulate the laws of inheritance.

Emasculation is the process of removal of anthers. This is carried out to carry out pollination in a controlled manner and avoid self-pollination.

True-breeding plants are taken as parental plants in crosses. Hence offsprings produced by the crossing of these true-breeding plants are F1 progeny.

Tall plants are dominant over dwarf plants. Being true-breeding parents, the offsprings will all be heterozygous. Moreover, hence phenotypically, all of them will be tall.

Violet is the dominant factor over white in pea flowers. Hence violet can express even in the presence of white. The cross of violet true-breeding and white true-breeding pea plants will produce all heterozygous offsprings. Thus, all of them will have violet flowers.

A dominant factor masks the expression of its recessive counterpart. Thus, it can express in both homozygous and heterozygous states.

Based on his studies on pea plants, he observed that the parental recessive traits were observed again only in the F2 progeny without any form of blending in F1 generation. This points out that the factors segregate or separate during the process of meiosis.

The presence of two different alleles at a particular locus results in _________
a) Homozygosity
b) Heterozygosity
c) Hemizygosity
d) Nullizygosity

Monohybrid refers to a hybrid that differs at only one gene. Thus, a plant that exhibits two alleles for one trait is a monohybrid.

The VV and vv upon crossing will produce all progeny with genotype Vv. This is the heterozygous state. Violet being dominant over white, all the progeny will have violet flowers.

Yellow being recessive will express only when both alleles are present. That occurs only when both parents can contribute an allele encoding for the yellow pod. For all progeny to have yellow pods, both parents have to be homozygous for yellow pods.

Inflated is the dominant phenotype. Hence it can be expressed in two genotypes: II and Ii. The F1 progeny can have it in all the mentioned cases except when both parents are recessive ii.

F1 progeny refers to the first generation of offsprings. This is also termed as the first Filial generation, thereby stating their filial relationship with the true-breeding plants.

Self-pollination leads to fertilization by the pollen from the same flower. A cross desires pollination and fertilization by pollen from a different plant. Hence self-pollination needs to be avoided.

One of the central problems in molecular biology was unraveling the structure of DNA. This was finally postulated by Francis Crick and James Watson in 1953. For this, they shared a Nobel Prize in 1962.

Inheritance or Heredity is the process of transfer of information from parents/ancestors to offsprings. This gives rise to patterns that can be studied using the subject of genetics.

The laws of inheritance in living organisms were proposed by Gregor Mendel. He was the first person to apply the scientific method to understand patterns of inheritance. However, the importance of his work was not recognized until after his death.

Gregor Mendel carried out the hybridization of pea plants with specific characters and used manual counting to carry out estimates of factors over generations. This gave rise to the laws of inheritance, as we know today.

All the 4 options refer to approaches of early humans that have benefitted society. However, the domestication of dog and cow and the artificial selection of wheat as a crop have used the principle of variation and selection of traits best suitable for a particular task.

Variation is the difference between individuals within a population. These arise between the progeny and parents/ancestors and form a backbone for natural selection to act on.

Genetics is the branch of biology that deals with questions of inheritance. It uses techniques from various disciplines like Molecular biology, Cell biology, and many more to understand the basis of inheritance.

Mendel discovered the laws of inheritance. He attributed these traits being encoded by factors. Later studies showed that these factors are genes.

Surgical methods are invasive. They work by using a surgical intervention to render one or both partners incompetent.

Surgical methods are non-reversible. Hence these render the person sterile. These methods are therefore called sterilization.