Biology

Genetics and Plant Breeding

1,177 Questions

Genetics and Plant Breeding explores the principles of heredity, chromosomal inheritance, and hybridization techniques. It includes key concepts like Mendelian genetics, gene linkage, and polygenic inheritance. This topic is essential for students tackling advanced biology or botany sections in competitive examinations.

Mendelian InheritanceChromosome TheoryGene LinkagePolygenic InheritancePlant HybridizationPopulation Genetics Equilibrium

Genetics and Plant Breeding Questions

Multiple choice

Snapdragons and four-o-clock plants are examples of

  1. incomplete dominance

  2. co-dominance

  3. sex-linked dominance

  4. epistasis
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Snapdragons and four-o-clock plants produce F1heterozygotes in which blending of dominant and recessive traits take place and this is termed as incomplete dominance.The dominant allele does not mask the phenotypic expression of recessive allele completely.

Multiple choice

The blood types of an individual are

  1. genetically inherited

  2. acquired after birth as a consequence of certain specific environmental factors

  3. genetically inherited but get changed after birth as a consequence of natural selection

  4. genetically inherited but determined by natural selection
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Blood types are acquired only by inheritance from parents and they cannot be changed. However, natural selection can have an effect on whether an individual survives to reproduce and pass on the alleles for his or her blood type.

Multiple choice

In a couple, both the parents are carriers for a genetically inherited fatal recessive disease decide to become parents, what will be the odds that their children will also be carriers?

  1. 1 out of 4

  2. 2 out of 4

  3. 3 out of 4

  4. 4 out of 4
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

There will be a 50% chance (2 out of 4) of having a carrier (Aa) child. Similarly, each time there will be a 25% chance of having an offspring who will inherit the disease (aa) and die.

Multiple choice

In a couple, if a woman is homozygous normal (XX ) and her husband is heterozygous ( Xx) for a genetically inherited recessive disease, what is the probability that they will have a healthy offspring?

  1. 1 out of 4

  2. 2 out of 4

  3. 3 out of 4

  4. 4 out of 4
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

All of the children will be healthy since none of them can be homozygous recessive (xx). However, there will be a 50% chance at each birth that the children will be carriers (Xx). The remaining 50% will be homozygous dominant (XX).

Multiple choice

In a couple, if both mother & father are heterozygous (Xx) for a genetically inherited dominant defect, what is the feasibility that they will have a child together who has this trait in his or her phenotype?

  1. 25%

  2. 50%

  3. 75%

  4. 100%
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

There is a 50% chance that the children will be heterozygous (Aa) and a 25% chance that they will be homozygous dominant (AA). Children with either of these genotypes will have this trait expressed in their phenotypes.

Multiple choice

On what factor does the strength of linkage depend?

  1. Size of genes

  2. Distance between the genes

  3. Types of nucleotides in the gene

  4. Length of chromosome
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The strength of linkage depends upon the distance between the genes. Distance between the genes is inversely proportional to strength, i.e. D is proportional to 1/S, where D is the distance and S is the strength of linkage.

Multiple choice

In which of the following is complete linkage observed?

  1. Drosophila males

  2. Maize

  3. Pea plant

  4. Amoeba
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Complete linkage is observed in Drosophila males. In complete linkage, the genes located on the same chromosome do not separate and are inherited together over the generations due to the absence of crossing over.