Biology

Genetics and Plant Breeding

1,240 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

The concept that different pairs of alleles are carried to offspring independently is Mendel's principle of

  1. unit inheritance

  2. segregation

  3. independent assortment

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

This is a definition of his principle of independent assortment. In other words, the genes that determine a trait assort independently of the genes for other traits. As a result, new combinations of genes, present in neither parents, are possible.

Multiple choice

An allele is defined as

  1. another word used for a gene

  2. a homozygous genotype

  3. a heterozygous genotype

  4. one among the many possible forms of a particular gene

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

An allele is one of two or more alternate forms of a gene. If an individual is homozygous (YY or GG) for a trait, it has inherited the same allele from both parents. If it is heterozygous (YG), it has inherited different alleles for the trait.

Multiple choice

The total consequence of positive assortative mating is an increase in the frequency of

  1. heterozygotes (Aa)

  2. dominant homozygotes (AA)

  3. recessive homozygotes (aa)

  4. all homozygotes (AA and aa)
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The reason is that mating is between individuals with the same genotypes -- AA X AA, aa X aa, or Aa X Aa. The first 2 mating combinations only produce homozygous offsprings, while 50% of the offsprings of the latter are homozygous as well.

Multiple choice

Kavita is homozygous normal but her husband is heterozygous for a genetically inherited recessive trait. The probability of having a normal child is

  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 (aa). However, there will be a 50% chance at each birth that the children will be carriers (Aa). The remaining 50% will be homozygous dominant (AA).

Multiple choice

Down's syndrome is a genetically inherited dominant trait. If two parents are heterozygous for it, what are the chances that they will have a child 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

Select the CORRECT explanations regarding Mendel, the father of genetics.

  1. His ideas and concepts regarding genetic inheritance were accepted by the scientific community when he published them in late 19th century.

  2. He believed that genetic characters of parents will typically come in their offsprings.

  3. His concept about genetics are applicable to both plants and animals.

  4. He was an English scientist who carried out research with Charles Darwin in the field of genetics & evolution.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

He gave us the concept of unit inheritance as the basis for understanding genetic inheritance in all living things, including humans.

Multiple choice

The phenotype is defined as

  1. genetic makeup

  2. physical appearance

  3. recessive allele

  4. dominant allele
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Phenotype includes the observable characteristics, including physical appearance. It results from the genotype and environmental influences. A phenotype includes not only easily measured traits like hair colour but also less apparent ones such as blood type.

Multiple choice

A radish-cabbage cross is a type of

  1. interspecific hybridisation

  2. intergeneric hybridisation

  3. cybridisation

  4. somatic hybridisation
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Radish and cabbage belong to two different genera, so it is intergeneric hybridisation.

Multiple choice

F1 hybrids are always sterile in

  1. interspecific hybridisation

  2. intergeneric hybridisation

  3. somatic hybridisation

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

F1 hybrids are always sterile in intergeneric hybridisation.

Multiple choice

Which of the following can be used as an identifier in Genbank?

  1. Entry Name

  2. Locus

  3. Both of these

  4. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In GenBank records, the LOCUS field is a primary unique identifier that appears at the beginning of each entry. While GenBank also uses Accession numbers and GI identifiers, 'Entry Name' is not a standard GenBank identifier category, making Locus (B) the correct answer.