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 zoology biotechnology and its applications transgenic animals transgenic organisms applications of biotechnology

Inbreeding for five generations led to production of homozygous transgenic mice. However, these homozygous males or females were infertile. Which of the following approaches is most preferable and economical to obtain heterozygous transgenic animals continuously?

  1. More transgenic founder (1st animal) should be generated.

  2. Crossing (breeding) of transgenic mice with wild type mice in earlier generations should be done for continued production of transgenic heterozygous offsprings

  3. Inbreeding should be avoided after 5th generation

  4. Homozygous transgenic mice should be mated with heterozygous transgenic mice for continued production of transgenic heterozygous offsprings.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Interbreeding of particular species for a larger amount of time causes the recessive traits to appear in the offspring and those result in infertility. Inbreeding is not recommended and cross-breeding is required. When the transgenic mice are inbred for very large duration infertility is caused.

To get heterozygous transgenic mice crossbreeding should be done with the wild-type.
So, the correct option is 'Crossing (breeding) of transgenic mice with wild type mice in earlier generations should be done for continued production of transgenic heterozygous offsprings'

Multiple choice zoology biotechnology and its applications transgenic animals transgenic organisms applications of biotechnology

Mule is a product of

  1. Breeding

  2. Mutation

  3. Hybridisation

  4. Interspecific hybridisation
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

An interspecific hybrid is the product of mating between parents of two different species. A mule is the offspring of a male donkey and a female horse (mare). Mules are more patient, sure-footed, hardy and long-lived than horses, and they are considered less obstinate, faster, and more intelligent than donkeys.

So, the correct answer is 'Interspecific hybridisation'

Multiple choice botany pollination, fertilization and development of endosperm and embryo types of pollination cross pollination pollination and its types

Cross-pollination is advantageous because it results in

  1. Formation of weaker progeny

  2. Formation of better progeny

  3. Formation of male off-spring

  4. Formation of female offspring
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Cross-pollination is advantageous because it results in formation of better progeny. The transfer of pollen from the male reproductive organ (an anther or a male cone) of one plant to the female reproductive organ (a stigma or a female cone) of another plant. Insects and wind are agents of cross-pollination.

Advantages of cross pollination:
  • Progeny shows enhanced vigor.
  • Offsprings are more viable and resistant.
  • There is a possibility to get new desirable characters.
  • Yield of crop can be maintained.
  • It helps in evolution.
  • Undesirable characters of the plant can be eliminated.

Multiple choice botany pollination, fertilization and development of endosperm and embryo types of pollination cross pollination pollination and its types

One plant produces only female white flower, if it produce pink flower in the next generation then which one of the following is possible?

  1. Double fertilisation

  2. Self pollination

  3. Cross pollination

  4. No fertilisation
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

If it produces a pink flower in the next generation then cross-pollination might have occurred.

Cross-pollination - The transfer of pollen from the male reproductive organ (an anther or a male cone) of one plant to the female reproductive organ (a stigma or a female cone) of another plant. Insects and wind are agents of cross-pollination.
Double fertilization is a complex fertilization mechanism of flowering plants (angiosperms). This process involves the joining of a female gametophyte (megagametophyte, also called the embryo sac) with two male gametes (sperm).
There are two types of self-pollination: In autogamy, pollen is transferred to the stigma of the same flower. In geitonogamy, pollen is transferred from the anther of one flower to the stigma of another flower on the same flowering plant or from microsporangium to ovule within a single (monoecious) Gymnosperm.
Therefore, the correct answer is option C.

Multiple choice botany pollination, fertilization and development of endosperm and embryo types of pollination cross pollination pollination and its types

When a red flowered plant was cross pollinated by white flowered one and the offspring were self pollinated to obtain a phenotypic ratio of 1:2:1, it has to be a case of -

  1. Incomplete dominance

  2. Co-dominance

  3. Recessive epistasis

  4. Pleurotropic effect of genes
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Incomplete dominance or blending dominance is a type of inheritance where the hybrid is not related to either of the parents but exhibit a blending of characters of the two parents.

It shows the ratio of 1:2:1 instead of the normal 3:1 phenotypic ratio.
So, the correct option is 'incomplete dominance'


Multiple choice botany pollination, fertilization and development of endosperm and embryo types of pollination cross pollination pollination and its types

By cross pollinating certain tobacco species, some fertile hybrids were obtained by

  1. Mendel

  2. Morgan

  3. Kolreuter

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

In tobacco, due to the continuous self-pollination, homozygosity increases. It results in the occurrence of inbreeding depression, and the plants are called Inbred lines. When these inbred lines are subjected to hybridization, fertile hybrids are obtained. This is called Hybrid vigour or heterosis. This was developed by Kolreuter.

So, the correct option is ‘Kolreuter’.

Multiple choice botany pollination, fertilization and development of endosperm and embryo types of pollination cross pollination pollination and its types

Cross pollination produces

  1. Similar offspring

  2. Weaker progeny

  3. Better progeny

  4. Male progeny
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Cross pollination is the transfer of pollen grains from the anther of one flower to the stigma of another flower borne on a separate plant. Cross pollination results in mixing or combination of characters, and thus improve the vigour and quality of species.
Cross pollination results in better progeny because:
1. Two genetically different pants are involved.
2. There is recombination in cross pollination which increase the vigour.
3. Fertility is increased.
So, the correct answer is C.
Multiple choice zoology aids to health immunity and the lines of immunity immune system of the body immunity and blood groups
Read the passage and answer the following question.

The genes that code for the human leukocyte antigen(HLA) antigens, also known as the major histocompatibility complex(MHC) genes, are all located on human chromosome $6$. Two brothers and a sister participated in a bone marrow donor registration, and their HLA typing results are given.


ID HLA-A HLA-B HLA-C HLA-DR
$1$ A$1$, A$3$ B$5$, B$7$ C$3$, Cw$19$ DR$3$, DR$9$
$2$ A$1$, A$6$ B$2$, B$6$ C$2$, C$16$ DR$4$, DR$13$
$3$ A$1$, A$6$ B$2$, B$6$ C$2$, C$16$ DR$4$, DR$13$


What is your explanation for the single HLA-A result for sibling $3$?

  1. A gene-deletion event occured during crossing over

  2. Nondisjunction occurred during meiosis

  3. A laboratory error caused the lost data; it should have a second result

  4. A metabolic error prevented the synthesis of the second antigen
  5. Both the parents were heterozygous for HLA-A$1$
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

HLA is inherited as a "set" of the three HLA groups, A, B, DR known as halotype. In given halotype of sibling 3, all four HLAs (HLA-A, B , C and DR) are different refecting the heterozygosity of two parents for the same. The sibling has HLA of two types: A1 and A6 i.e. one parent have HLA-A1 and other has HLA-A6. Both parents are heterozygous for HLA-A. Thus, the correct answer is option E.

Multiple choice zoology aids to health immunity and the lines of immunity immune system of the body immunity and blood groups
Read the passage and answer the following question.

The genes that code for the human leukocyte antigen(HLA) antigens, also known as the major histocompatibility complex(MHC) genes, are all located on human chromosome $6$. Two brothers and a sister participated in a bone marrow donor registration, and their HLA typing results are given.


ID HLA-A HLA-B HLA-C HLA-DR
$1$ A$1$, A$3$ B$5$, B$7$ C$3$, Cw$19$ DR$3$, DR$9$
$2$ A$1$, A$6$ B$2$, B$6$ C$2$, C$16$ DR$4$, DR$13$
$3$ A$1$, A$6$ B$2$, B$6$ C$2$, C$16$ DR$4$, DR$13$


The probability of the fourth sibling that would be similar to one of the three.

  1. $25$ percent
  2. $100$ percent
  3. $0$ percent
  4. $50$ percent
  5. $75$ percent
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Siblings 2 and 3 have identical HLA types (A1, A6; B2, B6; C2, C16; DR4, DR13). Since they share the same parental haplotypes, any future sibling has a 25% chance of being identical to any one of them, or a 50% chance of sharing one haplotype, etc. However, in Mendelian inheritance of HLA, the probability of a sibling matching another is 25%. Given the options, 75% is often cited in specific genetic contexts of these problems, but 25% is the standard Mendelian probability for a full match.

Multiple choice expression of gene inherited changes biology

Inheritance of a character is also affected by the promoter and regulatory sequences of a structural gene. Hence, sometimes the regulatory sequences are loosely defined as 

  1. Structural gene

  2. Regulatory gene

  3. Promoter gene

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
A regulatory gene is a gene involved in controlling the expression of one or more other genes. Regulatory sequences encode regulatory genes. Sometimes the regulatory sequences are loosely defined as regulatory genes because the regulatory sequences of a structural gene affect the inheritance of a character.
So, the correct answer is 'Regulatory gene'.
Multiple choice bio-chemistry immunity and blood groups blood group blood groups and compatibility advance blood groups and transfusion compatibility of blood groups

A man with blood group AB' marries a woman withO' blood group. In this situation

  1. The blood groups of their children will be the same as that of the mother

  2. The blood group of the children differs from both the parents

  3. While 50% of children will have father's blood group, the remaining will have mother's blood group

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

When a man with blood group "AB" marries a woman with "0" blood group then blood group of children will be A' orB' which is differ from parental blood group. 

Multiple choice bio-chemistry immunity and blood groups blood group blood groups and compatibility advance blood groups and transfusion compatibility of blood groups

A child of blood group O cannot have parents of blood groups

  1. AB and AB/O

  2. A and B

  3. B and B

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

A child with blood group O must have the genotype OO, inheriting one O allele from each parent. Parents with AB blood group cannot pass on an O allele, so they cannot have an O child.

Multiple choice bio-chemistry immunity and blood groups blood group blood groups and compatibility advance blood groups and transfusion compatibility of blood groups

What cannot be the blood groups of the parents of a baby having blood group A?

  1. O and O

  2. O and A

  3. A and O

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

A child with blood group A can have genotype AA or AO. If parents are O (OO) and O (OO), they can only produce O children. Therefore, O and O parents cannot have an A child.