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

Fill blank (viii).

Directions: Read the following passage having some numbered blanks.

In jaguars, the mutation is (i)_______. Hence, black jaguars can (ii)_______ both black and (iii)______ cubs, but spotted jaguars only (iv)_______ spotted cubs when bred together. In leopards, the (v)_______ is recessive and some spotted leopards can produce the black cubs if both (vi)________ carry the gene in hidden form, while black leopards always breed true when mated together. In (vii)______ mounted specimens, black leopards often (viii)_______ to a rusty color, but black jaguars fade to chocolate brown. (ix)_______ black jaguar was (x)________ a separate species by indigenous people.

  1. fade

  2. blanch

  3. dissolve

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

Here, ‘fade’ is the correct option as ‘fade’ implies the process of becoming less bright. ‘Blanch’ implies to  grow pale from shock, fear or a similar emotion; ‘dissolve‘ implies to become incorporated into a liquid so as to form a solution and ‘evaporate’ implies to turn from liquid into vapour.

Multiple choice

Fill blank (ix).

Directions: Read the following passage having some numbered blanks.

In jaguars, the mutation is (i)_______. Hence, black jaguars can (ii)_______ both black and (iii)______ cubs, but spotted jaguars only (iv)_______ spotted cubs when bred together. In leopards, the (v)_______ is recessive and some spotted leopards can produce the black cubs if both (vi)________ carry the gene in hidden form, while black leopards always breed true when mated together. In (vii)______ mounted specimens, black leopards often (viii)_______ to a rusty color, but black jaguars fade to chocolate brown. (ix)_______ black jaguar was (x)________ a separate species by indigenous people.

  1. on

  2. an

  3. a

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

Here, ‘the’ is the correct option as here it is used with a singular noun to indicate that it represents a whole species or class. ‘On’ as a preposition is used as a medium of transmitting or storing information etc. ‘An’ is used instead of ‘a’ in places where the words start with a vowel. ‘A’ is used before a single countable noun.

Multiple choice

Fill blank (v).

Directions: Read the following passage having some numbered blanks.

In jaguars, the mutation is (i)_______. Hence, black jaguars can (ii)_______ both black and (iii)______ cubs, but spotted jaguars only (iv)_______ spotted cubs when bred together. In leopards, the (v)_______ is recessive and some spotted leopards can produce the black cubs if both (vi)________ carry the gene in hidden form, while black leopards always breed true when mated together. In (vii)______ mounted specimens, black leopards often (viii)_______ to a rusty color, but black jaguars fade to chocolate brown. (ix)_______ black jaguar was (x)________ a separate species by indigenous people.

  1. stagnation

  2. mutation

  3. dullness

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

Here, 'mutation' is the correct option as it implies a sudden departure from the parent type in one or more heritable characteristics, caused by a change in a gene or a chromosome. ‘Stagnation’ is the state of no change, ‘dullness’ is being sluggish and ‘inactivity’ is the state of being inactive. As the sentence is about the genes and genes mutate, so all the other options are incorrect.

Multiple choice

Fill blank (i).

Directions: Read the following passage having some numbered blanks.

In jaguars, the mutation is (i)_______. Hence, black jaguars can (ii)_______ both black and (iii)______ cubs, but spotted jaguars only (iv)_______ spotted cubs when bred together. In leopards, the (v)_______ is recessive and some spotted leopards can produce the black cubs if both (vi)________ carry the gene in hidden form, while black leopards always breed true when mated together. In (vii)______ mounted specimens, black leopards often (viii)_______ to a rusty color, but black jaguars fade to chocolate brown. (ix)_______ black jaguar was (x)________ a separate species by indigenous people.

  1. chief

  2. dominant

  3. eminent

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

Here, 'dominant' is the correct option as here we are talking about a characteristic of genes which is controlling in jaguars. 'Chief' implies something most important, 'eminent' implies someone famous and respected within a particular sphere, and 'famous' is someone or something known about by many.

Multiple choice

Fill blank (vii).

Directions: Read the following passage having some numbered blanks.

In jaguars, the mutation is (i)_______. Hence, black jaguars can (ii)_______ both black and (iii)______ cubs, but spotted jaguars only (iv)_______ spotted cubs when bred together. In leopards, the (v)_______ is recessive and some spotted leopards can produce the black cubs if both (vi)________ carry the gene in hidden form, while black leopards always breed true when mated together. In (vii)______ mounted specimens, black leopards often (viii)_______ to a rusty color, but black jaguars fade to chocolate brown. (ix)_______ black jaguar was (x)________ a separate species by indigenous people.

  1. stuffed

  2. crammed

  3. filled

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

Here, ‘stuffed’ is the correct option as ‘stuffed and mounted’ are the terms used in the art form of taxidermy where dead animals are prepared in a lifelike state so that they can be exhibited. It is relevant to the context as the topic is about animals. 'Crammed' means to fill something tightly in insufficient space; 'filled' is used when something is put into a container as much as the available space would allow, and 'packed' means compressed to capacity.

Multiple choice

Fill blank (x).

Directions: Read the following passage having some numbered blanks.

In jaguars, the mutation is (i)_______. Hence, black jaguars can (ii)_______ both black and (iii)______ cubs, but spotted jaguars only (iv)_______ spotted cubs when bred together. In leopards, the (v)_______ is recessive and some spotted leopards can produce the black cubs if both (vi)________ carry the gene in hidden form, while black leopards always breed true when mated together. In (vii)______ mounted specimens, black leopards often (viii)_______ to a rusty color, but black jaguars fade to chocolate brown. (ix)_______ black jaguar was (x)________ a separate species by indigenous people.

  1. considered

  2. assumed

  3. endorsed

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

Here, 'considered' is the correct option as it implies thinking or believing (carefully about the black jaguar as a separate species) before making a decision. To assume is to suppose without any proof, to endorse is to declare the approval publically and to support is to bear the weight or maintain.

Multiple choice

The phenomenon in which following successful Ig gene rearrangement, further rearrangement on the sister chromatid is suppressed, is termed as

  1. class switching

  2. productive rearrangement

  3. clonal selection

  4. allelic exclusion

  5. gene shuffling
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

All of the immunoglobulin gene loci (heavy, kappa light, lambda light) exhibit allelic exclusion, as do all of the T-cell receptor gene loci, except the alpha chain. Thus, a B-cell is able to express only one light and one heavy chain specificity.

Multiple choice

The high concordance rate for monozygotic vs dizygotic twins in type 1 diabetes indicates ___________.

  1. a strong environmental element

  2. a major influence of sex

  3. the influence of HLA

  4. a strong genetic element

  5. that microbial infection cannot be involved
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The higher concordance rate for genetically identical monozygotic compared to the genetically non-identical dizygotic twins brought up in the same environment clearly favours a strong genetic element.

Multiple choice

Diagonal hybridisation is the term used for

  1. sp3d2 hybridisation

  2. 'sp' hybridisation

  3. sp2 hybridisation

  4. sp3 hybridisation
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In this type of hybridisation one '2s' and one '2px' orbitals get hybridised to form two equivalent orbitals called 'sp' hybrid orbitals. The remaining 2py and 2pz do not take part in hybridisation. The two unhybridised orbitals are directed along the 'y' and 'z' axes while the two hybridised orbitals are directed towards the 'x' axis. This hybridisation is often known as diagonal hybridisation as the two hybridised orbitals are at 180o due to mutual repulsion of their electron clouds. Each hybrid orbital has equal 's' and 'p' character.

Multiple choice

A cross in which parents are distantly related is

  1. intravarietal cross

  2. intervarietal cross

  3. interspecific cross

  4. intergeneric cross
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

An intergeneric cross involves breeding between two different genera, which represents a very distant relationship compared to intervarietal or interspecific crosses.

Multiple choice

Heterosis is

  1. hybrid vigour

  2. hybrid incompatibility

  3. hybrid sterility

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

Heterosis, or hybrid vigour, is the phenomenon where the progeny of two genetically diverse parents exhibit superior traits compared to the parents.

Multiple choice

'Sharbati Sonora' is a result of

  1. selection

  2. polyploidy

  3. hybridization

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

Sharbati Sonora is a wheat variety developed in India through mutation breeding using gamma radiation on the Sonora 64 variety.