Biology

Cell Cycle and Chromosomes

1,348 Questions

Explore a curated list of questions covering the cell cycle, mitosis, and meiosis. Topics include DNA replication, chromosomal structures, and genetic disorders. This material is essential for students preparing for biology and general science competitive exams.

Cell cycle eventsDNA replicationMeiosis processChromosomal structuresGenetic disorders

Cell Cycle and Chromosomes Questions

Multiple choice

a change or mistake in the DNA causes

  1. mitosis

  2. an accident

  3. a mutation

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

A mutation is a permanent alteration in the DNA sequence that makes up a gene, such that the sequence differs from what is found in most people.

Multiple choice

DNA is divided into segments on a chromosome known as

  1. allele

  2. genes

  3. chromosome

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

A gene is a specific segment of DNA located on a chromosome that carries instructions for a trait. Chromosomes are the larger structures, and the double helix is the shape of the DNA molecule itself.

Multiple choice

different forms of a gene

  1. allele

  2. DNA

  3. chromosome

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

An allele is defined as one of two or more alternative forms of a gene that arise by mutation and are found at the same place on a chromosome. DNA is the molecule, and chromosomes are the structures containing genes.

Multiple choice botany chromosomal basis of inheritance linkage and crossing over linkage and recombination genetics: inheritance

Genes on same chromosome can be

  1. Linked

  2. Homologous

  3. Autosomes

  4. Identical alleles
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
  • When two genes are close together on the same chromosome, they do not assort independently and are said to be linked and will segregate together during meiosis, producing only two kinds of gametes. Whereas genes located on different chromosomes assort independently and have a recombination frequency of 50%, linked genes have a recombination frequency that is less than 50%.
  • Hence Genes on the same chromosome can be Linked.
  • So, the correct answer is 'Linked'.
Multiple choice botany chromosomal basis of inheritance linkage and crossing over linkage and recombination genetics: inheritance

The number of linkage groups in a cell having 10 pairs of chromosomes are

  1. 5

  2. 10

  3. 15

  4. 20
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The total number of linkage groups in an organism equals to the number of autosomes in its haploid cell. The cell has ten pairs of chromosomes which means that the number of autosomes in its haploid cell is 10. Hence, total number of linkage groups will be 10 provided all the genes are mapped. Correct answer is B.

Multiple choice botany chromosomal basis of inheritance linkage and crossing over linkage and recombination genetics: inheritance

Maize has $10$ pairs of chromosomes. How many linkage groups does it have?

  1. $20$
  2. $10$
  3. $5$
  4. $40$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
The total number of Linkage groups in an individual is equal to their total number of haploid sets of chromosomes.
Haploid number of chromosome = Linkage groups
In Maize there are 10 linkage groups, since 10 haploid chromosomes.
So, the correct answer is '10'.
Multiple choice botany chromosomal basis of inheritance linkage and crossing over linkage and recombination genetics: inheritance

A linkage group is defined as

  1. All the linked genes of a chromosomal pair

  2. Different groups of genes present on different chromosomes

  3. All the genes located on the same chromosome

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Linkage group, in genetics, all of the genes on a single chromosome. They are inherited as a group; that is, during cell division they act and move as a unit rather than independently.
So, the correct answer is 'All the linked genes of a chromosomal pair'.
Multiple choice botany chromosomal basis of inheritance linkage and crossing over linkage and recombination genetics: inheritance

All genes located on the same chromosome:

  1. From different groups depending upon their relative distance.

  2. Form one linkage group.

  3. Will not from any linkage groups.

  4. Form interactive groups that affect the phenotype.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

 Linkage group is a group of a linked gene on the same chromosome and corresponds to the genome of an organism.

So, the correct option is 'Form one linkage group'.

Multiple choice botany chromosomal basis of inheritance linkage and crossing over linkage and recombination genetics: inheritance

Number of linkage groups in Drosophila are

  1. 4

  2. 8

  3. 6

  4. 10
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Linkage: Tendency of the genes located on the same chromosome, to stay together in hereditary transmission is known as linkage. The genes located on the same chromosome are called as linked genes. The principle of linkage was discovered by Bateson and Punnet in 1906 in the sweat pea plant, Lathyrus odoratus. However, linkage as a concept was put forth by Thomas Hunt Morgan in 1910 based on his experiment on Drosophila melanogaster. It has 4 linkage groups.

Multiple choice botany chromosomal basis of inheritance linkage and crossing over linkage and recombination genetics: inheritance

Genes when close together on a chromosome, it is called as

  1. Mutation

  2. Linkage

  3. Translation

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

Sudden inheritable changes in genetic material are called as mutations. Translation is the process of synthesis of polypeptides by polymerization of amino acids on ribosomes using the mRNA triplets as template. Transcription is the process of synthesis of RNA by RNA polymerase using DNA template strand. Thus mutation, translation and transcription are independent of distance between the genes on chromosomes which makes options A, C, and D wrong. Linkage is the tendency of closely placed genes on a chromosome to stay together during inheritance; it produces more parental combination and less/no new combinations of gene. Genes present together on a chromosome show linkage and do not follow independent assortment resulting in more parental types and less recombinants in progeny. Correct answer is B.

Multiple choice botany chromosomal basis of inheritance linkage and crossing over linkage and recombination genetics: inheritance

Drosophila has four homologous pairs of chromosomes. What is the number of linkage groups (homologous) in this animal?

  1. Four

  2. Two

  3. Eight

  4. Uncertain
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
In the diploid nucleus, each chromosome is represented twice: by a homologous pair and there are same genes on homologous chromosomes.
In Drosophila, there are four pair of chromosomes: 2 pairs of large autosomes, (one slightly smaller than the other pair), 1 pair of very small autosomes, and a pair of sex chromosomes. Genes present on one chromosome form a linkage group. Homologous chromosomes carry same set of genes (the alleles may differ), hence same linkage group.
So, the correct answer is 'Four'.
Multiple choice botany chromosomal basis of inheritance linkage and crossing over linkage and recombination genetics: inheritance

All genes located on the same chromosome

  1. Form different groups depending upon their relative distance

  2. Form one linkage group

  3. Will not from any linkage groups

  4. Form interactive groups that affect the phenotype
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

All the genes located on a single chromosome, are inherited together. So, they constitute a linkage group. They don't move independently during the process of cell division. They always in a group. They form a set of genes on different loci in a single chromosome. But the chromosome should not be a cross over one.

So, option B is the correct answer.

Multiple choice botany chromosomal basis of inheritance linkage and crossing over linkage and recombination genetics: inheritance

Gametic maps of chromosomes are based on

  1. Non disunction

  2. Tranlocation

  3. Dominance

  4. Genetic recombination

  5. Chromosomal aberrations.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A linkage or genetic chromosome map is a linear graphic representation of the sequence and relative distance of the various things present in a chromosome. A chromosome app is also called a linkage map or the genetic map. The percent of crossing over between two genes is directly proportional to the distance. The unit of crossing over has been termed as centiMorgan.


So, the correct option is 'Genetic recombination'.

Multiple choice botany chromosomal basis of inheritance linkage and crossing over linkage and recombination genetics: inheritance

How many linkage groups are present in human male?

  1. 24

  2. 23

  3. 46

  4. 22
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Humans can have 2 linkage groups based on gender. 
Male have 22 pairs of autosomes and 1X and 1Y. So, in all 24 linkage groups. 
While females have 22 pairs autosomes and 1X pair. So, total 23 linkage groups
Thus, the correct answer is '24'.