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

Monosomy and Trisomy are represented as:

  1. 2n + 1, 2n + 3

  2. 2n - 1, 2n - 2

  3. 2n, 2n + 1

  4. 2n -1, 2n + 1
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

 The term "monosomy" is used to describe the absence of one member of a pair of chromosomes.The term "trisomy" is used to describe the presence of an extra chromosome — or three instead of the usual pair.

Multiple choice

Chiasmata formation in Drosophila

  1. generally takes place in males and females

  2. takes place only in males

  3. never or rarely takes place in males

  4. never or rarely take place in females
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In Drosophila, the situation is very different.

Multiple choice

Which statement is not true for karyotype?

  1. It provides information about chromosome number, relative size, position of centromere, etc.

  2. It is described in the form of idiogram.

  3. C-banding brings about AT rich region.

  4. Cells are treated with colchicine at metaphase.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

It stains regions having constitutive heterochromatin. Q-banding shows AT rich regions.

Multiple choice

In case of mitosis in 'Gnetum', which of the following is the correct explanation for the term ‘karyochoresis’?

  1. During cell division, the karyotheca disappears completely.

  2. During cell division, the karyotheca and the nucleolus disappear completely.

  3. During cell division, the karyotheca does not disappear.

  4. During cell division, the mitotic spindle is not formed.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Karyochoresis is that type of mitosis in which the nuclear membrane (karyotheca) does not disappear, but it persists throughout the cell division and it can be seen even at the telophase. During karyochoresis, the spindle formation is internal. After telophase, the parent nucleus undergoes centripetal constriction and divides into two daughter nuclei.

Multiple choice

Colchicine is employed to diploid a haploid cell as it

  1. inhibits karyokinesis

  2. inhibits formation of mitotic spindle

  3. allows replication of DNA twice in one cell cycle

  4. inhibits formation of centromere
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Colchicine, a drug, which inhibits spindle fibre formation during mitosis and halts cell division at metaphase. This often will result in a doubling of the chromosome number since colchicine typically inhibits cytokinesis, but not karyokinesis. The doubled chromosomes will fuse within a single nucleus, thus diploidising the haploid cell.

Multiple choice

Which of the following processes takes place during the G2 phase of cell division?

  1. Synthesis of RNA, proteins, nucleotides and amino acids

  2. Synthesis of factors required for initiation and completion of mitosis and checks for any abberrations resulting from DNA synthesis

  3. Synthesis of RNA and proteins leading to the growth of cell to normal size

  4. Synthesis of DNA leading to chromosomal replication
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

All these changes occur in G2 phase and halts to complete this process.

Multiple choice

The purpose of adding phytohemagglutinin to peripheral blood cultures for chromosomal analysis is

  1. swelling of cells to permit chromosome visualization

  2. collection of large number of cells at metaphase

  3. chromosome condensation

  4. stimulation of lymphocyte cell division
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Phytohemagglutinin stimulates the division of T-cells. A mitotic arresting drug such as colchicine is used to collect dividing cells at metaphase and hypotonic treatment swells the cells to permit chromosomes to be visualized.