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

How many chromosome pairs do humans have?

  1. 13

  2. 23

  3. 34

  4. 46
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Humans typically have 46 chromosomes in each somatic cell, organized into 23 pairs. One set of 23 is inherited from each parent.

Multiple choice

Why does DNA replication take place?

  1. To create new cells in growth and repair

  2. To fix mutations

  3. For human cells to have 92 chromosomes

  4. To visualize the DNA
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

DNA replication is essential for cell division (mitosis), ensuring that each daughter cell receives an identical copy of the genetic material for growth and tissue repair.

Multiple choice botany cell and cellular organization cell theory microscope cell and its discovery

Which microscope is best to study cell division in functional state?

  1. EM

  2. SEM

  3. Phase contrast microscope

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

Phase contrast microscopy is particularly important in biology. It reveals many cellular structures that are not visible with a simpler bright field microscope. These structures were made visible to earlier microscopists by staining, but this required additional preparation and killed the cells. The phase contrast microscope made it possible for biologists to study living cells and how they proliferate through cell division. So, phase contrast microscope is best to study cell division in functional state compared to EM, SEM and simple microscope.

Multiple choice botany cell and cellular organization cell theory microscope cell and its discovery

Separation of chromatids during metaphase and behaviour of chromosomes during mitotic and meiotic divisions can be best studied by

  1. Phase contrast microscope

  2. SEM

  3. X-ray microscope

  4. Cell-fractionation method
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Phase contrast microscope has a phase plate and an annular diaphragm. They bring about changes in light rays passing through the specimen producing differences in light intensity. Denser parts alter path of light more than the thinner parts. This produces varying contrast for different regions. 

The microscope is useful in the study of small living organisms, living cells, constituents of living cells, effect of various factors over living structures, and study of various cellular events like behaviour of chromosomes during mitosis and meiosis, spindle formation, cytokinesis, pinocytosis, phagocytosis, cyclosis, glandular secretions, spermatogenesis, oogenesis etc.

Multiple choice botany cell and cellular organization cell theory microscope cell and its discovery

A student wants to study the metaphasic behaviour of chromosomes in a living cell. The technique most suitable is

  1. Phase-contrast microscope.

  2. X-ray microscope.

  3. Cell fractionation.

  4. Scanning electron microscope.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Phase contrast microscopy is a type of microscopic technique which converts phase shifts in light passing through a transparent specimen to brightness changes in the image. This technique made possible to study living cells without staining.

Hence A is the correct option. 

Multiple choice

A human egg cell with 24 chromosomes is fertilized by a sperm cell with 23. The result is:

  1. resemble the mother more than the father

  2. inherit a disorder due to the extra chromosome.

  3. resemble the father more than the mother

  4. inherit a disorder due to a missing chromosome.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A normal human zygote has 46 chromosomes, receiving 23 from each parent. If a gamete with 24 chromosomes fertilizes a normal gamete with 23, the resulting offspring will have 47 chromosomes. This extra chromosome leads to genetic disorders, such as Down syndrome.

Multiple choice

Process of cell division can take place by

  1. heterosis

  2. fusion

  3. mitosis

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

Mitosis is the process of cell division by which a single cell divides into two genetically identical daughter cells, maintaining the chromosome number.

Multiple choice

Division of nucleus is called

  1. Karyokinesis

  2. Cytokinesis

  3. Cytogenisis

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

Karyokinesis refers to the division of the cell nucleus during cell division. This is followed by cytokinesis, which is the division of the cytoplasm to form two distinct daughter cells.

Multiple choice

How many autosome chromosomes present in human cells ?

  1. 44

  2. 46

  3. 2

  4. 42
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Human somatic cells contain a total of 46 chromosomes, which consist of 22 pairs of autosomes (44 in total) and 1 pair of sex chromosomes (2 in total). Autosomes carry genes for general body characteristics rather than sex determination.

Multiple choice

Which of the following is true regarding cell division?

  1. Eukaryotic cells divide by binary fission

  2. Prokaryotic cells divide by mitosis

  3. Eukaryotic cells divide using sexual conjugation

  4. Prokaryotic cells divide by binary fission
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Prokaryotic cells, which lack a nucleus and membrane-bound organelles, reproduce asexually through a process called binary fission. Eukaryotic cells divide their nucleus via mitosis or meiosis.