Mitosis Practice Questions
20 free Mitosis practice questions for the NCERT Biology. Tap an option to answer — you get instant feedback, the correct answer, and a detailed explanation for every question.
Which stage of mitosis is characterized by the initiation of condensation of chromosomal material?
- A Prophase
- B Metaphase
- C Anaphase
- D Telophase
Correct answer: Prophase
Prophase is the first stage of mitosis where chromosomal material condenses to form compact mitotic chromosomes. During this phase, the nuclear envelope, nucleolus, Golgi complex, and ER also disappear.
The complete disintegration of the nuclear envelope marks the start of which phase of mitosis?
- A Early Prophase
- B Metaphase
- C Anaphase
- D Telophase
Correct answer: Metaphase
The second phase of mitosis, Metaphase, begins once the nuclear envelope is completely broken down. This allows the chromosomes to spread through the cytoplasm of the cell.
Small disc-shaped structures at the surface of the centromeres are called:
- A Chromatids
- B Centrioles
- C Kinetochores
- D Spindle fibers
Correct answer: Kinetochores
Kinetochores are disc-shaped structures on the centromere that serve as the sites of attachment for spindle fibers. They are essential for the proper alignment and segregation of chromosomes.
At which stage of mitosis are morphology and the number of chromosomes most easily studied under the microscope?
- A Prophase
- B Metaphase
- C Anaphase
- D Telophase
Correct answer: Metaphase
During metaphase, chromosomes are shortest and thickest due to maximum condensation. They align at the metaphase plate, making this the best stage to observe their size and shape.
The plane of alignment of the chromosomes at metaphase is referred to as the:
- A Polar body region
- B Cleavage furrow zone
- C Equatorial plate
- D Centrosome cluster
Correct answer: Equatorial plate
The equatorial plate, or metaphase plate, is the central plane where all chromosomes align. This alignment is facilitated by spindle fibers attached to kinetochores from opposite poles.
Which phase is characterized by the splitting of centromeres and the separation of chromatids?
- A Metaphase
- B Anaphase stage
- C Telophase
- D Interphase
Correct answer: Anaphase stage
In anaphase, the centromere of each chromosome splits simultaneously, allowing sister chromatids to separate. These chromatids, now referred to as daughter chromosomes, move toward opposite poles.
As chromosomes move away from the equatorial plate during anaphase, the centromere of each chromosome is directed:
- A Towards the equator
- B Towards the pole
- C Sideways
- D Randomly
Correct answer: Towards the pole
During anaphase, the centromeres move first toward the poles, dragging the chromosomal arms behind them. This leads to the characteristic V, L, J, or I shapes of chromosomes.
Chromosomes cluster at opposite spindle poles and their individual identity is lost during:
- A Metaphase
- B Anaphase
- C Telophase
- D Prophase
Correct answer: Telophase
Telophase is the final stage of mitosis where chromosomes decondense and lose their individuality. They reform into chromatin masses at the poles, and the nuclear envelope reappears.
Nuclear envelope, nucleolus, Golgi complex, and ER reform during which stage?
- A Anaphase
- B Metaphase
- C Prophase
- D Telophase
Correct answer: Telophase
Telophase acts as the reverse of prophase. During this stage, the nuclear envelope assembles around the chromosome clusters, and the nucleolus and other organelles reappear.
In animal cells, cytokinesis is achieved by the appearance of a ______ in the plasma membrane.
- A Cell plate
- B Cleavage furrow
- C Spindle fiber
- D Middle lamella
Correct answer: Cleavage furrow
Cytokinesis in animal cells occurs via a cleavage furrow that forms in the plasma membrane. The furrow gradually deepens and joins in the center to divide the cytoplasm into two cells.
Why can plant cells not undergo cytokinesis by the furrowing method?
- A They lack centrioles for spindle formation.
- B They have a large central vacuole blocking division.
- C They have a rigid, inextensible cell wall.
- D They contain more DNA than animal cells.
Correct answer: They have a rigid, inextensible cell wall.
Plant cells are encased in a rigid, inextensible cell wall that prevents the membrane from constricting. Instead, they divide by forming a cell plate that grows from the center toward the periphery.
The cell plate in plant cells represents the formation of:
- A Primary wall
- B Secondary wall
- C Middle lamella
- D Plasma membrane
Correct answer: Middle lamella
The cell plate is formed by the fusion of vesicles in the center of the cell. It eventually develops into the middle lamella, which cements the walls of adjacent plant cells.
In some organisms, karyokinesis is not followed by cytokinesis, resulting in a multinucleate condition called:
- A Syncytium
- B Bivalent
- C Chiasmata
- D Diplonema
Correct answer: Syncytium
A syncytium is a single cell containing multiple nuclei. A classic example is the liquid endosperm in a coconut, where nuclear division occurs without immediate cell wall formation.
Mitosis is also known as equational division because:
- A It occurs in equal time intervals so each daughter cell matures at the same rate
- B The daughter cells have the same number of chromosomes as the parent cell
- C The cytoplasm is divided equally between the two resulting daughter cells
- D It occurs only in diploid cells where both chromosome sets must be preserved
Correct answer: The daughter cells have the same number of chromosomes as the parent cell
Mitosis is termed equational division because the chromosome number remains constant — daughter cells receive the same number (2n) as the parent cell. The genetic material is distributed equally, ensuring no gain or loss of chromosomes.
Which of the following is NOT a significance of mitosis?
- A Production of diploid daughter cells with identical genetic complement
- B Growth of multicellular organisms
- C Cell repair and replacement
- D Introduction of genetic variations
Correct answer: Introduction of genetic variations
Genetic variation is a result of meiosis (due to crossing over), not mitosis. Mitosis produces genetically identical clones, which is essential for growth and tissue repair.
The growth of multicellular organisms is due to mitosis. Mitosis helps in maintaining a high:
- A Surface area to volume ratio
- B Nucleo-cytoplasmic ratio
- C Rate of respiration
- D Number of mitochondria
Correct answer: Nucleo-cytoplasmic ratio
As a cell grows, the nucleus becomes less efficient at controlling a large volume of cytoplasm. Mitosis restores the nucleo-cytoplasmic ratio by dividing the cell into two.
Cells of which layer of the skin are constantly replaced by mitosis?
- A Dermis
- B Subcutaneous layer
- C Stratum basale (basal layer)
- D Hypodermis
Correct answer: Stratum basale (basal layer)
The stratum basale is the deepest layer of the epidermis and the site of active mitosis. New keratinocytes produced here push older cells upward toward the surface, continuously replacing those shed from the skin.
Mitotic division in the _______ tissues results in a continuous growth of plants throughout their life.
- A Parenchyma
- B Meristematic
- C Sclerenchyma
- D Permanent
Correct answer: Meristematic
The apical and lateral cambium meristems are sites of active mitosis. This allows plants to increase in length and girth continuously.
If a diploid cell has 24 chromosomes, how many chromatids are present during Metaphase?
- A 12
- B 24
- C 48
- D 96
Correct answer: 48
In metaphase, each chromosome consists of two sister chromatids joined at the centromere. A cell with 24 chromosomes therefore contains 24 × 2 = 48 chromatids.
Which structure disappears first during prophase?
- A Nuclear membrane
- B Nucleolus
- C Chromosome threads
- D Centriole pairs
Correct answer: Nucleolus
During prophase, the nucleolus is the first structure to disappear as rRNA synthesis ceases and the cell reorganizes for division. The nuclear envelope breaks down later, at the transition to prometaphase.