Amitosis, Definition, Discovery, Process and Significance

Amitosis is a type of cell division that is distinct from the more common process of mitosis. Unlike mitosis, which is characterized by a series of organized steps, amitosis is a simpler and more direct method of cell division. This process occurs primarily in certain unicellular organisms and in some specialized cells within multicellular organisms. Amitosis is important for the  NEET Exam and is included in the NEET syllabus , highlighting its significance in understanding cellular processes.

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Amitosis Definition

Discovery of Amitosis

Process of Amitosis

• Elongation of Parent Cell Nucleus : The nucleus of the parent cell elongates, taking on a dumbbell-like appearance as nuclear material accumulates at both ends. This shape prepares the nucleus for division.
• Replication of DNA: Inside the elongated nucleus, DNA undergoes replication, resulting in a doubling of the genetic material. However, unlike mitosis, there is no structured formation of chromatids or precise segregation mechanisms.
• Karyokinesis : The elongated nucleus then divides into two, though the distribution of DNA between the nuclei may be unequal. Without spindle fibers to guide chromosome movement, the division is random.
• Cytokinesis: After nuclear division, the cytoplasm begins to constrict inward, forming a furrow. This constriction deepens and eventually leads to the separation of the parent cell into two daughter cells.

Significance of Amitosis

• Rapid Division : Amitosis allows for rapid cell division, which is essential for unicellular organisms that need to reproduce quickly in response to environmental changes.
• Adaptation : In multicellular organisms, amitosis can occur in specialized cells, helping them to adapt to specific functions, such as tissue repair.
• Genetic Stability : Although amitosis results in daughter cells that are genetically similar to the parent cell, it allows for quick propagation of cells, especially in conditions where rapid growth is necessary.
• Evolution of New Species : Amitosis contributes to the evolution of new species by fostering genetic diversity. As random genetic variations arise through amitosis, these variations can accumulate over generations.
• Evolution of New Species : Amitosis contributes to the evolution of new species by fostering genetic diversity. As random genetic variations arise through amitosis, these variations can accumulate over generations.

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MCQs of Amitosis

Q1. Anastral mitosis is found in:

1. Animals
2. Higher plants
3. Bacteria
4. Cyanobacteria

Q2. Amitosis is found in bacteria. A bacterial cell divides once every minute. It takes an hour to fill a cup. The time taken to fill half a cup is:

1. 10 minutes
2. 30 minutes
3. 50 minutes
4. 59 minutes

Q3. Amoeba shows:-

1. Intranuclear mitosis
2. Amitosis
3. Endomitosis
4. Open mitosis

Answers of MCQs of Amitosis