What is the Difference Between Meiosis II and Mitosis

The main difference between meiosis II and mitosis is that the meiosis II essentially occurs in haploid cells that have gone through meiosis I whereas the mitosis mainly occurs in diploid cells. Moreover, meiosis II occurs in the production of gametes in sexual reproduction while mitosis occurs in asexual reproduction. 

Meiosis II and mitosis are two types of cell division. Meiosis I and II are the two steps of meiosis in which the number of chromosomes in the parent cell reduces by half. During mitosis, the number of chromosomes in the parent cell remains the same in their daughter cells. 

Key Areas Covered 

1. What is Meiosis II
     – Definition, Process, Importance
2. What is Mitosis
     – Definition, Process, Importance
3. What are the Similarities Between Meiosis II and Mitosis
     – Outline of Common Features
4. What is the Difference Between Meiosis II and Mitosis
     – Comparison of Key Differences

Key Terms: Anaphase, Cell Division, Meiosis II, Metaphase, Mitosis, Prophase, Telophase 

What is Meiosis II 

Meiosis II is the second step of the meiosis. Meiosis is the type of cell division, which occurs during the production of gametes. The two steps of meiosis are meiosis I and II. During meiosis I, paired homologous chromosomes are separated into two daughter cells. These two daughter cells are haploid and they undergo meiosis II individually. The four steps of meiosis II are prophase 2, metaphase 2, anaphase 2, and telophase 2.

Figure 1: Meiosis I and Meiosis II

1. Prophase 2 – Chromatids are thickened and the second spindle apparatus is formed rotated by 90 degrees with respect to the first spindle apparatus.
2. Metaphase 2 – Individual chromosomes are aligned at the cell equator and spindle microtubules are attached to the centromere. 
3. Anaphase 2 – Sister chromatids are separated from the centromere and start to move towards the opposite poles.  
4. Telophase 2 – Sister chromosomes form the daughter nuclei and the spindle apparatus disappears.  

What is Mitosis 

Mitosis is the vegetative type of cell division, which results in daughter cells with the same chromosome number with respect to the parent cell. It proceeds through prophase, metaphase, anaphase, and telophase. The process is very similar to that of meiosis II. But, before entering the prophase, the cells undergo interphase where DNA replication and protein synthesis required for the cell division take place.

Figure 2: Mitosis

1. Prophase – During early prophase, the nucleus of the parent cell disappears. Duplicated chromosomes are condensed. The mitotic spindle is formed. 
2. Metaphase – Individual chromosomes are arranged in the cell equator. Each centromere is attached to a spindle microtubule. 
3. Anaphase – Two sister chromatids are separated from the centromere due to the pulling force of the spindle microtubules and they start to move towards the opposite poles of the cell. 
4. Telophase – Sister chromosomes are at the opposite poles and the daughter nuclei are formed. 

Similarities Between Meiosis II and Mitosis 

• Meiosis II and mitosis are two types of cell division. 
• Both meiosis II and mitosis proceed through prophase, metaphase, anaphase, and telophase.  
• Individual chromosomes are arranged in the cell equator in both types of divisions.  
• Both types of divisions separate sister chromatids from chromosomes. 
• Both produce two daughter cells from a parent cell. 
• The ploidy of the parent cell remains the same in daughter cells.  
• Both types of divisions are followed by cytokinesis in order to result in two daughter cells.  

Difference Between Meiosis II and Mitosis 

Definition 

Meiosis II refers to the second step of meiosis in which the number of chromosomes is reduced by half while mitosis is the vegetative cell division in which the number of chromosomes remains the same. 

Steps 

Meiosis II is the second step of meiosis while mitosis is a single step process.  

Process 

Meiosis II occurs through prophase 2, metaphase 2, anaphase 2, and telophase 2 while mitosis occurs through prophase, metaphase, anaphase, and telophase.  

Occur in 

Meiosis II occurs in the production of gametes during sexual reproduction while mitosis occurs in the vegetative cell division or asexual reproduction. 

Parent cells 

The parent cells that involve in meiosis II are haploid whereas the parent cells that involve in the mitosis are diploid.  

Interphase 

No interphase occurs prior to meiosis II while interphase occurs prior to mitosis in which the DNA replication is taken place. 

Time 

Meiosis II occurs for days or weeks while mitosis occurs for two days. 

Nucleoli 

No nucleoli appear at the end of meiosis II while nucleoli appear in the daughter nuclei as a result of mitosis. 

Conclusion 

Meiosis II is the second step of meiosis, which occurs during the production of gametes. Mitosis is the vegetative cell division. Meiosis II occurs in the haploid cell meiosis II essentially occurs in haploid cells that have gone through meiosis I while mitosis occurs in diploid cells. The main difference between meiosis II and mitosis is the ploidy of the parent cells. 

Reference:

1. Alberts, Bruce. “Meiosis.” Advances in Pediatrics., U.S. National Library of Medicine, 1 Jan. 1970, Available Here 
2. Alberts, Bruce. “Mitosis.” Advances in Pediatrics., U.S. National Library of Medicine, 1 Jan. 1970, Available Here

Image Courtesy:

1. “Meiosis Stages” By Ali Zifan – Own work; Used information from Campbell Biology (10th Edition) by: Jane B. Reece & Steven A. Wasserman. (CC BY-SA 4.0) via Commons Wikimedia   
2. “Diagrama Mitosis” (CC BY 3.0) via Commons Wikimedia