Mitosis and meiosis are similar processes which however have definite differences. Gametes are produced through meiosis and are essential for sexual reproduction; they are ova and spermatozoa, as well as spores and pollen. Mitosis, on the other hand, is part of the reproduction of all other types of cells in the body. It is the process by which we create new skin, bone, blood and other cells known as "somatic cells". You can tell the difference between mitosis and meiosis by considering the stages of both processes.
Steps
Part 1 of 2: Identifying Mitosis
Step 1. Consider what happens in mitosis
With this process, diploid cells are created. Without mitotic replication, your body would not be able to heal and grow. When mitosis occurs, your DNA replicates. The cells divide and show clear phases, known as interphase, prophase, metaphase, anaphase and telophase. The basic process of mitosis is as follows:
- To begin with, DNA condenses into chromosomes that line up.
- The child chromosomes are separated and move to the poles of the cell (on the edges).
- Eventually, the cell divides into two new cells, in a process called cytokinesis or cytokinesis.
Step 2. Count the number of divisions
In mitosis, cells divide only once. The new cells are called "daughters". Many human cells reproduce by dividing into 2 new cells.
- Check the number of daughter cells. In mitosis there should be only 2.
- The original cell is no longer present at the end of mitosis.
Step 3. Make sure a full set of chromosomes is present
The two daughter cells are identical in quantity and type of chromosomes with respect to the nucleus of the progenitor cell. If the new cell does not have a full set of chromosomes, it has been damaged or mitosis has not been completed. All healthy human somatic cells should have a full set of chromosomes.
Cells that have excess or few chromosomes do not function well and die or become cancerous
Part 2 of 2: Identifying Meiosis
Step 1. Consider how gametes are produced in meiosis
Meiotic replication is responsible for an organism's ability to reproduce half the number of "daughter" cells also known as haploid cells. When an organism reproduces, it creates gametes. These cells do not have a complete set of DNA. They have half as many chromosomes as those created with mitotic replication.
- For example, egg and sperm cells are meiotic and contain half of a complete set of chromosomes.
- Pollen is a gamete. Like human gametes, it contains half as many chromosomes as other plant cells.
Step 2. Consider the synapse
This term indicates the process by which two chromosomal pairs share and exchange DNA. The process is a part of meiosis, but not of mitosis, so it helps you to distinguish the 2 types of reproduction.
- Synapse occurs when two ends of chromosomes meet and share genetic information. When the cells separate, the information is mixed in two of the four cells.
- This happens during prophase 1 of meiosis.
- This process is distinct from chromosomal crossover, in which homologous chromosomes exchange genetic material.
Step 3. Count the number of divisions in meiosis
In this process, the cell divides more times than in mitosis. This is crucial for the reproduction of gametes. Since gametes must contain half as many chromosomes as normal cells, in meiotic reproduction, cells divide twice, in the stages called meiosis I and meiosis II. This means that all the phases indicated for mitosis are repeated twice in meiosis:
- To begin with, DNA replicates itself, as in mitosis.
- Then, one cell splits in two, just like in mitosis. Homologous pairs divide into the first series of cell divisions (meiosis I). Then, the sister chromatids divide again in the second series (meiosis II).
- Eventually, the two cells divide again. This third cell division is not present in mitosis, so it will help you spot the differences between the two processes.
Step 4. Check the number of daughter cells
With meiotic division, the final daughter cells are 4. This number is needed to create cells that contain half the chromosomes of the progenitor ones. Without the reduction in chromosomes, the gametes would not be able to perform their function in sexual reproduction. For example, when sperm and ova (haploid cells) meet, they form a complete diploid cell.
