Overview
What is the basic unit of life? What is the smallest constituent that makes up an entire body? A cell! A cell is the smallest and basic unit of any life form. And we know from cell theory that new cells arise from pre-existing cells. However, we should also see how these cells replace old cells. They do this by dividing themselves. Cell division is a phenomenon by which a cell goes through the different phases of a cell cycle to grow and divide into its daughter cells. There are two ways in which cells multiply and reproduce. They are Mitosis and Meiosis. Keep reading to find out a detailed explanation.
What is a cell cycle?
As students, we know that all cells divide. However, it is not entirely true. There are some cells that do not divide once they reach their maturation state, for example, neurons. Nevertheless, there are cells in our body that need to divide in order to grow and reproduce constantly. And when a cell undergoes different events and stages in order to divide, the process is termed a cell cycle.
It is interesting to know that a cell goes through discrete phases where it prepares itself for cell division. The division is usually part of a larger cell cycle. It involves the splitting of a single cell into two cells, and these two are further divided into four daughter cells. The key features of a cell cycle are-
- The duplication of DNA takes place during a cell cycle.
- Every cell that is formed after the cell cycle also goes through cell division later in its life.
- The different phases of a cell cycle include- Interphase, M phase, and Cytokinesis.
Why do cells need to divide?
It is crucial for a cell to divide in order to grow and replace worn-out cells. You may have witnessed how your body heals itself from a wound or injury. It is a result of cell division. However, it is equally crucial for a cell to know when to stop dividing, or else it may develop into a disease called cancer.
If the factors that control cell division are compromised, the different phases that lead to the completion of the cell cycle are incorrectly regulated. Nonetheless, the genes inside our bodies regulate each cell cycle so as to provide life continuity to all living organisms. The main reasons why a cell chooses to divide are-
- To replace old cells
- To repair skin on wounded areas
- To bring about genetic variation
- To retain the information passed by the previous cell
- For the growth of the organism
We know how our body heals a wound by itself. But, can you find out which cell division leads to the production of new cells on the part of the wound? If not, read about the two different cell cycles that happen inside of our bodies. |
What are the two cycles of cell division?
- Mitosis
Definition
Mitosis is the type of cell division that results in the formation of two daughter cells, each with the same number and kind of chromosomes as the parent cell.
Overview
- Mitosis is regarded as the fundamental process for life.
- It is known as the equational division, in which the number of chromosomes remains the same.
- During this type of cell division, a cell duplicates all its genetic material and splits into two identical daughter cells.
- Basically, the result of a mitotic cell division is two nuclei that are identical to the parent nucleus.
- The phases during a mitotic division are- prophase, metaphase, anaphase, and telophase.
Pop quiz four cells undergo mitotic cell division, how many cells will form at the end of this cell cycle? |
- Meiosis
Definition
Meiosis is a type of cell division that results in the formation of four daughter cells, each with half the number of chromosomes as the parent cell.
Overview
- Meiosis differs from Mitosis in reducing the number of chromosomes taking part in the process. Hence, known as the reduction division.
- Also, it is a two-step process that includes the reduction of the chromosome number by half, i.e. from 46 to 23.
- This type of cell division usually occurs in reproductive cells (gametes) like sperm and egg (ovum).
- The half number of chromosomes that are formed during Meiosis is compensated after fertilisation.
- The sperm and the egg both contribute 23 chromosomes, thereby making it a total of 46 chromosomes in the resulting embryo cell.
- Meiosis consists of two phases- meiosis l and meiosis ll.
Do you often get confused between Mitosis and Meiosis? Refer to the table below! |
What are the key differences between Mitosis and Meiosis?
Mitosis | Meiosis |
It occurs in body or somatic cells. | It occurs in reproductive cells or gametes. |
Two daughter cells are formed at the end of each cell division. | For daughter cells, nuclei are formed at the end of each meiotic division. |
Prophase is usually a short stage. | Prophase consists of various other stages and takes a longer period of time until metaphase. |
The daughter cells that are formed have the same number of chromosomes as the parent cell. | The daughter cells that are formed at the end of each mitotic cell division contain half the number of chromosomes. |
It is known as the equational division. | It is known as the reduction division. |
The mitotic division contributes to the growth repair and replacement of the cell. | Meiosis takes part in gamete formation and maintains the chromosome number after each generation. |
The mode of reproduction is asexual. | The mode of reproduction is sexual. |
Cytokinesis happens only once after telophase. | Cytokinesis happens twice after telophase i and telophase ii. |
Curiously enoughNow that we know Mitosis and Meiosis are two different cell cycles that have different outcomes, are you curious enough to know the similarities between the two of them? Let us find it out! |
What are the similarities between Mitosis and Meiosis?
Both Mitosis and Meiosis represent cell division which is a significant phenomenon in humans and animals. Even though these cell division processes have different goals and outcomes, they also share several aspects of production and application, which makes them somewhat similar.
Some peculiar similarities between Mitosis and Meiosis are-
- Both the processes lead to the formation of new cells.
- Both these mechanisms are involved in the reproduction of new multicellular living beings.
- Mitosis, as well as Meiosis, carry out the nuclear division.
- The major phase of both the types of cell division includes interphase, prophase, metaphase, anaphase, and telophase.
- The genetic material of the parent cell is replicated before the cell division.
- Mitosis is the same as meiosis ll.
- Both Mitosis and Meiosis end up producing new cells that contain the genetic material from the parent cells.
- Cytokinesis is the end stage of both the cell cycles.
Pop quiz: Which type of cell division took place if the daughter cell has 23 chromosomes while the parent cell has 46? |
How to distinguish whether a cell has gone through Mitosis of Meiosis?
If you see a microscopic image of a cell, it shouldn’t be difficult for you to tell whether the cell has gone through Mitosis or Meiosis. As we know mitotic divisions happen when the number of chromosomes remains the same throughout the cell division, whereas the number of chromosomes is reduced to half during meiotic divisions.
So, if the daughter cell contains the same number of chromosomes as the parent cell, the cell is said to be going through mitotic division. And if the number of chromosomes in the daughter cell is half of the number of chromosomes in the parent cell, the cell is said to be going through meiotic cell division. Anaphase is an appropriate stage at which a total number of chromosomes can be observed.
Are you facing any doubts concerning Mitosis and Meiosis? Or are you wondering who could solve your queries? Please refer to the FAQs down below to get the answers to your doubts! |
Frequently asked questions about Mitosis and Meiosis
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