Mitosis and meiosis are two fundamental processes that take place in living organisms, specifically in eukaryotic cells. These processes are crucial for the growth, development, and reproduction of all living organisms, including humans. In this blog post, we will explore the differences and similarities between mitosis and meiosis.
Mitosis:
Mitosis is a type of cell division that occurs in all eukaryotic cells, except for the reproductive cells (gametes). The main purpose of mitosis is to create two identical daughter cells, each containing the same number of chromosomes as the parent cell. Mitosis is divided into four stages: prophase, metaphase, anaphase, and telophase.
During prophase, the chromatin condenses into visible chromosomes, and the nuclear membrane dissolves. The spindle fibers, which are responsible for moving the chromosomes, start to form. In metaphase, the chromosomes align at the equator of the cell, and the spindle fibers attach to the centromeres of the chromosomes. In anaphase, the spindle fibers pull the sister chromatids apart, and they move towards opposite poles of the cell. Finally, in telophase, the nuclear membrane reforms around each set of chromosomes, and the cell undergoes cytokinesis, where the cytoplasm divides to form two new daughter cells.
Meiosis:
Meiosis is a type of cell division that occurs only in the reproductive cells (gametes) of eukaryotic organisms. The main purpose of meiosis is to produce four genetically diverse daughter cells, each containing half the number of chromosomes as the parent cell. Meiosis is divided into two stages: meiosis I and meiosis II.
During meiosis, I, the homologous chromosomes pair up and exchange genetic material through a process called crossing-over. This results in the shuffling of genetic information and increases genetic diversity. The paired chromosomes then separate, and two new haploid daughter cells are formed. During meiosis II, the sister chromatids of each chromosome separate, resulting in the formation of four haploid daughter cells.
Differences between mitosis and meiosis:
- Mitosis produces two identical daughter cells, while meiosis produces four genetically diverse daughter cells.
- Mitosis occurs in all eukaryotic cells except for the reproductive cells, while meiosis occurs only in the reproductive cells.
- Mitosis results in the formation of diploid cells, while meiosis results in the formation of haploid cells.
- In mitosis, there is no exchange of genetic material between the chromosomes, while in meiosis, there is a crossing-over, resulting in the shuffling of genetic information.
Similarities between mitosis and meiosis:
- Both processes involve the division of the cell\’s nucleus.
- Both processes involve the separation of the chromosomes.
- Both processes involve the formation of new daughter cells.
Mitosis and meiosis are two important processes in the life cycle of eukaryotic organisms. While mitosis results in the formation of two identical daughter cells, meiosis results in the formation of four genetically diverse daughter cells. Both processes involve the separation of chromosomes, but meiosis also involves the exchange of genetic material through crossing over. Understanding the differences and similarities between these two processes is crucial for understanding the biology of living organisms.
WHAT IS MITOSIS?
Mitosis is a cell or nuclear division following the duplication of the chromosome, whereby each daughter cell or nucleus has exactly the same chromosome content as was in the parent cell. So in other words mitosis is the division of cells in which the daughter cell has the number of chromosomes as the parent cell.
Mitosis takes place in somatic cells. That is the body cells that are not involved in the production of gametes.
Mitosis takes place during an organism’s growth, development and asexual reproduction. In plants, mitosis takes place in the terminal bud of the shoot, at the tips of the shoots and roots.
Mitosis produces diploid cells. In other words, the number of chromosomes in each somatic cell of an organism is called the diploid number (2n)
STAGES OF MITOSIS
There are five stages of mitosis or phases of mitosis. These are
i. INTERPHASE OF MITOSIS: this is the latent or resting stage of the cell. At this stage, the cell has a normal appearance of non-dividing cell condition. Chromosomes are too thread-like for clear visibility
ii. PROPHASE OF MITOSIS: the prophase is divided into two. They are late and early prophase. During early prophase, the chromosomes become visible as they contract and the nucleolus shrinks. Centroids are formed on opposite sides of the nucleus. Spindles are formed during the late prophase, the chromosomes become shorter and fatter. Each is seen to contain or consist of a pair of chromatids joined at the centromere and the nucleus disappears.
PROPHASE ENDS WITH THE BREAKDOWN OF THE NUCLEAR MEMBRANE
iii. METAPHASE OF MITOSIS: Metaphase also exists in early and late forms. During the early metaphase of mitosis, the chromosomes arranged themselves on the equator of the spindle and at late metaphase, the chromatids draw apart at the centromere region.
iv. ANAPHASE OF MITOSIS: anaphase of mitosis also exist in early and late forms. During early anaphase, the chromatids part company and migrate to opposite poles of cells while in late anaphase, the chromosomes reach their destination.
v. TELOPHASE OF MITOSIS: Telophase is equally divided into early and late stages or forms. During the early Telophase, the cells start to constrict across the middle. During late Telophase, the constrictions continue.
WEED AND THEIR BOTANICAL NAMES
1. ENVIRONMENTAL FACTORS AFFECTING AGRICULTURAL PRODUCTION
2. DISEASES
3. 52. SOIL MICRO-ORGANISMS
4. ORGANIC MANURING
5. FARM YARD MANURE
6. HUMUS
7. COMPOST
8. CROP ROTATION
9. GRAZING AND OVER GRAZING
10. IRRIGATION AND DRAINAGE
11. IRRIGATION SYSTEMS
12. ORGANIC MANURING
13. FARM YARD MANURE
14. HUMUS
The nuclear membrane and the nucleolus reform in each daughter cell. Spindle apparatus generates. The chromosomes eventually regains their thread-like form and the cells return to resting condition.
THE IMPORTANCE AND ROLES OF MITOSIS IN CELL DIVISION
The importance of mitosis can be seen in the following ways, are
1. Mitosis helps in the repair or replacement of damaged tissues
2. Mitosis promotes cell growth in the cell
3. Mitosis serves as the bases for sexual or vegetative propagation In plants
4. Mitosis produces genetically identical offspring which are identical to the parents in all aspect
5. Mitosis helps to maintain the diploid number of the chromosome of the cell
EXAMPLES OF LIFE PROCESSES INVOLVED IN MITOSIS
An example of life processes of mitosis in animals includes the following
i. The process of mitosis involves the formation of new cells in the Malphighian layer of the skin
ii. Life processes of mitosis involve the production of red blood cells and white blood cells in the bone marrow
iii. Life process in mitosis helps cell division in the liver
iv. Life processes of mitosis help in cell division in meristem or tips of roots
v. Life processes in mitosis help in binary fission
vi. Life processes in mitosis helps in the growth of spermatogenesis
vii. Life processes in mitosis helps in the repair or healing of the wound.
WHAT IS MEIOSIS AND WHAT TYPES OF MEIOSIS
Definition of meiosis
Meiosis is a two successive cell division with only one duplication of the chromosome.
In meiosis, four daughters are formed. Meiosis is a reduction in cell division resulting in the reproduction of four daughters called haploid.
WHERE DOES MEIOSIS TAKE PLACE?
In animals, meiosis occurs in the formation of gametes which is sex cells such as eggs and spermatozoaTHE PROCESS OF GAMETE FORMATION IS CALLED GAMETOGENESIS.
STAGES IN MEIOSIS
Meiosis consists of two successive division, they are
i. First meiotic division: this is very first stage when the parent cell divide into two
ii. Second Meiotic division: this second stage of meiosis is when the cells then divides itself again given a total of four daughter cells
Let’s look at the first stages of meiotic division.
THE FIRST MEIOSIS STAGE OF CELL DIVISION
The 1st stages of meiotic division in meiosis is divided into five stages and they are
1. INTERPHASE OF MEIOSIS: this is the resting stage of the cell. At this stage of meiosis, the chromosomes are not seen
2. PROPHASE 1: PROPHASE 1 OF MEIOSIS is divided into three stages and they are
i. Early prophase: at this stage in the prophase of meiosis, the chromosomes contract, becoming more clearly visible and the nucleus shrinks
ii. MID PROPHASE 1 OF MEIOSIS: in this stage of meiosis, the homologous chromosomes come together as synapsis forming a bivalent
iii. LATE PROPHASE 1 OF MEIOSIS: during this stage of prophase in meiosis, the chromosomes is seen to consist of a pair of chromatid at prophase 1, and crossing over takes place. The points on the chromosomes where crossing over takes place are known as Chiasmata
4. ANAPHASE 1 OF MEIOSIS: In this stage of Anaphase in meiosis, the bivalent separates completely and each member chromosome moves to the opposite pole of the spindle
SECOND MEIOTIC DIVISION IN MEIOSIS
The second meiotic division in meiosis is made up of four stages and the division is similar to mitosis. At the end of the second division of meiosis, four groups of daughter cells are formed. The following are the stages outlined here for you
1. PROPHASE 11 OF MEIOTIC DIVISION IN MEIOSIS: IN prophase 11 of meiotic division, the two daughter cells prepare for the second meiotic division. This is where the centrioles replicate and a new spindle is formed.
2. METAPHASE 11 OF MEIOTIC DIVISION IN MEIOSIS: Metaphase 11 of meiosis is where the chromosomes arrange themselves on the spindle in the usual way. Here the chromosomes appear doubled and the centromere starts to divide in the position of the equatorial plane,
3. ANAPHASE 11 OF MEIOTIC DIVISION IN MEIOSIS: in Anaphase 11 of meiotic division, each chromosome finally split into two. Where the actual chromosomal division takes place at Anaphase 11, each moves to the opposite poles of the cells
4. TELOPHASE 11 OF MEIOTIC DIVISION IN MEIOSIS: at this stage in the meiotic division, the two cells are divided into four cells which are TETRAD. The four haploid cells are produced from the original diploid mother cell
IMPORTANCE OF MEIOSIS AND THE ROLES OF MEIOSIS
There are a lot of things to write about the importance of meiosis but I shall be limiting myself to the following
i. Meiosis aids the formation of male gametes or sperms in animals
ii. Meiosis aids in the formation of ova eggs or female gametes in female animals
iii. Meiosis aids in the formation of pollen grains in anthers of flowering plants
iv. Meiosis also aids in the formation of ovules in the ovaries of flowering plants
AREAS WHERE MEIOSIS OCCURS
1. Meiosis occurs in ovaries and anthers of plants
2. Meiosis occurs ovaries and testes of animals
DIFFERENCES BETWEEN MITOSIS AND MEIOSIS
There are a lot of differences but let us consider the major ones that are feasible to deal with and they as follows
MITOSIS
1. Mitosis takes place during the growth of body or somatic cells
2. In mitosis, the number of chromosomes in the parents and new cells is the same
3. In mitosis, two offspring are formed
4. In mitosis, there is no exchange of materials between variations; the chromatids
5. In mitosis, chromosomes are arranged in pairs in both parents and new cells
6. There is no formation of bivalent in mitosis
7. There is no crossing over in mitosis
8. Mitosis involves only one stage of division
MEIOSIS
1. Meiosis takes place only in the production of gametes
2. In meiosis, the number of chromosomes in the new cell is half the number in the parent cells
3. In meiosis, four offspring are formed
4. In meiosis, chromosomes are arranged in pairs in the parent cell but new cells have only one of the homologous pair
5. In meiosis, there is the exchange in materials
6. In meiosis, the whole chromosomes form bivalent
7. In meiosis, there is a crossing over
8. Meiosis involves two stages of division
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