[Biology Class Notes] on Difference Between Haploid and Diploid Pdf

In Biology, learning about what is Haploid and Diploid is an important topic. According to various sources, the term ‘Ploidy’ refers to the number of sets of Chromosomes that are present within a nucleus. There are different types of Ploidy, and the two most prominent types of Ploidy are Haploid and Diploid. Haploid Cells contain one set of Chromosomes. On the other hand, Diploid Cells contain two sets of Chromosomes. It should be noted that in Diploid, both sets of Chromosomes are from the parents, one from each. 

Also, if there are more than two sets of Chromosomes for all Cells, then that state is known as Polyploidy. In the case of Polyploidy, the sets of Chromosomes can range from three, which are known as triploid, to as high as 64, which are known as tetrahex contaploid. Readers might also be shocked to find that in silkworm a 10,48,576 Ploidy is found!

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The Meaning of Haploid and Diploid

Haploid Cells

Now, let’s first look at what Haploid Cells are. As mentioned above, Haploid Cells have only a single set of Chromosomes. The most common type of Haploid Cells is Sex Cells or gametes. These Cells are produced through Meiosis and are quite diverse in terms of Genetics.

When the Haploid Cells from both male and female gametes fuse together during fertilization, it forms Diploid Cells. Gametes are reproductive Cells that are found in many organisms. These Cells are formed during the process of Reproduction.

The number of Chromosomes present in gametes is half the number of Chromosomes that are present in somatic Cells. The male gamete carried the paternal set of Chromosomes. On the other hand, the female gamete carries the maternal set of Chromosomes.

Gametes are important because these Cells help in maintaining the constant number of Chromosomes in organisms that reproduce Sexually. The number of Chromosomes in Sex Cells of Humans is equal to 23 Chromosomes.

Diploid Cells

In Diploid Cells, there are two sets of Chromosomes. Diploid Cells are formed due to the fusion of two Haploid Cells. Most mammals are Diploid. This means that mammals have two homologous copies of each Chromosome in the Cells. These Cells are produced through mitosis.

All somatic Cells in Human beings are Diploid Cells. It should be noted that every Cell except the proliferating Cells of the reproductive system classifies under the category of somatic Cells. One set of Chromosomes is inherited from the father, while the other set of Chromosomes is inherited from the mother.

It is interesting to note that there are also some organisms in which the somatic Cells are tetraploid, which have four sets of Chromosomes, or hexaploid, which have six sets of Chromosomes.

The chances of spontaneous mutations are also higher in somatic Cells than Haploid Cells. There are also around 220 types of somatic Cells in Humans. Hence, the nature and the content of the Cells in Humans depend on the type of somatic Cells. Also, the total number of Chromosomes in somatic Cells of Human beings is 46.

In this section, the difference between Diploid and Haploid Cells is discussed. These differences are mentioned in the table below.

Differentiate Between Haploid and Diploid

 
Meiosis

The process in which the parent Cell divides twice into 4 daughter Cells holding half the original portion of genetic information is called Meiosis. In this process, the daughter Cells are Haploid. The gametes are created by the process of Meiosis. In other words, it is a form of nuclear Cell division that produces the daughter Cells that have half of the Chromosome numbers as the initial Cell.

 

When Meiosis occurs in Diploid organisms, the outcome is Haploid Cells. All the daughter Cells receive 1 whole set of Chromosomes which includes each homologous pair of Chromosomes. This, in Humans, is the Chromosome number reducing from 46 to 23. 

 

The Cells that experience Meiosis become sperm or eggs. Later at the time of fertilization in Humans, the fusion of a sperm and egg brings back the number of Chromosomes again to 46. 

Features of Meiosis 

Some features of Meiosis are-

• The daughter Cells in this process are Haploid.

• Meiosis results in the formation of four daughter Cells with every cycle of Cell division.

• The daughter Cells are identical to the mother Cell in shape and size but different in Chromosome number.

• Recombination and segregation occur in this process.

• Meiosis happens in the reproductive organs and impacts the formation of gametes.

• The process is divided into 2 types, Meiosis-I and Meiosis-II. Meiosis-I decreases the Chromosome number to half and is also called reductional division. While, on the other hand, Meiosis-II is just like the mitotic division.
  

Stages of Meiosis II

Meiosis II is divided into 4 stages- 

• Prophase II – Prophase II  sets off after the cytokinesis when the daughter Cells are developed. The Chromosomes start to condense attended by the dissolution of the nuclear membrane. It also begins the disappearance of the Golgi apparatus and ER complex.

• Metaphase II – The Chromosomes are joined to the centriole poles at the kinetochores of sister chromatids. It is connected through the microtubules and they also get aligned at the equator to create the metaphase plate.

• Anaphase II – There is a simultaneous splitting of the centromere of each Chromosome and the sister chromatids are drawn away towards the opposite poles in Anaphase II. 

• Telophase II – The Chromosomes dissolve again into an undifferentiated lump. A nuclear envelope then evolves around it. Followed by cytokinesis, telophase II marks the end of Meiosis and 4 Haploid daughter Cells are formed.