Living organisms are made up of cells that contain genes. These genes are responsible for controlling the function and traits of all living beings. From a single cell organism like amoeba to multicellular organisms like humans, everything’s appearance and functionality are defined by genes. These genes contain chromosomes, which have the genetic material DNA and RNA. The chromosomes are present in different sets in distinct organisms. These sets are known as ploidy. For NEET 2022, a student must know two basic yet important types of ploidy known as ‘haploid’ and ‘diploid’.
When the chromosomes inside a nucleus have only a single set, they are termed haploid. Likewise, when the set of chromosomes is doubled in any organism, that set is known as a diploid set. It is crucial to comprehend that each set in diploid comes from parents. One set from the mother and another from the father. In Biology syllabus and especially NEET UG 2022, Haploid and diploid are critical topics.
Living organisms are not limited to just two types of ploidy. There are even states which exceed two sets of chromosomes. When there exist three or more sets of chromosomes, the set is known as polyploidy. A set of three chromosomes is called a triploid. The ploidy ranges from 3 to 64 sets of chromosomes for living organisms. But, there is an exception, a small silkworm has 10,48,576 Ploidy!
Next in this article, we shall start with a detailed explanation of haploids and diploids. The student will find all the important concepts related to this topic for NEET 2022.
Haploids
Haploids are the single set of chromosomes present in the cell’s nucleus. This is the reason why they are also known as monoploids. The term Haploid is derived from ‘haplous’, which means single or one. These cells are the result of a process known as meiosis. The haploids are quite diverse. They are completely different from their genetic parents. In the human body, the sex cells or gametes are the only haploids. It is the sperm in males and the egg cell in females.
An interesting fact about haploids is that when a male haploid fuses with a female haploid during fertilisation, they form a diploid cell. The human gametes are haploids to maintain the number of chromosomes in the offspring. Note that haploid cells are just half the number of diploid cells full stop. If the number of diploid cells is 2n, then the number of haploid cells is n.
Sex cells or gametes are types of haploid cells, not in the case of just humans but also in many advanced forms of life. The diploid cells, known as the somatic cells, contain two copies of the genes. These cells produce gametes by a process known as gametogenesis. This process uses the methods of meiosis to half the number of chromosomes. This is done so that one set of chromosomes comes from the male parent during the fertilisation and the other comes from the female parent, making the zygote a diploid. Through this process, the chromosomal numbers have been preserved for multiple generations.
For instance, humans are multicellular organisms with hereditary 46 chromosomes in the genes. This is a pair of 23 chromosomes. The father passes on one team, and another pair is passed on from the mother. That tells us the human sex cells are monoploids. The male sperm has 23 chromosomes, and the female egg cell has another 23 chromosomes. During fusion, the zygote growth undergoes a process known as Mitosis. This process fuses the two different haploids into a pair to maintain the somatic cell chromosome number of 46 in humans.
Diploids
Di means two; hence diploids are cells that contain two sets of chromosomes. Although, the word diploid is taken from the Greek word ‘diplous’, which means double or two. Hence, a double chromosomal gene is known as a diploid. As discussed above, a diploid cell can only be formed by fusing two monoploid cells. They are created in the mitosis stage. All somatic cells come under the category of diploids. Somatic means that two chromosomes are involved in the cellular structure. If diploids are present in any organism’s nucleus, it ensures that the organism has two copies of homologous chromosomes. Homologous implies that the chromosomes are of the same species.
That is the reason why species can only reproduce among themselves. It is impossible to have offspring of a male dog and a female cat. The reason behind this is the difference in chromosomal figures. Dogs have 78 diploids, while cats have 38 diploids. When diploids reproduce, the offspring carry the genetic material of both parents. Hence the offspring is identical to its biological parents. That is why a child’s face, the colour of the eyes and hair, the skin, etc., matches with either of the parents.
A detailed explanation of haploids and diploids for the NEET 2022 syllabus has been discussed above. Let us now look at the essential topic of this article, that is, the difference between haploids and diploids. Many questions in the previous question papers have been asked about this topic.
Difference Between Haploids and Diploids
There exist considerable differences between haploids and diploids. The way they reproduce, their origin, the cell type in each case, etc., are some of the parameters on which we will study the difference between haploids and diploids. Some of the important differences are mentioned below:
Parameters | Haploids | Diploids |
Origin | Present in eukaryotes during the production of gamete or sex cells. | Present in eukaryotes during the production of non-sex cells or somatic cells. |
Cell Division | Follows Meiosis cell division for cell formation. | Follows Mitosis cell division for the cell formation. |
Chromosome count | Haploids contain a single cell hence the number of chromosomes is half that of diploid cells. | Diploid cells are double the amount of haploids. They contain two homologous chromosomes (1 male and another female). |
Cell types | The cells formed by haploids are sex cells or gametes. | The cells formed by haploids are non-sex cells or somatic cells. |
Egg types | They are developed as a result of unfertilized cells. | They are developed due to proper fertilisation of eggs. |
Significance | These cells are important for genetic diversity since they produce their unique signature and are employed in sexual reproduction. | These cells are crucial in an organism’s growth, functioning, and overall development. |
Similarity with parents | They are identical to their parents. | They have a mixture of genetic identities due to the crossing of genes. |
Organisms | Insects like ants and bees. | Humans, dogs, elephants, etc. |
Examples | Sperm in males and egg in females. | Somatic cells, including red blood cells, white blood cells, muscle cells, etc. |
Conclusion
There are 23 haploid chromosomes and 46 diploid chromosomes in humans. Somatic cells, not gametes, are responsible for the likelihood of mutations. In humans, there are around 220 different types of somatic cells. As a result, somatic cells determine the composition of cells in the human system, including their nature and contents. In conclusion, haploid cells are involved in sexual reproduction and genetic variety. In contrast, diploid cells are involved in the growth and development of numerous species. That concludes our discussion on haploids and diploids.
The NEET application form is going to be released soon. Until the NEET dates are disclosed, we recommend checking the students’ NEET 2022 Eligibility Criteria, NEET 2022 syllabus, and NEET 2022 Important Chapters. You can check the answers to the question related to this topic on NCERT Solutions for Class 12 Biology.