A gamete is another word for a reproductive cell. A gamete can either be a Sperm cell in males, or an Ovum , also known as an Egg cell, in females. Gametes are Haploid cells, meaning they only contain 23 chromosomes, compared to Somatic cells , which contain a full set of 46 chromosomes. When a Sperm cell and Ovum join during Fertilisation , they form a Zygote . The zygote is a combination of the two haploid cells, making it a Diploid cell, therefore providing it with a full set of 46 chromosomes. Following the days after fertilisation, the zygote rapidly divides. Approximately 2 weeks of constant cell division after fertilisation, the zygote is then classed as an Embryo.
Structure and Function of a Sperm
The Spermatozoa consists of a head, middle boy, and tail. The head of the spermatozoa contains the haploid nucleus with 23 chromosomes, which is contained by a cytoplasmic layer containing a range of Polysaccharides. The head is key in the Acrosome Reaction as it contains 2 key enzymes; the hyaluronidase and zona acrosin, which are crucial for allowing the sperm to penetrate the ovum. The middle body of the sperm consists of the mitochondrial sheath, which is critical for providing the sperm cell with ATP, used for energy to rotate the flagella for motility. The tail of the sperm is vital for rotating and propelling the sperm, enabling it to travel towards the ovum. The tail is made out of microtubules, which are in a 9+2 arrangement.
Figure 1 - Structure of a Sperm.
Function of an Ovum
The female ovum, which is significantly larger than the male spermatozoa, also has the same purpose as the spermatozoa; fertilisation. The ovum cannot move like the spermatozoa, since it has no flagella attached. Instead, the ovum contains essential nutrients needed for zygote development into an embryo.
- ↑ Wright DB. Human Physiology and Health. Oxford: Heinemann Educational Publishers. 2000:152
- ↑ Cherry K. The Zygote Phase in Reproduction. 2018 [cited 17/10/18]; Available from: https://www.verywellfamily.com/what-is-a-zygote-2796031
- ↑ Chavarría ME, Reyes A, Rosado A. The male factor. II. Spermatozoa. Structure and function. 1997 [cited on 17/10/18]; Available at https://www.ncbi.nlm.nih.gov/pubmed/9432472
- ↑ Sutovsky P, Tengowski MW, Navara CS, Zoran SS, Schatten G. Mitochondrial sheath movement and detachment in mammalian, but not nonmammalian, sperm induced by disulfide bond reduction. 1997 [cited 17/10/18]; Available at https://www.ncbi.nlm.nih.gov/pubmed/9110318
- ↑ Jain K. Structure, Functions and Types of Mature Sperms in Animals. 2018 [cited 17/10/18]; Available at http://www.biologydiscussion.com/notes/structure-functions-and-types-of-mature-sperm-in-animals-biology/768
- ↑ Villarreal MR. Sperm. 2006 [cited 17/10/18]; Available at https://en.wikipedia.org/wiki/Sperm
- ↑ Soffar H. The structure and function of the ovum in the female reproductive system. 2015, [cited on 17/10/18]; Available at https://www.online-sciences.com/the-living-organisms/the-structure-and-function-of-the-ovum-in-the-female-reproductive-system/