PUMPA - SMART LEARNING
எங்கள் ஆசிரியர்களுடன் 1-ஆன்-1 ஆலோசனை நேரத்தைப் பெறுங்கள். டாப்பர் ஆவதற்கு நாங்கள் பயிற்சி அளிப்போம்
Book Free DemoIn 1923, Theophilus Painter, an American zoologist, discovered the number of human chromosomes. He detected 24 pairs of chromosomes using the microscope, which equates to 48. It was not until 1956 that Indonesian-borncytogeneticist Joe Hin Tjio discovered the correct number as 46. These 46 chromosomes have different functions.
Example:
Chromosome 2 consists of 1,200 to 1,300 genes that provide instructions for creating proteins. These proteins have a wide range of functions in the body.
Each chromosome differs from one another based on the length, thickness, centromere position, shape.
The number, size, and shape of chromosomes in an organism's cell nucleus is called a karyotype.
Human karyotype
Lev Delaunay is the first to describe the karyotype as the phenotypic appearance of somatic chromosomes in 1922 without considering their genetic contents. Nettie Stevens discovered sex chromosomes in mealworms in 1905, when she saw that male cells had one chromosome that was smaller than the others, whereas female cells had all chromosomes that were the same size.
Any living entity (animal or plant) has the same number of chromosomes. Each cell in the human body has 23 pairs of chromosomes. The autosomes makeup 22 pairs, while the allosome, or sex chromosome, makes up the 23'rd pair.
The chromosomes are usually found in pairs in the body cells of sexually reproducing organisms, referred to as a diploid condition (2n). The organisms produce gametes with a single pair of chromosomes. Thus, the gametes are described as haploid (n).
Important!
An ideogram is a diagrammatic representation of a species' karyotype. It comprises all metaphasic chromosomes arranged in homologous pairs to decrease length, thickness, centromere position, shape, and so on, with the sex chromosomes at the end.
Register for free to see more content