how many chromosomes do humans have cell

Heredity depends upon the protoplasmic continuity between the parent and the offspring. It is the gametes that establish the continuity between parent and offspring and hence, the mechanism of inheritance operates across this exceedingly slender protoplasmic bridge. The machinery of inheritan..

Chromosomal Basis of Inheritance - Heredity depends upon the protoplasmic continuity between the parent and the offspring. It is the gametes that establish the continuity between parent and offspring and hence, the mechanism of inheritance operates across this exceedingly slender protopla..

These are giant chromosomes found in the salivary gland cells of the fruitfly Drosophila. They are many times larger than the normal chromosomes reaching a length of 2000 and are visible even under a compound microscope. The polytene chromosomes appear to ..

It is a comprehensive international effort started in 1990 by molecular biologists to map the entire human genome by determining the complete nucleotide sequence of DNA of each chromosome..

The organisms have a thick body wall to prevent the evaporation of water, so exchange of materials between the body cells and the environment by diffusion is not possibl..

Closed Circulatory System in Humans - The closed circulatory system can be represented as follows. Diagram showing inter-relationship between artery, vein and capillary The closed blood vascular system is a very well developed system This is so because, a) The organisms have a thick body ..

Human Reproductive System - In human beings, sexual reproduction takes place. Sexes are separate and hence they are known to exhibit sexual dimporphism. Males have sex organs called the tetes while the females have sex organs called the ovaries. Even in the external appearance, ..

During this phase the meristematic cells divide to form new cells. Division is restricted to the apical meristems, both at root and shoot tips. The newly formed daughter cells are thin walled and have dense protoplasm. The daughter cells have the same number ..

Prokaryotic Cells Eukaryotic Cells Very minute in size Fairly large in size Nuclear region (nucleoid) not surrounded by a nuclear membrane Nuclear material surrounded by a nuclear membrane Single chromosome present More than one chrom..

Waldeyer is credited with the discovery of chromosomes in the year 1888 within the nucleus. He observed them as darkly stained bodies. However, it was the American William Sutton who noticed the similarities between the behaviour of the mendelian factors or genes and that of the ..