DNA is the genetic material in all except certain viruses. In Prokaryotic cells, DNA occurs in the cytoplasm and is the only component of the chromosomes. Whereas, in Eukaryotic cells, DNA is largely confined to the nucleus. Do you know, A human DNA contains 3 billion chemical letters. Yes, it is true. There are several other amazing and fun facts about DNA that we don’t know.
In 1868, T. H. Huxley described protoplasm as the “physical basis of life”. Protoplasm is a clear, colorless and jelly-like substance which seemed to make up the contents of the cell. It was also described as “substance of life” or “living material”. Continue reading What is the physical basis of life?
An average Human cell (diploid) contains about 6.4 billion base pairs of DNA divided among 46 chromosomes. The length of each base pair is about 0.34 nm. Therefore, if the DNA molecule in a diploid cell were laid out end to end, the total length of DNA would be approximately 2 meters. Continue reading How a 2 meters long DNA is fitted into a 2 micrometers Nucleus?
The concept that the cell is the basic unit of life is known as the Cell Theory. It is one of the most fundamental generalizations of biology and ranks with Charles Darwin’s theory of organic evolution and T.H. Morgan’s theory of the gene of modern biology. Continue reading What is Cell Theory?
Cellular Totipotency is the ability of a single cell to produce all cell types and to organize them into an entire organism when cultured in a suitable culture medium at an appropriate temperature and aeration conditions. Spores and Zygote are examples of totipotent cells. Continue reading What is meant by Cellular Totipotency?