Meiosis is a process of cell division that takes place only in sex organs, in order to produce sperm or egg cells. Sperm or egg cells must have half the number of chromosomes of normal, somatic cells, so that when they fuse during fertilization, the result is a zygote with the complete number of chromosomes. [...]
Chapter: Cell Division
The difference between mitosis and meiosis
Mitosis is the process of cell division where one cell divides into two cells which are identical to the original cell. This takes place in all our somatic (“normal”) cells. Meiosis is a special form of cell division that only takes place in the sex organs (gonads) of organisms that undergo sexual reproduction, in order [...]
The difference between chromatin, chromatid and chromosome
It’s easy to confuse these 3 terms! Let’s try to clear things up here. DNA, the blueprint of life, is organized into structures called chromosomes. In prokaryotic cells, chromosomes are circular, whereas in eukaryotic cells, they are linear strands. Different organisms have different numbers of chromosomes: human cells usually have 46 chromosomes, dogs have 78 [...]
Cytokinesis
Cytokinesis is the final stage in the cell cycle. The cytoplasm of the dividing cell is separated in two. The way this happens is different for animal and plant cells. In animal cells, the cell forms a contractile ring in the middle of the dividing cell. As the ring contracts, it creates a cleavage furrow, [...]
Interphase
Dividing cells spend most of their time (around 90%) in interphase. However, they are not just resting, but preparing for the next division. The first part of interphase, the G1 phase (Gap 1), is the period during which cells are growing, synthesizing proteins and making more organelles. Cells need to double their organelles and size [...]
Cell Division
Cell Theory states that cells come from pre-existing cells. What does this mean? Our body is made up of billions of cells, and all of them originate from only TWO basic cells – the sperm and egg. To get from 2 cells to a billion, these 2 cells divide many many MANY times. A lot [...]