cell

1. cell

2. What is cell? • is the basic structural, functional and biological unit of all known livingorganisms. Cells are the smallest unit of life that is classified as a living thing, and are often called the "building blocks of life".

3. Pioneers of cell • Robert Hooke • Matthias JakobSchleiden • Theodor Schwann

4. Robert hooke • The cell was discovered by Robert Hooke in 1665. • He uses a cork to discover a cell.

5. Matthias JakobSchleiden and Theodor Schwann • states that all organisms are composed of one or more cells, that all cells come from preexisting cells, that vital functions of an organism occur within cells, and that all cells contain the hereditary information necessary for regulating cell functions and for transmitting information to the next generation of cells

6. the two types of cell

7. Eukaryotic cell • is an organism whose cells contain a nucleus and other organelles enclosed within membranes. • Cell division in eukaryotes is different from that in organisms without a nucleus (Prokaryote). There are two types of division processes. In mitosis, one cell divides to produce two genetically identical cells. In meiosis, which is required in sexual reproduction, one diploid cell (having two instances of each chromosome, one from each parent) undergoes recombination of each pair of parental chromosomes, and then two stages of cell division, resulting in four haploid cells (gametes). Each gamete has just one complement of chromosomes, each a unique mix of the corresponding pair of parental chromosomes.

8. Prokaryotic cell • are a group of organisms whose cells lack a membrane-bound nucleus (karyon). The organisms whose cells do have a nucleus are called eukaryotes. Most prokaryotes are unicellular organisms, although a few such as myxobacteria have multicellular stages in their life cycles[1] or create large colonies like cyanobacteria. The word prokaryote comes from the Greekπρό- (pro-) "before" and καρυόν (karyon) "nut or kernel