Biochemistry 2280A Chapter : SamenvattingEssentialCellbiology.pdf
Document Summary
It is enclosed by a membrane, in the middle lies the nucleus. Around the nucleus lies the cytoplasm, that fills the cell"s interior together with the organelles. The entire cell is surrounded by the extracellular matrix, which separates one cell from another. The external membrane of a cell is called the plasma membrane, while the membranes surrounding organelles are called internal membranes. Cells that have a nucleus are called eucaryotes, cells that do not have a nucleus are prokaryotes. The possession of a nucleus goes hand in hand with possession of other organelles. The nucleus is enclosed within 2 concentric membranes that form the nuclear envelope. The nucleus contains dna, these giant molecules become visible under the microscope as chromosomes. Bacteria do not keep their dna enclosed in a envelope. The mitochondria is enclosed in 2 separate membranes (inner one is folded).