Type: Synthesis Essays
Sample donated: Byron Christensen
Last updated: February 18, 2019
Cell structure and itscomponents Cell:Human body is made upof several small units called cells. Thecell is a basic structural and functional unit of all living organisms.The cell was discoveredby the scientist Robert Hooke.The name was taken fromthe Latin;’cellula’ means “a small chamber”.
Classificationof cells:Typeof cells:1. Prokaryotic cell.2.
Eukaryotic cell.Prokaryoticcell:A cell that does notcontain membrane-bound organelles and a well defined nucleus is called aprokaryotic cellIt is known as simplecell.Example: Bacteria.Eukaryoticcell:A cell that contain a welldefined nucleus, a nuclear membrane and membrane-bound cell organelles iscalled a eukaryotic cell It is known as acomplete cell.The two types of Eukaryoticcells are:1. Animal cell.2.
Plant cell.The animal and plantcells are not same. They vary in theirsize and structure according to their functions, but both the cells are similarin their basic organisation.Animalcell:Plasma membrane:· It gives shape to the cell.· It controls the movement of substancesin and out of the cell.· It protects the cell.
Cytoplasm: · It is a fluid like material inside thecell.· Made of carbohydrates and proteins.Nucleus:· It controls all the activities of the cell.· It carries the genetic information.Mitochondria:· Involved in cell respiration.
· Provide energy to the cell.· It is known as “power house of thecell”.Golgi bodies:· They secrete enzymes and hormones.· It is in tubular forms.· They store protein.
Endoplasmic reticulum:· It involves in transportation ofmaterials.· It involves protein synthesis.Ribosome:· It is called protein factories of thecell.
Lysosomes:· It helps in intracellular andextracellular digestion.· It is called suicidal bags of the cell.Centrosome:· It is present only in animal cell.· It is help in cell division.Vacuoles:· They control intracellular pressure.· They store cell sap.
Plantcell:The plant cell differfrom animal cell by,· The centrosome is absent in the platcell.· Plants are rigid in shape.· They have plastids.· They have large vacuoles.Cell wall:· Outer layer gives shape to the cell.· Made up of cellulose. Plastids:· They contain pigments.
Classified into 3 types:1.Chloroplast – green pigment2.Chromoplast – orange and yellow pigment3.Leucoplast – no pigmentDifferencebetween plant cell and animal cell: Plant cell Animal cell Cell wall is present Cell wall is absent Large vacuoles are present Small vacuoles are present Chloroplast is present Chloroplast is absent. Rigid in shape not in rigid shape