Cells are the basic structural and functionalunits of life
Prokaryotic cells lack a nucleus; their genetic information is found in the nucleoid. They lack membrane-bound organelles and are generally smaller in size and simpler in structure. They are unicellular. E,g. Bacteria, Archaea
Eukaryotic cells have a nucleus, membrane-bound organelles, and a cell membrane. They are generally largerin size and more complex in structure. It can exist as unicellular or multicellular. E,g. Algae, Yeast, Protists, Fungi, Plants, Animals
Endosymbiotic Theory: Suggests eukaryotic cells evolved from prokaryotic cells
Endosymbiosis: A type of symbiosis in which one organism lives in the other
Mitochondria and Chloroplast contain DNA
Technology to determine cell structure
Light microscope, Fluorescent microscope, Electron microscopes (TEM and SEM), Computer enhanced technology, Stains and dyes
Resolution: Ability of the microscope to distinguish between two closely spaced objects
Magnification: Increase in size, typically expressed as a ratio
Light Microscope
Uses light and lenses to magnify specimens, suitable for observingliving and non-living specimens
Fluorescent Microscope
Uses ultraviolet light to excite fluorescent molecules in specimens, can visualise specific structures or molecules labelled with fluorescent dyes and offers higherresolution and sensitivity
Electron Microscope
Uses electron beams and electromagnets to magnify specimens, cannot view living specimens, two main types: SEM and TEM
Transition ElectronMicroscopes (TEM)
Produces detailed, two-dimensional images of internal structures, electrons are transmitted through the specimens
Scanning Electron Microscope (SEM)
Produces detailed, three-dimensional images of specimen surfaces, bombards the surface of a specimen with a beam of electrons, very detailed images but cannot give internal details
Cellular Respiration
Responsible for the production of ATP, carried out by cells, inside the mitochondria
Glucose + Oxygen --> CarbonDioxide + Water + Energy