Cell Theory | * Building blocks of which all living organisms are made * 1839- Matthias Schleiden and Theodor schwann stated their cell theory as follows: * All living things made up of cells * Smallest units of life * 1858 – Rudolf Virchow added to the theory saying; * all cells come from pre-existing cells * these three statements form modern day cell theory. * Robert Hooke helped in the development of the compound microscope, including the use of the iris diaphragm. * He used the microscope in 1665, too view a thin piece of cork. He was the first to describe what he saw as ‘pores or cells’. * Robert Brown identified structures inside plant cells. In 1831, he was the first to identify the nucleus as a large body found inside cells. | Magnification and Resolution | * Light microscopes- x1000 * Electron microscopes – x 1000000 * Microscopes allow us the distinguish two objects close together as separate objects. * The degree to which a microscope can do this is called resolving power. * 10^-6, 10 ^-9 | Cell contents | Light microscope- * Reveled that cells are not empty, and that protoplasm is not a uniform structure. * Certain structures in common * Defined shape or boundary * Cell membrane^ * Organelles have a particular job to do for the cell.organelles and the cell membrane are contually changing, breaking down and reforming in a dynamic patern of activity. * Nucleus seen. * And nucleolus and chromosomes.- by staining. * Cytoplasm looks like a clear fluid with particles in it. The fluid is known as cytosol. * Some mitochondria can be seen, but not in detail. * Chloroplasts contain the pigment chlorophyll, which gives plants their green colour.Plant cells – * Cytoplasm * Vacuoles * Chloroplast * Nucleus * Membrane * Cell wall * Nuclear membraneAnimal cells- * Cell membrane * Nucleus * Nuclear membrane * Cytoplasm * No cell wall * No large vacuoles * No chloroplasts | Substances in a cell | Organic- molecules always contain carbon atoms. The major groups of organic molecules found in cells are carbohydrates, lipids, proteins and nucleic acidsInorganic – molecules do not usually contain carbon atoms and are found in living and non-living things. Some simple carbon compounds, including CO2, are often considered to be inorganic even though they contain carbon.Carbohydrates are compounds consisting of carbon, hydrogen and oxygen atoms (c,h,o) | Monosaccharides | Are the simplest carbohydrates, consisting of single units of sugar. | Disaccharides | Are also simple carbohydrates, consisting of double units of sugar. | PolysaccharidesEg- starch | Are complex carbohydrates consisting of multiple sugar units condensed to form huge molecules. | Lipids Eg- fats, oils, waxes | Contain carbon, hydrogen, and oxygen, but the ratio of H to O is never 2:1. Very little oxygen. Usually insoluble. | Proteins | The most abundant organic molecules in cells, needed by the body for growth and repair.Contain C,H,O and N.Large molecules made up of smaller molecules called AMINO ACIDS joined together by PEPTIDE BONDS to form POLYPEPTIDE. | Nucleic Acids | Are organic molecules which contain linked sugar molecules, nitrogen bases and phosphate groups. | Tests for chemical substances | Protein – biuret - + purplrGlucose – Benedicts Solution - + orange/redStarch – iodine - + blue/blackLipid – brown paper - + translucent markChloride – silver nitrate - + white precipitation. | Membrane | * Fluid mosaic model. * Selectively permeable *