Science

• Organism


  Any contiguous living system such as an animal, plant, fungus, protist, archaeon, or bacterium
• Unicellular Organism

  An organism that consists of one cell
• Multicellular Organism

  An organism that is made up of many cells
• Microscopic Organism

  Cannot be seen by the human eye without the use of a microscope (e.g. euglena)
• Macroscopic Organism

  Can be seen by the plain human eye (e.g. multicellular organism like animals)
• Microscope

  An instrument used to magnify a tiny object
• Microscope

  • Romans discovered the first lens
  • Derived from the Latin word lentil- as it resembled the shape of a lentil bean
  • Zacharias Janssen made the first compound microscope
  • Robert Hooke built his own microscope and used thin slice of cork as a specimen
• Cellula

  Small compartment, which eventually becomes the word "cell"
• Micrographia

  One of the first detailed handbook on microscopy and imaging
• Anton Van Leeuwenhoek

  • Studied the bacteria, blood cell, and protists
  • Made a microscope which had a more powerful magnification than what Hooke built
• Matthias Jakob Schleiden

  • Stated that all plants are composed of cells
• Theodor Schwann

  • Studied several slides of animal tissue and stated that animals are composed of cells
• Postulates of Cell Theory

  • All organisms are made up of cells
  • The basic unit of life is cell
  • All cells come from pre-existing cells
• Rudolf Ludwig Karl Virchow

  • Postulated the of Omnis cellula e cellula (all cells come from cells)
• Spontaneous Generation of Cells

  Theory that organisms came from non-living things
• Francesco Redi

  • Disproved that maggots could be spontaneously generated from meat using a controlled experiment
• John Needham

  • Believed that life can arise spontaneously, but was not successful in killing all microbes while boiling broth
• Lazzaro Spallanzani

  • Disagreed with the theory of spontaneous generation after observing absence of small organisms in some chicken broth placed in sealed flasks heated for 30 minutes
• Louis Pasteur

  • Disproved spontaneous generation through an experiment where beef broth was sterilized through boiling in two flasks, one that was exposed to air and another that was protected from it
• Animal Cell

  Eukaryotic cells, or cells with a membrane-bound nucleus
• Organelles

  Different parts of a cell
• Cell Membrane

  Composed of phospholipid bilayer with embedded proteins and carbohydrates
• Semipermeable Membrane

  Allows Oxygen and CO2 to enter
• Microvilli

  Finger-like folds of the cell membrane that boost the cell's absorption function
• Cytoplasm

  Fluid containing cytosol that fills the cell, where molecules first pass through after entering or before exiting the cell membrane, and where organelles are found and move freely
• Cytosol

  Fluid that contains electrolytes, the site of cytosolic activities like signal transduction, DNA transcription, replication, glycolysis, enzyme activities, etc.
• Electrolytes

  Substances that produce electrically conductive solutions, metabolites, and other substances produced during metabolism
• Glycolysis

  Conversion of glucose into another form
• Cytoskeleton

  Provides the structure or the shape of the cell, with three major filaments (Microfilament, microtubule, and intermediate filament)
• Microfilament

  Composed of actin (contractile protein) and is about 7 nanometers
• Microtubule

  Composed of tubulin (globular proteins) and is about 25 nanometers
• Intermediate Filament

  Provides tensile strength in the cell and is about 10 nanometers
• Centrioles

  Come in pairs and are at right angles with each other, helping in the separation and transfer of chromosomes
• Centrosome

  Where microtubules get organized
• Spindle Fibers

  Essential to separating chromosomes during cell division
• Nucleus

  The control center of the cell
• Nuclear Envelope

  The outer boundary of the nucleus
• Nucleoplasm

  The substance inside the nuclear envelope
• Chromatin

  The substance within the nucleoplasm, a combination of DNA and proteins
• DNA

  Deoxyribonucleic Acid