SCIENCE

• An organism is any contiguous living system such as an animal, plant, fungus, protist, archaeon, or bacterium.
• A unicellular organism is an organism that consists of one cell.
• A multicellular organism is made up of many cells.
• A microscopic organism cannot be seen by the human eye without the use of microscope.
• A macroscopic organism can be seen by the plain human eye.
• Microscope is an instrument used to magnify a tiny object
• The romans discovered the first lens
• Zacharias Janssen made the first compound microscope
• Robert Hooke is known to built his own microscope. He used thin slice of cork as a specimen in his microscope
• Cellula means small compartment. It eventually became the word cell
• Micrographia is one of the first detailed handbook on microscopy and imaging.
• Anton Van Leeuwenhoek is a scientist who studied the bacteria, blood cell, and protists. He made a microscope which had 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 tissues in which he stated that animals are composed of cells.
• The basic unit of life is cell
• All cells come from pre- existing cells
• Rudolf Ludwig Karl Virchow postulated the idea of Omnis cellula e cellula (All cells comes from cells)
• Theory of Spontaneous Generationstates that organisms came from non- living things
• Francesco Redi was able to disprove the theory that maggots could be spontaneously generated from meat using a controlled experiment
• John Needham believed that life can arise spontaneously. He repeated Redi's experiment but yielded different result because he was not successful in killing all microbes while boiling broth
• Lazzaro Spallanzani disagreed to the theory of spontaneous generation after observing absence of small organisms in some chicken broth placed in sealed flasks heated for 30 minutes
• Pasteur also discovered that bacteria are present everywhere, even in air
• Animal cells are eukaryotic cells
• Organelles- different parts of a cell
• Cell Membrane- composed of phospholipid bilayer with emebedded proteins and carbohydrates.
• Semipermeable Membrane- allows oxygen and CO2 to enter
• Microvilli- finger like folds cell membrane that boost cell's absorption function. It increases the cell's surface area
• Cytoplasm- fluiding containing cytosol that fills the cell. This is where the molecules first pass through after entering or before exiting the cell membrane. This is also where the organelles are found and move freely.
• Cytosol- fluid that contains electrolytes. This is the site of cytosolic activities like signal transduction, DNA transcription and replication, glycolysis, enyzme actvities, etc.
• Electrolytes- substance that produces electrically conducting solutions, metabolites, and other sunstances produced during metabolism
• Glycolysis- conversion of glucose into another form
• Cytoskeleton- provides the structure or shape of the cell. It has three major filaments (microfilament, microtubule, and intermediate filament)
• Microfilament- composed of actin (contractile protein) and is about 7 nanometer. Fibrous proteins; form the cellular cortex
• Microtubule- composed of tubulin (globular proteins) and is about 25 nanometer. Form the mitotic spindle and maintain cell shape
• Intermediate Filament- provides tensile strength in the cell and is about 10 nanometer. Fibruos proteins that hold organelles in place
• Centrioles- come in pairs and are at right angles with each other. They help in the seperation and transfer of chromosomes.
• Centrosome- it is where microtubules get organized
• Spindle fibers- they are essential to seperating chromosomes during cell division
• Nucleus- the control center of the cell
• Nuclear envelope- the outer boundary of the nucleus