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 a microscope.
• A macroscopic organism can be seen by the plain human eye.
• A microscope is an instrument used to magnify a tiny object.
• The Romans discovered the first lens.
• It was derived from the Latin word lentil - as it resembled the shape of a lentil bean.
• Zacharias Janssen made the first compound microscope.
• Robert Hooke is known to built his own microscope. He used a 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 a more powerful magnification than what Hooke built.
• Matthias Jakob Schleiden, a professor of botany in Germany. He stated that all plants are composed of cells.
• Theodor Schwann is a professor of physiology at the University of Belgium. He studied several slides of animal tissues in which he stated that animals are composed of cells.
• All organisms are made up of cells.
• The basic unit of life is the cell.
• All cells come from pre-existing cells.
• Rudolf Ludwig Karl Virchow postulated the idea of Omnis cellula e cellula (All cells come from cells).
• Theory of Spontaneous Generation states that organisms came from nonliving things.
• • Francesco Redi was able to disprove the theory that maggots could be spontaneously generated from meat using a controlled experiment. Disproved the theory above.
• John Needham - believed that life can arise spontaneously. He repeated Redi’s experiment but yielded different results because he was not successful in killing all microbes while boiling broth.
• Lazzaro Spallanzani - disagreed with the theory of spontaneous generation after observing the 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 cells are 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 are finger-like folds cell membrane that boost the cell's absorption function.
• Microvilli (Microvillus) - Increases the cell's surface area.
• Cytoplasm - Fluid 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, enzyme activities, etc.
• Electrolytes - Substance that produces electrically conducting solutions, metabolites, and other substances produced during metabolism.