ELS 2

• Biology


  Study of living organisms
• Branches of Biology


  • Zoology (animals)
  • Botany (plants)
  • Microbiology (microorganisms)
  • Histology (tissues)
  • etc.
• Branches of Biology


  • Taxonomy - naming and classifying organisms
  • Cytology - study of cells
  • Embryology - formation and development of organisms
  • Anatomy - structure and body parts
  • Physiology - functions of organisms and their parts
  • Biochemistry - biological composition
  • Genetics - heredity and variation
  • Evolution - origin of organisms
  • Ecology - the relationship of organisms with the environment
• Divine Theory of Creation


  The belief that a supernatural being (God) created life
• Si Malakas at si Maganda

  Philippine Folklore
• Abiogenesis


  Spontaneous generation - living organisms came from non-living organisms
• In science, if there is an A from the start - means "no"
• John Needham


  • Theory was anchored in the Philosophical views of Aristotle
  • Used a flask then put liquid with nutrients it then boiled it. He closed the flask and after a few days, there were changes; microorganisms were found when he looked under the microscope
• The flask was not sealed immediately; therefore organisms had already entered the flask making the setup contaminated
• Biogenesis


  Life comes from a pre-existing life
• Francesco Redi


  • Experimentation using meat
  • Placed a piece of meat inside a bottle and let it stay for a couple of days
  • After a few days, maggots became visible
  • He did another experiment, this time he closed the jar. After a few days, nothing happened
  • Scientists said that air is vital to the experiment
  • Then another experiment, taking into account air, instead of being closed completely, gauze was used. Yet, no new organisms were found
• Louis Pasteur


  • Pasteurization
  • He made use of a special flask (S-curved flask), allowing air to enter the flask at the same time the bacteria is trapped in a certain part of the flask
  • The infusion was boiled for a long time to kill all microorganisms present
  • After several days, no microorganisms appeared in the infusion
  • The S-curve part of the flasks was removed to allow the trapped microorganisms to enter the infusion. Microorganisms quickly multiplied in the infusion
• Charles Darwin


  Theory of evolution
• George Louis Buffon


  Species change as they migrate to new environments
• Jean Baptiste Lamarck


  • Species change gradually to adapt to their needs
  • It takes a long time for the structure to change
• A living organism has a cell
• We breathe - metabolism is a form of respiration
• The ability to reproduce
• Characteristics of Life


  • Growth and Development
  • Reproduction
  • Homeostasis
  • Metabolism
  • Motility
• Growth and Development


  • Growth/ increase in size
  • Development of new body parts
  • Voice change
  • Puberty
  • Occurs through cell division
• Reproduction


  • Use of sex cells or gametes
  • Most organisms need a partner and some can produce on their own (asexual reproduction)
• Homeostasis


  • Self-regulating process by which biological systems tend to maintain stability in response to environmental changes
  • The body balances the temperature inside and outside
• Metabolism


  Ability of an organism to acquire and use energy
• All organisms can move
• Robert Hooke


  • Coined the term cell
  • Observed a "cork" from the bark of a tree: obtained the outer layer of an oak tree then observed it under a microscope
  • He only used a simple microscope - using only one lens to magnify a small object
  • He saw empty compartments (little pores), thus the term "cell"
• Antoine Van Leeuwenhoek


  • Father of microbiology
  • Pioneering work in the field of microscopy
  • Did further analysis and observation of cells
  • Magnification: 270x
  • Observed different things in the microscope: pond water
  • Named the organisms observed as "animacules"
• Matthias Schleiden


  Concluded that all plants are made of cells
• Theodore Schwann


  Concluded that all animals are made of cells (unicellular or multicellular)
• Rudolf Virchow


  Concluded that all cells came from pre-existing cells
• Cell Theory


  All living things are made up of cells. Cells are the basic unit of structure and function in an organism. New cells arise from preexisting cells.
• Main Types of Cells


  • Prokaryotes
  • Eukaryotes
• Prokaryotes


  • Before the Nucleus
  • No nucleus
  • Has a less complex structure with fewer parts
• Eukaryotes


  • True Nucleus
  • Has a nucleus
  • More complex structure with more parts
• The Cell Kingdom


  • Archaea - Prokaryote
  • Eubacteria - Prokaryote
  • Protista - Eukaryote
  • Fungi - Eukaryote
  • Plantae - Eukaryote
  • Animalia - Eukaryote
• Most organisms are eukaryotes
• If an organism is multicellular, then most likely it is eukaryotic
• The oldest organisms found on the planet are prokaryotes
• Prokaryotes vs Eukaryotes


  • DNA: Prokaryotes - DNA is naked, circular, usually no introns. Eukaryotes - DNA bound to protein, linear, usually has introns.
  • Organelles: Prokaryotes - No nucleus, no membrane-bound, 70S ribosomes. Eukaryotes - Has a nucleus, membrane-bound, 80S ribosomes.
  • Reproduction: Prokaryotes - Binary fission, haploid - single chromosome. Eukaryotes - Mitosis and meiosis, diploid or more - Chromosomes paired.
  • Average Size: Prokaryotes - Smaller - ~1-5um. Eukaryotes - Larger - ~10 -100um.
• Cell Membrane / Plasma Membrane


  • Present in both plant & animal cells; more distinguished in animal cells due to its composition
  • Protection from outside environment
  • Filters materials that enter and exit the cell
  • Serves as the skin and outer covering of the cell, separating the cell from the external environment
  • Holds the cell together
  • Made of phospholipids, proteins, and cholesterols
  • Double membrane
  • Flexible structure
• Phospholipid Bi-Layer


  • Hydrophilic Head: water-loving
  • Hydrophobic Tail: water-hating