BIOLOGY 1

• Cell


  A basic unit of living matter separated from its environment by a plasma membrane
• Robert Hooke


  • English scientist
  • Sliced a very thin slice of cork from an oak cork and observed it under his own microscope
  • Discovered the minute hollow compartments known as CELL
  • Initially discovered CELL in 1665
  • Hooke devised the compound microscope and illumination system
  • Hooke's law, law of elasticity discovered in 1660
• Antonie Van Leeuwenhoek


  • Dutch naturalist
  • Universally acknowledged as the father of microbiology
  • Expert in grinding lenses and the one who discovered the tiny living organisms which he called "animalcules" from the drop of rain water
  • Most of the "animalcules" are now referred to as unicellular organisms
  • He was also the first to document microscopic observations of muscle fibers, bacteria, spermatozoa, red blood cells, crystals in gouty tophi, and blood flow in capillaries
• Robert Brown


  • Scottish botanist and palaeobotanist
  • His contributions include one of the earliest detailed descriptions of the cell nucleus and cytoplasmic streaming
  • He discovered the center part of the cell which is the nucleus
  • Brownian motion - the continuous motion of minute particles in solution
• Félix Dujardin


  • French biologist
  • Discovered a semi-transparent living substance known as Sarcode, in which later on was changed in protoplasm, the colorless materials comprising the living part of the cell
• Matthias Jakob Schleiden


  • German Botanist
  • He proposed on his studies about the entire parts of the plant and concluded that all plants are made out of cell
• Theodor Schwann


  • Zoologist, physician and physiologist
  • His most significant contribution to biology is considered to be the extension of cell theory to animals
• Rudolf Ludwig Carl Virchow


  • Physician, Biologist, Pathologist, etc.
  • Known as "the Father of Modern Pathology" and as the founder of social medicine
  • He contributed to the cell theory and states that "cells arise from pre-existing cells."
• Early Cell Theory


  Cells are the building block and functional unit of all living organisms; it includes the life cycle, metabolic activities and the ability to transfer character traits<|>All living organisms contain one or more cells<|>Cells arise from the pre-existing cells
• Modern Cell Theory


  All living organisms are composed of trillions of cell in their body<|>Cell is the fundamental and building blocks of all living organisms<|>Cells come from other cells by cell division<|>The cell consists of genetic material which is passed from generation up to the last generation<|>All cells are made up of the same chemical composition
• Prokaryotic


  Organelles lack a membrane<|>Genetic material floats in the cytoplasm (DNA and RNA)<|>Circular DNA<|>Unicellular<|>Cells are smaller in size<|>Has larger number of organisms
• Eukaryotic


  Organelles are covered by membrane<|>Membrane covered Genetic material<|>Linear DNA<|>May be multicellular or unicellular<|>Cells are larger in size<|>Has smaller number of organisms

  
• Shapes of Prokaryotic Cells

  • Cocci = spherical (round)
  • Bacillus = (rod shaped)
  • Spirilla = helical (spiral)

  
• Prokaryotic Cells


  Are the simplest type of cell<|>Unicellular organisms that are found in all environments<|>Do not have a nuclear membrane. Their circular shaped genetic material dispersed throughout cytoplasm<|>Do not have membrane-bound organelles<|>Have a simple internal structure<|>Are smaller in size when compared to Eukaryotes

  
• Eukaryotic Cells


  Are generally more advanced than prokaryotes<|>Nuclear membrane surrounds linear genetic material (DNA)<|>Unlike prokaryotes, eukaryotes have several different parts<|>Organelles have coverings known as membranes<|>Have a complex internal structure<|>Are larger than prokaryotes in size

  
• Similarities of Prokaryotic and Eukaryotic Cells

  • Both types of cells have cell membranes (outer covering of the cell)
  • Both types of cells have ribosomes
  • Both types of cells have DNA
  • Both types of cells have a liquid environment known as the cytoplasm

  
• Plasma Membrane


  Also called the cell membrane, is found in all cells and separates the interior of the cell from the outside environment<|>Can regulate the flow of materials in and out of the cell<|>A semipermeable membrane that selectively controls the entrance and exit of materials<|>Double phospholipid layer with embedded proteins
• Components of Plasma Membrane

  • Cholesterol molecules – helps strengthen the membrane, flexible but less fluid
  • Carbohydrates – attached as identity tags
  • Transport proteins – extend from the phospholipid layer to help materials cross the membrane
  • Channel Proteins – form tunnels that help cells to import or export needed and waste materials
  • Cell Recognition Proteins – enable cells to distinguish their own cells from that other organisms, such as pathogens that may invade the body
  • Enzymic Proteins – participate in metabolic reactions (degradative and synthetic reactions)
  • Cytoskeleton Proteins – act as muscle and skeleton to maintain cell shape and motility
  • Junction Proteins – assist cell-to-cell adhesion and communication
  • Receptor proteins – facilitate exchange of signals with other cells by changing its shape to allow a specific molecule, ligand, to bind to

  
• Membrane Transport


  Selectively permeable membrane<|>Osmosis<|>Protein channels<|>Active transport<|>Fluid mosaic model
• Animal cells have no cell wall, have cell membrane
• Animal cells are basically smaller with less distinct boundaries and no definite wall
• Animal cells consist almost entirely of cytoplasm
• Animal cells have food vacuoles that are small and not permanent
• Animal cells have no definite cell wall and do not have cellulose
• Plant cells have cell wall and cell membrane
• Plant cells are usually larger with distinct outlines and a definite cell wall
• Plant cells have a thin lining of cytoplasm with large food vacuole
• Plant cells are covered with cell wall that consist of cellulose
• Phospholipid layer


  • Embedded proteins
• Membrane transport


  Selectively permeable membrane
• Cholesterol molecules


  • Helps strengthen the membrane, flexible but less fluid
• Carbohydrates


  • Attached as identity tags
• Transport proteins


  • Extend from the phospholipid layer to help materials cross the membrane

  
• Channel proteins


  • Form tunnels that help cells to import or export needed and waste materials
• Cell recognition proteins


  • Enable cells to distinguish their own cells from that other organisms, such as pathogens that may invade the body
• Enzymic proteins


  • Participate in metabolic reactions (degradative and synthetic reactions)
• Cytoskeleton proteins


  • Act as muscle and skeleton to maintain cell shape and motility
• Junction proteins


  • Assist cell-to-cell adhesion and communication
• Receptor proteins


  • Facilitate exchange of signals with other cells by changing its shape to allow a specific molecule, ligand, to bind to it
• Cell wall


  Outermost structure of plant cells which consist of cellulose