lesson 6

• cell


  the smallest, basic unit of life that is responsible for all of life's processes. •the structural, functional and biological units of all living things that can replicate itself independently
• TYPES OF CELLS

  prokaryotic cell and eukaryotic cell
• PROKARYOTIC CELL


  Derived from the words "pro" and "karyon", which means "before" and "kernel/nut" respectively. Prokaryotic cells are cells which do not have a membrane-bound nucleus. • ex: archaebacteria, blue-green algae and eubacteria
• Glycocalyx- an outer layer that provides protection and helps bacteria to hold on to surfaces. 


  Cell wall – a structure that confers rigidity and shape to the cell.
• Plasma membrane – a structure that prevents the loss of water and electrolytes inside the cell. It is also composed of a phospholipid bilayer.
• Cytoplasm – the whole inside region of the cell where the chromosomes, ribosomes, and other cellular inclusions are suspended.
• Pilus (Pili, plural) – a short hairlike appendage on the surface of some bacteria. It helps bacteria adhere to surfaces of host cells.
• Fimbriae – bristle-like fibers that are shorter than pili that is primarily used for bacterial attachment to tissue surfaces.
• Flagellum (flagella, plural) – a long, threadlike structure that facilitates movement in bacteria.
• Ribosome – the sites where proteins are created or synthesized.
• Plasmid – a small, circular, extrachromosomal DNA molecule found in the cytoplasm.
• Nucleoid – the region where the DNA is concentrated
• Eukaryotic cell


  Derived from the Greek words “eu” and “karyon” meaning “true and “nut” • These are cells that are bigger and more complex than a prokaryotic cell. Eukaryotic cells are cells which organelles are enclosed by a membranebound nucleus. • ex: cells from animals, plants, protists and fungi
• CELL MEMBRANE


  aka plasma membrane, is a thin layer that forms a boundary separating an individual cell from its external environment
• 1. CELL MEMBRANE


  It acts as gatekeeper for regulating the passage of important molecules, ions, gases between outside and inside of a cell.
• PHOSPHOLIPID BILAYER OF A CELL MEMBRANE

  Each phospholipid molecule is composed of three basic parts: two fatty acid chains, charged phosphate group, and glycerol. • Fluid Mosaic Model
• CELL WALL


  a rigid layer that gives protection, rigid support and shape to the cell. • usually present in plants and fungi
• CYTOPLASM

  a semifluid region of the cell that surrounds the nucleus and holds the organelles of a cell. • fills the space between nucleus and the cell membrane. • Cytosol - fluid portion consisting mainly of water
• NUCLEUS

  a roughly spherical-shaped part of the eukaryotic cell located at the center of a cell. • it serves as the storehouse of genetic information in the form of DNA inside the cells
• NUCLEUS

  protects the DNA from the damages from its external environment
• Nuclear envelope - a special membrane that encloses the DNA
• Nuclear pores - filled with holes that allow large molecules to pass between the nucleus and cytoplasm.
• Nucleolus - dense region where small organelles essential for making proteins are assembled.
• ENDOPLASMIC RETICULUM

  a network of intercommunicating channels composed of membraneenclosed sacs and tubules. • Two Forms: Rough Endoplasmic Reticulum (RER) and Smooth Endoplasmic Reticulum (SER)
• GOLGI APPARATUS

  series of flattened sacs with a characteristic convex shape. It is responsible for the processing, packaging, and sorting of secretory materials within the cell
• VESICLES

  small, membrane-bound sacs that enclose proteins or other materials for transferring, storing or secreting purposes
• VACUOLES

  a fluid-filled sac for the storage of materials needed by the cell that includes water, food molecules, inorganic ions, and enzymes
• LYSOSOMES


  are small, spherical, membranebound organelles which contain various kinds of enzymes that can break down materials in the cell.
• MITOCHONDRIA

  bean-shaped with two membranes. • power plant of the cell. it contains enzymes that help the chemical oxidation of food molecules and produces ATP (energy).
• RIBOSOME


  cite for the production of protein or the molecules that synthesize proteins.