MODULE 2

• Cellular Microorganism – organism that contains cells, either unicellular or multicellular.

  • Unicellular
  • Unicellular/Multicellular
• Unicellular – Prokaryotes (Archaea, Bacteria, Cyanobacteria)
• Unicellular /Multicellular -Eukaryotes (Algae, Fungi, Protozoa)
• Acellular Microorganism – organism that doesn’t contain cell.

  • Virus
  • Viroids
  • Prions
• Prokaryotic Cell

  • “No” true nucleus
  • Ave size: 0.2 – 2.0 μm (diameter.) 2 – 8 μm (length)
  • Lack membrane-enclosed organelles
  • No cytoskeleton
  • Transverse binary fission
  • Monomorphic or pleomorphic
• Archaea

  • means ancient
  • Archaea bacteria look identical microscopically to members of the Bacteria domain.
  • chemical composition of cell wall differs: Archaea do not have peptidoglycan.
  • have the ability to grow in extreme environments :extreme temperatures: hot or cold, acidic or alkaline conditions, extreme salt concentration
• Bacteria

  • single-celled prokaryote
  • comprised of specific shapes: bacilli, cocci, spirilla
  • bacterial cells multiply by binary fission
• Bacilli - rod shaped
• Cocci - spherical shaped
• Spirilla - spiral shaped
• Prokaryotic Cell Structure

  Internal to the cell wall

  • Cell membrane
  • Cytoplasm
  • Chromosomes
  • Ribosomes
  • Inclusions
  • Endospores (some)
• Appendages

  • Glycocalyx
  • Flagella
  • Fimbriae
  • Pili
• Glycocalyx

  • The outer layer usually made up of bound polysaccharides on the cell surface and superficial layer of unbound proteoglycans and glycoproteins.
• Flagella

  • Long, slender, threadlike, whip-like extension of certain cells or unicellular organisms used mainly for movements (others for signal transduction).
• Flagella Arrangements:

  • Atrichous
  • Monotrichous
  • Lophotrichous
  • Amphirichous
  • Peritrichous
• Fimbriae

  • Hair-like structures made of "pilin"
  • Enable bacterial cell to adhere to surfaces
• Pili

  • Short, filamentous projection on a bacterial cell, used not for motility but for adhering to other bacterial cell (especially for mating) or to animal cells.
  • Joins bacterial cell for DNA transfer during conjugation.
  • Sex pili
• Axial Filaments - Flagella-like fibrils arising at the ends.
• Prokaryote: Cell Wall

  • Composed of peptidoglycan (murein)
  • N-acetylglucosamine (NAG)
  • N-acetylmuramic acid (NAM
• Prokaryote: Cell Wall

  • Used to characterize bacterial cells
  • Gram Positive – teichoic acid and lipoteichoic
  • Gram Negative – lipoproteins, LPS and phospholipid
• Plasmid - Contains extra-chromosomal DNA which carry genes that confer protective trait that may be duplicated and passed on to an offspring.
• Ribosomes - A minute particle composed of protein and ribonucleic acid (RNA) that serves as the site of protein synthesis.
• Inclusions - An abnormal structure in a cell nucleus or cytoplasm having characteristic staining properties.
• Endospore - Bacteria undergo sporulation during exposure to harsh conditions.
• Eucaryotic Cell (Eukaryotes)

  • all members of the living world except the prokaryotes are considered Eucarya.
  • contain basic organelles: cell membrane, cytoplasm, nucleus
• Algae

  • photosynthetic eukaryotes with a wide variety of shapes that occur in most habitats, ranging from marine and freshwater to desert sands and from hot boiling springs to snow and ice belonging to Kingdom Protista.
  • They important role in balancing the environment.
• Fungi

  • can be single celled or very complex multicellular organisms.
  • Found in just about any habitat but most live on the land, mainly in soil or on plant material
• Protozoa

  • They come in many different shapes and sizes ranging from an Amoeba which can change its shape to Paramecium with its fixed shape and complex structure.
  • They live in a wide variety of moist habitats including fresh water, marine environments and the soil.
• Acellular Structure - without cell parts
• Virus

  • considered acellular, non-living, obligate intracellular parasite
  • often considered the parasites of the microbial world
• Viroids

  • very small, circular RNA (may appear linear), and infectious in plants. They do not contain a capsid
• Prions

  • contain only protein
  • causative agent for some neurodegenerative diseases in humans and animals
• Eukaryote

  • larger
  • compartmentalized by membrane-bounded sacs or organelles.
  • contain a nucleus with multiple chromosomes
  • divide by complex process of mitosis
• Prokaryote

  • smaller
  • not compartmentalized
  • do not have a nucleus
  • divide by binary fission
• Cell Division

  • the process by which a parent cell divides into two or more daughter cells.
  • usually occurs as part of a larger cell cycle.
• Cell Division 2 Genetic States: Haploid

  • one copy of chromosome.
  • in humans, gametes (sperm & ova) are haploid
• Cell Division 2 Genetic States: Diploid

  • two copies of chromosome
  • in humans, all body cells are diploid found in skin, blood and muscle cells also known as somatic cells
• Mitosis - the chromosomes condense, divide, and are separated into two sets, one for each daughter cell
• Meiosis I - homologous chromosomes segregate into separate cells, changing the genetic state from diploid to haploid.
• Meoisis II - the two haploid cells divide to form a total of four haploid cells called gametes.