MICROBIOLOGY Monera Protista Fungi REVIEW 2 MICROBIOLOGY Microbiology

MICROBIOLOGY Monera, Protista & Fungi

REVIEW 2

MICROBIOLOGY • Microbiology = study of microscopic organisms (called micro-organisms or microbes) • Microscopic = can’t see without microscope • Viruses, bacteria, protists, fungi • Pathogen = microbe that can cause disease 3

MICROBIOLOGY • Cells & Microscopes • Viruses & the immune system • 3 kingdoms: Monera, Protista & Fungi 4

MICROBIOLOGY 5 PROKARYOTIC CELLS EUKARYOTIC CELLS “Before nucleus” “True nucleus” Smaller & simpler, no membrane-bound organelles Larger, with membrane-bound organelles including nucleus, ER, Golgi, etc. Cell walls containing peptidoglycan Animals & Protists walls Unicellular & multicellular Only Monera Protista, Fungi, Plantae, Animalia no cell

MICROSCOPES Parts EYE PIECE BODY TUBE ARM NOSE PIECE OBJECTIVE LENS STAGE COARSE ADJUSTMENT KNOB FINE ADJUSTMENT KNOB BASE 6 DIAPHRAGM LIGHT SOURCE

MICROSCOPES Lenses • Low power = 4 x • Med power = 10 x • High power = 40 x • Eyepiece lens magnifies another 10 x 7

MICROSCOPES How to focus: 1. Make sure lowest objective is in place and put slide on centre of stage 2. Use coarse focus knob to bring specimen into focus. 3. Use fine adjustment knob to bring to perfect focus before switching to next highest objective. • After the lowest objective only use fine adjustment knob (very slowly) for all focusing • Before each switch to a higher power, it should be brought to the best focus possible in previous objective 8

MICROSCOPES Care and handling • Use two hands to carry (one under base, one holding arm). • Use only lens paper to clean lenses. Do not touch lenses with fingers. • Start with lowest objective and increase objectives one at time. • Do not use objective marked “oil” without oil! • Pull from plug, not cord. • Store with lowest objective in place. Do not rotate past highest objective in order to do this. • Cord should be wrapped and placed under stage and cover replaced for storage. 9

VIRUSES Recall: • Living things • Are made of cells • Reproduce • Grow and develop • Respond to their environment • Obtain and use energy 10 • Viruses • No • Yes, but not on their own • No

VIRUSES – CLASSIFICATION • Based on host: • Plant viruses • Animal viruses • Bacteriophage • Genetic material • DNA or RNA • Single-stranded or double-stranded • Capsid shape 11

BACTERIOPHAGE • Virus that invades bacteria • Easy to study because their hosts multiply quickly 12

BACTERIOPHAGE REPRODUCTION 1. Infection • Virus comes into contact with the right kind of host • Injects its DNA into the cell (in most cases, entire virus doesn’t enter) 2. Growth • Host cell enzymes are used to read the virus’ DNA (host cell can’t tell it apart from its own DNA) and produce viral proteins 13

BACTERIOPHAGE REPRODUCTION 3. Replication LYTIC • uses cell materials to make thousands of copies of its nucleic acids and proteins • Host cell becomes full of new viruses until it lyses (bursts open) releasing new viruses so that they can infect new cells LYSOGENIC • Integrates into host DNA and replicates along with cell • Eventually lytic cycle activated 14

BACTERIOPHAGE REPRODUCTION Lytic Cycle 15

BACTERIOPHAGE REPRODUCTION 16

DEFENSE AGAINST VIRUSES • Human Immune System = protection against pathogens • Remember pathogen = microbes that cause disease • 3 lines of defense • First = Keep them out • Second = Non-specific attack (innate) • Third = Specific, targeted attack (acquired) 17

3 LINES OF DEFENSE 18

FIRST LINE OF DEFENSE = physical & chemical BARRIER prevents pathogens from getting in • Skin and internal linings physical barrier • Mucous & cilia (respiratory tract, ears) trap pathogens • Sweat slightly acidic, kills some microbes • Tears remove pathogens and other debris from eyes • Stomach acid kills bacteria that are ingested 19 • Saliva enzymes

SECOND LINE OF DEFENSE • Innate non-specific (response is the same for all pathogens) • Includes: Inflammation, Phagocytes, fever 20

THIRD LINE OF DEFENSE • Targets particular pathogens that get past other defense systems • Antigen = foreign substance that triggers an immune response • Antibody = binds to specific antigen and destroys virus containing it • B-cells = recognize antigens, produce and release antibodies • T-cells = activate B-cells, find and kill infected cells 21

THIRD LINE OF DEFENSE 22

VACCINES • Contain a weakened or mild form of pathogen/antigen • When introduced to blood stream, Tcells activate B cells to produce antibodies to the antigen • If/when a person is exposed in the future, antibodies can be quickly and • Vaccines helped (mostly) eliminate diseases such as easily made so that virus is quickly smallpox, diphtheria, tetanus, eliminated and the person doesn’t get yellow fever, whooping sick cough, polio and measles 23

OTHER WAYS TO STAY HEALTHY • Handwashing • Before eating • After touching commonly touched objects such as: • Avoiding coughing/sneezing towards others or into hands (use inside of elbow) • Proper preparation of food (cook to high temps and store at cold temps) 24 • Avoid sharing things like water bottles, lip gloss, etc.

REVIEW • Monera • Prokaryotic – lack membrane-bound organelles (including nucleus) • Cell wall containing peptidoglycan • Unicellular 25

Prokaryotic Cell Structure • No nucleus • No golgi • No endoplasmic reticulum 26

Prokaryotic Cells DO have • Nucleoid circular DNA chromosome in centre of cell, not bound by nucleus • Plasma membrane • Cell wall contains peptidoglycan, allows bacterium to hold its shape • Capsule third layer of protection, protects from drying and phagocytosis • Ribosomes • Inclusion bodies used for storage • May have flagella, or pili for movement 27

How to prokaryotes reproduce? • Binary Fission (like mitosis) • DNA doubles, then cell splits into 2 cells, each with a full copy 28

How to prokaryotes reproduce? • Conjugation • DNA passed from one cell to another • Allows for variation usually only seen in sexually reproducing species 29

Surviving harsh conditions • Spore formation when conditions aren’t favourable, bacterium produces a thick internal wall and stays dormant for a period of time. • Examples of unfavourable conditions: • Dry • low nutrients • Non-optimal temperature (too hot/cold) • Non-optimal p. H (This is why freezing food DOES NOT kill bacteria! You still need to cook it to proper temperatures!) 30

PROKARYOTIC CLASSIFICATION Eubacteria • True bacteria vs. Archaebacteria • Ancient bacteria • Only found in harsh environments such as hydrothermal vents or places that lack O 2 like an animals digestive tract 31

PROKARYOTIC CLASSIFICATION Two types of cell wall: • Based on how they react to gram stain method • Quick, easy way to narrow down (or eliminate) culprit of infection 32

PROKARYOTIC CLASSIFICATION • Cell shape 33

PROKARYOTIC CLASSIFICATION • The way they obtain energy Autotrophic -get energy from inorganic sources Heterotrophic -get energy from organic matter Phototrophic -get energy from sunlight Phototrophic autotrophs Get energy directly from sunlight Phototrophic heterotrophs Get energy both from organic matter and from sunlight Chemotrophic -get energy from matter Chemotrophic Autotrophs Get energy from inorganic molecules Chemotrophic heterotrophs Get energy from eating organic matter and breaking it down 34

The way they use energy • Obligate aerobes • Require constant supply of oxygen to survive • Obligate anaerobes • Require an oxygen-free environment • Facultative anaerobes • Don’t require oxygen but can live in an environment that contains it 36

The type of cell wall • Classification of prokaryotes examples Escherichia coli (E. coli) is a rod-shaped, gram negative, facultative anaerobe bacteria often found in the gut of warmblooded animals 37 Streptococcus pyogenes (S. pyogenes) is a round-shaped, gram positive, aerobe bacteria that infects the respiratory systems of humans (strep throat).

Beneficial Prokaryotes • Production of foods: • Cheese, sour cream, yogurt, pickles vinegar • Industry: • Oil spill clean-up, genetic engineering (GMOs), sewage treatment • Environment: • “fix” nitrogen for plant use • Mutualism such as in our digestive tracts 38 • E. coli help break down food, provide vitamins,

Antibacterial agents • Sterilization = killing of all bacteria • High temps such as boiling • Must be sealed immediately • Sterile = free of bacteria • Aseptic = free of disease-causing organisms • Disinfectants = chemicals used when high temps are not practical (ex: a toilet), to kill (99. 9% of) bacteria 39

Antibiotic resistance • Antibiotics = drugs used to kill bacteria that have caused an infection 40

REVIEW • Fungi • Eukaryotic • Multicellular (except yeast) 41 • Heterotrophic • Cell walls containing chitin

FUNGI STRUCTURE 42

FUNGAL CELLS Cell wall Mitochondria Nucleus Septum 43 Vacuole Golgi ER Ribosome Plasma membrane

FUNGI STRUCTURES • Mycelium = mass of branched filaments (hyphae) • Hyphae = tiny feathery strands one cell thick – high SA for nutrient absorption. Spore = microscopic reproductive cells that move through air until landing and germinating on food source 44

HOW FUNGI OBTAIN ENERGY • Absorb nutrients from environment • Secrete digestive enzymes to break down food for absorption • Mutualistic relationship with plants: Help host obtain H 2 O and nutrients (b/c of large SA), host provides food (photosynthesis) 45

PHYLA OF FUNGI • Zygomycota • Molds, Rhizopus • Basidiomycota • Mushrooms, puffballs, 46 toadstools

PHYLA OF FUNGI • Ascomycota • Yeasts, morels, truffles, ringworm • Mutualistic associations with roots of trees (mychorizae, lichen) 47

PHYLA OF FUNGI • Deuteromycota • Aspergillus, penicillium, athletes foot, candida albicans • Human uses: penicillin, cheeses 48

REVIEW • Protista • Eukaryotic • Unicellular • No cell walls (ALL) (Most) • Protists are basically all the Eukaryotes that aren’t fungi, plants or animals. Very diverse! 49 • Makes classification messy. • Reproduction – binary fission & conjugation • Three types: fungi-like, plant-like and animal-like

Animal-like Plant-like 50

Evolution • Thought to have evolved from prokaryotic cells who developed nuclei 51

Endosymbiont Hypothesis • First eukaryotic cell was formed by symbiosis between several prokaryotes • Organelles in protists resemble other monerans (chloroplasts and mitochondria; algae & bacteria) • Started as symbiosis, became an organelle 52

Animal-like protists • Cilia-bearing – paramecium • Fresh and salt water, free-living consumers Macronucleus Contractile Vacuole Food vacuole Cilia Micronucleus 53 Anus Gullet