Presentation on theme: "Morphology Structure Function"— Presentation transcript:
1 Morphology Structure Function Anatomy of BacteriaMorphologyStructureFunction
2 Binary Fission“a method of asexual reproduction involving halving of the nucleus and cytoplasm of the cell followed by the development of each half into a new individual”septumprogeny cellsgeneration time
4 Sizeprokaryotic (bacteria) cells are very small compared to eukaryotic cellsprokaryotic cells are the most abundant form of life on earthprokaryotic cells can survive in conditions that are too extreme for eukaryotic cells
5 Shape Readings question one: What are the three basic shapes that most bacteria exhibit?
6 Spiral (Vibrio, Spirillum, Spirochete) Vibrio: “curved or bent rods that resemble commas”Spirillum: “a corkscrew shape with a rigid cell wall and hair-like projections called flagella that assist in movement”Spirochete: “a flexible cell wall but no flagella in the traditional sense. Movement occurs by contractions (undulating) of long filaments (endoflagella) that run the length of the cell.”
7 Arrangement Readings question two: What are the three basic arrangements that most bacteria exhibit?Additional arrangements:Tetracocci: “grouping of four spherical shaped cells”Sarcinae: “a cube-like packet of eight spherica bacteria”
8 Structure and Function up until the 1950’s prokaryotes were believed to simply be “bags of enzymes”prokaryotes have a simpler construction than eukaryotesprokaryotic cell has 5 essential structural components:Nucleoid (bacterial chromosome)RibosomesCell membraneCell wallCapsule
9 Nucleoid bacterial chromosome typically one large circular molecule of DNAfloats freely in the cytoplasmgenetic control center of the celldetermines all of the properties and functions of the bacterium
10 Ribosomes proteins and RNA prokaryotic ribosomes are smaller than eukaryotic ribosomesprotein synthesis“granular”appearance
11 Cell Membrane and Cell Wall Readings question three:What is the difference between the cell membrane and the cell wall?
12 Capsule“the membrane that surrounds some bacterial cells; a loose gel-like structure that, in pathogenic bacteria, helps to protect against phagocytosis”glycocalyxslime layer
13 Cytoplasm Readings question four: What is the cytoplasm of prokaryotic cells?primary structures: nucleoid and ribosomesplasmids: extrachromosomal pieces of DNA
14 Endospores“a thick-walled spore within a bacterium”
15 Endosporesproduced by the bacterium to help it survive in an unfavorable environmentformed by vegetative cells- “sporulation”one of the most resistant forms of lifegermination
16 Clostridium tetani deep wound punctures that become anoxic tetanus toxin spreads and causes diseasespastic paralysis and can result in death
17 Clostridium botulinum botulinum toxin in improperly preserved foodsbotulism can result in death due to respiratory failure as a result of muscle paralysis
18 Clostrideium perfringens most prevalent reported cause of food poisoningenterotoxins in the intestinesdiarrhea and intestinal cramps with no fever or vomiting
19 Flagellaprotein structures attached to the cell surface that resemble “whip-like” appendagesdistributed in distinguishing patternsflagella of prokaryotic cells differ from eukaryotic cells
20 Pili (Fimbriae)short, hair-like structures on the surface of prokaryotic cells composed of proteinshorter, thinner, and straighter than flagellaallow bacteria to attach to surfacese.g. Neisseria gonorrhoeae
21 Gram-staining Readings question five: What is the purpose of gram-staining? What are the characteristics of gram-positive bacteria and gram-negative bacteria?
28 Thermophiles Fossilized Microbes from Yellowstone’s Hot Springs They become preserved as the spring cools.
29 TemperaturesMinimum: “temperature below which bacterial growth will not take place”Optimum: “temperature at which organisms grow best”Maximum: “temperature above which bacterial growth will not take place”
30 What are the embalming implications associated with the temperature preference of bacteria?
31 pH Readings question four: Describe the pH scale. Acidophiles: bacteria that are remarkably tolerant of acidity
32 Light Cyanobacteria: oxygen producing prokaryotes Yeasts and Molds thrive in the presence of lightYeasts and Moldsprefer dark areasSome bacteria are destroyed by ultraviolet light.
33 Osmotic Pressure“pressure that develops when two solutions of different concentrations are separated by a semi-permeable membrane”microorganisms require water for growth and are made up of 80-90% waterhigh osmotic pressure removes necessary water from a cellplasmolysishypertonic solutions
34 Moisturemaximum, optimum and minimum requirement for all microorganismsPathogenic bacteria are usually found in the body’s tissuesFungal diseases are usually found on the body surface.
35 Chemical Requirements Readings question two:Describe the differences between autotrophic bacteria and heterotrophic bacteria.
36 Heterotrophic Bacteria 3 categories:1) strict (obligate) saprophyte2) strict (obligate) parasite3) facultative bacteria:Facultative saprophyte: “prefers live organic matter as a source of nutrition but can adapt to the use of dead organic matter under certain conditions”Facultative parasite: capable of living and growing with the nutrients that its host provides
37 Carbon one of the most important requirements for microbial growth structural backbone of living matterneeded for all the organic compounds that make up a living cell½ of the “dry weight” of a bacterial cell is carbon
38 Nitrogen, Sulfur, and Phosphorus needed by microorganisms for the synthesis of cellular materiale.g. protein, DNA, RNA, ATP
39 Trace Elements iron, copper, and zinc essential for the function of certain enzymes
40 OxygenMicrobes that use molecular oxygen (aerobes) produce more energy from nutrients than microbes that do not use oxygen (anaerobes)Reading question two:Describe the difference between obligate aerobes and obligate anaerobes.
41 Microaerophilic Organisms “a microorganism that requires very little free oxygen”only grow in oxygen concentrations that are lower than those in airrequire about 2 – 10% free oxygen
42 Facultative Organisms Facultative Aerobes: “a microorganism that prefers an environment devoid of oxygen but has adapted so that it can live and grow in the presence of oxygen”Facultative Anaerobes: “a microorganism that prefers an oxygen environment but is capable of living and growing in its absence”E.g. Bacillus anthracis, Corneybacterium diphtheriae, Escherichia coli
43 Aerotolerant Organisms can grow in the presence or absence of oxygene.g. Streptococcus pyogenes
44 Microbial Associations normal flora (microbiota)transient microbiotasymbiotic relationship: “organisms live in close nutritional relationships; required by one or both members”distinguished by the degree to which the host organism is harmed
45 Mutualism“a symbiotic relationship in which organisms of two different species live in close association to the mutual benefit of each”e.g. E. coli in the human digestive tract
46 Commensalism“the symbiotic relationship of two organisms of different species in which one gains some benefit such as protection or nourishment and the other is not harmed or benefited”e.g. bacteria on skin surface; microorganisms within the digestive tract
47 Parasitism“an interactive relationship between two organisms in which one is harmed and the other benefits”many disease-causing bacteria are parasitestypically the host is macroscopic and the parasite is microscopicroundworms and flatworms are parasites that are large multi-cellular organisms
48 Readings question five: What is the synergistic effect?
49 Antagonism“mutual opposition or contrary action. The inhibition of one microorganism by another.”Involves competition among microbesnormal microbiota protect the host against colonization by potentially pathogenic microbesnormal flora produce substances harmful to the invading microbes (pH, oxygen)