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York University
Natural Science
NATS 1670
Motti Anafi

NATS 1670 {MIDTERM REVIEW} Midterm 1 May 19, 2012 Diversity of Microorganisms Chapter 11: Characterizing and Classifying Prokaryotes Arrangements of Prokaryotic cells Result from two aspects of division during binary fission: the planes in which cells divide and whether or not daughter cells completely separate or remain attached Coccus (spherical shaped prokaryotes) Bacillus (rod shaped prokaryotes) Diplococci: Single bacillus: Streptococci: Diplobacilli: Tetrads: Steptobacilli: Sarcinae: Palisade: Staphylococci: V-Shape: Archaea Reproduce asexually No archaea are known to cause disease-no human pathogens Extremophiles: microbes that require extreme conditions of temperature, pH, and/or salinity to survive Thermophiles-do not function with a temperature of lower than 45 degrees (recombinant DNA technology) Hyperthermophiles- require temperatures over 80 degrees (found in hot springs) Halophiles- require extreme saline habitats (usually 17-23% NaCl) Methanogens- convert CO , H2and2organic acids into methane gas (CH ) (lar4est group of known archaea) Live in the intestinal tract of cows, producing 400 liters of methane a day If all the methane trapped in ocean sediments were released, it would wreak havoc with the worlds climate Viruses Many infections of humans are caused by acellular (non-cellular) agents, including viruses and other pathogenic particles Have one or several pieces of nucleic acid (contain a viral genome) either DNA or RNA Lack a cell membrane Virion consistsof a protein coat (capsid) surrounding a nucleic acid core. Some have an envolpe that surrounds the nucleocapsid Cannot carry out any metabolic pathway Cant grow or respond to environment Cannot reproduce independently (rely on the cells they infect) NATS 1670 {MIDTERM REVIEW} Midterm 1 May 19, 2012 Take control of cells metabolic machinery to produce more molecules of viral nucleic acid which create viral proteins which then assemble to create new viruses Cause common cold, influenza, herpes, SARS, AIDS Immunizations exist for many viruses Fungi Decompose dead organisms and recycle their nutrients Fungi produce antibiotics such as penicillin and cephalosporin (makes organ transplants possible) Reproduce through spores Yeast-oval, involved in human disease (i.e. yeast infections), commonly used in food industry (aerobic= bakers yeast, anaerobic= alcohol production) From the DNA to the organism Chapter 2: The Chemistry of Microbiology An organisms basic structure and complicated chemical reactions required of life are fulfilled by organic molecules. There are 4 major macromolecules lipids, carbohydrates, proteins, and nucleic acids. Lipids Group of macromolecules that are hydrophobic (insoluble in water) Lipids are insoluble in water because the bonds between carbon and atoms are covalent, not ionic. Ionic bonds are polar, allowing the polarity of hydrogen bonds to break the bonds between atoms Stored energy Fats 1) Also called triglycerides: contain three fatty acids linked to a molecule of glycerol 2) Saturated fats: saturated with hydrogen, all carbon atoms are linked by single bonds covalently to two hydrogen atomssolid at room temperature (butter) (because the carbon atoms are linked by single bonds, theyre three fatty acids are straight, allowing more to be compact together) 3) Unsaturated fats: containing at least one double bond between adjacent carbon atoms (if more than one double bond exists it is a polyunsaturated fat) liquid at room temperature (oil) (because the carbon atoms contain at least one double bond, this causes a kink or bend in the fatty acid chains, they cannot be compact together, so less form the liquid at room temperature) Phospholipids 1) Only contain two fatty acid chains rd 2) The 3 carbon atom of glycerol is linked to a phosphate group, instead of a fatty acid 3) Tail is hydrophobic, head is hydrophilic , therefore always form into phospholipid bilayers in aqueous solutionsNATS 1670 {MIDTERM REVIEW} Midterm 1 May 19, 2012 Waxes 1) Only contain one long-chain fatty acid linked to a long-chain alcohol 2) No hydrophilic head=non water soluble 3) Mycobacterium tuberculosis is surrounded by a waxy wall, which makes the bacteria resistant to drying Steroids 1) Consist of four rings fused to one another and attached to various side chains 2) Important in human metabolism 3) Hormones, cholesterol, sterols, etc. Proteins Proteins perform many cell functions (structural, enzymatic catalysis, regulation [gene expression], transportation, defense and offense) A proteins function is dependent on its shape Amino acids 1) Proteins are polymers composed of monomers called amino acid 2) Most organisms use 21 amino acids in the synthesis of proteins 3) Contain positive and negative charge, soluble in water Nucleic Acids Nucleic acids DNA and RNA are vital as genetic material of cells and viruses Each monomer of nucleic acid is a nucleotide and consists of a phosphate, a pentose sugar,
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