MicroLab Week2&3

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MicroLab Week2&3
2014-02-25 02:37:26
Microbiology lab
Lab week 2&3
Show Answers:

  1. What is an endospore
    Cell formed within cells of certain bacteria.

    Inner protective shell
  2. Why do bacteria form endospores?
    • To protect themselves from
    • Temp
    • Desiccation (dehydration) 
    • UV light
    • Lack of nutrients 
    • pH
  3. Two major Genera that form endospores
    Clostridium and Bacillus
  4. Species of Clostridium studied in lab
    • C. botulinum
    • G(+), soil organism 
    • Botulin toxin (a neurotoxin)
    • Used in BOTOX
  5. Species of Bacillus studied in class
    • B. anthracis
    • G(+)
    • Used to make Anthrax
  6. Phases of bacterial growth
    • Leg Phase 
    • Log Phase
    • Stationary Phase
    • Death Phase
  7. Leg Phase
    • First step in bacterial growth curve
    • When bacteria are no multiplying but synthesizing enzymes, proteins, RNA ect.
  8. Log Phase
    • Second step of the bacterial growth curve
    • Bacterial cells multiply rapidly (binary fission)
  9. Stationary Phase
    • Third phase of bacterial growth curve 
    • Growth of bacterial cells plateau (growth/death =1)
    • Towards end of this phase is when endospores are made.
  10. Death phase
    Last phase of growth curve
  11. Sporulation
    • The creation of endospores 
    • (towards the end of stationary phase)
  12. steps to making an endospore stain
    • Make smear, air dry and heat fix
    • Flood with malachite green(basic)
    • Steam for 5 minutes 
    • Rinse
    • Counterstain with safranin(basic) for 2mins
    • rinse and oil immersion
  13. Why do you steam the endospore slide?
    To allow the malachite green(basic) to penetrate endospore
  14. OCD stand for ____
    Original Cell Density
  15. Finding OCD or CFU
    • = Colonies counted/DF x Volume plated
  16. FDF
    Final Dilution Factor
  17. How to find the FDF
    DF x volume plated
  18. If 37 colonies were on the 10-4 plate find the CFU
    • 37/(10-4)x(1mL)
    • =370,000 = 3.7x10CFU/mL
  19. Phenol Red (PR) Broth
    • A simple broth that has sugar in it
    • PR is a pH indicator
    • ph <6.8 it turns yellow 
    • 6.9<pH<7.3 turns red
    • pH > 7.4 it turns pink or magenta
  20. Why is glucose preferred in PR broth
    Because it is the preferred carbohydrate of bacterial cells to metabolize
  21. Name the 4 bacilli used in the PR tubes and their similarity
    • Escherichia coli
    • Enterobacter aerogenes 
    • Alcaligenes faecalis
    • Proteus vulgaris 

    They are all gram (-) bacilli
  22. What does Oxidation-fermentation (OF) Glucose Test tell us
    Differentiates bacteria based on oxidative or fermentative metabolism of carbohydrates
  23. Fermentation
    Energy production under anaerobic condition

  24. Dye used in OF tests
    • Bromthymol blue dye 
    • pH  6 it turns yellow
    • pH
  25. What is a phospholipid?
    Complex Lipid
  26. Complex Lipid/Phospholipid are made up of what?
    Contain carbon, hydrogen, and oxygen like simple lipids but also contain phosphorus, nitrogen, and sulfur
  27. What is a complex lipid?
    Phospholipid or steroids

    Contain P,N and S along with the normal C,H, and O in simple lipids
  28. What are cell membranes primarily made of?
  29. What is a steroid?
    A 4 carbon ring with an -OH group attached to one ring
  30. What are proteins made of?
    • Carbon, Hydrogen, Oxygen, and Nitrogen
    • Amino Acids

    Complex, and 3-D shape
  31. What are enzymes?
    A type of protein that speed up biochemical reactions
  32. What do amino acids make up?
  33. What make up amino acids?
    A carboxyl group (-COOH) and one amino group (-NH2) attached to the same carbon atom
  34. Two stereoisomers of amino acids
    • L-amino acid (Left hand; COOH)
    • D-amino acid (Right hand; HOOC)

    L-forms are most often found in nature
  35. What is a peptide bond?
    A bond between amino acids
  36. How are peptide bonds formed? What are they formed from?
    • They are formed by dehydration synthesis 
    • Formed from the carboxyl(-COOH) and the amino acid (NH2)
  37. What happens during the creation of a peptide bond?
    one water molecule is released
  38. What are the 4 levels of protein structure
    • Primary structure
    • Secondary structure
    • Tertiary structure
    • Quaternary structure
  39. Primary structure
    • 1st level of protein structure
    • Amino acids are linked together to form a polypeptide chain (protein)
  40. Secondary structure
    • 2nd protein structure 
    • Twists and folds; shape held together by H-bonds
    • Spirals or helices 
  41. Tertiary bond
    • 3rd protein structure
    • Irregular folding due to bonding between AA's in the polypeptide chain
    • Disulfied bonds
    • Hydrogen bonds
    • Ionic Bonds
  42. Quaternary structure
    • 4th level of protein structure 
    • Not in all proteins 
    • May require covalent, hydrogen, ionic bonds or hydrophobic reactions
    • Easily denatured by pH, temp or chemicals
  43. Conjugated proteins
    • Consist of a combination of amino acids and other organic molecules.
    • Glycoproteins (Contain sugars)
    • Nucleoproteins (Contain nucleic acids)
    • Lipoproteins (Contain Lipids)
  44. Full name for DNA
    Deoxyribonucleic acid
  45. Nucleic acids are made from what?
    • Nucleotides
    • DNA, RNA, ATP
    • Acidic found in nucleus 
    • Sugar-phosphate backbone