Quiz 2 - Micro

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Quiz 2 - Micro
2012-09-24 10:54:22

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  1. How are Amino Acids linked and what do they form?
    Linked by peptide bonds and form polypeptides (PROs)
  2. Describe Nucleotide Structure.
    • Nitrogenous Base ( A, C, G, T, U)
    • Ribose
    • Phosphates
    • Linked by phosphodiester bonds
  3. Which nitrogenous bases are purines and which are pyrimidines?
    • Purines: Adenine and Guanine
    • Pyrimidines: Thymine, Cytosine, and Uracil
  4. What is the structure of DNA?
    • Usually double stranded
    • Strong Covalent Bonds
    • Base Pairing
    • H-bonds between bases form helixs
    • Phosphodiester bonds
  5. What are the functions of Nucleic Acids?
    • Passes parent to offspring as genetic info
    • Information for protein synthesis (DNA - long term storage info, RNA - ss info storage during protein synthesis)
  6. All cells contain both DNA and RNA. ___________ contain ________ DNA or RNA. ATP energy currency.
    Viruses, either
  7. ATP has a _______ structure.
  8. What is anabolism?
    Synthesis, bond formation, requires energy
  9. What is catabolism?
    Bonds broken, energy released
  10. What are reduced molecules?
    Contain electrons and potential energy (e.g. CHO, lipids)
  11. What are oxidized molecules?
    Contain fewer electrons and less energy
  12. What are prokaryotic cells?
    • Cell wall
    • Bacteria (no small organelles)
    • High Surface area : volume ratio, allows for survival without specialized organelles
  13. What is Eukaryotic cells?
    • Animals, plants, fungi, and protozoa
    • Large nucleus, other organelles
  14. What are the typical prokaryotic morphologies?
    • Coccus - Sphere
    • Coccobacillus - elongated sphere
    • Vibrio - banana
    • Bacillus - Rod
    • Spirillum - wave
    • Spirochete (corkscrew, almost always motile)
  15. Describe bacterial arrangements.
    • Single-celled arrangement very common
    • Diplo: Two joined
    • Strepto: Chains
    • Staphylo: Clusters
    • Tetrads: Four Cells
  16. Describe the cell membrane of a prokaryotic cell.
    • Exterior to cell membrane, complex, semi-rigid
    • Borders cytoplasm
    • Composed of phospholipid bilayer + proteins(act as bilayer in and out)
    • No sterols (e.g. cholesterol)
    • Barrier
  17. What are the functions of the cell wall?
    • Determines shape
    • Protects cell membrane from osmotic pressure changes
    • Composed of peptidoglycan lattic
  18. What is the structure of peptidoglycan lattice?
    • Carbohydrate, backbone of NAG-NAM disaccharide repeats
    • Peptide chains + cross-bridges (4 AA)- cross-link and strengthen CHO backbone
    • CHO backbones can be 30-40 thick
  19. Describe the peptidoglycam in gram positive and in gram negative.
    • Gm (+): Thick layer of peptidoglycam, Teichioic acids , no outer membrane
    • Gram (-): Thin peptidoglycam, Outer membrane contains LPS or endotoxin(which stimulate immune response), periplasmic space - between cell membrane and cell wall, metabolically active, hydrolysis of organic nutrients
  20. How are AA linked in peptidoglycan lattice?
    AA linked together by stable peptide bonds
  21. What can inhibit cross-link formation?
    Cell wall synthesis inhibitors (e.g. penicillin)
  22. What is gram stain procedure?
    Based on cell wall differences, is critical to bacterial identification
  23. What is the importance of the nuclear region of the cell?
    • Contain a singular chromosome
    • Other nucleic acid: Plasmids
  24. What are plasmids?
    • Small circular extrachromosomal DNA molecules
    • Common location of antibiotic resistance genes
  25. What are ribosomes?
    • Structurally distinct from eukaryotic
    • Antibiotic target
  26. What are endospores?
    • Resistant structures produced by some (not all) bacteria
    • Can survive in extreme conditions
    • Dehydrated, metabolically inert, comped of core, cortex, spore coat layers
    • Not for reproduction (1 per bacteria)
  27. How are endospores produced?
    Vegetative (active) cell produced endospore under stress
  28. How is an endospore activated?
    Germination: Endospore activates, enters vegetative cycle
  29. What are the layers of an endospore?
    • Endospore
    • Spore Coat
    • Cortex
    • Core
  30. During endospore formation, what occurs during "good times" and what occurs during "bad times" or stress?
    • Vegitative cycle: Good times
    • Sporulation: Bad times
  31. What are the external structures located outside of the cell?
    • Flagella: Motility
    • Basal Body: Anchors flagella to plasma membrane/cell wall
    • Taxis: Response to stimuli
  32. What are the different kinds of taxis>
    • Chemo: Attracted to or away from a chemical
    • Phototaxis: Maintain themselves in the upper layer of the water / ability to move towards a light source
  33. What is Pili? What are the two types?
    • Pili: Attachment, not motility
    • Attachment pili: Allow attachment to surfaces (key virulence factor for some pathogens)
    • Conjugation pili (sex pili): Allow transfer of DNA (conjugation), Usually a plasmid from one cell to the next
  34. What is the Glycocalyx?
    • Enternal to cell wall
    • Usually composed of polysaccharides, provides 'slippery' outer layer
    • Prevents desiccation, acts as virulence factor by protecting cell from phagocytosis, can also aid in attachment
    • Not thick