Unit II Study Guide

  1. Microorganisms require large quantities of this nutrient for use in cell structure and metabolism
  2. Microorganisms require small quantities of this nutrient for enzyme function and maintenance of protein structure
  3. What compound has the highest concentration in a cell?
  4. Most of the dry weight of a microbial cell is from
  5. An organic nutrient that cannot be synthesized by the organism and must be provided is called a/an
  6. An important mineral ion that is a component of chloroplasts and stabilizer of membranes and ribosomes is
  7. The term autotroph refers to an organism that:
  8. The term heterotroph refers to an organism that
  9. The term phototroph refers to an organism that
  10. The term chemotroph refers to an organism that
  11. The movement of molecules from an area of high concentration to an area of lower concentration is called
  12. Diffusion of water through a semi permeable membrane is called
  13. The movement of substances from higher to lower concentration across a semi permeable membrane that must have a specific protein carrier but no energy expenditure is called
  14. Salts and sugars work to preserve foods by creating ______.

  1. Which line best depicts an obligate anaerobe in the presence of O2?
  2. Which line best depicts a mesophile with an optimum temperature of 35°C incubated at 40°C?
  3. Which line best depicts an incubated at acidophile at pH 4.5?
  4. Micrococci are facultative halophiles. In the figure above, which line best depicts the growth of M. luteus in a nutrient medium containing 7.5% NaCl?
  1. The breakdown of peptidoglycan to N-acetylmuramic acid, N-acetylglucosamine and peptides is an example of
  2. A holoenzyme is a combination of a protein and one or more substances called
  3. Enzymes that are only produced when substrate is present are termed
  4. Enzymes that catalyze removing electrons from one substrate and adding electrons to another are called
  5. Enzymes that catalyze removal of carbon dioxide from a substrate are called
  6. During aerobic cellular respiration, the final electron acceptor is
  7. Enzymes that are secreted by a cell to hydrolyze reactions are

  1. Which compound is being oxidized in the reaction? Which is being reduced?
  2. What is the oxidized form of NAD? What is the reduced form?
  1. Name the cause of cell death resulting from damage to each of the following:

Cell wall

Plasma membrane

Proteins

Nucleic acids

  1. The thermal death time for a suspension of Bacillus subtilis endospores in 30 min in dry heat and less than 10 min in an autoclave. Which type of heat is more effective? Why?
  1. If pasteurization does not achieve sterilization, why is food treated by pasteurization?
  1. List three factors that can alter thermal death point.
  1. The antimicrobial effect of gamma radiation is due to ______and______. The antimicrobial effect of ultraviolet radiation is due to ______.
  2. Contrast bacteriostatic and bactericidal agents. Explain why viable count does not drop immediately to zero at the moment of application of the bactericidal agent?
  1. Fill in the following table

Method of Sterilization / Temp. / Time / Type of heat / Pref’d use / Type of action
Autoclaving
Dry heat
Pasteurization
  1. Name one food that is preserved with sugar and one that is preserved with salt. Why are these considered physical rather than chemical methods of microbial growth?
  1. List factors to consider before selecting a disinfectant.
  1. Give the method of action and at least one standard method of use of each of the following types of disinfectants:

Phenolics

Iodine

Chlorine

Alcohol

Heavy metals

Aldehydes

Ethylene oxide

Quats

Hydrogen peroxide