Exam 2

macronutrients - a chemical substance required in large quantities

1. macronutrients needed to support microbes - carbon, hydrogen, oxygen

2. macronutrients involvement - role in cell structure and metabolism

micronutrients - a chemical substance required in small quantities 

1. micronutrients involvement - role in enzyme function and maintenance of protein structure

essential nutrients - any substance that must be provided to an organism

1. essential nutrients for microbes - carbon, hydrogen, oxygen, nitrogen, phosphate, and sulfur (CHONPS)

two categories of essential nutrients - macronutrients and micronutrients 

Chemoheterotrophs - microorganisms that derive its nutritional needs from organic compounds

chemoautotroph - an organism that relies upon inorganic chemicals for its energy and carbon dioxide for its carbon

photoheterotroph - an organism that uses light for energy, but can not use carbon dioxide as their sole carbon source

1. mesophile - organisms that grow at intermediate temperatures, 20-40C

2. psychrophile - organisms that grow at low temperatures, 0-15C

3. thermophile - organisms that grow at high temperatures, 45-80C

4. Capnophile - microorganisms that thrive in high concentrations of carbon dioxide 

5. halophile - a microbe whose growth is stimulated by salt or requires a high concentration of salt

6. osmophile - a microorganism that thrives in a medium having a high osmotic pressure

7. Acidophile - a microorganism that can survive and grow in acidic environments, preferably 2 pH

8. Alkaliphile - a microorganism that thrives and grows in highly alkaline environments, preferably 9 ph

9. Aerobes - organisms that survive/grow in an oxygenated environment

10. anaerobes - organisms that can live without oxygen 

11. obligate aerobes - organism that can not survive/grow without oxygen

12. obligate anaerobes - organisms that will die when exposed to any levels of oxygen

13. microaerophile - organisms that can only grow in reduced levels of oxygens

14. facultative anaerobes - organisms that can survive/grow with or without oxygen

15. aerotolerant anaerobes - organisms that do not use oxygen but can survive with or without oxygen

16. Generation time - time required for a complete fission cycle; from parent cell to two new daughter cells 

17. viable plate count procedure - a traditional method used to observe the population growth pattern and estimate the total number of living cells over a period, a single colony on a plate represents a single cell from the original sample

    1. step 1 - placing a tiny number of cells into a. sterile broth

    2. step 2 - incubating this culture over several hours

    3. step 3 - sampling the broth at regular intervals during the incubation

    4. step 4 - plating each sample onto the media 

    5. step 5 - counting the number of colonies present on each agar plate after incubation

18. colony - a macroscopic cluster of cells appearing on a solid medium, each arising from the multiplication of a single cell

19. microbial growth curve phases - 

    1. lag phase - 1, the early phase of population growth during which no signs of growth occur

    2. exponential growth phase - 2, the period of maximum growth rate in a growth curve, cell population increases logarithmically 

    3. stationary growth phase - 3, survival mode in which cells either stop growing or grow very slowly

    4. death phase - 4, the end of the cell growth due to lack of nutrition, depletion of environment, and accumulation of wastes, the population of cells begins to die 

20. Growth curve phase best for controlling and treatment - exponential growth phase

21. binary fission - the formation of two identical new cells of approximately equal size as the result of parent cell division

22. stage 1 - a young cell

23. stage 2 - chromosomes are replicated, and new and old chromosomes move to opposite sides of the cell

24. stage 3 - A protein band forms in the midsection of the cell, the cell wall is also elongated

25. Stage 4 - septum formation begins, cytokinesis occurs(cytoplasm division), protein band disperse throughout the cell

26. stage 5 - septum is completed, two identical daughter cells are separated 

the top two most resistant microbes - prions and bacterial endospores 

1. Bactericide - an agent that kills bacteria

2. bacteriostatic - any process or agent that inhibits bacterial growth 

3. microbial death - the permanent loss of reproductive capability, even under optimum growth conditions

4. Sterilization - process that destroys or removes all viable microorganisms

   1. Physical control agents used to achieve sterilization - heat (autoclave), sterilants (chemical agents), radiation, filtration, ultrasonic waves, cold

5. disinfection - physical process or chemical agent to destroy vegetative pathogens but not bacterial endospores, removes harmful products of microorganism from material

6. sanitization - a cleansing technique that mechanically removes microorganisms as well as other debris to reduce contamination to safe levels

7. degerming - a mechanical process that reduces the number of microbes on the human skin

8. antisepsis - the process, of inhibiting/destroying microorganisms on living tissues

9. asepsis - a state/condition of being free from viable pathogenic microorganisms

10. antiseptic - chemical substances used to do antisepsis

11. Dry heat - hot air or an open flame

    1. controlling microbes with dry heat - 2 methods: incineration and hot-air oven

       1. incineration - an open flame, reduces microbes to ashes and gas, can sterilize 

       2. hot-air oven - radiates heat within an enclosed compartment, destroys endospores, can sterilize 

12. moist heat - in the form of hot water, boiling water, or steam 

    1. controlling microbes with moist heat - 3 methods: boiling water: disinfection, pasteurization: disinfection of beverages, steam under pressure: autoclaving, sterilization

       1. boiling water: disinfection - 

13. autoclave - a sterilization chamber that allows the use of steam under pressure to sterilize materials, common temp/pressure combination would be 121C and 15 psi

14. pasteurization - heat treatment of perishable fluids to destroy heat-sensitive vegetative cells, followed by rapid chilling to inhibit growth of survivors and germination of spores. Prevents infection and spoilage

15. Moist heat destroys microorganisms by - coagulation and denaturation of proteins, quickly and permanently halts cellular metabolism

16. Dry heat destroys microorganisms by - dehydrating the cell, removing extra water that is necessary for metabolic reactions, denaturing proteins, oxidizing cells; burning into ashes

Filtration controls microbes by - using thin membranes and plastic that include pore sizes that could be controlled, can catch viruses and some proteins

1. Filtration - removing microbes from air and liquids

2. Radiation - electromagnetic waves or rays given off from an energy source and is disperse at a high velocity through matter or space

3. ionzing radiation - an alternative for sterilizing materials that are sensitive to heat or chemicals

4. Nonionizing radiation - a method of disinfect that uses UV rays to destroy fungal cells, spores, bacterial vegetative cells, protozoa, and viruses

5. Chemical agents target - proteins, nucleic acids, cell walls, and cytoplasmic membrane

6. Chemical agents that are used as antiseptics - iodine(halogen), hydrogen peroxide(oxidizing agent), chlorhexidine, organic mercury tinctures (heavy metal compounds), phenol(carbolic acid)

7. Chemical agents that are used for degerming - alcohol

8. Chemical agents that are halogens - iodine, sodium chlorite, sodium hypochlorites

9. Halogen chemical agents are used as - a topical antiseptic, disinfectant for plastic and rubber instruments

10. Chlorhexidine’s mode of action - targets bacterial membranes specifically ones where their selective permeability is lost, causing cell wall and proteins to denature

11. Alcohol’s mode of action - dissolves membrane lipids, disrupts cell surface tension, and compromises membrane integrity when concentrations is >50%

12. Limitations of alcohol - rate of evaporation decreases the effectiveness

13. Best % of alcohol for infection - 50%-95%

14. Quats - cationic detergents, quaternary ammonium compounds

15. Bacterial genera that are resistant to quats - spore-forming bacteria, mycobacteria, gram-negative bacteria

16. Cold temperatures - can slow down the growth of cultures and microbes in food during processing and storage

17. Cold is microbistatic

18. Infection - the invasion and growth of microorganisms in the body 

19. Antibiotics - substances produced by natural metabolic processes of some microorganism that can inhibit or destroy other microorganisms, drug-treating bacteria

20. narrow-spectrum drugs - antimicrobials effective against a limited arrow of microbial types

21. broad-spectrum drugs - antimicrobials effective against a wide variety of microbial types

22. Prophylaxis - use of a drug to prevent infection of a person at risk

23. selectively toxic - should kill or inhibit microbial cells without simultaneously damaging host tissues

24. Beta-lactam ring structure - four-membered ring structure found in many antibiotics

25. Beta-lactam ring function - binds to enzymes that cross-link peptidoglycans, prevents crosslinking, kills the bacteria

26. Kirby-Bauer test - agar diffusion test that provides useful data on antimicrobial susceptibility, determines how susceptible bacterial are to antibiotics

27. Therapeutic index - the ratio of the index dose to the effective therapeutic dose that is used to assess the safety and reliability of the drug

28. Safe dosage number - when the ratio # is much bigger, or when the index # is much closer to the toxic dose #

29. Common drugs used for treating fungal infections - macrolide polyene antibiotics, azoles, echinocandins, and allylamines

30. Antiviral drugs’ mode of action - barring penetration of the virus into the host cell, blocking the transcription and translation of viral molecules, preventing the maturation of viral particles

31. antibiotics not effective against viruses because - virus uses the same host cell’s mechanisms and metabolic functions that antibiotics target, making it difficult to disrupt without harming the host cell

32. Antibiotic resistance develops through - spontaneous mutations in critical chromosomal genes, or the acquisition of entire new genes or sets of genes via horizontal transfer from another species

33. Different ways bacteria can prevent/disable drugs - new enzymes are synthesized that destroy the active component in the drug, changing the cell wall permeability, modifying membrane proteins that pump out the antimicrobials quickly, or alter the number of binding sites