Bio 2025 Midterm 2

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  1. Sterilization vs Disinfection : 
    Define Sterilization and Disinfectant and Antiseptic.
    • Sterilization : destroys all forms of life.
    • Disinfectant : antimicrobial agent used on inanimate objects.
    • Antiseptic  : used on living tissue.
  2. Bacteria -Cidal vs. -Static :
    • bacteriacidal : Kills bacteria 
    • Bacteriastatic : Inhibits bacterial growth
  3. Factors that effect Antimicrobial Activity :
    - Time, temp, concentration of antimicrobial agent, type of microbe, activity of microbes and presence of organic matter.
  4. Targets of antimicrobial agents :
    • cell Membrane 
    • enzyme and proteins 
    • DNA and RNA
  5. Physical Methods of Microbial Control :
    • Heat : works by denaturing enzymes and proteins.
    • a. Thermal Death Point (TDP) : lowest temp. at which all microorganism in a liquid culture are kille din 10 minutes.
    • b. Thermal Death Time (TDT) : minimum length in which all microorganisms in a liquid culture are killed at a given temperature.
  6. Moist Heat : 
    What does boiling water do?
    What is not effective against?
    What’s the most preferred method of sterilization? 
    When does water boil and increase of what increases what?
    What degree/time is good enough to sterilize everything?
    • Boiling water : Kills vegetative bacterial cells, Fungi and many viruses. Not effective for endospores and some viruses. 
    • Autoclave : preferred method of sterilization. Water boils at 100*C and increasing the pressure increases the temperature.
    • 121*C for 15 min is good enough to sterilize everything.
  7. Pasteurization : 
    What is it?
    What’s the high temp/ short time pasteurization?
    What does it do and give some examples?
    • Mild heating sufficient to kill microbes that cause food spoilage.
    • High temp short time pasteurization is 72*C for 15s 
    • Increases the life of most food products. Ex : canned foods, creams and etc.
  8. Kilit Ampule : 
    What is it?
    What’s the pH indicators?
    What happens when a bacteria is able to ferment the sugar?
    • Spores of Bacillus stearothermophilus. (Heat loving) Fermentable sugar.
    • pH indicator : basic = red and acid = yellow. 
    • the pH indicator would turn yellow.
  9. Dry Heat :
    What are the 3 methods and what do they use?
    • 1. Direct Flaming : Inoculating Loop and Needle 100% effective. 
    • 2. Incineration : disposable wastes (paper cups, bags and dressings.)
    • 3. Hot Air sterilization : Oven (170 C for 2 hours). Used on substances what would be damaged by moist heat sterilization. (Gauzes, dressings or powders.
  10. Filtration :
    What is it?
    • Removes microorganisms from solutions that might be damaged by heat.
    • Culture media, enzymes, vaccines and antibiotics.
  11. Radiation : 
    What are the 2 types?
    What do they use and the substances that could be damaged by the heat?

    What’s thymine Dimers?
    • 1. Ionizing Radiation (short wavelength more energy) Gamma rays and x-rays which penetrates most substance.
    • Used on substances that coul deb damaged by heat.
    • Ex : plastic petri dishes, plastic syringes, catheters, surgical gloves.
    • 2. Non-Ionizing Radiation uses UV light (does not penetrate plastic, glass or proteinaceous matter. Used to reduce microbial populations in hospital rooms, nurses and operating rooms. 
    • - a form of DNA
  12. How do many of the disinfectants work by?
    • Destroys the PM integrity and results in the cell leakage. 
    • Degrades the cell surface proteins.
  13. Phenols : 
    How does it work?
    Derived from waht?
    What ingredient makes lysol and what do phenols work well with?
    • Works by injuring lipid-containing plasma membranes and causing cell leakage. 
    • From cresol
    • O-phenolphenol is the main ingredient in Lysol. Works really well on Mycoplasma tuberculosis and M. Leprosy
  14. BisPhenols : 
    What type of group does it contain?
    Used as what?
    Has what?
    • contains 2 phenol groups. 
    • used as lotions to control gram (positive and negative.)
    • Soluble in plastics. Can be made into antimicrobial plastics. 
    • Triclosan-bisphenol incorporated into many products like cutting boards, calculators and knife handles. 
    • Inhibits fatty acid synthesis and prevents formation of lipid base cell wall.
    • Bacteria start to become more resistant to these products and etc.
  15. Biguanides : 
    What’s an example?
    What is it and what does it do?
    • Chlorhexidine
    • Similar to phenolics but are less toxic.
    • Disrupts the plasma membrane. Excellent as surgical scrubs and for patient preps, irritant to the eyes.
  16. Halogens : 
    How is it special?
    How does it work against and inhibits what?
    • One of the oldest methods around. 
    • Works against all bacteria and many endospores, fungi and viruses. 
    • Inhibits the functions of microbial proteins and alters plasma membrane. 
    • Tincture - iodine combined with alcohol.
    • Iodophor - iodine combined with an organic carrier molecule. Betadine.
  17. Alcohols : 
    What does it do?
    How does it do it?
    • Kills bacteria and fungi but not endospores and most viruses. 
    • Denaturing proteins, but disrupts membranes and dissolves lipids (fats).
    • Biological organic material allows the protection of bacteria. ex: poooop.
  18. Heavy Metals :
    What happens to them at low concentrations?
    What does silver nitrate do?
    How does Mercury and Zinc relate to this?
    • works to denature proteins, including enzymes. 
    • Silver Nitrate : used to treat eye infections in newborns caused by gonorrhea.
    • Mercury : used to keep vaccines sage from contamination. 
    • Zinc : in cough drips : distrips the enzyme in the viruses.
  19. Surface-active agents (Surfactants) : 
    Describe SOAP
    • microbes to be mechanically removed. Breaks up the oily film that covers skin and allows microbes and dirt to wash away.
    • (anion) reacts with the plasma membrane of microbes to degrade it.
    • has cation charge and less effective against gram-negative, endospores, tuberculosis bacteria. Can kill fungi, amoebas, and some viruses.
  20. Chemical Food preservatives : 
    Used for what?
    What happens to what when exposed to what?
    • used to retard spoilage, and are believed o be safe for consumption. 
    • Sodium nitrate added to meat like bacon and hot dogs to prevent.
    • Obligate aerobes die in presence of sodium nitrite.
  21. Aldehydes : 
    What type of gas can be used as a disinfectant?
    What is it?
    What’s use for viruses, endospores and TB?
    Why is drinking moonshine bad?
    • Formaldehyde gas
    • - Formalin, a 37% aqueous solution, preserve biological specimen.
    • Glutaraldehyde-Cidex
  22. Gaseous Chemical Sterilants : 
    What does ethylene oxide do?
    Requires and can be used as?
    • kills all microbes and endospores.
    • Highly toxic and explosive. 
    • Requires long soaking times and can be used for things not autoclaved like mattresses.
  23. Plasma Sterilization :
    How does it work?
    What is it used for?
    Is it expensive?
    • 4th state of matter in which gas is excited by EM filed, creation a mixture of positive and negative particles.
    • sterilize things like long hollow tubes.
    • hella!
  24. Peroxygens : 
    What are they?
    What does Hydrogen peroxide help do?
    What about Benzoyl Peroxide?
    • oxidizing agents — these oxidize cellular components of microbes. 
    • Hydrogen peroxide helps release O2 and makes conditions bad for anaerobic bacteria. 
    • Benzoyl Peroxide : main ingredient in many acne treatments and may be used in treating wound infections caused by anaerobes. 

    - H2O2 -> H2O + O2 attacks S. Acne
  25. Define :
    • the study of heredity, how genes carry information, replication, and passage to subsequent generation.
    • Collection of genetic material within a cell or organism.
    • segments of DNA that code for functional product (proteins), except viruses. Some are made from RNA.
  26. How does low fidelity benefit a microbe/bacteria?
    - Increases the rate for mutation. This causes resistance to antibiotics and even viruses can evade form immune system.
  27. A topoisomerase is used on eukaryotic cells. What about prokaryotic?
    - Use Gyrase.
  28. Genetic transfer ONLY in Bacteria - Difference between :
    • introducing brand new genes into the bacteria.
    • transfer of DNA genetic material. Uses pilli.
    • - passing DNA from one bacterium to another using a virus as a carrier.

    Go into more detail Lecture 10 #20-33
  29. Define Mutagen
    What's spontaneous mutation?
    Harmful mutation?
    Lethal Mutation?
    Beneficial Mutation?
    • any agent (chemical or radiation) that brings about mutation. 
    • Spon. Mutation : absence of any mutation causing agent, there is a base change. Typically occurs as abase pair substitution (frame shift).
    • Harmful : changes in DNA that cause errors in the protein sequence, creates partially or completely non-functional proteins.
    • Lethal : Changes in DNA that cause errors in the protein sequence, yields a non-functional protein.
    • Beneficial : changes in the DNA that causes errors in the proton sequence. Yields a functional proteins that helps in survival.
  30. What’s nucleoside analog?
    What’s AZT and Aflatoxin-apergillus flavus?
    • similar to nucleotide base but chemically different.
    • AZT : used as an antiviral drug to treat HIV
    • Aflatoxin : mold found on peanuts and are frameshift mutagen.
  31. What does Ionizing Radiation do to DNA? Examples?
    • free radicals combine with DNA and induces base changes. 
    • ex: x-Rays and Gamma rays and causes free radicals (molecules with unpaired electrons) to form.
  32. PCR : 
    What is added to find the complementary DNA?
    This relies on 2 things…?
    • Strands of DNA serve as a template and primers, nucleotides, and Taq polymerase added. 
    • Makes billions of copies of DNA. 
    • 1. polymerase being bale to stand the high temp. to synthesize DNA.
    • 2. Primers are made specific to the DNA of the microbe one wants to detect.
  33. DNA Vaccines : 
    What is it?
    What does it do?
    How does it do this?
    • use of plasmids (clones and grown in bacteria) with a viral gene under the control of a human promoter.
    • Produces an immune system réponse against invaders like HIV, Influenza and malaria. 
    • Manipulates plasmids in the lab with restriction enzymes to cut and paste DNA into plasmids.
  34. Gene therapy : 
    What is it?
    What can be added to treat cancer cells?
    What types of virus does it use?
    • removal of certain cells and addition of defective or missing gene back into patient. Cells can then function normally when placed back into humans.
    • Uses lenti- and retro- viruses.
    • p53
  35. General Characteristics of a Virus : 
    Type of cell?
    Does not have…?
    Why is it important.
    Where can the virus attach to?
    • acellular 
    • no ribosomes (can’t protein synthesize), ATP generating system, nucleic acid replication.
    • Antivirals interfere with protein synthesis and DNA/RNA replication.
    • specific receptors on cell wall, flagella and fimbraie.
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Bio 2025 Midterm 2
2014-11-09 05:33:39
Bio 2025 Midterm
Bio 2025 Midterm 2
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