Exam 3 - Microbiology

True or False
Viruses are considered the most abundant microbes on earth
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True or False
Viruses are considered the most abundant microbes on earth
True
Select the factors that impact the death rate of microbes:
A) Concentration of agent
B) Temperature of environment
C) pH of environment
D) Number of microbes
E) All of the above
Answer: All of the above. All of these factors have an impact on the death rate of microbes, including the presence of solvents, inhibitors, oils or other organic matter.
Select all that apply.
What is a virus?
A) Contains genetic material like DNA or RNA and can be double-stranded or single-stranded.
B) Is an infectious, obligate intracellular parasite.
C) Does not need host cells to replicate.
D) Consists of a protein shell that surrounds the nucleic acid core.
E) All the above.
Answer: A, B, and D
What germicide damages the protein and DNA of microbes while also decomposing to O2 gas?
a.) Alcohol
b.) Lysol
c.) Hydrogen peroxide
d.) Soap
The answer is C) Hydrogen peroxide.
True or False: Viruses leave sign behind that show they have been there.



True!
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True or False
The microbial control methods include physical agents, mechanical removal methods, and chemical agents. All three methods are used for sterilization and disinfection.
True!
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True or False
The capsid's sole function is to protect the nucleic acid when the virus is outside of a host cell.

False: A capsid also helps the virus bind to a cell surface and assists the penetration of the viral DNA or RNA into a suitable host cell.
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Cold _____ microbial growth
A. Speeds
B. Slows
C. Stays the same
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DNA Viruses are only double stranded and circular shaped. True or False?
False because they can be either single or double stranded with circular or linear shape
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TRUE OR FALSE?
Antibiotics are secondary metabolites.


TRUE. They are not directly involved in the growth of the bacterium unlike primary metabolites which are involved in metabolic or cellular growth.
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1) Infection A) Poisonous chemical to plants, microbes, and some animals 2) Pathogen B) Toxin secreted that acts on a specific cellular target 3) Toxin C) Any agent that infects body tissues and causes damages 4) Exotoxin D) An intracellular toxin that is not released 5) Endotoxin. E) Cell membrane that engulfs particles or cells into vesicles 6) Phagocytes F) Multiplication of pathogenic organisms within a host Key 1 - F 2 - C 3 - A 4 - B 5 - D 6 - EWhat is an antimicrobial agent that kills most gram positive and gram negative bacteria? answer: broad spectrumThe ability to target somethings but not others is interferon. True or False? False the correct answer is Selectively ToxicT OR F Mammalian viruses capable of initiating tumors are called Oncoviruses Answer: T Oncoviruses are viruses with a DNA or RNA genome capable of inducing tumors.True or False: Oligodynamic action is having antimicrobial effects in exceedingly small amounts. Answer: TrueAll viruses have an external covering called an envelope, True or false? Answer: False (Not all do, those lacking an envelope are naked)Name a type of antibacterial, describe how it works, and is it dangerous? 1) Cell Wall Synthesis- antibacterials like penicillin target the peptidoglycan of the cell wall, essentially causing gaps or holes to develop. This cause the process of osmosis to become disrupted and less controllable by the cell wall eventually cause it to bust. It is not dangerous to eukaryotic cells because they do not have peptidoglycan.2) Protein Synthesis- Interferes with cellular protein synthesis. Eukaryotic cells also go through protein synthesis thus can be very dangerous to humans. 3) Transcription- This disrupts enzymes used in transcription for bacteria, which differ from the enzymes used in eukaryotic transcription. This is not dangerous to humans. 4) Cell Membrane Function- This method bonds to the phospholipid bilayer which causes weakening of the membrane and making it spongy. This method is very dangerous to humans since eukaryotic cells have a phospholipid bilayer too. This medicine is mostly used to treat fungi infections. 5)Metabolic Pathways- This method interrupts and blocks chain reactions in protiens and enzymes. For example if step C is interrupted in a chain of steps A, B, C, D, E, F, & G; then this would cause steps D, E, F, & G to not happen. This causes a break down of the cells systems. This is considered safe to humans.Microbial control methods that kill _____ are able to sterilize A. virusesB. the tubercle bacillus C. endosporesD. cyst Answer: CTrue or False: When two or more antibiotics are prescribed to treat an infection, a synergist works simultaneously with another antibiotic to produce a more potent effect. True!capsomers A. All viruses have capsids B. those lacking an envelope naked C. capsid and nuclei acid together is nucleocapid D. some viruses have an external covering called enveloped E. each capsid is made of identical protein subunits called multiple choiceWhich method of moist heat control utilizes an autoclave? A. Pasteurization B. Boiling water C. Steam under pressure D. Tyndallization ANSWER: C. Steam under pressure. An autoclave is a machine in which sterilization occurs due to the increasing of pressure in order to increase the steam's temperature.Icosahedral viruses can lack an outer envelope. True or False Answer: TRUE Examples: 1) Rotavirus (naked)2) Herpes simplex (enveloped)True or False Virus families are sometimes named for their microscopic appearance. True! Some examples of this are rhabdoviruses, which have a bullet-shaped envelope, and togaviruses, which have a cloaklike envelope.OncovirusesA.) Any cleansing technique that mechanically removes microbes2.) AntibioticB.) Does not directly kill the bacterium but inhibits growth3.) SanitizationC.) A process that destroys all viable microbes, including viruses and endospores4.) VirologyD.) The study of viruses5.) SterilizationE.) A subset of antimicrobials that are naturally produced by biosynthetic of molds or other bacteria6.) BacteriostaticF.) Mammalian viruses capable of initiating tumors 1.) F 2.) E 3.) A 4.) D 5.) C 6.) B-static agents prevent growth, while -cidal agents terminate the organism outright. True!Multiple Choice What is the study of viruses called? A) Botany B) Entomology C) Virology D) Ornithology Correct Answer: C) VirologyThe biggest virus is approximately the size of the smallest bacteria. TRUEViroids are the smallest infectious pathogens known. T/F? Answer: TTrue or False Hepatitis B has a very broad host range. False: Hepatitis B has a narrow host range. This virus has very specific protein spikes that are only compatible with human liver cells.