Microbio Final

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What are contaminants?

Substances that pollute or make something impure (correct)
Elements that enhance the quality of something
Essential nutrients for growth
Natural resources that are renewable

What are the three general methods used in the decontamination process?

General cleaning, sterilization, disinfection (correct)
Filtration, sedimentation, decantation
Evaporation, condensation, sublimation
Heating, cooling, mixing

Are all contaminants equally susceptible to physical and chemical means of decontamination?

False (B)

How do sterilization and disinfection differ?

Sterilization eliminates all forms of microbial life, while disinfection reduces the number of pathogenic microorganisms to a safe level. Signup and view all the answers

Can something be almost sterile? Explain.

Yes, something can be almost sterile if it is free from most, but not all, microorganisms. It can be considered "almost sterile" because achieving absolute sterility is nearly impossible; even with rigorous cleaning methods, a very small number of microbes might still remain. Signup and view all the answers

What is the difference between a -cidal agent and a -static agent?

-cidal agents kill microorganisms, while -static agents inhibit their growth without killing them. Signup and view all the answers

If you take bacteriostatic antibiotics for an infection, what will happen when you stop taking the antibiotic?

The infection may relapse or worsen. (B) Signup and view all the answers

What is disinfectant primarily used on, and what are some examples?

Surfaces; Bleach and Alcohol (A) Signup and view all the answers

What is an antiseptic used for, and what are some examples?

Used on skin and includes alcohol and hydrogen peroxide (A) Signup and view all the answers

Your bathroom in a public restroom may say "sanitized for your protection." Is sanitization the same as sterilization?

False (B) Signup and view all the answers

When is a microbe considered dead?

When it no longer exhibits metabolic activity (A), When it can no longer reproduce (B) Signup and view all the answers

How do the number of organisms and their state of growth (spores vs vegetative cells) affect microbial death rate?

Vegetative cells are typically more susceptible to death than spores. (C) Signup and view all the answers

What is the difference between physical and chemical methods of microbial control?

Physical methods use heat or radiation, while chemical methods use disinfectants. (A) Signup and view all the answers

How does a chemical agent's concentration affect the microbial death rate?

Higher concentration leads to a faster death rate (A) Signup and view all the answers

What are the four major cellular targets for antimicrobial agents?

Cell wall synthesis, Protein synthesis, Nucleic acid synthesis, cell membrane Signup and view all the answers

Which of the following agents specifically target bacterial cell walls?

Penicillin (A), Amoxicillin (C), Vancomycin (D) Signup and view all the answers

How do surfactants work?

They decrease surface tension by reducing intermolecular forces. (B) Signup and view all the answers

How many proteins can be denatured?

All proteins can be denatured (B) Signup and view all the answers

Which is more effective for sterilization, moist heat or dry heat?

Moist heat (A) Signup and view all the answers

Moist heat [blank] proteins and [blank] nucleic acids, while dry heat [blank] cell components.

denatures, destroys, oxidizes Signup and view all the answers

If organism A has a TDT of 15 minutes and organism B has a TDT of 35 minutes, using the same temperature, which organism is most resistant to heat?

Organism B (B) Signup and view all the answers

Why is pressure added to the steam present in an autoclave?

To increase the boiling point of water (A) Signup and view all the answers

What is the process of [blank] that involves heating for a specific period, allowing for the destruction of highly resistant microorganisms?

tyndallization Signup and view all the answers

Does boiling water sterilize the water?

True (A) Signup and view all the answers

Does pasteurization sterilize milk?

False (B) Signup and view all the answers

What is pasteurization?

A method of sterilizing food by heating it to a high temperature. (A) Signup and view all the answers

Why is cold not used to kill microbes? (Multiple)

Cold temperatures only slow down microbial growth. (A), Microbes can survive in cold environments with no effect. (C) Signup and view all the answers

Why does ionizing radiation limit microbe growth?

It damages DNA, preventing replication (A) Signup and view all the answers

Why does nonionizing radiation limit microbe growth?

It causes damage to DNA. (A) Signup and view all the answers

How is the usefulness of non-ionizing radiation limited?

It cannot penetrate materials deeply. (A) Signup and view all the answers

When is filtration an effective method to remove contaminants?

When the contaminants are larger than the pore size of the filter (A) Signup and view all the answers

How do aqueous solutions differ from tinctures?

Aqueous solutions consist of water as a solvent, while tinctures use alcohol as a solvent. (A) Signup and view all the answers

Which of the following characteristics should an ideal chemical antimicrobial agent have? (Select all that apply)

Effective against a wide range of pathogens (A), Non-toxic to human cells (B), Stable in storage and use (C) Signup and view all the answers

How does bleach work as a disinfectant?

By oxidizing cellular components of microorganisms (A) Signup and view all the answers

How does alcohol kill bacteria?

Denaturing them (A) Signup and view all the answers

What is the cellular target of detergents?

Cell membrane. Signup and view all the answers

What are the cellular targets of heavy metals?

Proteins, enzymes, and cellular membranes Signup and view all the answers

Glutaraldehyde is used to sterilize contaminated areas; how does it kill microbes?

By cross-linking proteins and nucleic acids, which disrupts cellular function. (A) Signup and view all the answers

Ethylene oxide is a sterilant. Why is it not used on human tissue?

It can cause severe skin irritation and burns. (A) Signup and view all the answers

Contaminant

A substance that makes something impure or pollutes it

Decontamination Methods

General cleaning, sterilization, and disinfection

Physical vs. Chemical Control

Physical methods use heat, radiation, etc., while chemical methods use disinfectants, antiseptics, or antibiotics.