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Questions and Answers
Which of the following is NOT a common type of microorganism studied in microbiology?
Which of the following is NOT a common type of microorganism studied in microbiology?
- Viruses
- Bacteria
- Insects (correct)
- Fungi
Viruses are considered living organisms because they have a nucleus and cytoplasm.
Viruses are considered living organisms because they have a nucleus and cytoplasm.
False (B)
Name three precautions that should be taken before working in a microbiology lab to prevent contamination or infection.
Name three precautions that should be taken before working in a microbiology lab to prevent contamination or infection.
Wear a lab coat, wear safety goggles, and sterilize the work surface.
Petri dishes are sterilized after use by a process called _______, which involves burning them at high temperatures to kill microorganisms.
Petri dishes are sterilized after use by a process called _______, which involves burning them at high temperatures to kill microorganisms.
Match the following methods with their primary action against microbes:
Match the following methods with their primary action against microbes:
What did Louis Pasteur's swan-neck flask experiment demonstrate?
What did Louis Pasteur's swan-neck flask experiment demonstrate?
Pasteurization completely sterilizes milk.
Pasteurization completely sterilizes milk.
Explain why it is important to avoid breathing into a petri dish when working with it.
Explain why it is important to avoid breathing into a petri dish when working with it.
The ideal temperature range for most bacteria to grow is between _______ and _______ degrees Celsius.
The ideal temperature range for most bacteria to grow is between _______ and _______ degrees Celsius.
What happens when milk sours?
What happens when milk sours?
The log phase of bacterial growth is when the rate of cell division equals the rate of cell death.
The log phase of bacterial growth is when the rate of cell division equals the rate of cell death.
List three methods to prevent microbial growth in food.
List three methods to prevent microbial growth in food.
In the bacterial growth curve, the phase where bacteria adapt to their environment is called the _______ phase.
In the bacterial growth curve, the phase where bacteria adapt to their environment is called the _______ phase.
Which of the following factors does NOT affect microbial growth?
Which of the following factors does NOT affect microbial growth?
Disinfectants are safe to use on human tissues to prevent infection.
Disinfectants are safe to use on human tissues to prevent infection.
What is the purpose of wearing safety goggles in a microbiology lab?
What is the purpose of wearing safety goggles in a microbiology lab?
The zone of _______ is used to measure the effectiveness of antiseptics and disinfectants on a petri dish.
The zone of _______ is used to measure the effectiveness of antiseptics and disinfectants on a petri dish.
What characterizes the death phase of a bacterial growth curve?
What characterizes the death phase of a bacterial growth curve?
Microbes can only grow in the presence of oxygen.
Microbes can only grow in the presence of oxygen.
Why is it important to wash your hands after a practical?
Why is it important to wash your hands after a practical?
The process of heating milk to kill most bacteria and prolong its shelf life is known as _______.
The process of heating milk to kill most bacteria and prolong its shelf life is known as _______.
Which of the following is a defining characteristic of bacteria?
Which of the following is a defining characteristic of bacteria?
Fungi do not have a cell wall.
Fungi do not have a cell wall.
Why should cuts be covered before entering a lab?
Why should cuts be covered before entering a lab?
_______ slows or stops growth of bacteria, does not harm human tissues.
_______ slows or stops growth of bacteria, does not harm human tissues.
Which causes HIV and influenza?
Which causes HIV and influenza?
Pasteurization completely sterilizes milk, removing all microorganisms.
Pasteurization completely sterilizes milk, removing all microorganisms.
Explain the importance of placing used petri dishes in an autoclave.
Explain the importance of placing used petri dishes in an autoclave.
The procedure to keep milk cool and refrigerated, pasteurising it, and keeping it sealed from air is completed to prevent _______.
The procedure to keep milk cool and refrigerated, pasteurising it, and keeping it sealed from air is completed to prevent _______.
Why do plastic petri-dishes have to be disposed of after autoclaving?
Why do plastic petri-dishes have to be disposed of after autoclaving?
Microbiology only studies bacteria and viruses.
Microbiology only studies bacteria and viruses.
What is the main similarity that Bacteria and Fungi have in common?
What is the main similarity that Bacteria and Fungi have in common?
_______ kills everything, use only on non-living substances.
_______ kills everything, use only on non-living substances.
If temperatures are above 45, what happens to the microbes?
If temperatures are above 45, what happens to the microbes?
Antibiotics can kill viruses
Antibiotics can kill viruses
What is another word for stops/slows growth of bacteria, does not harm human tissues?
What is another word for stops/slows growth of bacteria, does not harm human tissues?
_______: Kills all bacteria/virus, does not harm human tissues.
_______: Kills all bacteria/virus, does not harm human tissues.
Are viruses alive?
Are viruses alive?
Bacteria has a cell wall and a nucleus.
Bacteria has a cell wall and a nucleus.
Why is it important to wash our hands to get rid of most bacteria?
Why is it important to wash our hands to get rid of most bacteria?
_______ proved that spontaneous generation did not exist.
_______ proved that spontaneous generation did not exist.
What is the rate of the Microbes divide during Log phase?
What is the rate of the Microbes divide during Log phase?
Flashcards
Microbiology
Microbiology
The study of organisms too small to be seen with the naked eye, including bacteria, fungi, viruses, and protists.
Viruses
Viruses
Not alive, lacks cytoplasm and a nucleus; causes diseases like HIV and influenza.
Bacteria
Bacteria
Has a cell wall but lacks a nucleus; causes diseases like E. coli and cholera.
Fungi
Fungi
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Safety goggles (in lab)
Safety goggles (in lab)
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Sterilization
Sterilization
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Autoclaving Petri Dishes
Autoclaving Petri Dishes
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Pasteurization
Pasteurization
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Antiseptic
Antiseptic
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Disinfectant
Disinfectant
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Antibiotics
Antibiotics
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Lag Phase
Lag Phase
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Log Phase
Log Phase
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Stationary Phase
Stationary Phase
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Death Phase
Death Phase
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Study Notes
- Microbiology studies organisms too small to see with the naked eye.
- These organisms include bacteria, fungi, and viruses, and sometimes protists.
Viruses
- Viruses are not alive and lack a cytoplasm or nucleus.
- They can cause diseases like HIV and influenza.
Bacteria
- Bacteria have a cell wall but lack a nucleus.
- They can cause diseases like E-coli and cholera.
Fungi
- Fungi have a cell wall and a nucleus.
Lab Safety
- Always wear a lab coat to prevent microbes from contacting your skin.
- Wear safety goggles to protect your eyes from harmful splashes.
- Sterilize your table with a Bunsen burner and disinfectant to prevent contamination.
- Cover cuts to prevent microbes from entering your bloodstream.
- When working with a petri-dish, minimize lid opening and don't breathe into it
- Wash your hands thoroughly after a practical to remove microbes.
- Disinfect your table after a practical to kill microbes.
- Properly seal the dish to prevent microbes from escaping.
- Used petri dishes must be autoclaved (burned at 121°C or 132°C).
- Autoclaving sterilizes and kills 99.99% of bacteria, viruses, and fungi.
- Alternatively, soak in a strong disinfectant.
Microbial Control
- Washing hands is important to remove most bacteria, especially before surgery or medical procedures.
- Pasteur proved spontaneous generation does not exist with his swan-neck flask experiment.
Pasteurization
- Pasteurization kills most bacteria and preserves taste, prolonging shelf life.
- It's commonly used in milk production.
Antimicrobial Agents
- Antiseptics stop or slow bacterial growth and are safe for human tissues.
- Disinfectants kill everything but are for non-living surfaces only.
- Antibiotics kill all bacteria or viruses, and are safe for human tissues.
Testing Antimicrobial Efficiency
- To test their efficiency, apply antimicrobials to a small paper circle on a bacteria-filled petri dish.
- Measure the zone of exclusion to determine effectiveness.
Bacterial Growth Phases
Lag Phase
- Microbes adapt to their environment and divide slowly.
Log Phase
- Microbes divide rapidly, doubling every 20 minutes with lots of food available.
Stationary Phase
- The rate of cell division equals the rate of cell death due to limited food.
Death Phase
- Food is depleted and toxic waste levels are too high, causing the population to decrease to zero.
Microbial Requirements
- Microbes need food, moisture, correct temperature (20°C-45°C), and space to disperse waste.
- Temperatures below 20°C slow growth and may cause dormancy.
- Temperatures above 45°C slow growth and may result in death.
Preventing Microbial Growth
- Use disinfectants and keep work surfaces dry.
- Preserve food by salting, pickling, freezing, or sealing it from air.
Milk Spoilage
- Milk goes sour due to lactic acid bacteria (Lactobacillus and Streptococcus) producing lactic acid.
- Prevent spoilage by keeping milk cool, refrigerated, pasteurized, and sealed from air.
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