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Questions and Answers
If food/water samples are stored at improper temperatures, then the number of microbial ______ will be higher.
colonies
The ______ variable is the storage temperature of food/water samples.
independent
The ______ variable is the number of microbial colonies grown on the agar plate.
dependent
The ______ variables are the type of food/water sample and incubation time.
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You would expect the health of the birds in cage a (with ______) to deteriorate compared to those in cage B.
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Aseptic techniques prevent ______ in microbiology.
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Symptoms of the disease might include ______ issues and behavioral changes/distress.
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Validity ensures that the method accurately measures what's ______ to.
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To test if the sun is causing the disease, you would place one group of birds in a ______ position.
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Agar acts as a ______ rich medium that supports microbial growth.
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The term ______ refers to the physical appearance of an infectious disease.
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Aerobic bacteria require ______ to thrive, whereas anaerobic bacteria can grow without it.
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Proper food handling and storage are justified as they significantly reduce microbial growth, ensuring ______ safety.
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The researcher who infected himself with the bacteria raises ______ concerns, including the risk of severe health consequences.
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An investigation was carried out after sewage was dumped into the ______.
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The graph shows what happened to a fish in the ______ after the dumping of raw sewage at point A.
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As the ______ in the water increased, the dissolved oxygen dipped.
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The ______ in the swan neck flask did not decay because the bacteria cannot go in.
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The curved neck of the swan neck flask trapped ______ and microorganisms, preventing them from reaching the broth.
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Koch's postulates are used to identify a microorganism as the ______ agent of a specific disease.
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Suspected pathogens must be present in all cases of the ______ and absent from healthy individuals.
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The long curved neck of the swan neck flask allowed ______ to enter, but trapped dust and microorganisms.
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If the swan neck was broken off the flask, ______ microorganisms would enter directly into the broth.
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Bacteria consume ______ during metabolic activities, reducing the amount of oxygen available in water.
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To prevent contamination, the neck of the flask is bent into an ______ shape.
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Data that involves numbers, such as colony counts, is considered ______ data.
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The absence of microbial growth in the controlled environment reaffirms Pasteur's findings that microbes come from ______ contamination.
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A hazard of the swan neck flask experiment is the risk of ______ from the Bunsen burner.
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One of the possible causes of disease in the birds is the use of a new ______.
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To determine the cause of the disease, the bird breeder set up two groups of birds, including a ______ group without disinfectant.
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The bird breeder ensured that everything else was identical in each cage, including the number of ______.
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The bird breeder took ______ precautions, such as wearing gloves and glasses, to minimize the risk of hazards.
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Louis Pasteur was appointed to the Uni of ______ in 1854.
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Dr. John Snow conducted pioneering investigations on ______ epidemics in England and particularly in London in 1854.
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Rabies is a disease caused by a ______ that affects mammals.
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Louis Pasteur was not able to observe the rabies ______ because viruses are too small to be seen with a light microscope.
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Dr. John Stone was gathering evidence to support the hypothesis: A specific water pump was contaminated with ______, responsible for causing the cholera outbreaks.
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Louis Pasteur studied samples of ______ under a microscope.
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Louis Pasteur found that good and bad fermentation is due to the activities of different ______.
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In 1880 Louis Pasteur investigated dogs that were suffering from ______ in order to find the cause.
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Study Notes
Hypothesis and Variables
- A hypothesis is a statement predicting the outcome of an investigation, e.g., "If food/water samples are stored at improper temperatures, then the number of microbial colonies will be higher."
- Independent variable: the storage temperature of food/water samples
- Dependent variable: the number of microbial colonies grown on the agar plate
- Controlled variables: type of food/water sample and incubation time
Controlled Variables
- Controlled variables are kept constant to ensure that any differences in microbial growth are due solely to the independent variable
- Example: incubation times are standardized across all experiments to ensure consistency
Aseptic Technique
- Aseptic techniques prevent contamination, ensuring only targeted microbes are studied
- Techniques include using sterilized instruments and maintaining a clean workspace
Validity, Reliability, and Accuracy
- Validity: ensures the method accurately measures what's intended to be measured
- Reliability: ensures consistency across trials and tests
- Accuracy: how close results are to the true value
Agar and Microbial Growth
- Agar acts as a nutrient-rich medium that supports microbial growth, allowing for the observation and quantification of colonies
- Proper food handling and storage significantly reduce microbial growth, ensuring food safety and preventing foodborne illnesses
Swan Neck Flask Experiment
- Sterilize broth in a flask, then bend the neck into an 'S' shape
- Heat to kill existing microbes, then incubate
- The bend traps dust and microbes, preventing contamination
Quantitative and Qualitative Data
- Quantitative data involves numbers, e.g., colony counts
- Qualitative data describes characteristics without numbers
Risk Assessment and Hazards
- Hazards include skin burns from Bunsen burners
- Safety precautions include wearing PPE (glasses, gloves, apron) and using burners safely
Disease Investigation
- The student's investigation reaffirms Pasteur's findings that microbes come from external contamination, not spontaneous generation
- Potential causes of disease in birds: new disinfectant, increased sunlight, stress from environmental changes
Symptoms and Incubation Period
- Symptoms: physical appearance of an infectious disease, e.g., respiratory issues, behavioral changes/distress
- Incubation period: the time between exposure and the appearance of symptoms
Louis Pasteur's Experiment
- If the swan neck was broken off the flask, airborne microorganisms could enter the broth, leading to microbial growth
- The curved neck trapped dust and microorganisms, preventing them from reaching the broth, yet allowing air to enter
- Koch's postulates are used to identify a microorganism as the causative agent of a specific disease
Rabies and Viruses
- Rabies is caused by a viral agent that infects the nervous system of mammals, not by bacteria
- Louis Pasteur was not able to observe the rabies virus because viruses are too small to be seen with a light microscope
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Description
Understand the relationship between storage temperature and microbial growth in food and water samples. Explore the variables involved in this investigation and their effects on contamination.
