Week 7: Introduction To Microbiology Flashcards
What is the theory of spontaneous generation?
The theory states that living organisms could arise from non-living matter.
This theory was disproved by Louis Pasteur.
Who disproved the theory of spontaneous generation?
Louis Pasteur.
Pasteur’s experiments provided critical evidence against this theory.
What experimental method did Pasteur use to demonstrate his findings?
Swan-neck flasks.
These flasks allowed air to enter while preventing contamination from microbes.
What conclusion did Pasteur reach regarding air and spontaneous generation?
Air alone is not sufficient to allow for spontaneous generation.
The potential for spontaneous generation might be destroyed by heating.
What is the germ theory of disease?
The theory states that diseases are caused by microorganisms.
This marked a significant advancement in understanding disease causation.
Who developed postulates to prove the germ theory of disease?
Robert Koch.
Koch’s postulates provide a framework for linking specific microorganisms to specific diseases.
Fill in the blank: The theory of _______ states that living organisms could arise from non-living matter.
spontaneous generation.
True or False: Louis Pasteur’s experiments supported the theory of spontaneous generation.
False.
Pasteur’s experiments disproved the theory.
List the contributions of Robert Koch to microbiology.
- Developed the germ theory of disease
- Created postulates to prove specific microorganisms cause specific diseases.
What are Koch’s postulates?
- The suspected pathogenic organism should be present in all cases of the disease and absent from healthy animals.
- The suspected pathogenic organism should be grown to pure culture.
- The pure culture should cause the disease when inoculated into a healthy animal.
- The organism should be isolated from the inoculated, diseased animal and identified as being identical to the original organism.
Koch’s postulates are a set of criteria established to link specific pathogens to specific diseases.
Fill in the blank: The suspected pathogenic organism should be present in all cases of the disease and _______ from healthy animals.
absent
This criterion ensures that the organism is specifically associated with the disease.
What is the second postulate of Koch’s postulates?
The suspected pathogenic organism should be grown to pure culture.
This step is essential for ensuring that the organism being studied is not mixed with other microorganisms.
What should happen when the pure culture is inoculated into a healthy animal according to Koch’s postulates?
It should cause the disease.
This demonstrates that the organism is capable of causing the disease when introduced to a susceptible host.
What is the final step of Koch’s postulates?
The organism should be isolated from the inoculated, diseased animal and identified as being identical to the original organism.
This confirms that the same organism is responsible for the disease in both the original and the inoculated hosts.
Who is considered the father of microbiology?
Antonie van Leeuwenhoek
He is known for his pioneering work in observing microorganisms.
What instrument did Antonie van Leeuwenhoek use to make observations of microorganisms?
A simple microscope
His use of simple microscopes allowed for detailed observations.
What has Antonie van Leeuwenhoek’s observations contributed to?
Our understanding of bacterial morphology
His detailed observations helped establish foundational knowledge in microbiology.
What is a key difference between eukaryotic and prokaryotic cells?
Eukaryotic cells have a nucleus and membrane-bound organelles, while prokaryotic cells lack a nucleus
This distinction is fundamental in cell biology.
What is the evolutionary history of bacteria?
Bacteria have a long evolutionary history and are among the oldest life forms on earth
This highlights the significance of bacteria in the history of life.
What is the purpose of the Ziehl-Neelsen Stain?
Differentiates acid-fast bacteria from other bacteria
Acid-fast bacteria include organisms like Mycobacterium tuberculosis.
What are the steps involved in the Ziehl-Neelsen Stain?
- Stain with carbol fuchsin
- Rinse
- Treat with acid
- Counterstain with methylene blue
What is the result of the Ziehl-Neelsen Stain for acid-fast bacteria?
Retain red stain due to waxy lipids in cell wall; others stain blue
What is the purpose of Gram Staining?
Differentiates bacteria based on cell wall structure
What are the two types of bacteria identified by Gram Staining?
- Gram-positive (stain purple)
- Gram-negative (stain pink)
What is the importance of Gram Staining?
Provides clues to bacterial identity and treatment options
What are Koch’s Postulates?
Established foundation for applied medical microbiology and immunology
What is the purpose of Koch’s Postulates?
To identify the specific causative agent for a disease
Who proved that bacteria can cause disease?
Robert Koch
Koch is a key figure in microbiology and is known for his postulates.
What purification procedures did Koch develop?
Purification procedures for microorganisms on solid media
This was essential for isolating pure cultures of bacteria.
Which bacterium causes tuberculosis?
Mycobacterium tuberculosis
Koch’s research was pivotal in linking this bacterium to tuberculosis.
What staining procedure did Koch develop for Mycobacterium tuberculosis?
A staining procedure specifically for Mycobacterium tuberculosis
This was crucial for identifying the bacterium in clinical samples.
What characterizes Gram-positive bacteria?
Thick layer of peptidoglycan, stain purple
Gram-positive bacteria retain the crystal violet stain used in Gram staining.
What characterizes Gram-negative bacteria?
Thinner layer of peptidoglycan, stain pink
Gram-negative bacteria do not retain the crystal violet and are counterstained pink.
What is the Gram staining technique?
Uses crystal violet, iodine solution, ethanol, and safranin
This technique differentiates between Gram-positive and Gram-negative bacteria.
What type of cell wall does Mycobacterium tuberculosis have?
Thick, waxy, and hydrophobic
This unique structure contributes to its resistance to certain antibiotics.
How does Mycobacterium tuberculosis appear in Gram staining?
Stains purple, appears Gram-positive
Despite its unusual cell wall, it retains the purple color in the Gram stain.
What are methods used for bacterial identification?
Selective growth media, specialized tests (Enterotube), immuno-tests, PCR and sequencing
These methods help in accurately identifying and differentiating bacteria in clinical samples.
What is the goal of bacterial identification?
To accurately identify and differentiate bacteria in clinical samples
This is crucial for effective diagnosis and treatment.
How many bacteria do humans harbor compared to their own cells?
Humans harbor 10x more bacteria than cells
This highlights the extensive microbial presence in the human body.
How does the genetic diversity of bacteria compare to humans?
Bacteria have 100x more genes than human genes
This indicates a vast genetic diversity and adaptability among bacteria.
What percentage of bacteria in our bodies are considered harmless or beneficial?
95% harmless/beneficial
This suggests that the majority of bacteria contribute positively to human health.
What historical context is provided regarding fungi?
Fungi were known, and mycologists studied spoilage of crops. Unicellular pathogenic fungi were discovered later.
This highlights the early understanding of fungi in agriculture and their later recognition as pathogens.
What was the sequence of discovery for bacteria and viruses?
Bacteria were identified in plants, then animals, and finally humans. Viruses were discovered later.
This sequence illustrates the progressive understanding of microbial life.
What do Koch’s Postulates validate?
They remain valid for proving that a specific fungus or virus causes a disease.
Koch’s Postulates are a set of criteria for establishing a causative relationship between a microbe and a disease.
What is Saccharomyces cerevisiae commonly known as?
Baker’s yeast.
This organism is widely used in research due to its significance in fermentation and cellular studies.
Why is Saccharomyces cerevisiae considered a model organism?
Due to its easy manipulation and understanding of cellular metabolism.
Model organisms are crucial for biological research as they allow scientists to understand complex life processes.
What advantages does Saccharomyces cerevisiae provide for research?
Provides accessible research tools for investigating life processes, with similar features across all cells (e.g., bacteria, yeast).
These similarities make it easier to extrapolate findings to other organisms.
What impact has Saccharomyces cerevisiae had on scientific fields?
Has led to enormous advances in genetics, biochemistry, and understanding of cellular metabolism.
The use of this yeast in research has significantly contributed to multiple scientific breakthroughs.
What is the first step in identifying the cause of an infection?
Simple observation isn’t enough
Which areas of the body are typically sterile?
Spinal fluid, blood, joint fluid, pleural fluid, middle ear, and urine
What is a challenge when collecting samples from sterile sites?
Samples can be easily contaminated upon exiting the body
What technique is used to separate bacteria on agar plates?
Streaking technique
At what temperature should bacteria be incubated to grow overnight?
37°C
What is the first of Koch’s Postulates?
Isolate the organism
What is the second of Koch’s Postulates?
Grow a pure culture
What is the third of Koch’s Postulates?
Inject into a healthy animal
What is the fourth of Koch’s Postulates?
Re-isolate the same bacteria from the sick animal
