Chapter 1 Flashcards
What was Leeuwenhoek’s discovery?
He discovered tiny animals, fungi, algae, and single-celled protozoa, ‘animalcules’ or ‘wee beasties’ Inadvertently supported spontaneous generation. Known as the father of Microbiology.
How did Leeuwenhoek’s discovery impacted science?
, best known for his work on the development and improvement of the microscope and also for his subsequent contribution towards the study of microbiology.
What are 3-4 groups of organisms that are studied in Microbiology?
Bacteria/Archea. Viruses. Protozoa. Fungi. Algae. Helminths, or worms.
What are the characteristics of viruses?
- Acellular (no cell parts or pieces) - 100th times than eukaryotic cells! - Not found until 1932 - found in and around all living things, obligatory parasite.
What are characteristics of Bacteria and Archea?
- Unicellular and lack nuclei (prokaryotic cells). - Approx. 10x smaller than eukaryotic cells. - reproduce Asexually. - Bacteria peptidoglycan; some lack cell walls.
What are characteristics of fungi?
- Eukaryotic (have membrane-bound nucleus) - Obtain food from other organisms. - Possess cell walls made of carbohydrate chitin - composed of: Molds and Yeasts.
Define spontaneous generation!
The idea that living organisms could arise directly and rapidly from non living organisms.
What are the basic differences between prokaryotic and eukaryotic cells?
Prokaryotes
- Lack nucleus
- Lack membrane bound organelles
- Are small (~1.0 um diameter)
- Have a simple structure
- Include bacteria and archaea
Eukaryotes
- Have nucleus
- Have internal membrane-bound organelles
- Are larger (10-100 um diameter)
- Have more complex structure
- Include algae, protozoa, fungi, animals and plants
What was the Redi’s experiment about? Did it support or refute the idea of Spontaneous generation?
- When decaying meat was kept isolated from flies, maggots never developed. Meat exposed to flies was soon infested. As a result, scientists began to doubt Aristotle’s theory of Spontaneous generation.
What was Needham’s experiment about? Did it support of refute the idea of Spontaneous generation?
Needham’s experiments with beef gravy and infusions of plant material reinforced this idea. He boiled beef gravy and infusions of plant material in vials, which he then tightly sealed with corks. Some days later, he observed that the vials were cloudy, & examination revealed an abundance of “microscopical animals of most dimensions”, As he explained it, there must be a “life force” that causes inanimate matter to spontaneously come to life, because he had heated the vials sufficiently to kill everything.
What was Spallanzani’s experiment? Did it refute and support the idea of Spontaneous generation?
This experiment concluded that:
- Needham failed to heat the vials sufficiently to kill all microbes or had not sealed vials tightly enough.
- Microorgnisms exist in air and can contaminate experiments.
- spontaneous generation of microorganisms does not occur.
What was Pasteur’s experiment about? Did it refute or support the idea of Spontaneous generation?
- When the ‘swan-necked flasks’ remained upright, no microbial growth appeared. 18 months later.
- When the flask was tilted, dust from the bend in the neck seeped back into the flask and made the infusion cloudy with microbes within a day.
- “Never will spontaneous generation recover from the mortal blow of this simple experiment.”
What are Louis Pasteur’s discoveries and contributions to microbiology?
- Pasteur discovers the chemical process behind fermentation. (Discovered fermentation; Invented Pastuarization)
- Pasteur then develops a method to reduce the amount of wine that spoils due to contamination. Thus, Pasteur saves not only science, but the French wine industry.
- Germ theory of disease (Pasteur) - Disease is caused by microorganisms. Since, if bacteria spoiled wine (and other foods), then can they “spoil” people too?
What are the steps Gram Stain?
- Crystal Violet – Primary Stain:Dark purple stain composed of tiny particles that become ‘stuck’ in the basket weave structure of peptidoglycan.
- Gram’s Iodine – Mordant: Binds with the crystal violet particles to create CVI (Crystal violet complexes). Which will stuck more tighly in the peptidoglycan layer. Gram (-) has little or no oeffect on the crystal violet.
- Decolorizer – Gram (-) lipid rich outer membrane is dissolved by the decolorizer. Gram (+), the majority of the crystal violet in the thick peptidoglycan cell wall remains unmoved.
- Safranin – Seconday stain. All cells will absorb pink/red colored safranin, though the cells which have retained their purple color will somply show purple. Those who lost their color through decolorizing will acquire the pink/red color of the secondary stain.
what is the use of Gram Stain?
The technique that allows to differentiate b/w two major types of bacteria, ‘gram (+)’ and ‘gram (-)’ based on the layers of the bacterial envelopes.
- Gram(+) has two layers, a cell membrane, and a cell wall.
- Gram(-) has three layers, a cell membrane, a cell wall, and an outer membrane.
