Intro Flashcards
(37 cards)
Microorganisms are —– to be seen by the unaided human eye.
too small
How do microorganisms live in relation to other microorganisms?
They typically live in complex communities, their activities are regulated by interactions with each other and other environments.
How many estimated microbial cells exist on Earth?
2 x 10^30
Describe what Antony van Leeuwenhoek is known for regarding microbiology.
3 bullet points
Mnemonic: 1 Water Slide
- Was the first to see/observe microorganisms through a simple (single lense) light microscope
- Referred to these organisms as “wee animalcules”
- None of his slides were published until after he died, so he wasn’t famous or well-known in his time
1st, Wee animalcules, Slides
Describe what Louis Pasteur is known for regarding microbiology.
5 bullet points
Mnemonic: Few visit the foreign space
- Often referred to as the “father of modern micro”
- He refuted the theory of spontaneous generation in 1861 (organisms arise from non-living material)
- Demonstrated importance of sterilization
- Developed a few vaccines - anthrax, rabies
- Discovered fermentation is carried out by microorganisms
Father, Vaccines, Theory, Fermentation, Sterilization
When did microbiology become a strong science?
Around the 1800s
Describe what Robert Koch is known for regarding microbiology.
6 bullet points
Mnemonic: We need to push the person soon
- He won a Nobel Prize in the early 1900s
- Learned that microbes can cause wounds to go septic
- Developed pure culture technique (using petri dishes and agar)
- Stained bacteria and proved different diseases were caused by different germs
- Developed Koch’s postulates
- Identified the causative agents for TB and cholera
Wounds, Nobel Prize, Pure culture technique, TB, Postulates, Staining
What are Koch’s 4 postulates?
- Organisms must be present/discoverable in all instances of the disease
- The suspected pathogen must be grown in pure culture and maintained over several generations
- Cells from the pure culture must cause disease in a healthy animal - to reproduce the disease
- The pathogen must be reisolated and shown to be the same as the original
Helps to link cause and effect in an infectious disease
Describe some of the experiments that Koch performed when studying microorganisms.
Looking for 7 things
Staining, photomicrographs, techniques to estimate CFU/ml, steam to sterilize media, use of petri dishes, techniques to transfer bacteria, analyzing bacteria as distinct species
What is a pure culture?
Contains cells from only a single type of microorganism, a colony completely separated from everything else
Describe some of the purposes/functions of microorganisms.
6 bullet points
Mnemonic: No other man would control fire
- Involved in nitrogen fixation (N2 to nitrates, nitrites, or ammonia - gets N to usable form)
- Replenish Oxygen
- Serve as models to study genetics, metabolism, and biochemistry
- Degrade organic waste, inhabit digestive systems of cows and sheep (to degrade cellulose from grass and hay) and humans (gut microbiome) to break down things into usable products
- Important for nutrient cycling of N, S, and C which is important for agriculture
- Can cause food spoilage and foodborne diseas, others allo us to improve food safety and preserve food
Nitrogen, Oxygen, Models, Waste, Cycling, Food
What is the typical size range of prokaryotic cells?
Between 0.5 and 10 micrometers
But some can be bigger or smaller than this
What is the typical size range of eukaryotic cells?
Between 5 and 100 micrometers
But some can be bigger or smaller than this
How is size related to structure and function of microorganisms?
Eukaryotes can be bigger due to active transport and macromolecules in the cytoplasm. Prokaryotes rely on diffusion which limits their size (diffusion rate varies inversely with the square of prokaryotic size).
What is the advantage of an cell being small?
Small cells have higher SA:V ratios, which controls the growth rate and shape
How long ago did bacteria and archaea diverge? How long ago did eukarya diverge from archaea?
3.8 bya, 2.0 bya
When did oxygen originate? What is the evidence for this? What does the presence of oxygen allow?
- The first evidence for oxygen appears at 2.4 bya, current levels of oxygen weren’t achieved until 500-800 mya.
- Iron-banded rocks (reaction that occurs when oxygen is present) exist and serve as evidence.
- Oxygen alllows things to grow bigger.
What are stromatolites?
Early phototrophs lived in structures called microbial mats which harvest energy from the sun. Layers of microbes accumulate on rocks and become laminated, which can become 10 meters in size.
What is the pH of the stomach, small intestine, and large intestine? How many microbes exist in each?
- Stomach: pH 2, 10^4 cells/g
- Small intestine: pH 4-5, 10^8 cells/g
- Large intestine: pH 7, 10^11 cells/g
How do the death rates for the leading causes of death differ between 1900 and today because of our understanding of microbiology?
In the 1900s things like influenza, pneumonia, TB, and gastrointeritis were the leading causes of death. Today the leading causes of dealth are heart disease, cancer, stroke, pulmonary disease, accidents, etc. Today infectious diesease are largely preventable due to advances in microbiology.
Describe three applications of microbiology.
- Fermentation - process for making bread, wine, beer and cheeses
- Bioremediation - degradation of toxic material and wastewater treatment
- Biosynthesis and genetic engineering - production of antibiotics, amino acids, insulin, growth hormone, biofuels etc. –> genes from one organism are introduced into related or unrelated organisms
What are the interests or concerns of medical microbiology?
- Deals with infectious diseases affecting humans and animals (and plants)
- Concerned with new emerging diseases and old re-emerging diseases
Describe what Carl Woese is known for regarding microbiology.
- Recognized the evolutionary history recorded in DNA sequences
- Sequence of rRNA and genes that encode them could be used to infer evolutionary relationships btwn organisms
- Separated Archaea from Bacteria to reveal a new domain
Describe the domain of bacteria.
- Single cell prokaryotes
- Lack membrane bound organelles
- Contain a nucleoid
- Have peptidoglycan in the cell wall
