Chapter 1 Flashcards
Microbiology
- the study of microorganisms or microbes which are too small to be seen
- ex: bacteria, viruses,protozoans, fungi and microscopic algae
- the naked eye cannot see organisms smaller than 0.1mm
Health and disease
health- a state of physical, mental and social well-being
disease- a change from the state of health, a morbid process characterized by a collection of signs and syptoms
Signs and Symptoms
signs- OBJECTIVE findings that can be detected by examination
-fever, swelling, rash, white blood cell count
symptoms- SUBJECTIVE findings described by the patient
-headache, body aches, fatigue, numbness
Do microbes cause disease?
NO they do not. many microbes provide beneficial services for humans and the environment
Human Microbiome
- naturally occurring microbes that live in and on our body contribute to our health
- help regulate our digestion
- make compounds like vitamin K in our gut
- protect us from invading pathogenic organism
Beneficial Services of Microorganisms
- decompose organic waste
- landfills, compost, leaves in the woods - Can act as producers in the ecosystem using photosynthesis
- capture the sun’s energy and store it as food for animals to eat - produce fermented foods
- vinegar, cheese, beer, yogurt and bread - produce industrial chemicals
- ethanol and acetone - produce medicines
- antibiotics and insulin
pathogens
disease causing organisms
infectious disease
disease caused by a microbial infection (measles, colds, TB)
infection
growth of microbe in or on the body
noninfectious disease
disease not caused by a microbe (heart disease, cancer)
knowledge of microorganisms
allows humans to
- prevent food spoilage
- prevent disease occurrence
- make drugs and other compounds
-led to aseptic techniques to prevent contamination in medicine and in microbiology laborites
Naming and Classifying Microorganisms
- Linnaeus established scientific nomenclature
- 2 word name- genus and specific epithet
- called binomial nomenclature
scientific names
- the genus is the first word and the second word is the specific epithet
- both are italicized or underlined. Genus is capitalized
- they are “latinized” and worldwide
- descriptive or honoring scientist
- after first use, they may be abbreviated (E.coli)
2 Cell Types - Prokaryotic and Eukaryotic
Prokaryotic cells- do NOT have a membrane- enclosed nucleus (pro = before, karyo= nucleus)
Eukaryotic cells- do have a membrane enclosed- nucleus. (Eu= true) Also they have other membrane enclosed structures called organelles.
-Prokaryotic cells are more “primitive”
5- kingdom system
- bacteria (Monera)
- protozoans (Protista)
- Fungi
- plants
- animals
NOT USED IN THIS CLASS
Classification of Microorganisms- 3 domain system
- bacteria- prokaryotes with cell walls that contain peptidoglycan; single-celled
- archaea- prokaryotes without peptidoglycan in their cell walls; single-celled
- Eukarya- eukaryotes; 4 kingdoms in this domain
- protists- protozoans, algae, slime molds
- fungi- unicellular yeasts, molds and mushrooms
- plants- mosses, ferns, conifers and flowering plants
- animals- sponges, worms, insects and vertebrates (fish reptiles, amphibians, mammals)
Bacteria: Domain Bacteria
- prokaryotes
- peptidoglycan (chemical compound) in cell walls
- binary fission (divides in two)
- for energy, use organic chemicals, inorganic chemicals or photosynthesis
Archaea: Domain Archaea
- Prokaryotic
- lack in peptidoglycan in cell walls
- live in extreme environments
- include:
- methanogens- methane producing
- extreme halophiles- live in salt environments
- extreme thermophiles- live in hot, sulfurous water
- roots- phil= loving, halo= salt, thermo= heat
Fungi: Domain Eukarya
- eukaryotic cells
- larger than bacteria
- have membrane-bound true nucleus
- have other membrane- bound organelles
- many serve as decomposers in the environment
Fungi
use for organic chemicals for energy:
-absorb their food from their environment, are never photosynthetic
- Fungi divided into Molds and Yeasts
- Molds and mushrooms are multicellular consisting of masses of mycelia. which are composed of filaments called hyphae
- Yeast are unicellular
Examples of Fungi
- unicellular yeast- cells that are reproducing by budding. In budding cells, the “daughter” cell is pinched off the “parental” cell
- Multicellular, filamentous fungi, mold, showing the hyphae (filaments- multicellular) and the dark reproductive structures
Protozoa: Domain Eukarya
- Eukaryotic cells
- have membrane-enclosed nucleus and other membrane- bound organelles
- absorb or ingest nutrients
- may be motile via pseudopods, cilia, or flagella or may not be motile
- free-living or parasitic
- parasite harms the host but benefits from living on the host
Examples of Protozoan
- Amoeba move using pseudopods (false feet) that extend from the cell. The cytoplasm flows into the pseudopod and the cell moves forward
- ciliates contain small, hair-like structures, cilia, that move in coordination to propel the cell forward
- flagellates have a few, longer hair- like structures that whip back and forth to propel the cell forward
Algae: Domain Eukarya- Kingdom Protozoa
- eukaryotic cells
cellulose in cell walls
use photosynthesis for energy- trap the sun’s energy and convert the energy to sugars for food
-produce molecular oxygen and organic compounds
-many microscopic algae but also are large, multicellular algae like kelp in the ocean
- trap the sun’s energy and convert the energy to sugars for food
Multicellular Animal Parasites: Domain Eukarya- Kingdom Animals
- Eukaryotic cells
- multicellular animals
- parasitic flatworms and round worms are called helminths
- flatworms- flukes and tapeworms
- round worms- pinworms and hookworms
Viruses
- acellular
- only have one type of genetic material, contain either DNA or RNA core but not both
- core is surrounded by a protein coat
- coat may be enclosed in a lipid envelope
- viruses can only replicate by invading and using another cell : intracellular parasites
The first observations of Microbes
Antonia can Leeuwenhoek described live microorganisms that he observed in teeth scrapings, rain water and peppercorn infusions
The debate over spontaneous Generation
- the hypothesis that living organisms arise from nonliving matter is called spontaneous generation. according to the hypothesis, a “vital force” forms life. If the vital force is excluded from a container, then spontaneous generation cannot occur
Biogenesis
- the alternative hypothesis, that the living organism arise from preexisting life, is called biogenesis. Living cells can only be produced by other living cells
- the debate over spontaneous generation and biogenesis lasted almost 200 years
Evidence Pro and Con ( debate over Spontaneous Generation)
- Louis Pasteur proved that microorganisms are present in the air. When broth is boiled the microbes in the broth are killed so no new cells are produced. If the broth is contaminated by microbes from the air then there is microbial growth in the broth. If the microbes are excluded after boiling the broth, then new microbes don’t contaminate the broth and microbial growth doesn’t occur. Supports biogenesis.
Conditions: Nutrient broth placed in flask, heated not sealed. Result: Microbial growth
Conditions: Nutrient broth placed in flask, heated, then microbes prevented from entering. Result: No microbial growth
Theory of Biogenesis
Pasteur kept the broth in S shaped flask so air was able to come in but it kept the microbes out. This helped him prove biogenesis.
Fermentation and Pasteurization
- Pasteur showed that microbes are responsible for fermentation
- fermentation is the conversion of sugar to alcohol to make beer and wine
- microbial growth is also responsible for spoilage of food
- bacteria that use alcohol to produce acetic acid spoil wine by turning it to vinegar (acetic acid).
- Pasteur demonstrated that these spoilage bacteria could be killed by heat that was not hot enough to evaporate the alcohol in wine
- Pasteurization is the application of a high heat for a short time. This does not kill all microbes but kills spoilage organisms in wine and pathogens in milk.
Germ Theory of Disease
- Agostino Bassi showed that silkworm disease was caused by a fungus
- Pasteur believed that another silkworm disease was caused by a protozoan
- Ignaz Semmelwise advocated hand washing to prevent transmission of puerperal fever from one OB patient to another
- Joseph Lister- used a chemical disinfectant to prevent surgical wound infections after looking at Pasteurs work showing that microbes are in the air, can spoil food, and cause animal diseases
- Robert Koch proved that a bacterium causes anthrax and provided the experimental steps, Koch’s postulates, to prove that a specific microbe causes a specific disease. Bacillus anthracis.
Vaccination
Edward Jenner- inoculated a person with cowpox virus. The person was then protected from smallpox. First vaccine for humans. Viruses had not yet been discovered.
- vaccination is derived from vacca for cow
- protection is called immunity
Koch’s postulated (Germ Theory of Disease)
- it provides steps for connecting a disease with its causative agent
- same pathogen must be present in every case of disease
- the pathogen must be isolated from the disease host and grow in pure culture
- the pathogen from the pure culture must cause the disease when it is inoculated into a susceptible host animal
- the pathogen must be isolated from the inoculated host animal and shown to be the original organism
Chemotherapy
the treatment of disease by using a chemical substance
Antibiotic vs. Synthetic drug
Antibiotic- a substance produced in small amounts by bacteria or fungi that inhibits or kills other microbes
Synthetic drug- prepared from chemicals in the laboratory
-Note the difference between substance produced by microbes and substance produced in the lab
History of Chemotherapy
- early in man’s history used quinine from the bark of chinchona tree to treat malaria (quinines still used today)
- Ehlich- used salvarsan, an arsenic compound, to treat syphilis, called this a “magic bullet” because there was no cure for syphilis. Was difficult to adjust the concentration of the salvarsan so that it treated the syphilis but did not poison the patient
The Birth of Modern Chemistry: Fleming
- Alexander Fleming discovered the first antibiotic
- he observed that Penicillium fungus made an antibiotic, penicillin, that killed S. aureus
- Penicillin was tested clinically and mass produced
- Domagk- sulfonamides developed as chemotherapeutic agents
- drug resistance developed
- some patients develop allergies
Terminology in Micro
- bacteriology- study of bacteria
- mycology- study of fungi
- parasitology- study of protozoa and parasitic worms
- virology- study of viruses
- immunology- study of immunity
- vaccines and interferons are being investigated to prevent and cure viral diseases
Recombinant DNA
- is made when DNA from one source is combined with DNA from another source
- Recombinant DNA technology, or genetic engineering, involves using the new techniques to alter cells so that they can make new or improved products. Involves both microbial genetics and molecular genetics
Modern Biotechnology and Genetic Engineering
- biotechnology, the use of microbes to produce foods and chemicals, is centuries old.
- making fermented products such as yogurt, cheese, beer, sauerkraut, ethanol
- genetic engineering is a new technique that can be used in biotechnology. Through genetic engineering, bacteria and fungi can produce a variety of proteins including vaccines and enzymes
Bioremediation (Biotechnology using Genetic Engineering)
- bacteria degrade or detoxify pollutants such as oil and mercury spills.
- using genetic engineering can develop better microbes for these activities
- missing or defective genes in human cells can be replaced in gene therapy
- genetically modified bacteria are used to protect crops from insects and from freezing
Beneficial Activities of Microbes
- recycling nutrients and elements in nature
- microbes decompose dead organisms- leaves, animals, bacteria- and release the elements and nutrients that are tied up in the dead organism
- if these were not recycled, we would run short of these essential elements
- sewage treatment
- microbes in the sewage break down the suspended solids and dissolved organic molecules to clean up sewage
- bioremediation
- microbes are used to break down organic compounds that are contaminating water and/ or soil
- insect pest control
- use bacteria that infect and kill insects that are eating crops
- bacteria are harmless to the plants and humans
