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Tortura Microbiology Chapter 1


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What are microbes?
minute living things that individually are usually too small to be seen with the unaided eye.
What is a "germ"?
refers to a rapidly growing cell (grows with phenomenal speed). It is also a terrible word because it does NOT define the organism type! They are NOT germs!
What does the group called microbes include?
1. Bacteria
2. Fungi (yeasts and molds)
3. Protozoa
4. Microscopic algae
5. Viruses
How do the majority of microorganisms contribute to the welfare of the world's inhabitants?
by helping to maintain the balance of living organisms and chemicals in our environment.
What is microbiology?
--the study of small forms of life
Why don't microbes destroy us while we are alive?
because most microbes do NOT interact with humans.
What functions do microorganisms perform that are beneficial to humans?
1. decompose organic waste--e.g pine needles
2. are producers of the ecosystem by photosynthesis
3. produce industrial chemicals such as ethyl alcohol and acetone
4. produce fermented foods such as vinegar, cheese, and bread.
5. produce products used in manufacturing (e.g. cellulose) and treatment (e.g. insulin).
What does pathogenic mean?
-disease causing
Are all diseases caused by microbes?
Knowledge of microorganisms allows humans to:
1. prevent food spoilage
2. prevent disease occurrence
Knowledge of microorganisms led to:
aspetic techniques to prevent contamination in medicine and in microbiology laboratories.
What do microbes in the intestines of humans and other animals do?
digest and synthesize some vitamins that the human body requires, including some B vitamins for metabolism and vitamin K for blood clotting.
It used to be said that diseases were caused by...
evil spirits and were punishments
Carolus Linnaeus
In 1735 he established the system of nomenclature for organisms in use today
What two names does scientific nomenclature assign each organism?
1. genus-the first name and is always capitalized.
2. specific epithet (species name)--not capitalized, follows the genus name
The full name of the organism is called the _______.
scientific name
What can scientific names do?
1. describe an organism
2. honor a researcher
3. identify the habitat of a species
Until recently, people often divided living things into 5 kingdoms. List them.
1. Monera (bacteria)
2. Protista
3. Mycota
4. Plantae
5. Animalia
Currently, many biologists prefer to use larger groupings called domains. List them.
1. Eubacteria
2. Archaea
3. Eukarya
What are bacteria?
relatively simple, single-celled (unicellular) organisms.
Because their genetic material is NOT enclosed in a special nuclear membrane, bacterial cells are called _________.
What are the three common shapes of bacterial cells?
1. Bacillus (rod-like)
2. Coccus (spherical or ovoid)
3. spiral (corkscrew or curved)
Bacteria are enclosed in cell walls that are largely composed of a carbohydrate and protein complex called __________.
How do bacteria generally reproduce?
by dividing into two equal cells, a process called binary fission
What do most bacteria use for nutrition/energy?
1. use organic chemicals--derived from in nature from either dead or living organisms.
2. some manufacture their own food by photosynthesis
3. some use inorganic substances
How do bacterial cells move?
they can "swim" by using moving appendages called flagella.
All living things:
1. manipulate hydrogen
2. have to have energy
3. have to have carbon
Energy comes from 1 of 3 sources. List them.
1. photosynthesis (light)
2. Chemical Reactions:
(a) organic molecules
(b) inorganic molecules
Which domain is the most primitive domain?
Like bacteria, archaea consist of _____1_____, but if they have cell walls, the walls lack ______2_____.
1. prokaryotic cells
2. peptidoglycan
Archaea, often found in extreme environments, are divided into three main groups. List them.
1. methanogens--produce methane as a waste product from respiration.
2. extreme halophiles--salt loving--live in extremely salty environments such as the Great Salt Lake and the Dead Sea.
3. extreme thermophiles--live in hot sulfurous water such as hot springs at Yellowstone National Park.
Do the archaeans cause disease in humans?
Fungi are ____1_____, organisms whose cells have a distinct nucleus containing the cell's genetic material (DNA), surrounded by a special envelope called the _____2_____.
1. eukaryotes
2. nuclear membrane
What domain does fungi belong to? What kingdom?
1. domain eukarya
2. kingdom mycota
Are fungi multicellular or unicellular?
they can be both unicellular or multicelluar
True fungi have cell walls composed primarily of a substance called _________.
What are the unicellular forms of fungi?
yeasts--oval microorganisms that are larger than bacteria
Are molds and mushrooms unicellular or multicellular?
How do fungi reproduce?
sexually or asexually
What are ringworms?
a fungus
How do fungi obtain nourishment?
by absorbing solutions of organic material from their environment
What are slime molds?
Have characteristics of BOTH fungi and amoebas.
What domain do protists belong to?
Are protozoa unicellular or multicellular? Eukaryotes or Prokaryotes?
1. unicellular
2. eukaryotes
How do protozoans move?
1. pseudopods
2. flagella
3. cilia
Protozoans can live either as _____1_____ or as ____2______ that _________3___________.
1. free entities
2. parasites
3. absorb or ingest organic compounds from their environment.
How do protozoa reproduce?
sexually or asexually
Algae are ____1____ eukaryotes with a wide variety of shapes and both _____2____ and ____3_____ reproductive forms.
1. photosynthetic
2. sexual
3. asexual
The algae of interest to most microbiologists are usually ___________.
How do algae obtain energy?
they use photosynthesis
What do algae need for food production and growth?
1. light
2. water
3. carbon dioxide
What do algae produce as a result of photosynthesis?
molecular oxygen and carbohydrates
What are algae cell walls composed of?
Does all life need molecular oxygen?
What domain do viruses belong to?
Define a virus.
an acellular, obligate intracellular parasite
True or False. Viruses consist of DNA and RNA.
False. Viruses consist of DNA OR RNA, not both! Living cells have both.
What is the viral DNA or RNA core surrounded by?
a protein coat
The protein coat of a virus MAY be enclosed in a ___________.
lipid envelope
Viruses ________ only when they are in a living host cell.
Define acellular.
NOT composed of cells
True or False. All living things are composed of cells.
Define parasites.
organisms that live at the expense of another
True or False. Every living thing on the planet has at least one virus that can attack it.
True or False. Every cell on the planet has BOTH RNA and DNA, except for viruses.
What are the two major groups of parasitic worms?
1. flatworms
2. round worms
--Both of these are collecetively called helminths.
During some stages of their life cycle, helminths are ___________ in size.
What kingdoms belong to the domain Eukarya?
1. Protista
2. Mycota
3. Plantae
4. Anamalia
Who were the first life on earth?
ancestors of bacteria
Before the existence of microbes was known, all organisms were grouped into what two kingdoms?
1. animal kingdom
2. plant kingdom
Carl Woese
In 1978, Carl Woese devised a system of classification based on the cellular organization of organisms. It groups all organisms into three domains.
What are the three domains?
1. Bacteria (cell walls contain peptidoglycan)
2. Archaea (cell walls, if present, LACK peptidoglycan)
3. Eukarya, which includes the following:
(a) Protists (slime molds, protozoa, and algae)
(b) Fungi (unicellular yeasts, multicellular molds, and mushrooms)
(c) Plants (includes mosses, ferns, conifers, and flowering plants)
(d) Animals (sponges, worms, insects, and vertebrates)
Robert Hooke
In 1665, after observing a thin slice of cork, he reported that life's smallest structural units were "little boxes" or "cells."
When were the first microbes observed?
In 1673 by Anton van Leeuwenhoek.
Anton van Leeuwenhoek
1673-1723--he described live microorganisms (what he called ANIMALCULES) that he observed in rainwater, his own feces, teeth scrapings, and peppercorn infusions.
Define spontaneous generation.
the hypothesis that living organisms arise from non-living matter. According to this hypothesis, a "vital force" in contact with matter causes the formation of life.
Francis Redi
In 1668, he demonstrated that maggots appear on decaying meat only when flies are able to lay eggs on the meat. He filled 6 jars with decaying meat. He covered three of them with a fine net and left the other three uncovered. The jars with the fine net covering had no maggots.
John Needham
In 1745, he claimed that microorganisms could arise spontaneously from heated nutrient broth. He placed boiled nutrient broth into covered flasks and later observed microbial growth.
What is the cell theory?
the theory that all living things are composed of cells that come from pre-existing cells.
Lazzaro Spallanzani
In 1765, he repeated Needham's experiments and suggested that Needham's results were due to microorganisms in the air entering his broth. He heated nutrient broth IN flasks that were sealed and NO microorganisms grew.
What is biogenesis?
the hypothesis that living things arise from pre-existing life.
Anton Laurent Lavoisier
showed the importance of oxygen to life
Rudolf Virchow
In 1858, he challenged spontaneous generation with the concept of biogenesis, the claim that living cells can arise only from preexisting living cells.
Louis Pasteur
In 1861, he demonstrated that microorganisms are present in the air and can contaminate sterile solutions, but air itself does not create microbes. He offered proof of biogenesis. He invented the swan-necked flask.
What did Pasteur's discoveries lead to?
led to the development of aseptic techniques used in labs and medical procedures to prevent contamination by microorganisms.
The period from ___1___ to ___2___ has been appropriately named the ________3___________.
1. 1857
2. 1914
3. Golden Age of Microbiology
Why is the period from 1857 to 1914 called the Golden Age of Microbiology?
because during this period, rapid advances, mainly by Pasteur and Koch, led to the establishment of microbiology as a science.
List some of the discoveries made during the Golden Age of Microbiology.
1. relationship between microorganisms and disease
2. the role of immunity in the prevention and cure of disease
3. developed vaccines and surgical techniques
What discovery did Pasteur make regarding wine (alcohol)?
the YEAST ferment sugars to alcohol and that BACTERIA can oxidize the alcohol to acetic acid
Define fermentation.
the process by which yeasts convert sugars to alcohol
What are aseptic techniques?
techniques that prevent contamination by unwanted microorganisms
Who demonstrated that spoilage bacteria could be killed by heat?
What is pasteurization?
a heating process used to reduce spoilage and kill bacteria in milk as well as in some alcoholic drinks
What is the germ theory of disease?
the principle that microorganisms can cause disease
Agostino Bassi
proved that a silkworm disease was caused by a fungus
What did Pasteur prove in 1865 regarding silkworm disease?
that another silkworm disease was caused by a protozoan
Ignaz Semmelweis
In the 1840s, he advocated handwashing to prevent the transmission of puerperal fever from one OB/GYN patient to another.
Joseph Lister
In the 1860s, he used a chemical disinfectant (phenol) solution to prevent surgical wound infections. His findings proved that microorganisms cause surgical wound infections.
Who provided the first proof that bacteria actually cause disease?
Robert Koch
Robert Koch
In 1876, he provided proof that a bacterium (Bacillus anthracis) causes anthrax and provided the experimental steps used to prove that a specific microbe causes a specific disease.
What are Koch's postulate? (definition)
a sequence of experimental steps for directly relating a specific microbe to a specific disease
List Koch's postulates.
1. Isolate a specific microbe in pure culture from an organism sick with disease.
2. Inoculate a healthy organism with microbes from the pure culture.
3. Healthy organisms must get sick with the same disease as the organism in #1.
4. The same microbe must be isolated from the organism in #3 as was isolated from #1.
What are fastidious organisms?
organisms that cannot grow in pure culture--cannot grow outside of living things, etc.
e.g. viruses
Edward Jenner
In 1796, he demonstrated that inoculation with cowpox material provides humans with immunity to smallpox
Where does the the term vaccination come from?
vacca for cow
What is immunity?
the protection from disease provided by vaccination (or recovery from the disease itself)
What is chemotherapy?
the treatment of disease by using chemical substances
What are synthetic drugs?
chemotherapeutic agents prepared from chemicals in the laboratory
What are antibiotics?
chemicals produced naturally by bacteria or fungi to act against other microorganisms
What is the success of chemotherapy based on?
the fact that some chemicals are more poisonous to microorganisms than to the hosts infected by the microbes
What is Quinine?
a substance from tree bark used to treat Malaria
Paul Ehrlich
In 1910, he introduced an aresenic-containing chemical called salvarsan to treat syphilis
When were sulfonamides synthesized?
Alexander Flemming
In 1928, he observed that the Penicillium fungus inhibited the growth of a bacterial culture. He named the active ingredient penicillin.
How long has penicillin been used clinically?
since the 1940s
What is the study of bacteria?
What is the study of fungi?
What is the study of viruses?
What is the study of protozoa and worms?
What is the study of all of an organism's genes called?
What is the study of the immune system called?
Rebecca Lancefield
In 1933, she proposed the use of immunology to identify some bacteria according to serotypes
What is a serotype?
a variant within a species
What is recombinant DNA?
DNA made from two different sources
Paul Berg
In the 1960s, he showed that fragments of human or animal DNA (genes) that code for important proteins can be attached to bacterial DNA
In what two fields did recombinant DNA technology (or genetic engineering) have its origins?
1. microbial genetics
2. molecular biology
What is microbial genetics?
a field that studies the mechanisms by which microorganisms inherit traits
What is molecular biology?
a field that specifically studies how genetic information is carried in molecules of DNA and how DNA directs the synthesis of proteins
Who were the first to show how bacteria help recycle vital elements between the soil and the atmosphere?
Martinus Beijerinck and Sergei Winogradsky
What is microbial ecology?
the study of the relationship between microorganisms and their environment
What do bacteria recycle?
carbon, nutrients, sulfur, and phosphorus that can be used by plants and animals
What is bioremediation?
the use of microbes to remove an environmental pollutant
What is biotechnology?
the industrial application of microorganisms, cells, or cell components to make a useful product
What is gene therapy?
a technique of inserting a missing gene or replacing a defective one in human cells
What are normal microbiota?
the microorganisms that colonize a host without causing disease
Why was the term FLORA used to describe normal microbiota?
because at one time bacteria and fungi were thought to be plants
Are there normally bacteria INSIDE the body? What about the intestines?
1. NO! The inside of the body should be sterile.
2. Microorganisms present in the digestive tract are technically still OUTSIDE the body.
What is transient flora?
microorganisms that can make you sick
What do normal microbiota do?
1. protect against disease by preventing the overgrowth of harmful microbes
2. produce useful substances such as vitamin K and some B vitamins
What is resistance (in terms of disease)?
the ability to ward off diseases
What are some important resistance factors?
the skin, stomach acid, and antimicrobial chemicals
What do you see when you look at a person?
all you see are DEAD things, except for the surface of the eyeball, which is alive

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