MICRO - Ch1/Exam 1 Study Guide

Why study microbiology

1. understanding infectious diseases

2. protecting public health

3. developing meds and vaccines

4. food production and safety

5. environmental importance

6. industrial and scientific applications

Microbes Environmental habitats

Soil

Water

Air

Plants

Animals and Humans

Decaying organic matter

Extreme environment

Bacteria

They are

- Prokaryotic - their cells lack nuclei (so their genes are not surrounded by a membrane)

- bacterial walls are surrounded by petidoglycan

- reproduce asexually

- can live singly or with other bacteria, and live in areas with moisture

Algae

- unicellular or multicellular photosynthetic eukaryotes (they make their own food from carbon dioxide and water using energy from sunlight)

Fungi

- eukaryotic meaning that their cells contain a nucleus and is surrounded by a membrane

- obtain their food from other organisms

- differ from animal cells by having cell walls

Include molds and yeast

- molds (multicellular organisms that grow as long filaments. Reproduce by sexual and asexual spores

- yeasts (unicellular and typically oval to round) produce asexually by budding (process where a daughter cell grows off the mother). Some yeasts can produce sexual spores

Viruses

- acellular

- much smaller than bacteria and can only be seen with a microscope

- contain either DNA or RNA

- cannot reproduce on their own they must infect a living host and use them to make a virus

* obtain their nutrients from the living host that they infect

Protozoa

single celled eukaryotes similar to animals in their nutritional needs and structure

- live freely in water but some live inside animal hosts where they can cause disease and they reproduce asexually although some can reproduce sexually

- capable of locomotion (scientists categorize protozoa by their locomotive structures)

1. cilia - numerous short protrusions of a cell that beat rhythmically to propel the protozoan

2. flagella extensions of a cell but are fewer, longer and more whiplike

3. psuedopods - extensions of a cell that flow in the direction of travel

First person to observe living cells through a microscope and what cells did he study

Antoni van Leeuwenhoek

He studied protozoa, bacteria, archaea, fungi, algae, and small molecular animals

State the germ theory of disease and how it differs from spontaneous generation

- Bacteria are responsible for spoiling wine led naturally to his hypothesis in 1857 that microorganisms are also responsible for diseases

Spontaneous gen says that for example maggots on raw meat could spawn spontaneously to of nowhere where the germ theory states that life only comes from pre existing life (every microorganism has a parental cell)

Louis Pasteur's main contributions to microbiology

- investigated spontaneous generation

- he boiled infusions long enough to kill everything but instead of sealing the flask s he bent their neck into an S shape, preventing the introduction of dust and microbes into the broth

1. - "swan neck flasks" remained free of microbes because the flasks contained all the nutrients including air

2. He answered the question "what is fermentation" with experiments - he demonstrated that yeast can grow with or without oxygen - so yeast are facultative anaerobes (organisms that can live w/wo o2)

* HE PROVED THAT BACTERIA FERMENT SUGAR TO PRODUCE ACIDS AND THAT YEAST CELLS FERMENT SUGAR TO PRODUCED ALCOHOL

-> suggested a method for preventing the spoilage of wine and his name became a household word when he developed pasteurisaiton( heating a liquid enough to kill all bacteria but not change the juice)

pure culture

a laboratory culture that contains only one species (or one strain) of microorganism. It is grown from a single cell or a single colony, so all of the microorganisms in the culture are genetically similar.

Scientists use pure cultures to:

Accurately identify a microorganism.

Study its characteristics without interference from other microbes.

Test its response to antibiotics, disinfectants, or other treatments.

Koch's Pastulates

1. the suspected causative agent must be found in every case of the disease and be absent from healthy hosts

2. the agent must be isolated and grown outside the host

3. when the agent is introduced to a healthy, susceptible host the host should get the disease

4. the same agent must be found in the diseased experimental host

aseptic technique

aseptic technique is the practice of preventing contamination and the spread of microorganisms.

• Ignaz Semmelweis was the first to use it effectively by requiring handwashing to reduce infections.

The golden age of microbiology

for about fifty years scientists and the blossoming field of microbiology were driven by the search to the following 4 questions

- is spontaneous generation of microbial life possible

- what causes fermentation

- what causes disease

- how can we prevent infection and disease

competition between scientists shaped the course of microbiological research today

Redi

- when decaying meat was kept isolated from flies, maggots never developed

* meat exposed to flies were soon infested

Buchner

Buchner resurrected the chemical explanation by showing that fermentation does not require living cells - experiments demonstrated presence of enzymes (cell produced proteins that promote chemical reactions)

** Buchner's work began the field of biochemistry and the study of metabolism

Koch

- carefully examined blood of infected animals and in every case he identified rod shaped bacteria in chains

- he observed the formation of resting stages (endospores) within the bacterial cells and showed that these always produced anthrax when injected into mice.

Anthrax: can spread to humans and is a potentially fatal disease primarily of animals in which toxins produce ulcerations of the skin

* This was the first time that bacterium was proven to cause a disease

2. discovered the anthrax bacterium and then announced that the cause of TB was a rod shaped bacterium

*** he had a series of steps that must be taken to prove the cause of any infectious disease called Koch's Postulates

Gram

- developed the staining technique most widely used in microbiology to visualize and to begin identifying microbes under the microscope

Semmelweiss

Discovered the cause of childbed fever

he began requiring med students to wash their hands with chlorinated lime water

-> his efforts made it easier for later docs to institute changes

Lister

Became the founder of antiseptic surgery and opened new fields of research into antisepsis and disinfection

Nightingale

** founded modern nursing

Introduced cleanliness and other antiseptic techniques into nursing

- she and her assistants used scrubbing brushes and she arranges for each patients filthy closed and dressings to be replaced or cleaned at a different location removing sources of infection

- also documented statistical comparison using a pie chart

Jenner

vaccine

- she proved that it was possible to provide some protection to smallpox by inoculating children with pus taken from a patient suffering with a mild case of the disease

- she also began the field of immunology which is the study of the body's defenses against pathogens

Snow

- set a good standard for good hygiene to prevent spreading infectious diseases

- His study was the foundation for two branches of microbiology - infection control and epidemiology which is the study of the occurrence, distribution and spread of disease in humans

Ehrlich

"magic bullets"

- he discovered a chemical active against the causative agent of syphilis though it can have serious side effects in humans

- his discoveries began the branch of medical microbiology known as chemotherapy