Ch.1 The Microbial World and You Flashcards
Microorganisms
organisms that are too small to be seen with the unaided eye
Microbes include
bacteria, fungi, protozoa, microscopic algae, and viruses
pathogenic
disease producing
Microbes can…
- Decompose organic waste
- Generate oxygen by photosynthesis
- Produce chemical products such as ethanol, acetone,
and vitamins - Produce fermented foods such as vinegar, cheese,
and bread - Produce products used in manufacturing (e.g.,
cellulose) and disease treatment (e.g., insulin)
Knowledge of microorganisms allows humans to
*prevent food spoilage
* prevent disease
*understand causes and transmission of disease to prevent epidemics
an adult human is composed of __ _______ body cells and harbors another __ _______ bacterial cells
30 trillion
40 trillion
a group of microbes that live stably on/in the human body
microbiome
the microbiome (3 things)
– Help to maintain good health
– Can prevent growth of pathogenic microbes
– May help train the immune system to discriminate
threats
Normal microbiota is the
collection of acquired microorganisms on or in a healthy human being
Normal microbiota (3 things)
– Begin to be acquired as newborns
– May colonize the body indefinitely
– May colonize the body fleetingly (making them
transient microbiota)
colonization can only occur at body sites that ______ _______ and the right environment for the ________ __ _______
provide nutrients
microbes to flourish
The Human Microbiome Project
– Begun in 2007
– Goal of determining the makeup of typical microbiota of
various areas of the body
– Secondary goal of understanding relationship between
changes in microbiome and human diseases
The National Microbiome Initiative (NMI)
– Begun in 2016
– Explores the role microbes play in different ecosystems
Who established the system of scientific nomenclature in 1735
Carolus Linnaeus
Each organism has two names
The genus and the specific epithet
Scientific names
– Are italicized or underlined
▪ The genus is capitalized; the specific epithet is
lowercase
– Are “Latinized” and used worldwide
– May be descriptive or honor a scientist
After the first use, scientific names may be
abbreviated with the first letter of the genus and the
specific epithet:
– Escherichia coli and Staphylococcus aureus
are found in the human body
– E. coli is found in the large intestine, and S.
aureus is on skin
Types of Microorganisms
- Bacteria
- Archaea
- Fungi
- Protozoa
- Algae
- Viruses
- Multicellular Animal Parasites
Bacteria
- Prokaryotes
– “Prenucleus” - Single-celled
- Peptidoglycan cell walls
- Divide via binary fission
- Derive nutrition from organic or inorganic chemicals or
photosynthesis - May “swim” by using moving appendages called flagella
Archaea
- Are prokaryotes
- Lack peptidoglycan cell walls
– May lack cell wall entirely - Often live in extreme environments
- Include:
– Methanogens
– Extreme halophiles
– Extreme thermophiles - Generally not known to cause disease in humans
Fungi
- Eukaryotes
– Distinct nucleus surrounding DNA genetic material - Chitin cell walls
- Absorb organic chemicals for energy
- Yeasts are unicellular
- Molds and mushrooms are multicellular
– Molds consist of masses of mycelia, which are
composed of filaments called hyphae
Protozoa
- Eukaryotes
- Absorb or ingest organic chemicals
- May be motile via pseudopods, cilia, or flagella
- Free-living or parasitic (derive nutrients from a living
host)
– Some are photosynthetic - Reproduce sexually or asexually
Algae
- Eukaryotes
- Cellulose cell walls
- Found in freshwater, saltwater, and soil
- Use photosynthesis for energy
– Produces oxygen and carbohydrates - Sexual and asexual reproduction possible
Viruses
- Acellular
- Consist of DNA or RNA core
- Core is surrounded by a protein coat
– Coat may be enclosed in a lipid envelope - Are replicated only when they are in a living host cell
– Inert outside living hosts
Multicellular Animal Parasites
- Eukaryotes
- Multicellular animals
- Not strictly microorganisms
- Parasitic flatworms and roundworms are called
helminths
– Some microscopic stages in their life cycles
Classification of Microorganisms
developed by Carl Woese in 1978
Three domains based on cellular organization
– Bacteria
– Archaea
– Eukarya
▪ Protists
▪ Fungi
▪ Plants
▪ Animals
1665: Robert Hooke reported that all living things are composed of little boxes, or “cells”
- Marked the beginning of cell theory: all living things are composed of cells
- Perspective: Thomas Edison light bulb 1879
Anton van Leeuwenhoek observed the first microbes from
1623 to 1673
Magnifying lenses were used to view
Animalcules
Spontaneous generation
the hypothesis that life arises from nonliving matter; a “vital force” is necessary for life
Biogenesis
the hypothesis that living cells arise only from preexisting living cells
1858: Rudolf Virchow
said cells arise from preexisting cells
Pasteur also used S-shaped flasks
keep microbes out but let air in
Pasteur showed that microbes were responsible for
fermentation
fermentation
the microbial conversion of sugar to alcohol in the absence of air
Pasteurization
the application of a high heat for a short time to kill harmful bacteria in beverages
Vaccination 1796
Edward Jenner
Immunity
protection from disease
Chemotherapy
treatment of disease with chemicals
Antibiotics
chemicals produced by bacteria and fungo that inhibit or kill other microbes
Chemotherapeutic agents used to treat infectious disease can be
synthetic drugs or antibiotics
1928: Alexander Fleming
discovered the first antibiotic
Penicillium fungus made…
penicillin that killed S. aureus
overuse can lead to
resistance
Bacteriology
study of bacteria
Mycology
study of fungi
Parasitology
study of protozoa and parasitic worms
Immunology
study of immunity
Virology
study of viruses
Microbial genetics
study of how microbes inherit traits
Molecular biology
study of how DNA directs protein synthesis
Genomics
study of an organisms genes; has provided new tools for classifying microorganisms
Recombinant DNA
DNA made from two different sources
Microbial ecology
study of the relationship between microorganisms and their environment
Biotechnology
the use of microbes for practical applications, such as producing foods and chemicals
Recombinant DNA technology
enables bacteria and fungi to produce a variety of proteins, vaccines, and enzymes
Normal microbiota
microbes normally present in and on the human body
Resistance
the ability of the body to ward off disease
Emerging infectious diseases (EIDs)
new diseases and diseases increasing in incidence
Zika virus disease
– Virus discovered in 1947 in Uganda
– Human epidemics in Micronesia 2007, then in
French Polynesia and Brazil in 2013–2015
– Spread by bite of an infected Aedes mosquito; also
transmitted by sexual contact
– Infection during pregnancy can result in severe
birth defects
Middle Easy respiratory syndrome (MERS)
– Caused by Middle East respiratory syndrome
coronavirus (MERS-CoV)
– Common to SARS
▪ Severe acute respiratory syndrome
– 1,800 confirmed human cases and 630 deaths
since 2014
H1N1 influenza
– Also known as swine flu
– First detected in the United States in 2009
▪ Declared a pandemic, or worldwide large-scale
outbreak, by WHO in 2009
Avian influenza A (H5N1)
– Influenza A virus
– Primarily in waterfowl and poultry
– Sustained human-to-human transmission has not yet
occurred
Methicillin-resistant Staphylococcus aureus (MRSA)
– 1950s: Penicillin resistance developed
– 1980s: Methicillin resistance
– 1990s: MRSA resistance to vancomycin reported
▪ VISA: vancomycin-intermediate S. aureus
▪ VRSA: vancomycin-resistant S. aureus
Ebola hemorrhagic fever (EHF)
– Ebola virus
– Causes fever, hemorrhaging, and blood clotting
– Transmitted via contact with infected blood or body
fluids
– First identified near Ebola River, Congo
– 2014 outbreak in Guinea; over 28,000 infected
over 2 years, with 1/3 of those infected dead
Marburg virus
– Causes hemorrhagic fever similar to Ebola
– First cases in laboratory workers in Europe who
handled African green monkeys from Uganda
– 13 outbreaks identified in Africa between 1975 and
2016
▪ Involving 1 to 252 people, with 57% mortality
– African fruit bats are the natural reservoir for the
virus (and also suspected of being the reservoir for
Ebola virus)
