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
