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What is a virus?
a noncellular, infectious particle that can replicate only inside a living cell
What is a bacteriophage?
virus that infects bacteria
What is a pathogen?
disease-causing microbe
Why is Hawaii a good place for agriculture?
- good climate conditions
- can grow crops year round
What is human microbiota?
collectively, all of the types of microbes capable of living in or on humans
What are the reproduction types of bacteria, archaea, and viruses?
Bacteria: binary fission (asexual)
Archaea: binary fission (asexual)
Viruses: lytic and lysogenic pathways (asexual)
What is the difference between enveloped and nonenveloped viruses?
Nonenveloped: protein coat is the outermost layer (ex. bacteriophage)
Enveloped: have an outer viral envelope made of membrane from its former host. (ex. animal viruses)
How long did it take to go from maize to corn?
9,000 years
Why would there be differences in microbiota diversity between a person living in the Amazon vs a person living in the city?
- use of antibiotics
- less time outdoors
- diets low in fiber
- better hygiene
What are extreme halophiles and extreme thermophiles?
Extreme thermophile: organism that grow in very high temperatures (ex. volcano vents, hot springs)
Extreme Halophiles: organism that grows in highly salty water (ex. Dead Sea, Salt Lake)
What group of people have the most diverse microbiota systems?
Yanomami people
What is the difference between gram positive and gram negative bacteria?
Gram positive: thick layer of peptidoglycan or murein cell wall; stained purple
Gram negative: thin layer of peptidoglycan and lipopolysaccharide component; stained red/pink
What is a methanogen?
anaerobic organism that produces methane
What are the 4 types of bacterial metabolism and what do they mean?
Photoautotroph: use light energy to assemble organic compounds from CO₂ and water (ex. bacteria, archaea, plants, photosynthetic protists)
Chemoautotroph: obtain energy by oxidizing inorganic molecules (ex. bacteria and archaea)
Photoheterotroph: harvest energy from light, and carbon from small organic molecules (bacteria and archaea)
Chemoheterotroph: obtain energy and carbon by breaking down carbohydrates, lipids, and proteins (ex. most bacteria, some archaea, fungi, animals, and nonphotosynthetic protists)
What are the 2 examples of bacteria, archaea, and viruses?
bacteria = E. coli, Chlamydia trachomatis
archaea = Pyrolobus fumarii, Pyrodictium abyssi
viruses = influenza, ebola, zika, HIV/AIDS
Human microbiota is mostly in ___? (5)
colon, skin, mouth, respiratory tract, urogenital tract
What structures are unique to bacteria?
- cell wall made of peptidoglycan
- sticky coat called a capsule to attach to surfaces
- small rings of DNA called plasmids unicellular
What are the shapes of bacteria, archaea, and viruses? (5)
spherical, rod shaped, spiral, flat, needlelike
Explain lytic and lysogenic pathways and their differences.
lytic: viral genes are expressed immediately;
1. viral DNA directs the host to copy viral DNA and
make viral proteins
2. viral DNA and proteins self-assemble as viral particles
3. a viral-encoded enzyme breaks down the bacterial cell wall, releases viral particles
lysogenic: viral genes are not expressed, so the cell stays healthy; allows bacteriophage to reproduce without killing its host
1. viral DNA is injected into a bacterial cell and is integrated into the host’s genome
2. when the host cell reproduces, viral DNA is copied and passed along with its genome
3. reactivation of the viral DNA in the descendant cells, puts the cells on the lytic pathway.
What structures are unique to archaea?
- lipids in cell wall
- histones
How many known human pathogens are there?
1,400
Describe the parts of a bacteriophage.
- head is a polyhedral capsid enclosing viral DNA
- hollow helical tail in which the DNA passes through during infection
- six leglike fibers attached to a baseplate at the base of the tail (bind to the cell’s surface)
Describe the difference between transduction and transformation (horizontal gene transfer).
Transformation: when a prokaryotic cell takes up DNA from its environment and integrates it into its genome
Transduction: bacteriophages transfer genes between cells
What are the 8 parts of bacteria and archaea cell structure and what does each do?
Pilus: hairlike protein filament which allows them to adhere
Nucleoid: concentrated region of DNA
Flagellum: tail for movement
Cell wall: made of sugars; tougher than the plasma membrane
Ribosomes: proteins are synthesized in cytoplasm
Plasma membrane: separates the interior from the outside environment; provides cell structure
Cytoplasm: jellylike substance where organelles are suspended
Are we all gonna ace this test?
yes :)