Test 2 - Prokaryotes & Viruses

What is taxonomy

classification of the tree of life

Name the 8 levels of taxonomy

Domain, Kingdom, Phylum, Class, Order, Family, Genus, and Species.

What is a dichotomous key

Tool that helps identify natural objects.

How to do binomial nomenclature?

italicized, genus before species, genus capitalized, species lowercase.

How was the earth 4.6 billions years ago?

uninhabitable, volcanism, atmosphere composed of H2O (vapour) CO CO2 H2 N2, sun harmful radiation.

How was the earth 3.8 billions years ago?

liquid water, organic compounds produced from primitive gaseous atmosphere with presence of outside energy sources (volcanism).

When was the first prokaryote fossil? What was it like?

3.5 billions years ago

What are stromatolites?

formed 3.4 billion years ago, cyanobacterias produced rock-like structures, signs of first autotrophs

What happened 2.2 billion years ago?

modern photosynthesis evolved, conducted photosynthesis with oxygen as a by-product, and helped create ozone in atmosphere.

What happened 1.4-1.6 billion years ago?

eukaryotic cells evolved by using oxygen in their metabolic pathways, when mitochondria & chloroplasts evolved from single-celled organisms to organelle in a eukaryote (endosymbiosis theory).

What are heterotrophs and what processes help them get food?

consumers that get energy from food they eat through:

1. aerobic respiration: oxygen converts nutrients into energy (ATP), carbon dioxide, and water (glycolysis, Krebs cycle, the electron transport chain).
2. fermentation: carbohydrates produces energy and compounds like alcohol or acids, generates ATP when oxygen is scarce.

What's a decomposer?

prokaryote gets food from dead organisms

What's a parasite?

prokaryotes gets food from living organisms.

What are autotrophs and what are two types of autotrophs?

primary producers that make their own energy:

1. photoautotrophs: uses light energy and photosynthesis to convert light energy into carbon compounds.
2. chemoautotrophs: uses energy released by chemical reactions to make food.

What are anaerobes?

survives without oxygen

What are aerobic organisms?

survives with oxygen

What are photoheterotrophs?

a heterotroph that can use light energy to make its food.

Which domains are prokaryotes?

bacteria and archaea

Whats the kingdom under the bacteria domain?

eubacteria

Whats the kingdom under the archaea domain?

archaeabacteria

Name 7 facts about prokaryotes.

• 1-10 um
• smaller than eukaryotes
• unicellular
• no nucleus/has nucleoid
• means before nucleus
• most abundant organism
• found everywhere

Bacteria in humans? (5)

• more bacteria in your body than cells
• some bacteria & you formed endosymbiosis
• found in intestines, respiratory tract, skin, etc
• Actinomyces viscosus & Actinomyces naeslundii produces plaque (mouth)
• Streptococcus mutans secrete acid to dissolve tooth enamel.

What are structures in prokaryotes?

• DNA in cytoplasm
• no membrane bound organelles & chromosomes
• endospores
• mesomomes (infoldings of the plasma membrane (invaginations) that can form into vesicles (transportation))

Name three bacteria shapes (scientific & plural name).

1. Spherical - coccus, cocci
2. Rod - bacillus, bacilli
3. Spirillum - Spirochete, spirilla

Name three ways bacteria move.

1. flagellum
2. glide slowly over secreted slime
3. non-motile

Name three parts of the bacteria.

1. outer membrane: capsule that protects cell from damage (not in all).
2. cell wall: peptidoglycan (polysaccharides & proteins), maintains shape, protects.
3. cell plasma membrane: lipid bilayer, transports ions, nutrients, & waste.

Name ways archaea differ from bacteria.

1. may have pseudopeptidoglycan cell walls
2. different lipids in cell membranes
3. lives in extremely harsh environments
4. dna sequences closer to eukaryotes (3 RNA polymerases, transcription & translation)
5. less susceptible to antibiotics

Describe 3 ways prokaryotes reproduce.

1. Binary fission: asexual, no chromosomes, most common
2. Conjugation: sexual, 2 prokaryotes approach each other, bridge forms, genetic info exchanged, cells divide with new info.
3. Spore formation: endospores, only done with conditions are unfavourable, thick internal wall around DNA, remains dormant for months.

Name 6 ways that bacteria are beneficial.

1. Gut flora: diverse probiotics, e.coli in intestines, obligate anaerobes, breaks down vitamin K&B.
2. nitrogen fixation: N2->NH3->NO2->NO3, cyanobacteria & actinomycetes help, decomposes dead & waste materials.
3. food production: cheese, lactobacillus produces yogurt, acetobacter produces vinegar and sauerkraut.
4. Digests petroleum & removes human-made waste products & poisons from water.
5. synthesize drugs & chemicals -> genetic engineering
6. heat-stable enzymes -> medicine, food production, industrial chemistry

How does bacteria grow? What is bacterial growth?

• measured by increase in number
• clusters of bacteria rather than single cells
• warmth, sweat, moisture, temperature, pH
• exponential growth
• divides every 20 mins (37 degrees celsius)

What are antibiotics? How do they work?

• medications that destroy or slow down bacterial growth (ruptures cell wall, targets protein synthesis, interferes metabolism).
• doesn't work on viruses
• one bacteria (kills 99

What can happen if you use too many antibiotics?

Bacteria (99.9%) may have mutations that allow resistance to antibiotics.

Describe viral structure (5).

• 20-400 mm
• non-cellular structure
• capsid protein coat
• some enclosed in protective envelope
• nucleic acid coire with DNA or RNA

Shapes of viruses.

• helical (cylinder)
• polyhedral (geometric ball thing)
• envelope (ball, membrane coat surrounding capsid or protein coat)
• complex (bacteriophages)

Describe viral taxonomy.

• no kingdom
• own family tree
• family names end in - viridae
• genus names end in - virus (coronavirus)
• viral species (shares genetic info & econological niche/host) (COVID)
• subspecies designated by number (COVID-19)

What hosts can viruses infect?

all kingdoms, kingdom specific may be species specific

How does a virus infect a host?

1. recognizes cell it can infect by matching its surface marker with the cells receptor site.
2. inserts its genetic instructions
3. hijacks host cell's functions to produce the components needed for it to reproduce

Describe lytic cycle (rapid increase).

1. Attachment: virus attaches to the surface of a host cell.
2. Penetration: virus injects its genetic material into the host cell.
3. Replication: viral genetic material takes over the host cell's machinery to replicate itself, producing many copies of the viral genome and proteins.
4. Assembly: newly synthesized viral components are assembled into new virus particles.
5. Lysis: host cell is lysed, releasing the newly formed viruses to infect other cells.

Describe lysogenic cycle (specifically seen in bacteriophages) (long term, dormancy).

1. Attachment: bacteriophage attaches to the host cell and injects its genetic material.
2. Integration: viral DNA integrates into the host's chromosome, becoming a prophage.
3. Replication: host cell replicates its DNA+viral DNA, during cell division, resulting in daughter cells that have viral DNA.
4. Potential for Lytic Cycle: Under specific triggers (like stress or DNA damage), the prophage can cut itself out and enter the lytic cycle.

Compare lytic to lysogenic cycle.

1. RNA vs DNA (more stable and resistant to degradation)
2. immediate lysis vs dormancy
3. independent DNA replication vs DNA integration into host
4. slow vs fast

How do vaccines kill off viruses?

• weakened form of the virus injected into patient (cowpox & small pox, variolation).
• mRNA vaccines give codes to cells to teach them how to code the virus transmitters.

What are vector controls?

stay home, cover mouth when coughing, wash hands, avoid contact with bodily fluids.

How can viruses help with gene therapy?

viruses can transport DNA & RNA into cells, so use viruses to spread CRISPR gene-editted cells.

What is lysis?

the process of cell breakdown

What does lyse mean?

to cause the cell breakdown

What are diplococci?

• a bacterium that occurs as pairs of cocci (daughter cell stays attached after cell division).
• Neisseria gonorrhoeae, Neisseria meningitidis, Streptococcus pneumoniae.

What does staphylococci bacteria cause?

• commonly found on human skin and mucous membranes
• often harmless
• infections: minor skin issues like boils to life-threatening conditions, such as bloodstream infections, pneumonia, or toxic shock syndrome.

What is a tetrad?

• group of four or,
• group of four chromatids formed during meiosis when homologous chromosomes pair up.

What is sarcina bacteria?

• aerobic bacteria arranges into characteristic packets or bundles of cells
• in tetrads or octets
• non-motile

What are replication forks?

Y-shaped structure formed during DNA replication, where DNA is unwound.

What is a bacteriophage?

virus that infects bacteria