Bacteria and Archaea Flashcards

Flashcards about Bacteria and Archaea for premedical biology based on lecture notes.

What are Bacteria and Archaea?

Prokaryotic organisms

How long ago did the history of Bacteria and Archaea start?

3.5 billion years ago

What is the metabolic diversity among prokaryotes compared to eukaryotes?

Metabolic diversity is greater among prokaryotes than all eukaryotes combined.

What is the metabolic relationship to oxygen for obligate aerobes?

Use cellular respiration

What is the metabolic relationship to oxygen for facultative anaerobes?

Use oxygen if present, fermentation in anaerobic environments

What is the metabolic relationship to oxygen for obligate anaerobes?

Poisoned by oxygen, use fermentation or anaerobic respiration

What structures are found in bacterial structure?

Pilus, Plasmalemma, Cell wall, Capsule, Cytoplasm, Flagellum, Ribosomes, Nucleoid, Mesosome

What are the three common shapes of prokaryotes?

Sphere (cocci), rods (bacilli), helices (spirilla, spirochetes)

What is the function of cell walls in prokaryotes?

Protection (hypotonic environment) and pathogenicity

What is peptidoglycan?

Polymers of sugar cross-linked by short peptides

What is the difference between Gram-positive and Gram-negative bacteria?

Gram-positive: thick layer of peptidoglycan; Gram-negative: thin layer of peptidoglycan, outer membrane with lipopolysaccharides (LPS)

Why are Gram-negative bacteria more threatening?

LPS of Gram-negative bacteria are toxic

How do antibiotics like penicillins work?

Inhibit synthesis of cross-links in peptidoglykan and prevent its formation

What are exotoxins?

Proteins secreted by prokaryotes (botulism, cholera)

What are endotoxins?

Components of the outer membranes of certain Gram-negative bacteria (Salmonella)

What is the most common mechanism for movement in prokaryotes?

Flagellar action

What is taxis movement?

Movement toward or away from a stimulus (chemotaxis, phototaxis)

Where is DNA concentrated in Bacteria?

Nucleoid region

What are plasmids?

Small rings of DNA encoding resistance to antibiotics or metabolism of unusual nutrients

What is binary fission?

Bacterial division in half

What are important conditions for the growth of populations in prokaryotes?

Temperature, pH, salt concentrations, and nutrient sources

What are endospores?

The ability of some prokaryotes to withstand hard conditions (lack of water, nutrients, extreme heat or cold, almost poisons)

What are the three mechanisms of recombination of genetic information (DNA molecule) in prokaryotes?

Transformation, Conjugation, Transduction

What is bacterial transformation?

Genes are taken up from the surrounding environment

What is bacterial conjugation?

Genes are transferred directly from one cell to another

What is bacterial transduction?

Genes are transferred between prokaryotes by viruses

What are the two strategies Bacteria have for energy and resources to synthesize organic compounds?

Autotrophic and Heterotrophic

What bacteria are chemoheterotrophs?

Pseudomonas, Staphylococus, Escherichia coli

What is mutualism in symbiosis?

Relationships when both symbionts benefit

What is commensalism in symbiosis?

Relationships when one symbiont receives benefits, while the other is not harmed or helped in any significant way

What is parasitism in symbiosis?

Relationships when one symbiont, called a parasite, benefits at the expense of the host

What are Methanogens?

Unique form of energy metablism, H2 is used to reduce CO2 to methane CH4. Oxygen is a poison. Live in swamps and marshes and other species inhabit the gut of animals.

What are Extreme halophiles?

Live in saline places as the Great Salt Lake and the Dead sea

What are Extreme thermophiles?

Thrive in hot enviroments, temperatures are of 60°C to 80°C, thermal springs

What are Proteobacteria?

purple bacteria – photoautotrophs, photoheterotrophs with bacteriochlorophylls, obligate anaerobes

What are Gram-positive bacteria?

Some are gram-negative, some are photosynthetic, most are chemoheterotrophs (Clostridium, Bacillus)

What are Cyanobacteria?

Photoautotrophs with plant-like photosynthesis, fresh water, marine species, symbionts, single-cell from, colonies and truly multicellular organisms

What are Spirochetes?

Helical chemoheterotrophs, some are very long (up to 0.25mm), internal flagelar-like filments providing corkscrew-like movement, Treponema pallidum, Borrelia Burgdorferi

What are Chlamydias?

Obligate intracellular parasites of animals, obtain ATP from the host cell, gram-negative, Chlamydia trachomatis cause blindness and sexually transmitted disease

What does Borrelia burgdorferi cause?

Lyme disease

What does Treponema pallidum cause?

Syphilis

What does Neisseria gonorrhoeae cause?

Gonorrhoea

What does Neisseria meningitis cause?

Cerebro-spinal meningitis

What does Salmonella typhi cause?

Typhus

What does Bordetella pertusis cause?

Whooping cough

What does Staphylococcus aureus cause?

Skin suppuration

What does Clostridium tetani cause?

Tetanus

What does Clostridium botulinum cause?

Botulism

What does Mycobacterium tuberculosis cause?

Tuberculosis

What does Vibrio cholerae cause?

Cholera