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BIO 202 > CH 27: Archaea and Bacteria > Flashcards

CH 27: Archaea and Bacteria Flashcards

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Biology 101 flashcards
1
Q

What are prokaryotes?

A

a paraphyletic group consisting of bacteria and archaea

-Both lack a membrane bound nucleus

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2
Q

What was the Great Oxidation Event?

A

No Oxygen on earth until Cyanobacteria evolved ability to photosynthesize
-Oxygen is byproduct of photosynthesis and built up over millions of years

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3
Q

Why are prokaryotes so diverse?

A
  • Short Generation times
  • Live in almost all habitats
  • Horizontal Gene Transfer
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4
Q

Which domain is Archaea more closely related to?

A

Eukarya

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5
Q

What gives Archaea its resilience, making them extremophiles?

A

Ether bonded lipids more resistant to heat

-Lipids have extra double/triple bonds that maintain shape and don’t denature under high temp/pH

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6
Q

What are extremophiles?

A

Organisms that can occupy habitats with extreme conditions

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7
Q

What are the types of extromphiles?

A

High Salt Content - halophiles

High Temperatures - Hyperthermophiles

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8
Q

What are the phyla that make up Domain Archaea?

A

1) Korachaeota
2) Nanoarchaeota
3) Thaumarchaeota
4) Crenarchaeota
5) Euryarchaeota

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9
Q

What kinds of living conditions do bacteria live in?

A

Mst favor moderate conditions

  • some are extremophiles
  • Some form symbiotic relationships with Eukaryotes
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10
Q

What are the Phyla we need to know for Domain Bacteria?

A
  1. Chlamydiae: Chlamydia
  2. Spirochaetes: Syphilis and Lyme disease
  3. Actinobacteria: Tuberculosis
  4. Cyanobacteria: O2 producers; blue-green algae; can cause toxic algal blooms
  5. Proteobacteria: Large group; metabolically diverse; E. coli, influenza
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11
Q

What are the characteristics of Phylum Cyanobacteria?

A
  • Photosynthetic bacteria generates Oxygen
  • Live in aquatic habitats, wetlands, arid soil surface
  • Plant chloroplasts are derived from cyanobacteria
  • Live as single cells, colonies or filaments
  • Produce Organic Carbon and Fix Nitrogen
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12
Q

What Major Subgroup of Phylum Proteobacteria had a large impact on humans?

A

α-proteobacteria

•Ancestors of mitochondria, Rhizobium, Agrobacterium

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13
Q

What is horizontal gene transfer?

A

Movement of one or more genes from one species to another
•Contrasts with vertical gene transfer from parent to progeny
•Increases genetic diversity

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14
Q

What are the mechanisms of horizontal gene transfer?

A

Transformation, Transduction, and Conjugation

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15
Q

Explain the mechanism of horizontal gene transfer, transformation.

A

Transformation

•DNA fragment from donor cell released to environment & taken up by another bacterial cell

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16
Q

Explain the mechanism of horizontal gene transfer, transduction.

A

Transduction
•Virus infects donor cell & bacterial chromosome fragments
•Phage transfers fragment DNA to a recipient cell

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17
Q

Explain the mechanism of horizontal gene transfer, conjugation.

A

Conjugation
•Requires direct contact between bacteria cells
•One bacterium acts as a donor & transfers DNA to recipient cell

18
Q

What are the important concepts of Bacteria and Archaea?

A
  • Both evolved from common ancestor
  • Eukaryotic nucleus and cytoplasm likely arose in ancient archaeal organism
  • Mitochondria and plastids originated from proteobacteria and cyanobacteria by endosymbiosis
19
Q

What are examples of more complex cell structures in bacteria?

A

Magnetosomes

  • Magnetite Crystals
  • Like compass that help bacteria find low O2 habitats

Gas Vesicle
-Adjust buoyancy

20
Q

What are the major shapes of Bacteria?

A

1) Sphere - cocci
2) Rods - bacilli
3) Comma - vibrios
4) Spiral - spriochaetes
5) Single Cells, pairs, or Filaments

21
Q

What is mucilage?

A

Also called glycocalyx

-Very sticky composed of polysaccharides and/or proteins

22
Q

What are the functions of mucilage?

A

1) Evade host defenses
2) Hold colony together (biofilm)
3) Help aquatic bacteria float
4) Binds mineral nutrients
5) Defense against predators
6) Prevents UV damage

23
Q

What are biofilms?

A

Biofilms: aggregates of microorganisms that secrete adhesive mucilage & glue themselves to surfaces
•Help remain in favorable areas for growth

24
Q

What is quorum sensing?

A

given enough individuals, signaling molecules released by individuals cause collective behavior
•Moving to a common location
•Secreting mucilage

25
Q

What are the major forms of bacterial cell walls?

A

Gram-positive or Gram-negative

-differ in peptidoglycan thickness, staining properties & response to antibiotics

26
Q

What are the two methods of motility for bacteria?

A

Flagella and Pili

27
Q

What are flagella used for in bacteria?

A
  • Important for swimming
  • Lack plasma membrane cover of proteins
  • Lack internal cytoskeleton of microtubules
  • Lack motor protein dynein
  • Eukaryotic flagella: repeatedly bend & straighten
  • Bacterial flagella: outboard motor
28
Q

What are pili used for in bacteria?

A
  • Twitch or glide across surfaces
  • Threadlike structures on surface of cell
  • If nutrients are low bacteria glide together & form tiny tree like colonies
  • Important for reproduction
29
Q

How do bacteria reproduce?

A

Binary fission –divide by splitting in two

  1. Circular DNA replicates within the cell
  2. DNA molecules migrate to opposite ends of cell
  3. Cell elongates
  4. Cell constricts at middle, pinches off

one cell can become millions in hours

30
Q

How do bacteria survive harsh conditions?

A

By forming akinetes and endospores

31
Q

What do all living cells require to build organic molecules?

A

Energy and a source of Carbon

32
Q

How can you classify bacteria and archaea?

A

Can be classified by:
•Nutrition
•Response to oxygen
•Presence of specialized metabolic processes

33
Q

What is a heterotroph and what are its types?

A

Heterotrophs: organisms that require at least one organic compound, and often more

Photoheterotroph: able to use light energy to make ATP but they must take in organic compounds from the environment

Chemoorganotroph: must obtain organic molecules for both energy and carbon source

34
Q

What is an autotroph and what are its types?

A

Autotrophs: produce all or most of their own organic compounds

Photoautotroph: Uses light as energy source for synthesis of organic compounds from CO2or H2S

Chemoautotrophs: Use energy obtained from chemical modification of inorganic compounds to synthesize organic compounds

35
Q

How are bacteria/archaea classified by oxygen response?

A
  • Obligate aerobes –require oxygen
  • Facultative aerobes –can use oxygen or not
  • Obligate anaerobes –cannot tolerate oxygen
  • Aerotolerantanaerobes –do not use oxygen but are not poisoned by it
36
Q

How are bacteria/archaea classified by special metabolism?

A

Diazotrophs–conduct nitrogen fixation
•Enzyme nitrogenase converts inorganic nitrogen gas (N2) into ammonia (NH3)
•Autotrophs need ammonia to make N containing compounds
•Heterocysts–specialized cells for nitrogen fixation in cyanobacteria

37
Q

What are the Ecological role of bacteria?

A

Carbon cycle
•Producers synthesize organic compounds used by other organisms as food
•Decomposers break down dead organisms to release minerals for reuse

  • Methanogens make methane
  • Methanotrophs consume methane
38
Q

What are the symbiotic roles of bacteria?

A
  • Symbiosis: An organism that lives in close association with one or more other organisms
  • Parasitism: One partner benefits at the expense of the other
  • Mutualism: Association is beneficial to both partners
39
Q

What are the symbiotic roles of bacteria?

A
  • Syntrophy–some bacteria live together and supply each other with essential nutrients
  • Consortia–larger community of nutrient exchangers
40
Q

What is a pathogen?

A

Pathogen–parasitic microbe causes disease symptoms

•Organisms that obtain organic compounds from living hosts (parasites)

BIO 202 (21 decks)

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