topic 6: prokaryotes Flashcards

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1
Q

living organisms are classified into 3 domains:

A
  • Bacteria
  • Archaea
  • Eukarya
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2
Q

which two domains consist of unicellular prokaryotes?

A

Domain Bacteria and Domain Archaea

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3
Q

what is Domain Eukarya divided into?

A

the eukaryotes, divided into 4 Kingdoms:
- protists
- fungi
- plants
- animals

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4
Q

prokaryotic micro-organisms

A
  • bacteria
  • archaea
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5
Q

prokaryotic macro-organisms

A

do not exist

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6
Q

eukaryotic micro-organisms

A
  • fungi
  • protists
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7
Q

eukaryotic macro-organisms

A
  • plants
  • animals
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8
Q

what are the micro-organisms categories?

A
  • bacteria: unicellular prokaryotic micro-organisms
  • archaea: unicellular prokaryotic micro-organisms
  • protists: eukaryotic micro-organisms (e.g. protozoa, algae)
  • fungi: eukaryotic micro-organisms (e.g. yeasts, mushrooms)
  • viruses: non-cellular pathogens
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9
Q

who discovered the antibiotic penicillin, and when was it discovered?

A
  • Alexander Fleming
  • 1929
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10
Q

prokaryotes are divided into 2 domains:

A

bacteria and archaea

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11
Q

what are 2 major categories of Domain Bacteria?

A
  • Eubacteria
  • Cyanobacteria
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12
Q

what are Eubacteria?

A

includes pathogenic bacteria => cause diseases

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13
Q

what are Cyanobacteria?

A
  • non-pathogenic
  • have chlorophyll, perform photosynthesis => produce oxygen
  • live in lakes, oceans
  • role in nitrogen fixation
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14
Q

what does Domain Archaea include?

A
  • Archaea (Archaeabacteria): live in extreme conditions
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15
Q

what are examples of Archaea?

A
  • halophiles: in salty lakes
  • methanogens: in the digestive track, anaerobes, produce methane
  • thermoacidophiles: in acidous, sulfur-rich hot spring, with optimum temperatures of 70-80˚C and pH 2-3
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16
Q

in taxonomy of living organisms, species are broken down into?

A
  • subspecies
  • variety
  • strain (in bacteria)
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17
Q

how is a species named?

A

species name = genus + characteristic property

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18
Q

what is an example of naming a species?

A

Staphylococcus aureus
- genus: staphylococcus
- property: aureus

19
Q

what does it mean for prokaryotes to have variable morphology?

A

a variety of shapes

20
Q

describe the morphology of prokaryotes

A

(1) spherical shape (cocci)
(2) rod-shaped (rods)
(3) spiral shape

21
Q

what is an example of a spherical shaped prokaryote?

A

Staphylococci, Streptococci
(cocci = spherical)

22
Q

what is an example of a rod-shaped prokaryote?

A

bacilli (E. coli)

23
Q

what is an example of a spiral shaped prokaryote?

A
  • Vibrio cholerae: shape C or S
  • Spirilla and Spirochetes
24
Q

what are the characteristics of a prokaryotic cells, different from a eukaryote?

A
  • smaller in size
  • absence of nuclear membrane
  • absence of membrane-bound organelles (mitochondria/chloroplasts)
  • no organized replicative cell cycle (mitosis)
  • replicated by binary fission instead
  • their cell wall has different composition from eukaryotic cells
25
Q

what are the structures in a prokaryotic cell, the essential and non-essential?

A

essential (present in ALL cells):
- cytoplasm
- cell wall
- plasma membrane
- nucleoid (region with circular DNA)

non-essential (present in some):
- fimbriae
- capsule
- sex pillus
- flagella

26
Q

what are the functions of prokaryotic cell wall?

A
  • maintains cell shape
  • protects the cell
  • prevents cell from bursting in hypotonic environment (osmotic pressure)
  • role in cell division
27
Q

compare the different cell wall compositions of eukaryotic, bacterial, and archaea cell walls

A

eukaryotic cell walls:
- made of cellulose (plant cells)
- made of chitin (fungi)

bacterial cell walls:
- contain peptidoglycan

archaea cell walls:
- contain polysaccharides and proteins
- LACK PEPTIDOGLYCAN

28
Q

what is peptidoglycan?

A

a network of polysaccharides and polypeptide

29
Q

what is gram staining?

A
  • staining technique used to classify bacteria in 2 major categories based on cell wall composition
  • uses crystal violet dye used for staining (violet color)
30
Q

what is gram-positive bacteria?

A
  • their cell walls mainly consist of peptidoglycan
  • they absorb crystal violet => have a purple (violet) color
31
Q

what is gram-negative bacteria?

A
  • their cell walls consist of a SMALL amount of peptidoglycan and a LARGE amount of lipopolysaccharides (LPS)
  • do not absorb crystal violet => have a pink color
32
Q

why are gram-positive bacteria violet in color?

A

the peptidoglycan in their cell walls traps crystal violet

33
Q

what are some examples of Gram (+) bacteria?

A
  • staphylococci
  • streptococci
  • micrococci
34
Q

what are some examples of Gram (-) bacteria?

A
  • Escherichia coli (E. coli)
  • Shigella
  • Salmonella
35
Q

what is an example of an antibiotic that targets the peptidoglycan and damages bacterial cell walls?

A

penicillin

36
Q

what are the functional differences between Gram (+) and Gram (-) bacteria?

A

Gram (+) bacteria:
- resistant to physical stress
- sensitive to lysozyme and penicillin

Gram (-) bacteria:
- resistant to lysozyme and penicillin

37
Q

what is more likely to be antibiotic resistant (antimicrobials/antibacterials)?

A

Gram-negative bacteria

38
Q

what is the capsule?

A

a polysaccharide or protein layer that covers some prokaryotes

39
Q

what is the capsule associated with?

A

increased virulence of wpathogenic bacteria

40
Q

what is virulence?

A

the ability of an infectious agent to produce disease (pathogenicity) => a measure of the severity of the disease it causes

41
Q

what are the functions of a capsule?

A
  • protects bacteria from phagocytosis by leukocytes
  • protects bacteria from the digestion upon phagocytosis
  • protects bacteria from infection by phages and drying
42
Q

some prokaryotes have fimbriae, which are?

A

structures that aid with the attachment of bacteria to each other or to other cells that they infect

43
Q

what is a special type of fimbriae, what is it used for?

A

special type of fimbriae (longer than regular fimbriae) that allow prokaryotes to exchange DNA

44
Q
A