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BIO 246: Microbiology of Human Disease > Ch 3: Bacteria > Flashcards

Ch 3: Bacteria Flashcards

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Biology 101 flashcards
1
Q

What are prokaryotes? What are the types?

A

Prokaryotes are simple cells without a nucleus The types of prokaryotes are bacteria and archaea

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2
Q

What types of metabolism do Bacteria and Archaea (prokaryotes) have?

A

Heterotrophic: feed on organic substrates Autotrophic: Utilize inorganic substrates

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3
Q

Pathogenic bacteria use organic molecules of the host for energy and building blocks for reproduction. Bacterial pathogens are?

A

Heterotrophs

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4
Q

List the following in order from largest to smallest. Virus, yeast, bacterium, white blood cell.

A

White Blood Cell, Yeast, Bacterium, Virus

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5
Q

What structures are present on all bacterial cells? What structures are only present on some bacterial cells?

A

All Bacterial Cells:

  1. Nucleoid Region
  2. RIbosomes
  3. Cell Membrane
  4. Cytoplasm

Some Bacterial Cells:

  1. Pilus
  2. Plasmid
  3. Actin Cytoskeleton
  4. Flagellum
  5. FImbria
  6. Cell Wall
  7. Glycocalyx
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6
Q

What is the flagellum?

A

Translates into “Whip”

Only present on some bacterial cells

Basal body acts as motor that rotates flagellum

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7
Q

What is chemotaxis?

A

chemical gradients influence bacterial movement

  1. tumble and runs
    • rotate counterclockwise: run (straight)
    • rotate clockwise: tumble (change direction)
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8
Q

How do we classify motile bacteria?

A

flagellar arrangement

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9
Q

What is the fimbria?

A

Protein filaments used for attachment and colonization

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10
Q

What is a pilus?

A

protein filament used for attachment and colonization

  • sex pilus: hollow tube used for conjugation
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11
Q

What is a glycocalyx?

A

sugar coat

  • slime layer or capsule
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12
Q

How does the glycocalyx (slime layer) help bacteria?

A

Helps bacteria form biofilms (plaque)

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13
Q

The glycocalyx helps form a capsule. What does the capsule do?

A

Prevents the bacteria from adhering to phagocytes

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14
Q

What do bacteria transfer using a sex pilus?

A

Transfer plasmids

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15
Q

What is the cell wall

A

Structural support

  • protection
  • target for antibiotics
  • Peptidoglycan: glycan sugar crosslinks to provide strength
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16
Q

Who is Hans Christian Gram?

A

Invented Gram Stain

-differential staining technique for classifying bacteria

  • Gram-Positive: Stains PURPLE b/c have THICK cell wall
  • Gram-Negative: Stains PINK b/c have THIN cell wall
17
Q

What are the characteristics of the gram-positive cell wall?

A

composed of a thick peptidoglycan layer with associated teichoic acids

18
Q

what are the characteristics of a gram-negative cell wall?

A

composed of a thin peptidoglycan layer

Two membranes (Inner and outer) with:

  • porins: prevent entry of antibiotics like penicillin
  • lipopolysaccharides: endotoxin that causes inflammation
19
Q

Which kind of bacteria has an irregular cell wall? What are the characteristics?

A

Mycobacterium has atypical cell wall

  • gram-positive cell wall but doesn’t stain well
  • most of the cell wall is mycolic acid (Wax) which repels stains
20
Q

What is significant about the mycoplasma bacteria?

A

Has NO CELL WALL

  • cell membrane contains sterols to make it stronger
21
Q

What kind of crosslinks of peptidoglycan gives a bacterial cell wall its strength?

A

Peptide crosslink

22
Q

What is contained in the nucleoid region of the bacterial cytoplasm?

A

Contains bacterial chromosome (single/circular DNA genome)

  • some bacteria have extrachromosomal DNA called Plasmids (multiple/circular)
23
Q

How do bacteria reproduce?

A

Asexual cellular reproduction called Binary Fission

24
Q

What are bacterial ribosomes?

A

Ribosomes perform protein synthesis

  • Translation: (mRNA⇒protein)

Contains two subunits

  • Large 50S and Small 30S together form the 70S Ribosome
25
Q

WHat are the various bacterial cell shapes?

A

Cytoskeleton (actin filaments) produce the following cell shapes:

  1. Bacillus: rod shaped
  2. Vibrio: wave
  3. Spirillum: sprial
  4. Spirochete: really spiraled
26
Q

What are the characteristics of the coccus (cocci)?

A

have no cytoskeleton

speherical shaped

27
Q

What are the arrangements of cocci bacteria?

A

arrangements result from cytoplasmic division w/o separation of cell walls of daughter cells

Cell Division in One Plane:

  1. Diplococcus: two cells
  2. Streptococcus: variable number

Cell Division in Two Planes:

  1. Tetrad: 4 cells
  2. Staphylococcus: irregular cluster
28
Q

How can you use cell morphology to tell the difference between Streptococcus and Staphylococcus?

A

Both are Gram-Positive so stained Purple

Streptococcus: chains

Staphylococcus: irregular cluster

29
Q

What are endospores?

A

When growth conditions are unfavorable bacteria the vegetative cell** undergoes **sporulation and form endospores

This allows bacteria to survive in a dormant state until conditions change

When conditions are favorable the bacteria undergo germination** and become a **vegetative cell again

30
Q

The Clostridium genus form endospores. What would occure when Clostridium tetani is introduced into a host via a puncture wound?

A

endospores will germinate and produce neurotoxins

BIO 246: Microbiology of Human Disease (22 decks)

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