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Bacteria cell structures Flashcards

1
Q

define glycoalyx/ capsule

A

gel like layer that adheres to external surface of the cell wall

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2
Q

what is the composition of the glycocalyx/ capsule?

A

polysaccharide (sugar), proteins, or both (glycoprotein)

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3
Q

what is the glycocalyx/ capsule other functions?

A
  1. )capsules protect bacteria cells from dehydration during periods of drying
  2. )capsules create a sticky surface on bacteria cell causing cells to adhere to each other
  3. )capsules mediate adherence of bacteria to host tissue surface aiding bacteria to establish infection
  4. )capsules protect bacteria from phagocytosis or engulfment by phagocytic cells
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4
Q

define phagocytosis

A

cellular “eating”

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5
Q

can some white blood cells carry out phagocytosis?

A

YES

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6
Q

which bacteria is easier to phagocytize?

A

unencapsulated

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7
Q

what does the cell wall’s composition depend on?

A

the bacteria

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8
Q

define peptidoglycan

A

a complex polysaccharide found in the cell wall of most (not all) bacteria

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9
Q

what does peptidoglycan provide?

A

rigidity to help maintain cell shape

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10
Q

what are examples of atypical bacteria?

A
  1. )archaebacteria have a cell wall but lack peptidoglycan (considered the oldest living organism on earth)
  2. )mycoplasma bacteria do NOT have a cell wall (has no definitive shape)
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11
Q

what are the cell wall functions?

A
  1. )Determines the shape of the bacteria cell
  2. )Protects cell from osmotic or water pressure changes
  3. )Holds the cell together and represents the external boundary of the cell
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12
Q

what color is the stain of a gram positive bacteria cell wall stain?

A

purple

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13
Q

what color is the stain of a gram negative bacteria cell wall stain?

A

pink-red

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14
Q

what 3 things do gram positive cell wall consist of?

A
  1. )peptidoglycan layer is 25 nanometers (nm) many layers
  2. )teichoic acid creates links between peptidoglycan layer
  3. )NO outer extra membrane
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15
Q

what 3 things do gram negative cell wall consist of?

A
  1. )peptidoglycan layer is 3 nanometer (nm) single layer
  2. )NO teichoic acid because there is only 1 layer of peptidoglycan
  3. )outer membrane: lipopoly- saccharide(LPS) bilayer
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16
Q

LPS molecule creates __________ membrane

A

selective

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17
Q

LPD can be _______ to animal or human in high quantities

A

TOXIC

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18
Q

can LPS elicit and immune response to help create immunity for future encounters?

A

YES

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19
Q

LPS can make bacteria cell _____ sensitive to certain antibiotics

A

LESS

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20
Q

what effect does penicillin have on the cell wall?

A

interferes with peptidoglycan linkages

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21
Q

what is the peptidoglycan content for gram positive cell wall?

A

80%-90% of cell wall

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22
Q

what is the peptidoglycan content for gram negative cell wall?

A

2%-12% of cell wall

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23
Q

are gram postive cell wall sensitive to penicilin?

24
Q

are gram negative cell wall sensitive to penicilin?

A

typically NO

25
Q

what is the cell membranes composition?

A

60% Protein - 40% Lipid

26
Q

is the phosphate head hydrophilic?

27
Q

hydro=?

28
Q

philic= ?

29
Q

are fatty acid cells hydrophobic?

30
Q

phobc=?

31
Q

pphospholipid bilayer is embedded with ________

32
Q

which part of the phospholipid is facing out and which part is facing inward?

A

phosphate head is facing out because its hydrophilic.

Fatty acid tail is facing inward because its hydrophobic.

33
Q

does penicillin effect mycoplasmas? why or why no?

A

NO. because mycoplasma bacteria do NOT have a cell wall, there is no peptidoglycan to destroy, penicillin can not treat a mycoplasma infection

34
Q

what are the functions of cell membrane?

A
  1. )surrounds cytplasm
  2. )boundary of cell
  3. ) selective membrane
  4. ) anchor DNA molecule (not necessary in eukaryotes because DNA is protected in nucleus)
  5. )site of cell metabolism or ATP production
35
Q

what is the composition of flagellum?

A

long strands of protein

36
Q

what are the functions of flagellum?

A
  1. )used for locomotion

2. )establish infection

37
Q

define positive chemotaxis

A

movement TOWARD a favorable environment such a food source

38
Q

define negative chemotaxis

A

move AWAY from a harmful environment such as a toxic chemicals

39
Q

what is the composition of pilus/ pili?

A

hollow tubes of protein

40
Q

what type of structure is pilus/ pili?

41
Q

does pilus/pili extend from cell?

42
Q

what is pilus/pili function?

A
  1. ) NO role in motility
  2. ) attach bacteria to body tissue
  3. ) “sex” pili allow tranfer of DNA between bacteria cells (conjugation)
43
Q

conjugation represents one way to do what?

A

one way that antibiotic resistance may be transferred between bacteria cells

44
Q

what are the 5 contents of the cytoplasm?

A
  1. )chromosome or DNA molecule
  2. )plasmids
  3. )ribosome
  4. )storage granules
    a) metachromatic granule b)glycogen granule
45
Q

define metachromatic granule

A

store extra phosphate

46
Q

define glycogen granule

A

storage form of glucose

47
Q

what is a plasmid?

A

small extra circular pieces of DNA not part of the main DNA chromosome

48
Q

how plasmind are there per cell?

A

0-100 per bacteria cell

49
Q

what do plasmids encode?

A

useful information such as antibiotic resistance

50
Q

are ribosomes free floating in prokaryote cells?

51
Q

can endospore reproduce?

52
Q

where can Metachromatic Granules be found in?

A

found in the cytoplasm of some bacteria such as the bacteria that cause Diphtheria disease

53
Q

how can endspores be formed?

A

by certain sporm forming bacteria

54
Q

define sporulation

A

reference to the production of 1 spore from 1 vegetative bacteria cell. It is always a 1 to 1 ratio.

55
Q

what initiates spore formation?

A

reduced food supply or adverse environmental conditions

Microbiology (6 decks)

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