Microbial Cell Structure and Function Flashcards

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1
Q

Bacterial habitats

A

Terrestrial and aquatic

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2
Q

How do bacteria reproduce? What is the term for this type of reproduction?

A

Reproduce asexually, called binary fission

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3
Q

Size range of bacteria

A

0.3-100 micrometers

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4
Q

Average size of bacteria (E. coli cell)

A

4 micrometers

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5
Q

Thiomargarita size

A

Greater than 100 micrometers

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6
Q

Coccus

A

Spherical shape

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7
Q

Diplococcus

A

Pairs of cocci (spheres)

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8
Q

Streptococcus

A

Chains of cocci (spheres)

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9
Q

Staphylococcus

A

Grape-like clusters of cocci (spheres)

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10
Q

Tetrads

A

4 cocci in square

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11
Q

Bacillus

A

Rod shape

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12
Q

Vibrio

A

Curved rod shape (crescent moon or comma)

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13
Q

Spirillum

A

Rigid helical shape

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14
Q

Spirochete

A

Flexible helical shape

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15
Q

Pleomorphic

A

Variable shape

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16
Q

Hyphae

A

Long filaments formed by some bacteria and many fungi

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17
Q

Mycelium

A

Network of hyphae

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18
Q

Deinococcus genus

A

Form tetrad shape

Radiation resistant

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19
Q

Mycoplasma genus

A

Form pleomorphic shape

Plasma membrane, but no cell wall

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20
Q

Shape of E. coli

A

Bacillus

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21
Q

Surface to volume ratio and size of cells

A

Smaller cells, higher surface to volume ratio

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22
Q

Advantages to small size of bacteria

A

More efficient nutrient uptake

Faster growth

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23
Q

Cell envelope: 3 components

A

Plasma membrane
Cell wall
Layers outside cell wall

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24
Q

Plasma membrane encompasses what?

A

Cytoplasm

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25
Q

Selectively permeable membrane

A

Plasma membrane is selectively permeable

Makes sure that only necessary compounds are brought into cell

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26
Q

Main site of energy generation in bacterial cell

A

Plasma membrane

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27
Q

What structure enables energy generation in plasma membrane?

A

Electron transport chains

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28
Q

Function of transport systems in bacterial cell

A

Bring nutrients into cell

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29
Q

Function of signal transduction systems in plasma membrane

A

Sense and respond to environment

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30
Q

Components of fluid mosaic model of plasma membrane

A
Lipid bilayers (polar heads and nonpolar tails)
Floating proteins
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31
Q

Lipids of bilayer have what type of bonds?

A

Flexible ester bonds

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32
Q

Term for molecules having both polar and nonpolar components

A

Amphipathic

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33
Q

Type of molecules that stabilize plasma membranes of eukaryotes

A

Sterols

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34
Q

Type of molecules that stabilize plasma membranes of bacterial cells

A

Hopanoids (similar to sterols)

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35
Q

Hopanoids are found in what fuel source?

A

Petroleum

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36
Q

Functions of bacterial cell wall

A

Maintain shape

Protection from toxic substances and osmotic lysis

37
Q

Osmosis definition

A

Movement of water from more dilute to more concentrated environment

38
Q

Bacteria are often found in what kind of osmotic solutions?

A

Hypotonic (concentration of solute inside cell is greater than concentration of solute outside cell)

39
Q

Gram positive bacteria stain what color?

A

Purple

40
Q

Gram negative bacteria stain what color?

A

Pink

41
Q

Peptidoglycan: what it makes up and what are its components

A

Makes up cell walls of bacteria
Components: two alternating sugars (N-acetylglucosamine, NAG, and N-acetylmuramic acid, NAM) which are crosslinked by alternating D- and L-amino acids

42
Q

Bond that connects N-acetylglucosamine and N-acetylmuramic acid in peptidoglycan

A

Beta-1,4 glycosidic bond

43
Q

Lysozymes target which part of peptidoglycan?

A

Beta-1,4 glycosidic bond

44
Q

What form are amino acids generally found in? What is the advantage to peptidoglycan having both forms?

A

Amino acids are usually in L-forms

D-forms aren’t usually recognized by enzymes

45
Q

Direct crosslinking of amino acids in peptidoglycan

A

Transpeptidation

Caused by chemical reaction

46
Q

Indirect crosslinking of amino acids in peptidoglycan

A

Peptide interbridges

47
Q

Difference between gram positive and gram negative bacteria

A

Gram positive: thick peptidoglycan wall

Gram negative: thin peptidoglycan wall with outer membrane (lipid bilayer)

48
Q

Periplasmic space

A

Space between plasma membrane and outer membrane

Large in gram negative, but small in gram positive

49
Q

Teichoic acids

A

Polymers of glycerol and ribitol

Provide stability to gram positive cell walls

50
Q

Lipopolysaccharides (LPS): where found

A

Part of outer membrane of gram negative bacteria

51
Q

Porins

A

Molecules in outer membranes of gram negative bacteria

Form pores

52
Q

3 parts of lipopolysaccharides (LPS)

A
Lipid A (embedded in membrane)
Core polysaccharide
O side chain (sticks out)
53
Q

Functions of lipopolysaccharide (LPS)

A

Protection from host defenses
Attachment
Stability

54
Q

What part of lipopolysaccharides (LPS) can vary?

A

O antigens (E.coli O157)

55
Q

Lipid A can perform what function?

A

Endotoxin: causes fever and septic shock

56
Q

Capsules: what are they, what are they made up of, features

A

Layer outside cell wall
Made up of polysaccharides
Organized, not easily removed

57
Q

Slime layers: what are they, what are they made up of, features

A

Layer outside cell wall
Made up of polysaccharides
Diffuse, unorganized, easily removed

58
Q

S layers: what are they, what are they made up of, features

A

Layer outside cell wall
Made up of protein
Organized

59
Q

Do all bacteria have outside layers?

A

No

60
Q

Capsules and S layers are common in what types of organisms?

A

Bacteria (gram positive and negative), Archaea

61
Q

Bacillus anthracis has what type of outside layer?

A

Capsule

62
Q

Outside layer functions

A

Attachment

Protection from chemicals, dessication, bacteriophages, and host immune responses

63
Q

Neisseria meningitidis: what it causes and what type of outside layer it has

A

Bacteria that causes meningitis

Has capsule

64
Q

What is suspended in cytoplasm?

A

Inclusions, chromosome, and ribosomes

65
Q

What is cytoplasm mainly composed of?

A

Water

66
Q

Inclusion function

A

Storage of nutrients

67
Q

Two types of carbon inclusions

A

Glycogen

Poly-beta-hydroxybutyrate (PHB) granules

68
Q

What is poly-beta-hydroxybutyrate (PHB) used to make?

A

Biodegradable plastic

69
Q

Phosphate inclusion

A

Polyphosphate (metachromatic) granules

70
Q

Sulfur inclusion

A

Sulfur globules

71
Q

What type of bacteria has sulfur globules?

A

Thiomargarita

72
Q

Carbon and nitrogen inclusion

A

Cyanophycin granules (chains of amino acids)

73
Q

Gas vacuoles: function

A

Control buoyancy

74
Q

What type of bacteria have gas vacuoles?

A

Cyanobacteria (photosynthetic bacteria)

Aquatic bacteria

75
Q

Magnetosomes: composition and function

A

Inclusions made from magnetite or greigite (iron-containing) chains
Act as magnets, orienting bacteria to north and south, helping them to find nutrients

76
Q

Thylakoids: what type of bacteria have them, and what are they?

A

Cyanobacteria have thlakoids

Photosynthetic membranes that contain clorophyll

77
Q

Carboxysomes: what are they, and what bacteria have them?

A

Microcompartments

Found in Cyanobacteria and other CO2 fixing bacteria

78
Q

Carboxysomes: what shape are they, and what are they composed of?

A

Polyhedral shape

Protein shell

79
Q

What 2 enzymes are inside carboxysomes, and what do they do?

A

Carbonic anhydrase: converts carbonic acid to CO2

RubisCO: adds CO2 to ribulose 1, 5 bisphosphate (RuBP), forming 3-phosphoglycerate (PGA)

80
Q

RubisCO’s reaction is the first key reaction of what process?

A

Calvin cycle: fixing CO2 into carbohydrate

81
Q

CO2 fixation is energy demanding. Where do Cyanobacteria gain the energy for CO2 fixation?

A

Photosynthesis

82
Q

What molecule transcribes DNA into mRNA?

A

RNA polymerase

83
Q

What molecules translate mRNA into protein?

A

Ribosomes

84
Q

In bacteria and archaea, do transcription and translation occur simultaneously or at different times?

A

Simultaneously

85
Q

Nucleoid

A

Region of bacterial cell that contains chromosome

86
Q

Bacterial chromosome features: shape, number per cell, membrane enclosed or not

A

Closed circular dsDNA (some bacteria have linear chromosomes)
Typically 1/cell (some bacteria have more than one)
Not membrane enclosed

87
Q

Plasmids: size/shape, do they replicate with chromosome, what types of genes do they carry

A

Small, closed circular DNA
Exist and replicate independently of chromosome
May carry genes that are advantageous to survival

88
Q

Conjugative plasmid

A

Can be transferred from one bacterium to another

89
Q

R plasmid

A

Conjugative plasmid that confers resistance to antibiotics