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Microbiology > Test Two > Flashcards

Test Two Flashcards

1
Q

when is a membrane potential generated

A

chemical or light energy is used to pump protons outside the cell

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2
Q

what type of process is diffusion

A

spontaneous

increase in entropy and negative free energy change

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3
Q

what is group translocation

A

a process that uses energy to chemically alter the substrate during its transport

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4
Q

function of membrane

A

separate what is outside the cell from what is inside

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5
Q

what do denitrifiers do

A

convert nitrate (NO3-) to N2

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6
Q

what is nitrification

A

ammonium to nitrate

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7
Q

what are organotrophs

A

use organic molecules as a source of electrons

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8
Q

what is denitrification

A

nitrate to N2

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9
Q

how does temp affect diffusion

A

increase temp moves molecules faster, faster they arrive at membrane

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10
Q

euglena are what type of trophic

A

mixotrophic

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11
Q

what are autotrophs

A

organisms that assimilate CO2 as a carbon source and reduce it to make complex cell constituents

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12
Q

what are chemoheterotrophs (organotrophs)

A

obtain energy from oxidation of chemicals and obtain C from organic compounds

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13
Q

what are chemoautotrophs

A

obtain energy from oxidizing inorganic molecules such as iron, sulfur or nitrogen. the energy is used to fix CO2 into biomass

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14
Q

what are two coupled transport systems

A

symport and antiport

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15
Q

how does surface area of the membrane affect diffusion

A

an increase in surface area results in an increased likelihood of molecules encountering the membrane

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16
Q

what is a glycerol transporter

A

more like a porin
glycerol or water binds and causes a conformational change, causing top to close and bottom to open to allow glycerol or water to pass through

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17
Q

what are siderophores

A

specialized molecules secreted to bind ferric ion (Fe3+) and transport it into the cell

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18
Q

what can nitrogen fixers do

A

possess enzyme, nitrogenase, which converts N2 to ammonium ions

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19
Q

where is phosphotransferase system is present in

A

all bacteria

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20
Q

is N2 stable

A

highly stable, requires energy to break bonds

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21
Q

what are heterotrophs

A

organisms that use of external sources of organic carbon compounds for biosynthesis

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22
Q

does active transport use energy

A

yes

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23
Q

what are chemoorganoheterotrophs

A

utilizing orgainc election sources

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24
Q

what is facilitated diffusion

A

a process of passive transport across the membrane facilitated by transport proteins
solutes move from high to low concentration

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25
Q

what is antiport

A

two different molecules transported in opposite directions

electroneutral

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26
Q

what is reduced nitrification

A

nitrate to ammonium

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27
Q

what are the two main types of ABC transporters

A

uptake ABC transporter

efflux ABC transporters

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28
Q

what forms an electrochemical potential

A

the hydrogen ion gradient plus the charge difference across the membrane

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29
Q

what is the structure of ABC transporters

A

2 hydrophobic protein that form membrane channel

2 peripheral cytoplasmic proteins that contain a conserved amino acid motif involved in ATP binding

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30
Q

what are chemolithoheterotrophs

A

utilizing inorganic electron sources

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31
Q

what are macronutrients

A

needed in large quantities

major elements in cell macromolecules

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32
Q

what is endocytosis

A

parts of the cell membrane bud into the cytoplasm and eventually separate from it to form endosomes

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33
Q

what are solute or substrate binding protein

A

in ABC transporter structure
extracytoplasmic protein that binds to substrate
“recruits”

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34
Q

how does concentration gradient of the dissolved solute affect diffusion

A

a larger gradient speeds up diffusion because the more molecules there are, the more will encounter the membrane and cross it

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35
Q

what are phototrophs

A

organisms that obtain energy from chemical reactions triggered by the absorption of light

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36
Q

how will thickness of the membrane affect diffusion

A

diffusion rates are inversely proportional to the square of the distance the solute must travel across the membrane
thinner means faster diffusion

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37
Q

what do nitirifiers do

A

oxidize ammonium (NH4+) to nitrate (NO3-)

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38
Q

based on niche, microbes have required additional what

A

growth factors

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39
Q

what are lithotrophs

A

use inorganic molecules as a source of electrons

40
Q

in gram neg organism, where are solute or substrate binding proteins

A

float in the periplasmic space between the inner and outer membrane

41
Q

all of earth’s life forms are based on…

A

carbon

42
Q

hypotonic environment

A

net uptake of water by cell

cell swells and cell components are diluted

43
Q

what is a membrane potential

A

energy stored by an electrical potential across a membrane

44
Q

what are cofactors

A

small molecules that fit into specific enzymes and aid in catalysis

45
Q

is coupled transport system active transport

A

yes

46
Q

how does the mass of molecule affect diffusion

A

friction between molecule and its medium is a source of resistance that slows down motion
large molecules move slow across membrane

47
Q

what are photoheterotrophs

A

obtain energy via light absorption and obtain carbon from organic compounds

48
Q

how do siderophores reduce iron

A

enzymes reduce it to more soluble forms

49
Q

what is diffusion

A

net movement from an area of high concentration to low concentration

50
Q

what molecules are impermeable to membrane

A

large,uncharged polar molecules

ions

51
Q

what are essential nutrients

A

compounds that a microbe cannot make itself but must gather from its environment

52
Q

isotonic environment

A

equal concentrations of solute inside and outside of cell

water enters and exits cell at equal rates

53
Q

where do nitrogen fixing bacteria live

A

free-living in soil or water, or they may for symbiotic associations with plants

54
Q

how does the nitrogen cycle work

A

N2, nitrogen fixers, ammonium, nitrifiers, nitrate, denitrifiers then N2

55
Q

what does ABC transporter stand for

A

ATP binding cassette

56
Q

what is uptake ABC transporters used for

A

transporting nutrients

57
Q

what are chemotrophs

A

obtain energy from oxidation-reduction reactions that transfer electrons from high energy compounds to make products of lower energy

58
Q

what molecules are slightly permeable

A

small, uncharged polar molecules

59
Q

algae are what type of trophs

A

photoautotrophs that produce biomass through photosynthesis

60
Q

what is exocytosis

A

intracellular vesicles fuse with the cell membrane and the contents are released to the environment

61
Q

what is mixotrophic

A

some organisms have than one type of metabolism

auto and heterotrophic

62
Q

what are symbionts

A

an organism that lives in intimate association with a second organism

63
Q

what is phagocytosis

A

cell eating; large extracellular particles are brought into cell

64
Q

hypertonic environment

A

net loss of water from cell to environment , cell shrinks and cell components are concentrated

65
Q

how does phosphotransferse system work

A

uses energy from phosphoenolpyruvate to attach a phosphate to a specific sugar
accommodates different substrates

66
Q

what molecules are freely permeable

A

hydrophobic molecules

o2, co2, n2

67
Q

what kind of transport does eukaryotes use

A

endocytosis, phagocytosis, pinocytosis, exocytosis

68
Q

what are some macromolecules in microbes

A

carbohydrates, lipids, nucleic acids, and proteins in cells

ions for protein function such as mg2+, Fe2+, K+, Ca2+

69
Q

where do siderophores release iron

A

released into the cytoplasm and reduced to ferrous form (Fe2+)

70
Q

what is pinocytosis

A

cell drinkinig; endocytocis of small volumes of extracellular fluid

71
Q

how does solubility of molecules in the membrane affect diffusion

A

hydrophobic molecules will dissolve in membrane

72
Q

what are photoautotrophs

A

obtain energy via light absorption by the photolysis of H2), H2S etc. The energy used to fix CO2 into biomass

73
Q

what are micronutrients

A

trace elements necessary for enzyme function

Co, Cu, Mn, Mo, Ni, Zn

74
Q

what is electrochemical energy

A

energy stored in the form of an electrical potential existing between compartments separated by a membrane

75
Q

when is active transport used

A

environments in which nutrient concentrations are low (aquatic systems)
environments where competition is high (soil systems)

76
Q

what is owed towards the plasticity of microbial genomes

A

through evolution, bacteria have evolved ingenious strategies to find, acquire, and metabolize a wide assortment of food sources

77
Q

where do you see siderophores

A

in all domains of life

78
Q

what is osmosis

A

diffusion of water across selectively permeable membrane from regions of high water concentration to regions of low water concentration

79
Q

what is chemical energy

A

energy stored in high energy phosphate bond in ATP

80
Q

eukaryotic microbes are what kind of trophic consumer

A

heterotrophic

81
Q

is phosphotransferase active transport

A

yes, still uses energy

82
Q

what is efflux ABC transporters used for

A

multidrug efflux pump

pump anitbiotic out of cell, pump toxic out of cell

83
Q

is Fe(OH)3 available for transport

A

no

84
Q

electrochemical potential is also called

A

proton potential

proton motive force

85
Q

what makes up 78% of earth’s atmosphere but is unavailable for use by most organisms

A

N2

86
Q

Chemoheterotrophs are subdivided into

A

chemolithoheterotrophs

chemoorganoheterotrophs

87
Q

in gram pos orgnanism, where are solute or substrate binding proteins

A

lack outer membrane, the proteins are tethered to the cell surface

88
Q

what are coupled transport systems

A

those systems that harness free energy from moving an ion down its concentration gradient (from high to low) to drive the transport of another solute up or against its concentration gradient

89
Q

what is an electrogenic process

A

unequal distribution of charge

90
Q

what is axenic growth

A

growth outside of host cells

91
Q

what is stored energy used for

A

to directly move nutrients in the cell via transport proteins
used to drive flagella motors
drive ATP synthesis

92
Q

what are two forms of energy

A

chemical

electrochemical

93
Q

how is selective permeability achieved

A
  1. substrate specific carrier proteins
  2. dedicated nutrient binding proteins that patrol the periplasmic space
  3. membrane spanning protein channels or pores
94
Q

what type of iron is in most cells for nutrients

A

Fe(OH)3

95
Q

what is the largest family of energy driven transport systems

A

ABC transporters

96
Q

what is symport

A

two different molecules transported in same direction

electrogenic process

97
Q

what is a defined mineral medium

A

medium that contains only those compounds needed for an organism to grow

Microbiology (16 decks)

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