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Test Two Flashcards

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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
what is antiport
two different molecules transported in opposite directions | electroneutral
26
what is reduced nitrification
nitrate to ammonium
27
what are the two main types of ABC transporters
uptake ABC transporter | efflux ABC transporters
28
what forms an electrochemical potential
the hydrogen ion gradient plus the charge difference across the membrane
29
what is the structure of ABC transporters
2 hydrophobic protein that form membrane channel | 2 peripheral cytoplasmic proteins that contain a conserved amino acid motif involved in ATP binding
30
what are chemolithoheterotrophs
utilizing inorganic electron sources
31
what are macronutrients
needed in large quantities | major elements in cell macromolecules
32
what is endocytosis
parts of the cell membrane bud into the cytoplasm and eventually separate from it to form endosomes
33
what are solute or substrate binding protein
in ABC transporter structure extracytoplasmic protein that binds to substrate "recruits"
34
how does concentration gradient of the dissolved solute affect diffusion
a larger gradient speeds up diffusion because the more molecules there are, the more will encounter the membrane and cross it
35
what are phototrophs
organisms that obtain energy from chemical reactions triggered by the absorption of light
36
how will thickness of the membrane affect diffusion
diffusion rates are inversely proportional to the square of the distance the solute must travel across the membrane thinner means faster diffusion
37
what do nitirifiers do
oxidize ammonium (NH4+) to nitrate (NO3-)
38
based on niche, microbes have required additional what
growth factors
39
what are lithotrophs
use inorganic molecules as a source of electrons
40
in gram neg organism, where are solute or substrate binding proteins
float in the periplasmic space between the inner and outer membrane
41
all of earth's life forms are based on...
carbon
42
hypotonic environment
net uptake of water by cell | cell swells and cell components are diluted
43
what is a membrane potential
energy stored by an electrical potential across a membrane
44
what are cofactors
small molecules that fit into specific enzymes and aid in catalysis
45
is coupled transport system active transport
yes
46
how does the mass of molecule affect diffusion
friction between molecule and its medium is a source of resistance that slows down motion large molecules move slow across membrane
47
what are photoheterotrophs
obtain energy via light absorption and obtain carbon from organic compounds
48
how do siderophores reduce iron
enzymes reduce it to more soluble forms
49
what is diffusion
net movement from an area of high concentration to low concentration
50
what molecules are impermeable to membrane
large,uncharged polar molecules | ions
51
what are essential nutrients
compounds that a microbe cannot make itself but must gather from its environment
52
isotonic environment
equal concentrations of solute inside and outside of cell | water enters and exits cell at equal rates
53
where do nitrogen fixing bacteria live
free-living in soil or water, or they may for symbiotic associations with plants
54
how does the nitrogen cycle work
N2, nitrogen fixers, ammonium, nitrifiers, nitrate, denitrifiers then N2
55
what does ABC transporter stand for
ATP binding cassette
56
what is uptake ABC transporters used for
transporting nutrients
57
what are chemotrophs
obtain energy from oxidation-reduction reactions that transfer electrons from high energy compounds to make products of lower energy
58
what molecules are slightly permeable
small, uncharged polar molecules
59
algae are what type of trophs
photoautotrophs that produce biomass through photosynthesis
60
what is exocytosis
intracellular vesicles fuse with the cell membrane and the contents are released to the environment
61
what is mixotrophic
some organisms have than one type of metabolism | auto and heterotrophic
62
what are symbionts
an organism that lives in intimate association with a second organism
63
what is phagocytosis
cell eating; large extracellular particles are brought into cell
64
hypertonic environment
net loss of water from cell to environment , cell shrinks and cell components are concentrated
65
how does phosphotransferse system work
uses energy from phosphoenolpyruvate to attach a phosphate to a specific sugar accommodates different substrates
66
what molecules are freely permeable
hydrophobic molecules | o2, co2, n2
67
what kind of transport does eukaryotes use
endocytosis, phagocytosis, pinocytosis, exocytosis
68
what are some macromolecules in microbes
carbohydrates, lipids, nucleic acids, and proteins in cells | ions for protein function such as mg2+, Fe2+, K+, Ca2+
69
where do siderophores release iron
released into the cytoplasm and reduced to ferrous form (Fe2+)
70
what is pinocytosis
cell drinkinig; endocytocis of small volumes of extracellular fluid
71
how does solubility of molecules in the membrane affect diffusion
hydrophobic molecules will dissolve in membrane
72
what are photoautotrophs
obtain energy via light absorption by the photolysis of H2), H2S etc. The energy used to fix CO2 into biomass
73
what are micronutrients
trace elements necessary for enzyme function | Co, Cu, Mn, Mo, Ni, Zn
74
what is electrochemical energy
energy stored in the form of an electrical potential existing between compartments separated by a membrane
75
when is active transport used
environments in which nutrient concentrations are low (aquatic systems) environments where competition is high (soil systems)
76
what is owed towards the plasticity of microbial genomes
through evolution, bacteria have evolved ingenious strategies to find, acquire, and metabolize a wide assortment of food sources
77
where do you see siderophores
in all domains of life
78
what is osmosis
diffusion of water across selectively permeable membrane from regions of high water concentration to regions of low water concentration
79
what is chemical energy
energy stored in high energy phosphate bond in ATP
80
eukaryotic microbes are what kind of trophic consumer
heterotrophic
81
is phosphotransferase active transport
yes, still uses energy
82
what is efflux ABC transporters used for
multidrug efflux pump | pump anitbiotic out of cell, pump toxic out of cell
83
is Fe(OH)3 available for transport
no
84
electrochemical potential is also called
proton potential | proton motive force
85
what makes up 78% of earth's atmosphere but is unavailable for use by most organisms
N2
86
Chemoheterotrophs are subdivided into
chemolithoheterotrophs | chemoorganoheterotrophs
87
in gram pos orgnanism, where are solute or substrate binding proteins
lack outer membrane, the proteins are tethered to the cell surface
88
what are coupled transport systems
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
what is an electrogenic process
unequal distribution of charge
90
what is axenic growth
growth outside of host cells
91
what is stored energy used for
to directly move nutrients in the cell via transport proteins used to drive flagella motors drive ATP synthesis
92
what are two forms of energy
chemical | electrochemical
93
how is selective permeability achieved
1. substrate specific carrier proteins 2. dedicated nutrient binding proteins that patrol the periplasmic space 3. membrane spanning protein channels or pores
94
what type of iron is in most cells for nutrients
Fe(OH)3
95
what is the largest family of energy driven transport systems
ABC transporters
96
what is symport
two different molecules transported in same direction | electrogenic process
97
what is a defined mineral medium
medium that contains only those compounds needed for an organism to grow

Microbiology (16 decks)

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