Microbial metabolism Flashcards
(113 cards)
1
Q
what is metabolism
A
chemical reactions inside the cell
2
Q
what are exergonic reactions
A
reactions that are spontaneous and release energy
3
Q
what are endergonic reactions
A
reactions that require energy
4
Q
what is anabolism
A
endergonic metabolic pathways involved in biosynthesis, converting simple molecular building blocks into more complex molecules, fuels by the use of cellular energy
5
Q
what is catabolism
A
exergonic pathways that break down complex molecules into simpler ones
6
Q
what pathway releases energy stored in complex molecules
A
catabolic pathways
7
Q
what are autotrophs
A
organisms that convert inorganic carbon dioxide into organic carbon compounds
8
Q
what are examples of autotrophs
A
plants and cyanobacteria
9
Q
what are heterotrophs
A
organisms that rely on organic compounds such as nutrients from autotrophs
10
Q
what is energy derived from
A
the transfer of electrons
11
Q
what are phototrophs
A
organisms that get their energy from light
12
Q
what are chemotrophs
A
organisms that obtain energy for electron transfer by breaking chemical bonds
13
Q
what are orgnotrophs
A
chemothrophs that get energy from organic compounds
14
Q
what are lithotrophs
A
chemotrophs that get energy from inorganic compounds, including hydrogen sulfide and reduced iron
15
Q
example of inorganic carbon chemoautotrophs
A
hydrogen
sulfur
iron
nitrogen
carbon monoxide oxidizing bacteria
16
Q
chemoheterotrophs examples
A
all animals, most fungi, protozoa, and bacteria
17
Q
photoautotroph examples
A
all plants, algae, cyanobacteria, green and purple sulfur bacteria
18
Q
Photoheterotrophs examples
A
Greenland purple non sulfur bacteria, heliobacteria
19
Q
What are oxidation reaction
A
reactions that remove electrons from donor molecules, leaving them oxidized
20
Q
what are reduction reactions
A
reactions that add electrons to acceptor molecules leaving them reduced
21
Q
what is a redox reaction
A
oxidation and reduction reactions happening in tandem
22
Q
how is the energy released from the breakdown of chemical bonds within nutrients stored
A
either electron carriers or in ATP
23
Q
what are electron carriers
A
molecules that bind to and shuttle high-energy electrons between compounds in pathways
24
Q
where do the principle electrons carrier come from
A
the B vitamin group
25
what is the most common mobile electron carrier
NAD+/NADH
26
what is NAD+
the oxidized from of nicotinamide adenine dinucleotide
27
what is NADH
the reduced form of NAD+
28
what is NADP+
nicotine adenine dinucleotide phosphate the oxidized from of an NAD+ that contains an extra phosphate group
29
what is NADP+ when reduced
NADPH
30
what is FAD
the oxidized form of flavin adenine dinucleotide
31
what is the reduced form of FAD
FADH2
32
what are NAD+/ NADH and FAD/FADH2 used in
energy extraction from sugars during catabolism in chemoheterotrophs
33
what are NADP+/NADPH used for
anabolic reactions and photosynthesis
34
what are FADH2, NADH and NADPH referred to
as having reducing power due to their ability to donate electrons to various chemical reactions
35
What molecule is at the heart of ATP
AMP- adenosine monophosphate
36
what is AMP composed of
an adenine molecule bonded to a ribose molecule and a single phosphate group
37
what is ribose
a five carbon sugar found in RNA
38
what is AMP a nucleotide of
RNA
39
what does a second phosphate group added to MAP form
ADP-adenosine diphosphate
40
what does the addition of a 3rd phosphate group added to MAP result in
ATP
41
why is phosphorylation
adding a phosphate group to a molecule
42
how do phosphate groups act in series
they are negatively charged and repel each other
43
what does phosphate repelling each other do to ADP and ATP
it makes them inherently unstable
44
what are the bonds in ADP and ATP called
high-energy phosphate bonds
45
what happens when high-energy bonds are broken to release phosphate
dephosphprylation, energy is released to drive endergonic reactions
46
what is a catalyst
a substance that helps speed up a chemical reactions
47
why are catalysts reusable
they are to used or changed during chemical reactions
48
what are enzymes
proteins that serve as catalysts for biochemical reactions inside cells
49
how do enzymes function
by lowering the activation energy of a chemical reaction in the cell
50
what is activation energy
energy needed to form or break a chemical bond and convert reactants to products
51
how do enzymes lower activation energy
by binding to the reactant molecules and holding them in such a way as to speed up the reaction
52
what are substrates
the chemical reactants to which an enzyme binds
53
what is an active site
the location within the enzyme where the substrate binds
54
what is the match between an enzyme and substrate like
a jigsaw puzzle
55
what happens when an enzyme binds to its substrate
the enzyme structure changes slightly to find the best fit between the transition state and the active site
56
what is induced fit
active-site modification in the presence of substrate with simultaneous formation of the transition state
57
what conditions influence enzymes
PH
substrate concentration
temperature
58
what happens to enzymes when environmental temperature is increased
reaction rate increases, they eventually denature and lose 3d structure and function
59
what happens to enzymes outside the suitable temperature range
chemical bonds in the active site are affected making them less well suited to bind substrates
60
what happens to enzymes at higher concentrations of substrates
activities increase at higher concentrations until ir reaches saturation and no longer bind
61
at what temperature to human pathogen enzymes work best
37C
62
what are the two helper molecules
cofactors and coenzymes
63
what are cofactors
inorganic ions such as iron and magnesium that help stabilize enzyme conformation and function
64
what enzyme requires bound zinc ion to function
DNA polymerase
65
what are coenzymes
organic helper molecules that are required for enzyme action
66
what are the most common sources of coenzyme
dietary vitamins
67
are coenzymes reusable
yes
68
what does coenzyme a do
binds to the enzymes active site aiding in the transition of a substrate to a product
69
what is an apoenzyme
an enzyme lacking a necessary cofactor or coenzyme and is inactive
70
what is a holoenzyme
an Enzyme with the necessary associated cofactor or coenzyme and is active
71
what are other coenzymes that provide high-energy electrons or phosphate groups to bind enzymes
NADH and ATP
72
what is a competitive inhibitor
a molecule similar enough to a substrate that it can compete with the substrate and bind to an active site by blocking the substrate from binding
73
what is required for a competitive inhibitor be effective
the inhibitor concentration needs to be approximately equal to the substrate concentration
74
how do sulfa drugs work
they bind to the active site of an enzyme within bacterial folic acid synthesis pathway prevention folic acid synthesis and bacterial growth
75
what does a noncompetitive inhibitor do
binds to the enzyme at an allosteric site to block substrate binding to the active site
76
how does a noncompetitive inhibitor block substrate
by inducing conformational change that reduces the affinity of the enzyme for its substrate
77
what concentration is needed for noncompetitive inhibitors
lower than substrate concentration
78
what does an allosteric activator do
binds to an enzyme away from the active site inducing conformational change, increasing the affinity of the enzymes active site for its substrate
79
what is feedback inhibition
the use of a pathway product to regulate its own further production
80
What is glycolysis
the most common pathway for the catabolism of glucose for bacteria, eukaryotes and archaea
81
What does glycolysis do
produces energy, reduced electron carriers and precursor molecules for cellular metabolism
82
does glycolysis use oxygen
no
83
where does glycolysis take place
the cytoplasm of cell
84
what does glycolysis begin with
6-carbon glucose molecule
85
what does glycolysis end with
two molecules of a three carbon sugar called pyrubate
86
what does glycolysis using the emp pathway consist of
energy investment phase
energy payoff phase
87
what happens in the energy investment phase of the EMP pathway
energy from two atp molecules modify a glucose so the 6 carbon sugar can be split evenly into two phosphorylated three carbon molecules called glyceraldehyde 3 phosphate
88
what happens during the energy payoff phase of EMP
energy is extracted by oxidizing G3P to pyruvate producing four ATP moleculsing and reducing 2 molecules of NAD+ to two molecules of NADH using electrons from original glucose
89
what do the ATP molecules produced during the energy payoff phase of glycolysis formed by
substrate-level phosphorylation
90
what happens during substrate level phosphorylation
a phosphate group is removed group is removed from an organic molecule and is directly transferred to an available ADP molecule producing ATP
91
what is the net gain from a single glucose molecule during glycolysis
2 ATP
2 NADH
2 pyruvate
92
what is the main glycolysis pathway
EMP pathway, used by animals and many bacteria
93
what is the alternate glycolytic pathway used by many prokaryotes
ED pathway
94
what is the 3rd type of glycolytic pathway that occurs in all cells
PPP
95
what is considered the most ancient universal glycolytic pathway
PPP
96
what are the intermediates from the PPP used for
biosynthesis of nucleotides and amino acids
97
when will the PPP pathway be preferred
when nucleic acid or protein synthesis is needed
98
what must happen for pyruvate to be further oxidized
it must first be decarboxylated
99
what enzyme is required o decarboxylate (transition reaction) pyruvate
pyruvate dehydrogenase
100
describe pyruvate dehydrogenase
a two carbon acetyl group
101
what must pyruvate dehydrogenase attach to
coenzyme a
102
where doe the transition reaction occur
the mitochondrial matrix of eukaryotes and cytoplasm of prokaryotes
103
what does the Krebs cycle do
transfers remaining electrons from the acetyl group produced during the transition reaction to electron carrier molecules reducing them
104
where does the Krebs cycle take place in prokaryotes
cytoplasm
105
what makes the Krebs cycle different from glycolysis
it is a closed loop,
106
what happens in the last step of the Krebs cycle
the compound using in the first step is regenerated
107
what does the kern cycle do
a series of chemical reactions that capture the 2 carbon acetyl group and adds them to a four carbon intermediate producing a 6 carbon intermediate citric acid
108
What does the Kreb cycle produce
2 CO2
1 ATP
3NADH
1 FADH2
109
what can be produced using the Krebs cycle
glucose metabolism
amino acids
chlorophylls
fatty acids
nucleotides
110
is the Krebs cycle anabolic or catabolic
both
111
when does oxidative phosphorylation occur
during cellular respiration
112
how is most ATP generated
oxidative phosphorylation
113
