5: Microbial Metabolism Flashcards
1
Q
energy in temporarily trapped in these high-energy bonds. “transient ephemeral”
A
phosphate-phosphate bond
2
Q
combine simpler substances into more complex molecules. requires energy
A
anabolic reaction
3
Q
breaks down complex organic compounds into simpler ones. releases energy
A
catabolic reaction
4
Q
ATP
A
adenosine triphosphate
5
Q
cavities (tooth decay)
A
dental caries
6
Q
what happens to the majority (60%) of energy released during catabolic processes
A
lost as heat
7
Q
Where are enzymes manufactured?
A
ribosomes > rough ER > subunits made in nucleus
8
Q
How do enzymes lower activation energies?
A
by properly aligning colliding molecules of substrate so they react more easily
9
Q
Name of the enzyme that breaks down penicillin
A
betalactimase, penicillinase
10
Q
allows some microorganisms to grow in or on the human body (i.e. dental plaque)
A
microbial metabolism
11
Q
proteins that act as catalysts in chemical reactions of importance to the cell
A
enzymes
12
Q
a substance that speeds up a reaction without being changed by it
A
catalyst
13
Q
the energy transferred by the particles in the collision can disrupt chemical bonds or form new chemical bonds
A
collision theory
14
Q
enzymes decrease the energy required to trigger the reation
A
reduce activation energy
15
Q
the “raw material” that will be transformed by the enzyme
A
substrate
16
Q
cephalosporins, carbapenems, penicillin, monobactam, etc.
A
beta-lactam antibiotics
17
Q
genes for beta-lactamases
A
R factors
18
Q
Where are the beta-lactamase R factors located in the bacteria? How are they transferred from bacteria to bacteria? Where in the body does this take place?
A
located on the plasmids, transferred by conjugation via sex pili, takes place in the large intestine
19
Q
diverse group of beta-lactamases produced by bacteria that are active against cephalosporins, carbapenems, and other antibiotics
A
carbapenemases
20
Q
NDM-1
A
New Delhi metallo-beta-lactamase
21
Q
example of carbapenemase that provides resistance to many antibiotics
A
NDM-1 (New Delhi metallo-beta-lactamase)
22
Q
protein portion of an enzyme
A
apoenzyme
23
Q
nonprotein portion of an enzyme
A
cofactor
24
Q
what can be a cofactor?
A
metal ion or coenzyme
25
complex organic molecule often derived from vitamins that serve as a cofactor
coenzyme
26
Name 3 coenzymes
NAD, FAD, CoA
27
Full name of NAD and what vitamin it is derived from
nicotinamide adenine dinucleotide, derived from niacin
28
Full name of FAD and what vitamin it is derived from
flavin adenine dinucleotide, derived from riboflavin
29
Full name of CoA and what vitamin it is derived from
Coenzyme A, derived from panthothenic acid
30
which coenzyme's job is to transport H+ ions and electrons like a 'taxicab'?
NAD
31
when both the cofactor and apoenzyme are combined into their active form, name for the whole enzyme
holoenzyme
32
acts as an anticoagulant by binding up the cofactor calcium needed for clotting enzyme activity
sodium citrate
33
Why isn't it dangerous to give patients blood units that contain sodium citrate?
living people metabolize sodium citrate, making it a reversible anticoagulant
34
The substrate contacts "_____" of enzyme propelled by "______"
acitve site, brownian motion
35
The _____ of enzyme reactions is due to the 3D shape of the active site.
specificity
36
4 factors influencing enzyme activity
temperature, pH, substrate concentrations, and inhibitors
37
How does temperature influence enzyme activity?
increased temperature causes increased brownian motion, causing increased enzyme activity and visa versa. Denaturation can occur at high temperatures.
38
How does high heat cause denaturation of enzymes?
it breaks bonds in the protein, causing loss of 3D shape, and inability to bind with substrate
39
Can you freeze human cells to preserve them?
yes, but not in water, because it forms ice crystals that rupture the cell membranes
40
what can you freeze human cells in to preserve them?
glycerol, it doesn't form ice crystals
41
medical condition that results from ice crystals forming in the tissues
frostbite
42
What happens to enzyme activity is pH rises or falls?
the enzymes will be denatured
43
When does substrate concentration stop increasing enzymatic activity?
saturation of active sites (most enzymes in living cells are not saturated)
44
2 categories of inhibitors
competitive inhibitors and noncompetitive inhibitors
45
competes for active site
competitive inhibitor
46
competitive inhibitors have what effect that may be reversible or nonreversible?
bacteriostatic
47
don't actively kill bacteria, just stops them from growing
bacteriostasis
48
an antibacterial agent that inhibits the normal reaction of PABA being converted to folic acid
sulfanilamide
49
PABA
para-aminobenzoic acid
50
Why doesn't sulfanilamide harm humans?
because human cells do not use PABA to make their folic acid, sulfanilamide inhibits bacteria but does not harm human cells
51
Is the effect of sulfanilamide reversible?
yes, some sunscreen lotions contain PABA
52
Which is the proper substrate for bacterial growth, PABA or sulfanilamide?
PABA
53
Which is the competitive analog that prevents bacterial growth, PABA or sulfanilamide?
sulfanilamide
54
When should bacteriostatic agents (such as sulfanilamide) NOT be used?
on immunocompromised patients
55
pH of human blood
7.4 (slightly alkaline)
56
may change the shape of the enzyme or may bind up an essential cofactor
noncompetitive inhibitors
57
type of noncompetitive inhibitor that acts on the enzyme to alter shape of the active site
allosteric inhibition
58
nerve gas
permanent noncompetitive allosteric enzymatic inhibition of the enzymes in the nervous system
59
what type of inhibitor is sodium citrate?
noncompetitive inhibitor (non-allosteric)
60
noncompetitive inhibitor that binds to iron in iron containing enzymes
cyanide
61
noncompetitive inhibitor that binds to calcium or magnesium
fluoride
62
noncompetitive inhibitor that binds to calcium
sodium citrate
63
reversible regulatory process done in cell when the end product accumulates and then inhibits the starting enzyme through "reversible allosteric noncompetitive inhibition". as the cell uses up the existing end product, the first enzyme's allosteric site more often remains unbound and pathway resumes activity
feedback inhibition
64
the addition of oxygen to a molecule or the removal of electrons from a molecule
oxidation
65
oxidation reaction where two electrons and two hydrogen ions are removed at the same time
dehydrogenation
66
the loss of an oxygen molecule or molecule picks up the electrons ( and H+ that typically travel with them)
reduction
67
oxidation coupled to a reduction reaction
oxidation-reduction reactions
68
usually an energy producing reaction
oxidation
69
energy released during oxidation reactions is trapped in ATP by what process?
phosphorylation (addition of a phosphate to ADP)
70
series of redox reactions that efficiently extract energy from organic compounds
biochemical pathway
71
to produce energy from glucose, microorganisms use what two general processes?
cellular respiration and fermentation
72
this entire process can be thought of as involving a flow of electrons from the energy-rich glucose molecule to the relatively energy-poor CO2 and H2O molecules
cellular respiration
73
Another name for glycolysis
Embden-Myerhof pathway
74
oxidation of glucose to pyruvic acid
glycolysis
75
beginning reactions of both respiration and fermentation
glycolysis
76
In glycolysis, there is a net gain of _____ for each molecule of glucose oxidized
2 ATP
77
Glycolysis is ________ on the presence of oxygen
not dependant
78
NAD is ______ to become NADH
reduced
79
Pyruvic acid produced by glycolysis can undergo further degradation by what two pathways?
respiration or fermentation
80
Where does glycolysis take place in prokaryotes? eukaryotes?
occurs in the cytoplasm for both
81
an ATP-generating process in which chemical compounds are oxidized and the final electron acceptor is almost always an inorganic molecule (O2, SO4 2-, NO3 2-, etc)
respiration
82
respiration where the terminal electron and hydrogen acceptor is oxygen
aerobic respiration
83
respiration where the terminal electron and hydrogen acceptor is typically an inorganic molecule other than oxygen
anaerobic respiration
84
"preparatory step" of aerobic respiration (other name)
transition reaction
85
The ________ requires that the pyruvic acids be converted to _______
transition reaction, acetyl groups (2C)
86
(in the transition reaction) the removed carbon molecules are released as carbon dioxide, a process referred to as ________
decarboxylation
87
how many carbon dioxide molecules are released in the transition reaction?
2
88
(in the transition reaction) ___ molecules of ______ are produced when the acetyl groups are formed. each of the acetyl groups then binds to a _______. The resulting complex is known as ________. These groups are then ready to enter the _________.
2 NADH, coenzyme A, acetyl coenzyme A, krebs cycle
89
How many molecules of CO2 gas are generated in glycolysis?
NONE!
90
Where does the transition reaction take place in prokaryotes? eukaryotes?
prokaryotes=cytoplasm, eukaryotes=mitochondrion
91
series of chemical reactions in which the chemical energy in the two carbon acetyl groups is released step by step
krebs cycle/citric acid cycle
92
As the krebs cycle proceeds the carbons in the _____ are removed and released as ______
2 acetyl groups, 4 CO2
93
How many ATP are produced directly by the krebs cycle as the acetyl groups are processed?
2 ATP
94
in the krebs cycle, most of the stored chemical energy released during the oxidation process is transferred via _____ to the coenzymes ____ and _____.
electrons and hydrogen ions, NAD, FAD
95
The processing of the two acetyl groups in the krebs cycle results in the production of _____ and _____
6 NADH and 2 FADH2
96
Where does the krebs cycle take place in prokaryotes? eukaryotes?
prokaryotes=inner surface of the plasma membrane and in the cytoplasm. eukaryotes=mitochondra
97
consists of a sequence of carrier molecules (cytochromes) that pass electrons from one to another, creating a stepwise release of energy, and ATP is generated
electron transport chain
98
one NADH processed by the electron transport chain will cause the production of ______
3 ATP
99
one FADH2, which enters the electron transport chain one step lower than NADH, will cause the production of _____
2 ATP
100
aerobic respiration results in _____ being indirectly produced in the electron transport chain
34 ATP
101
aerobic respiration produces a net gain of ______ for the prokaryotic cell
38 ATP
102
aerobic respiration produces a net gain of _____ for the eukaryotic cell
36 ATP
103
Where is sodium citrate metabolized?
krebs cycle, citric acid cycle
104
iron containing enzymes (iron cofactor)
cytochrome
105
Why do microbes get more energy from aerobic respiration than eukaryotic cells?
microbes dont have mitochondria, so they don't have to use 2 ATP for the mitochondria to transport electrons
106
In aerobic respiration, the terminal electron acceptor is oxygen, which is converted to water. This results in the production of what?
300-500ml of metabolic water daily
107
Where does the electron transport chain take place in prokaryotes? eukaryotes?
plasma membrane, mitochondria
108
What type of enzyme inhibition does cyanide use?
irreversible noncompetitive inhibition
109
Cyanide works by binding up _____, an essential cofactor needed by ________.
iron, cytochrome enzyme
110
Why does cyanide kill you instantly?
lose all ATP except from glycolysis, can't support brain and heart energy need, lack of high energy phosphate bonds
111
what is capable of anaerobic respiration
a few bacteria
112
which typically has a higher yield of ATP, anaerobic or aerobic respiration?
aerobic respiration
113
which organisms typically grow slower, anaerobic or aerobic? why?
anaerobic, due to lower yield of ATP in respiration
114
continuation of glycolysis which by passes the krebs cycle and the electron transport chain
fermentation
115
provides a way for the NADH generated in glycolysis to be recycled to NAD without the use of electron transport chain (respiration)
fermentation
116
2 types of fermentation
lactic acid fermentation and alcoholic fermentation
117
In lactic acid fermentation, what acts as the final electron acceptor from NADH?
pyruvic acid (an organic molecule)
118
In lactic acid fermentation, after pyruvic acid receives the H ions and electrons, the _____ is regenerated and the pyruvic acid is transformed into _____.
NAD, lactic acid
119
In alcoholic fermentation, pyruvic acid first has ___ molecule of _____ removed and released as ____
one CO2 gas
120
two carbon acetyl group
acetaldehyde
121
In alcoholic fermentation, what acts as the terminal electron acceptor from NADH?
acetaldehyde (two carbon acetyl group)
122
In alcoholic fermentation, after acetaldehyde receives the H ions and electrons, the _____ is regenerated and the acetyl group is transformed into _____.
NAD, ethanol
123
baker's yeast, brewer's yeast
saccharomyces cerevisiae
124
How many ATP are produced in fermentation?
none, only 2ATP produced in the initial reactions of glycolysis are gained
125
Aerobic respiration directly produces ____ATP, indirctly produces ___ ATP in prokaryotes, and _____ ATP in eukaryotes
4, 34, 32
126
skeletal muscles can still survive on this for about 2 hours after the heart and brain are dead. also how we can still contract muscles even with reduced O2
lactic acid fermentation
127
reversible once O2 is available.
lactic acid fermentation
128
How do you break down lactic acid once O2 is available?
by breathing hard. once your breathing is slowed, the lactic acid is gone
129
Why is alcohol carbonated?
release of CO2 gas from pyruvic acid
130
What makes bread rise?
CO2 gas released from the breakdown of pyruvic acid to acetaldehyde during alcohol fermentation. The alcohol evaporates out of the dough as the bread is baked
131
Why do you die from suffocation?
lack of terminal electron and hydrogen acceptor, lack of high energy phosphate bonds
132
How many ATP are lost due to suffocation?
32 from electron transport chain and 2 from transition step = 34 ATP total
133
Why does suffocation take longer than cyanide to kill you?
you can still use residual O2 as final electron and H acceptor. cyanide inhibits cytochrome instatly, regardless of how much O2 is available
