Exam 1 9/11 Nguyen Micro Flashcards
(122 cards)
1
Q
All known life on earth is:
A
carbon-based
2
Q
Autotrophs
A
self feeders; making of own food by reducing CO2
3
Q
Heterotrophs
A
cannot make their own food from CO2; must obtain food from outside sources (eating something else)
4
Q
Photoautotrophs
A
Use light and CO2 to make food
5
Q
Examples of photoautotrophs
A
Photosynthetic bacteria (green and purple sulfur), cyanobacteria, algae
6
Q
Chemoautotrophs
A
Use chemicals (inorganic compounds) as reducing agents and CO2 to make food
7
Q
What inorganic compounds can chemoautotrophs use to make food?
A
Hydrogen sulfide, sulfur, ammonium, ferrous ion
8
Q
True or false: chemoautotrophs require light to make food
A
False
9
Q
All human pathogens are:
A
heterotrophs
10
Q
Chemoheterotrophs another name
A
Organoheterotrophs
11
Q
Chemoheterotrophs cannot use ____ to make organic compounds; they must use ______
A
CO2; ready-made carbon (eating other organisms)
12
Q
Photoheterotrophs
A
Use light and ready-made carbon to make organic molecules
13
Q
Chemoheterotrophs
A
Use chemicals and ready made carbon to make organic molecules
14
Q
Examples of photoheterotrophs
A
Purple and green nonsulfur bacteria
15
Q
Examples of chemoheterotrophs
A
most bacteria, all protozoans, all fungi, all animals
16
Q
What organism is limited by available O2?
A
obligate aerobes; tend to settle at top of test tube with lots of oxygen around
17
Q
What bacteria are not limited by available O2?
A
Obligate anaerobes; tend to settle at bottom of test tube with no oxygen around
18
Q
Which bacteria grows in presence or absence of O2?
A
Facultative anaerobes; dispersed throughout test tube, but more towards the top
19
Q
Microaerophile
A
Low O2
20
Q
True or false: all oral bacteria are towards the surface of the gums so they can be brushed away
A
False - some are anaerobes so they are found in pockets away from where you brush
21
Q
When there is inflammation in a periodontal pocket, it is difficult for ____ to get in
A
saliva
22
Q
Which anaerobic bacteria is associated with periodontal pockets?
A
Fusobacterium nucleatum
23
Q
F. nucleatum tolerates up to ___% oxygen
A
6%
24
Q
Mesophiles are found between what temperatures?
A
25-40 celcius
25
Most medically important class of bacteria
Mesophiles
26
Neutral pH
6.5-7.0
27
Acidophiles
Like acidic environment or can make acid; tolerate as low as 1.0
28
Halophiles
High osmolarity; found in brine or pickle, very salty environments
29
Important inorganic ion, often limited in supply
Iron
30
Bacterial iron sequestration protein
Siderophores
31
Human iron ions binding and transport proteins
Lactoferrin
32
Where is lactoferrin found?
saliva, tears, bile, pancreas, breast milk
33
Lactoferrin is considered an _______
Antimicrobial (if we are taking the iron, bacteria can't use it)
34
How does siderophore sequester iron?
Secreted from bacteria, binds on to iron, then docks back onto the bacterial cell via receptor site
35
Major essential elements
CHONPS, K, Mg, Ca, Fe, Na, Cl
36
Minor essential elements
Zn, Mn, Mo, Se, Co, Cu, Ni, W
37
What enzyme do bacteria secrete to break down sucrose?
Sucrase
38
What enzyme do bacteria secrete to break down lactose?
Lactase
39
True or false: bacterial enzymes can remove glucose monomers from starch and glycogen
True
40
What carbohydrates serve as carbon sources for bacteria?
Sucrose, lactose, starch and glycogen
41
Main method of nutrient transport for bacteria
Active transport (ATP/proton pumps, permeases)
42
Active transport requires _____
energy (against conc gradient)
43
Growth phases of bacteria
1. Lag
2. Log
3. Stationary
4. Death/decline
44
Lag phase
adaptation; getting ready to grow, feeling out the environment, figuring out what genes to turn on
45
Log phase
rapid cell division when excess nutrients are available
46
During which growth phase would penicillin be most effective?
Log phase (since new cell walls are being built)
47
Stationary phase
Balance on nutrients/toxins
48
Death/decline
nutrient deficit, toxin buildup
49
What type of growth do we see when 2 or more substrates are present?
Biphasic/diauxic growth
50
Two growth phases in biphasic growth
1. primary growth
2. secondary growth
(separated by a short lag phase)
51
Describe primary growth during biphasic growth
Breaks down sucrose to use glucose as preferred metabolite
52
Why does a lag phase occur during biphasic growth?
1st substrate is depleted, cellular machinery makes alternate enzymes
53
Secondary growth uses preferred or alternative metabolite?
Alternative
54
What is broken down during secondary growth?
Lactose
55
What occurs during binary fission?
DNA replication, septum formation
56
Doubling time
Generation time; varies by species, can be minutes, hours, days
57
Bacterial cell replication steps
1. chromosome duplication
2. mesosome formation - cytoplasmic membrane anchor for chromosome
3. cell membrane involution
4. cell wall completion using transpeptidase enzyme
58
When there is high cell density of bacteria, they can exhibit group behavior as:
biofilm
59
Biofilm may secrete:
Autoinducers --> can be more virulent, turn on more genes, more siderophores
60
What triggers autoinduction of bacteria?
High numbers of bacterial cells
61
Examples of group bacterial behavior responses
Operons or PAI (pathogen associated islands), proteases, virulence factors, siderophores
62
How do bacteria know when to stop growing?
Starvation, buildup of toxic products triggers alarmones to stop growth
63
Growth regulation methods
quorum sensing and autoinduction, changes in temp and pH, too much waste, depletion of food
64
Bacteria use ____ to regulate peptidoglycan growth
D-amino acids
(signals growth inhibition and move to stationary phase)
65
True or false: If bacteria sense that they need to slow down growth, they use L amino acids instead of D
False - they use D amino acids in place of L
66
Bacteriostatic agent
Limits binary fission in stationary phase
67
Bacteriocidal agent
Kills or destroys bacteria, leading to death phase
68
Endospores are usually formed by gram ___ bacteria
Gram positive bacteria
69
When do bacteria form endospores?
Nutrient deprivation
70
How many spores are formed in sporylation?
1 spore
71
Spores can lay dormant for:
Years
72
Spores are resistant to:
Heat, dehydration, radiation, chemicals
73
True or false: endospores are metabolically active
False - metabolically inert
74
What occurs during sporulation?
1. chromosome replication
2. minimal cytoplasm
3. cell membrane separation, peptidoglycan
4. dipicolinic acid Ca2+ chelator (calcium dipicolinate
75
Structure of endospore - name the layers
76
Which bacteria are endospores commonly made by?
Bacillus, Clostridium
77
Cortex of endospore is made of:
peptidoglycan, dipicolinic acid, calcium
78
Growth assays methods
1. wet mounts (slides)
2. culture (plates)
3. turbidity (solutions)
79
Complex media contains:
carbon sources, water, various salts, source of nitrogen and amino acids
80
Minimal media
Contains minimal materials for bacterial growth - one selecting agent (particular sugar or amino acid)
81
Minimal media selects for:
Particular microbes
82
Selective media
Growth/selection of select microorganisms
83
Eosin-methylene blue agar (EMB) selective for
Gram - bacteria
84
Mannitol Salt Agar (MSA) selective for
Gram+ bacteria
85
Blood agar selective for
hemolytic Streptococcus
86
Differential media
Distinguishes 1 type of microorganism from another growing on the same media
87
Eosin-methylene blue agar (EMB) is differential for
Lactose and sucrose fermentation
88
Mannitol Salt Agar is differential for
Mannitol fermentation
89
MacConkey Agar differential for
Lactose fermentation
90
On MCK agar, lactose fermenting colonies will be:
Pink
91
MCK is selective for:
Gram - bacteria
92
When ATP is hydrolyzed to form ADP + inorganic phosphate, how much energy is released?
30.5 kJ
93
Where does cellular respiration occur in prokaryotes?
Cell membrane (no mitochondria)
94
Catabolism substrates
sugars, proteins, lipids
95
Anaerobic reactions
Fermentation - makes pyruvate, no TCA cycle. ATP and NADH products
96
Aerobic reactions
TCA cycle, electron transport chain
97
Glycolysis
Glucose to pyruvate catabolism
98
EMP metabolic pathway
Almost universal, most bacteria, animals and plants
99
Glycolysis via EMP pathway can occur in:
aerobic or anaerobic
100
Glycolysis via EMP net end products
2 ATP, 2 pyruvate, 2 NADH
101
ED pathway ATP net gain
1
102
Pentose phosphate shunt net ATP
1
103
Pentose Phosphate shunt involves:
hexose monophosphate shunt
104
TCA cycle net ATP
2
105
Fat input into TCA
Acetyl CoA
106
Protein input into TCA
1. Aspartic acid to oxaloacetate
2. glutamic acid to a-ketoglutarate
107
Pyruvate catabolism AA products
alanine, valine, leucine
108
Oxaloacetate catabolism AA products
Lysine, methionine, threonine, isoleucine
109
a-ketoglutarate catabolism AA products
lysine, proline, arginine
110
Glyoxylate cycle
When glucose is unavailable and acetate is the only carbon source
111
During glyoxylate cycle, bacteria convert _____ to _____ to make carbs
acetyl-coa to succinate
112
Final electron acceptor is O2
aerobic respiration
113
Final electron acceptor is an inorganic molecule, not O2
anaerobic respiration
114
Oxidative phosphorylation
ETC generates energy through proton motive force (pH and charge difference); electrochemical gradient
115
Aerobic respiration complete oxidation of glucose yields ___ ATP
30-38
116
Anaerobic respiration total ATP
5-36 (depends on organism and final e acceptor)
117
True or false: inorganic molecule as final e acceptor has greater redox potential than O2
False - less
118
Fermentation final e acceptor is:
organic molecule, usually pyruvate
119
____ can erode teeth enamels and cause caries
Lactic acid
120
Hosts make ____ and ____ that can damage anaerobes
Free radical superoxide (O2-); hydrogen peroxide (h2o2)
121
Microbes make enzymes to defend themselves against host metabolic products:
1. superoxide dismutase - converts superoxide O2- to h2o2
2. catalase enzyme converts h2o2 to o2
122
Positive catalase
Bubbling in rxn
