Ch. 3 Flashcards
(93 cards)
1
Q
Nutrients
A
Supply of monomers (or precursors of) required by cells for growth
2
Q
Macronutrients
A
Nutrients required in large amounts
3
Q
Micronutrients
A
Nutrients required in trace amounts
4
Q
___ is required by all cells.
A
Carbon
5
Q
Typical bacterial cell is ____% carbon
A
~50%
6
Q
What is a major element in all classes of macromolecules?
A
Carbon
7
Q
Heterotrophs use organic ___.
A
Carbon
8
Q
Autotrophs use carbon ___.
A
Dioxide
9
Q
Typical bacterial cell is ___ nitrogen.
A
13%
10
Q
What is a key element in proteins, nucleic acids, and many more cell constituents?
A
Nitrogen
11
Q
Phosphorus
A
Synthesis of nucleic acids and phospholipids
12
Q
Sulfur
A
- sulfur-containing amino acids
- vitamins and coenzyme A
13
Q
___ is required by enzymes for activity.
A
Potassium
14
Q
Magnesium
A
- stabilizes ribosomes, membranes, and nucleic acids
- also required for many enzymes
15
Q
___ helps stabilize cell walls in microbes and plays key role in heat stability of endospores.
A
Calcium
16
Q
Sodium
A
Required by some microbes
17
Q
Key component of cytochromes and FeS proteins involved in election transport
A
Iron
18
Q
Growth factors
A
Organic compounds required in small amounts by certain organisms
19
Q
Examples of growth factors
A
Vitamins, amino acids, purines, pyrimidines
20
Q
___ are the most commonly required growth factors.
A
Vitamins
21
Q
Vitamins mostly function as ___.
A
Coenzymes
22
Q
Culture media
A
Nutrient solutions used to grow microbes in the laboratory
23
Q
Defined media
A
Precise chemical composition is known
24
Q
Complex media
A
Composed of digests of chemically undefined substances
25
Enriched media
Contain complex media plus additional nutrients
26
Selective media
Contain compounds that selectively inhibit growth of some microbes but not others
27
Differential media
Contain an indicator, usually a dye, that detects particular chemical reactions occurring during growth
28
Pure culture
Culture containing only a single kind of microbes
29
Contaminants
Unwanted organisms in a culture
30
When grown on solid media, cells form isolated masses called ___.
Colonies
31
Solid media are prepared by addition of a gelling agent called ___.
Agar
32
Pure culture techniques:
Streak plate
Pour plate
Spread plate
33
Metabolism
The sum total of all of the chemical reactions that occur in a cell
34
Catabolic reactions (catabolism)
Energy-releasing metabolic reactions
35
Chemorganotrophs
An organism that obtains its energy from the oxidation of organic compounds
36
Chemolithotrophs
An organism that can grow with inorganic compounds as electron donors in energy metabolism
37
Phototrophs
Organisms that use light as their source of energy
38
Heterotrophs
An organism that uses organic compounds as a carbon source
39
Autotrophs
An organism capable of biosynthesizing all cell material from CO2 as the sole carbon source
40
Catalyst
Substance that:
- lowers the activation energy of a reaction
- increases reaction rate
- does not affect energetics or equilibrium of a reaction
41
Enzymes
- biological catalysts
- typically proteins
- highly specific
- generally larger than substrates
- typically rely on weak bonds
- increase the rate of chemical reactions by 10^8 to 10^20 times the spontaneous rate
42
Active site
Region of enzyme that binds substrate
43
Catalysis depends on:
- substrate binding
| - position of substrate relative to catalytically active amino acids in active site
44
Many enzymes contain small ___ ___ that participate in catalysis but are not substrates
Nonprotejn molecules
45
Prosthetic groups
- bind tightly to enzymes
| - usually bind covalently and permanently
46
Coenzymes
- loosely bound to enzymes
| - most are derivatives of vitamins
47
Energy from ___ reactions is used in synthesis of energy-rich compounds
Oxidation-reduction (redox)
48
Redox reactions occur in pairs
Two half reactions
49
Electron donor
The substance oxidized in a redox reaction
50
Electron acceptor
The substance reduced in a redox reaction
51
Redox reactions usually involve reactions between intermediates called ___
Carriers
52
Electron carriers are divided into two classes:
Prosthetic groups
| Coenzymes
53
___ and ___ facilitate redox reactions without being consumed; they are recycled.
NAD* and NADH
54
Two reaction series are linked to energy conservation in chemoorganotrophs:
Fermentation and respiration
55
Fermentation
Substrate-level phosphorylation; ATP is directly synthesized from an energy-rich intermediate
56
Respiration
Oxidative phosphorylation; ATP is produced from proton motive force formed by transport of electrons
57
___ substance is both an electron donor and an electron acceptor.
Fermented
58
Glycolysis
A common pathway for catabolism of glucose
59
How many ATP are produced from glycolysis?
Two
60
Fermentation classified by products formed:
- ethanol
- lactic acid
- propionic acid
- mixed acids
- butyric acid
- butanol
61
Fermentation classified by substrate fermented:
- usually not glucose
- amino acids
- purines and pyrimidines
- aromatic compounds
62
___ ___ can carry out fermentation or respiration
Saccharomycetes cerevisiae
63
Fermentation occurs when conditions are ___.
Anoxic
64
Aerobic respiration
- oxidation using O2 as the terminal electron acceptor
| - higher ATP yield than fermentations
65
Yeast can reproduce asexually by ___.
Budding
66
Electron transport systems
- membrane-associated
- mediate transfer of electrons
- conserve some of the energy released during transfer and use it to synthesize ATP
- many oxidation-reduction enzymes are involved in electron transport
67
NADH dehydrogenases
Proteins bound to inside surface of cytoplasmic membrane; active site binds NADH and accepts 2 electrons and 2 protons that are passed to flavoproteins
68
Flavoproteins
Contains flavin prosthetic group that accepts 2 electrons and 2 protons but donates the electrons only to the next protein in the chain
69
Cytochromes
- proteins that contain heme prosthetic groups
| - accept and donate a single electron via the iron atom in heme
70
Electron transport system oriented in cytoplasmic membrane so that..
Electrons are separated from protons
71
Electron carries arranged in membrane in order of their ___ ___.
Reduction potential
72
The final carrier in the chain donated the electrons and protons to the..
Terminal electron acceptor
73
Proton motive force
Results in generation of pH gradient and an electrochemical potential across the membrane
74
ATP synthase
Complex that converts proton motive force into ATP; two components
75
Citric acid cycle
Pathway through which pyruvate is completely oxidized to CO2
76
Microorganisms demonstrate a wide range of mechanisms for generating energy:
- fermentation
- aerobic respiration
- anaerobic respiration
- chemolithotrophy
- phototrophy
77
Anaerobic respiration
The use of electron acceptors other than oxygen
78
Chemolithotrophy
Used inorganic chemicals as electron donors
- typically aerobic
- begins with oxidation of inorganic electron donor
79
Photophosphorylation
Light-mediated ATP synthesis
80
Photoautotrophs
Uses ATP for assimilation of CO2 for biosynthesis
81
Photoheterotrophs
Uses ATP for assimilation of organic carbon for biosynthesis
82
Phototrophy
Uses light as energy source
83
Hemolysis
Ability to break down red blood cells
84
Alpha hemolysis
Partial destruction of red blood cells
85
Beta hemolysis
Complete destruction of red blood cells
86
Gamma hemolysis
No destruction of red blood cells
87
Chocolate agar
Partially lysed red blood cells
88
Blood agar
5% sheep blood
89
Anabolic
Building of macromolecules
90
Catabolic
Brohydration of macromolecules
91
Strict aerobes
Require oxygen all the time
92
Strict anaerobes
Can't be present with oxygen
93
Fabultative anaerobes
Grow with or without oxygen
