Exam 1 Learning Objectives Flashcards

1
Q

Macro

A

A nutrient that an organism needs in larger quantity. 6 Macros Carbon, Nitrogen, Phosphorus, Hydrogen, Oxygen and Sulfur make up the carbs, lipids, nucleic acids, and proteins of the cell.

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2
Q

Micro Nutrients

A

A nutrient that an organism needs in smaller quantity, typically a vitamin or a mineral. *Cobalt, Manganese, Molybdenum, Nickle, Zinc, and ambitious trace contaminants on glassware and in water. **Not added to media in labs, sufficient amount already present.

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3
Q

Cofactors

A

A metallic ion or a coenzyme required by an enzyme to perform normal catalysis such as Cobalt needed for B12.

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4
Q

What are the different types of microbial metabolism?

A
Heterotrophy
Autotroph
Phototroph
Chemolithotroph
Organotroph
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5
Q

Heterotrophy

A

those catabolizing reduced organic molecules (proteins, carbohydrates, amino acids, and fatty acids)

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6
Q

Autotroph

A

The metabolic reduction of carbon dioxide to produce organic carbon for biosynthesis.

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7
Q

Organotroph

A

The metabolic oxidation of organic compounds to yield energy without light absorption.

An organotroph is an organism that obtains hydrogen or electrons from organic substrates. i.e., animals and bacteria

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8
Q

Phototroph

A

The fixation of single-carbon compounds into organic biomass, using light as an energy source.

An organism that manufactures its own food from inorganic substances using light for energy. Green plants, certain algae, and photosynthetic bacteria are phototrophs.

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9
Q

Chemolithotroph

A

Metabolism in which single-carbon compounds are fixed into organic biomass, using energy from chemical reactions without light absorption.
**Organic compounds contain a carbon molecule and usually a hydrogen molecule, whereas inorganic compounds contain neither of those.

An organism that is able to use inorganic reduced compounds as a source of energy

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10
Q

Biosynthesis

A

The production of complex molecules within living organisms or cells… basically takes things and turns them into macros. Biosynthesis is essential because the products it produces are essential for life.

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11
Q

Membrane Potential

A

Is a potential gradient that forces ions to passively move in one direction

compares whats inside to whats outside

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12
Q

Proton Motive Force

A

The inwardly directed proton gradient is called proton motive force.

Is the force that promotes movement of protons across membranes downhill the electrochemical potential.

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13
Q

ATP Synthase

A

A protein complex that synthesizes ATP from ADP and inorganic phosphate using energy derived from the transmembrane proton potential. It is located in the prokaryotic cell membrane and in the mitochondrial inner membrane.

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14
Q

Nutrient Uptake

A

In order to support its’ activities, a cell must bring in nutrients from the external environment across the cell membrane. In bacteria and archaea, several different transport mechanisms exist.

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15
Q

Coupled Transport:

A

The movement of a substance against its electrochemical gradient using the energy provided by the simultaneous movement of a different chemical down its electrochemical gradient.

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16
Q

ABC Transport:

A

An ATP-powered transport system that contains an ATP binding cassette.

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17
Q

Siderophores:

A

Are secreted to bind ferric iron and transport it into the cell, where it is reduced to the more useful ferrous form. Siderophore-iron complexes enter cells with the help of ABC transporters.

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18
Q

Binary Fission

A

The process of replication in which one cell divides to form two genetically equivalent daughter cells of equal size.

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19
Q

Doubling Time:

A

The generation time of bacteria in culture. The amount of time it takes for the population to double.

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20
Q

Generation Time:

A

The species-specific time period for doubling of a population in a given environment, assuming no depletion of resources.

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21
Q

What are the bacterial growth curve phases?

A
  • -Lag Phase
  • -Log Phase
  • -Stationary Phase
  • -Death Phase
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22
Q

Lag Phase

A

“Prep” they are not growing yet but they are ensuring they have the nutrients they need, making enzymes and repairing any damage. *preparing cell machinery for growth.

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23
Q

Log Phase

A

Growth approximates an exponential curve

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24
Q

Stationary Phase:

A

: #dividing cells = #dying cells –> cells stop growing and shut down their growth machinery while turning on stress responses to retain viability. They are making too much waste, and the environment is getting toxic.

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25
Death Phase
Dying cells are more than dividing cells, cells die with a “half-life” similar to that of radioactive decay, a negative exponential curve.
26
Continuous Culture
Can be used to sustain a population of bacteria at a specified growth rate and cell density. (chemostat is the most common)
27
Heat-Shock Response
Produces a series of protective proteins in organisms exposed to temperatures near the upper edge of their growth range.
28
Water Activity
A measure of how much water in a solution is available for a microbe to use.
29
Osmolarity
The measure of the number of solute molecules in solution.
30
Halophile
An organism that requires a high extracellular sodium chloride concentration for optimal growth.
31
Reactive Oxygen Species (ROS)
A type of unstable molecule that can lead to cell death or damage
32
Which microbes can utilize oxygen for energy production?
- -Obligate Aerobes - -Facultative Anaerobes - -Microaerophiles
33
Which microbes can grow in the presence of oxygen?
—> Obligate Aerobes —> Facultative Anarobes —> Aerotolerant Anaerobes —> Microaerophiles
34
Obligate Aerobes:
Need O2
35
Obligate Anaerobes:
No O2! Can't grow!
36
Facultative Anaerobes:
High growth with oxygen present using aerobic respiration; can grow with or without O2. They have enzymes that destroy ROS, allowing them to grow in oxygen.*fermentation as primary source of energy
37
Aerotolerant Anaerobes:
An organism that does not use oxygen for metabolism but can grow in the presence of oxygen. They have enzymes that destroy ROS, allowing them to grow in oxygen.
38
Microaerophiles:
Need O2
39
Strict Aerobe:
Growth only in O2
40
Strict Anaerobe:
Growth only without O2
41
Why can't obligate anaerobes grow in the presence of oxygen?
Because they lack catalase and superoxide dismutase and thus are killed by oxidative damage from oxygen radicals.
42
Decimal Reduction Time
The length of time it takes for a treatment to kill 90% of a microbial population, hence a measure of the efficacy of the treatment.
43
Autoclave
High pressure to achieve temperatures that will sterilize
44
Cold
Low temperatures have two basic purposes in microbiology: to temper growth and to preserve strains. Not only grow more slowly in cold but die more slowly.
45
Pasteurization
The heating of food at a temperature and time combination that will kill spore-like structures of Coxiella burnetiid. (obligate bacteria and gram-negative)
46
Filtration
Filtration through micropore filters with pore sizes of 0.2 um can remove microbial cells physically but not viruses from solutions.
47
Bactericidal
Having the ability to kill bacterial cells
48
Bacteriostatic
Having the ability to inhibit growth of bacterial cells
49
How can food be preserved?
Pasteurization, Refrigeration, Filtration, Irradiation
50
What is optimal temperature?
The temperature when microorganisms grow best.
51
What is minimum and maximum temperature?
It defines growth limits. The lower limit and upper limits and the range at which microorganisms can sustain growth.
52
When does growth stop?
When temperatures rise and cause critical enzymes or cell structures such as the cell membrane to fail.
53
What happens at cold temperatures?
The membrane becomes too rigid. It needs to be fluid so it can expand as cells grow and so that proteins needed for solute transport can be inserted into the membrane.
54
Thermophilic
Hot, high temperatures between 50-80C
55
Hyperthermophilic
Very hot, extremely high temperatures, 80C and as high as 120C
56
Psychrophilic
Cold, optimal growth below 15C; can grow as low as -10C.
57
Mesophilic
Moderate temperatures, 15-45C. *all human pathogens are mesophilic
58
Halophilic
Prokaryotes that require salt to grow; growth in high salt >2 M NaCl
59
Acidophilic
Growth below pH 3
60
Alkalophilic
Growth above pH 9 --> flamingos
61
Extremophile
An organism that grows only in an extreme environment –that is, an environment including one or more conditions that are “extreme” relative to conditions for human life.
62
Neutralfiles
Normal pH levels between 5-8 (flora)
63
Barophile
Growth at High Pressure, greater than 380 atm
64
Barotolerant
Growth between 10 and 500 atm
65
Membrane Fluidity
Varies with composition of lipids in a membrane, which in turn dictates the temperature and pressure at which an organism can grow.
66
What determines the environmental habitat?
It is inhabited by a particular species is defined by the tolerance of that organisms’ proteins and other macromolecular structures to the physical conditions within that niche.
67
How is the environmental habitat affected by things like pH, temp, etc?
* a single enzyme works best under specific conditions and when those are altered it causes the protein to fold differently and become less active. It needs to be within the optimal to function properly. * temperature affects every aspect of microbes; they do not determine their temperature because it is determined by their environment. Average rate of molecular motion, microbial physiology, membrane fluidity, nutrient transport, DNA stability, RNA stability and enzyme structure and function are all affected. * optimal temp is when it grows quickly
68
Name two strategies that are used in human food preparation to minimize microbial growth during storage
Commercial Sterilization: uses heat at a temperature low enough to preserve food quality but high enough to destroy common pathogens responsible for food poisoning Refrigeration’s: slowing the growth of microorganism significantly and helping preserve products. *High pressure processing is used to kill bacterial, yeast, mold, parasites and viruses while maintaining food quality and shelf life
69
Autotroph Energy Source
use CO2 as a carbon source, either through photosynthesis or through lithotroph, and make organic compounds as biomass
70
Lithotroph Energy Source
The metabolic oxidation of inorganic compounds to yield energy and fix single-carbon compounds into biomass. H2, H2S, NH4+, NO2-, Fe2+
71
Heterotroph
consume the organic compounds made by autotrophs to gain carbon i.e., glucose
72
Which enzyme catalyzes the reaction: 2H2O2 → 2H2O + O2?
Catalase
73
Which enzyme catalyzes the reaction: H2O2 + 2H+ → 2H2O?
Peroxidase
74
which enzyme catalyzes the reaction O2- + O2- + 2H+ → H2O2 + O2?
Superoxide Dismutase (SOD)
75
Sterilization
Killing all organisms
76
Disinfection
Killing or removal of pathogens from inanimate objects
77
Sanitation
Reducing the microbial population to safe levels
78
Bacteriostatic
Halting microbial growth
79
Bactericidal
Killing Bacterial Cells
80
SODs vs Catalase and Perocidases
SODs convert superoxide racial into hydrogen peroxide and molecular oxygen O2 whereas the catalase and peroxidase convert hydrogen peroxide into water, and in the case of catalase, into oxygen and water.