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BIO 204 Microbiology > Ch 7 > Flashcards

Ch 7 Flashcards

1
Q

What is most of the dry weight of a microbial cell?

A
  • –organic compounds
  • proteins
  • nucleic acids
  • RNA
  • DNA
  • carbohydrates
  • Lipids
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2
Q

What is the most prevalent compound in a cell?

A
  • H20

- Water

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3
Q

What elements are most common in a cell?

A
  • Carbon
  • Oxygen
  • Nitrogen
  • Hydrogen
  • Phosphorus
  • Sulfur
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4
Q

Define macronutrient

A
  • required in large quantities

- play principle roles in cell structure and metabolism

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5
Q

Define trace elements

A
  • micronutrients
  • present in smaller amounts
  • involved in enzyme function and maintenance of protein structure
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6
Q

Define growth factors

A
  • organic compound like an amino acid, nitrogenous base, or vitamin that cannot be synthesized by an organism
  • must be provided by the environment
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7
Q

Define phototroph

A

-microbes that photosynthesize

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8
Q

Define autotroph

A
  • self-feeder
  • organism that uses inorganic CO2 as its carbon source
  • have the capacity to convert CO2 into carbon compounds
  • not dependent on other living things
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9
Q

Define chemotroph

A

Microbes that gain energy from chemical compounds

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10
Q

Define heterotroph

A
  • organism that must obtain carbon in organic form
  • dependent on other life forms
  • most carbon sources exist in a form that is simple enough for absorption
  • many carbon sources must be digested by the cell to be absorbed
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11
Q

Define photoautotroph

A
  • captures energy from light rays and transforms it into chemical energy for cell metabolism
  • produces organic molecules that can be used by themselves and heterotrophs
  • forms the basis for most food webs
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12
Q

Define chemoheterotroph

A

-use organic compounds for energy and inorganic compounds as a carbon source

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13
Q

Define diffusion

A
  • the movement of molecules in an area from high to low concentration or density.
  • diffusion across a cell membrane is made by the concentration gradient and the permeability of the substance.
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14
Q

Define facilitated diffusion

A
  • The movement of substances from higher to lower concentration across a semipermeable membrane
  • must have a specific protein carrier but no energy expenditure
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15
Q

Define active transport

A

-transports nutrients against a concentration gradient or with a concentration gradient at a faster rate

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16
Q

Define osmosis

A

-the movement of water across a selectively permeable membrane.

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17
Q

Define endocytosis

A

-The process by which a cell uses ATP to enclose a substance in its membrane, by forming a vacuole and engulfing it

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18
Q

Define phagocytosis

A

-endocytosis by amoebas and certain white blood cells that ingest whole cells or large solid matter

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19
Q

Define pinocytosis

A

-entry of oil or molecules in solution into the cell

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20
Q

Define exocytosis

A

-the transport of material out of a cell by means of a sac or vesicle that first engulfs the material and then is extruded through an opening in the cell membrane

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21
Q

What part of the bacteria mediates nutrient absorption?

A

-cell membrane

22
Q

What is the effect of cells when placed in a hypotonic environments?

A

The cells will swell and burst.

23
Q

What is the effect of cells when placed in a hypertonic environments?

A

The cells will shrink and shrivel.

24
Q

Define obligate

A

Necessary; essential to a particular condition of life

25
Define facultative.
Does not require oxygen for its metabolism; capable of growth in the absence of oxygen
26
Define halophile
Require high concentrations of salt for growth
27
Define mesophile
- majority of medically significant organisms - individual species grow at 10-50 degrees Celsius - optimum growth temp 30-40 degrees Celsius - most human pathogens: 30-40 degrees Celsius
28
Define thermophile
- grows at temp above 45 degrees Celsius to 80 degrees Celsius - lives in soil and water associated with volcanic activity, compost piles, habitats directly exposed to the sun
29
Define psychrophile
-organisms that have an optimum temp below 15 degrees Celsius -capable to grow at 0 degrees Celsius Cannot grow about 20 degrees Celsius
30
Define facultative psychrophile (psychrotroph)
- grows slowly in the cold | - have optimum temp between 15-30 degrees Celsius
31
Define extremophile
-An organism that has adapted to extreme environments
32
Define capnophile
- grow best at a higher CO2 tension than is normally present in the atmosphere - important in the isolation of some pathogens - incubation is carried out in a CO2 incubator that provides 3-10% CO2
33
Define aerobes
- can use gaseous oxygen in its metabolism - has the enzymes needs to process toxic oxygen products Obligate aerobe: an organism that cannot grow without oxygen
34
Define anaerobes
- lack metabolic enzyme system for using oxygen in respiration
35
Define facultative anaerobes
- An aerobe that does not require oxygen for metabolism - Capable of growth in the absence of oxygen - Metabolized by aerobic respiration when oxygen is present - Adopts anaerobic metabolism (fermentation)) when oxygen is absent.
36
Define microaerophiles
- does not grow at normal atmospheric conditions of oxygen - requires a small amount of oxygen in its metabolism - usually live in a habitat that provides a small amount of oxygen but not directly exposed to the atmosphere
37
What does it mean if an organism is considered thermoduric?
The organism can survive short exposure to high temperatures such as common contaminants of heated or pasteurized foods.
38
To survive in an oxygen environment, what enzymes would be key to a bacterium? How do they work?
Catalase and superoxide dismutase
39
Define parasitic
Derive nutrients from the cells or living tissues of a host
40
Define saprobic
Free-living microorganisms that feed primarily on organic detritus from dead organisms
41
Define commensal
Receives benefits
42
Define mutualistic relationships
- Obligatory, dependent | - both members benefit
43
Define pathogen
Can damage tissues and cause death
44
What is generation time?
- the time required for complete cycle - each new fission cycle doubles population - environment stays favorable, the doubling effect will stay a constant rate - It's the length of time measured of growth rate of an organism
45
What is the phases of the bacterial growth curve?
- Lag Phase - Exponential growth or log phase - Stationary growth phase - Death phase
46
What is the process for the viable plate count method? What do the results indicate?
- the total number of cells is counted over a given time period - the results indicate growth
47
Know about the environment in which methanogen bacteria are found.
anaerobic, hydrogen-containing microenvironments such as ocean vents and hot springs
48
what occurs in each phase? | Lag phase
- flat period on the graph - population appears not to be growing - newly inoculated cells require a period of adjustment, enlargement, and synthesis
48
what occurs in each phase? | Log Phase
- Growth curve increases dramatically | - phase will continue as long as cells have adequate nutrient and the environment is favorable
49
what occurs in each phase? | Stationary growth phase
- population enters survival mode | - cells stop growing or grow slowly
50
what occurs in each phase? | Death phase
- Limiting factors intensify - cells begin to die at an exponential rate - curve dips downwards

BIO 204 Microbiology (12 decks)

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