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BIO 204 Microbiology > Ch 7 > Flashcards

Ch 7 Flashcards

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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
Q

Define facultative.

A

Does not require oxygen for its metabolism; capable of growth in the absence of oxygen

26
Q

Define halophile

A

Require high concentrations of salt for growth

27
Q

Define mesophile

A
  • 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
Q

Define thermophile

A
  • 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
Q

Define psychrophile

A

-organisms that have an optimum temp below 15 degrees Celsius
-capable to grow at 0 degrees Celsius
Cannot grow about 20 degrees Celsius

30
Q

Define facultative psychrophile (psychrotroph)

A
  • grows slowly in the cold

- have optimum temp between 15-30 degrees Celsius

31
Q

Define extremophile

A

-An organism that has adapted to extreme environments

32
Q

Define capnophile

A
  • 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
Q

Define aerobes

A
  • 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
Q

Define anaerobes

A
  • lack metabolic enzyme system for using oxygen in respiration
35
Q

Define facultative anaerobes

A
  • 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
Q

Define microaerophiles

A
  • 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
Q

What does it mean if an organism is considered thermoduric?

A

The organism can survive short exposure to high temperatures such as common contaminants of heated or pasteurized foods.

38
Q

To survive in an oxygen environment, what enzymes would be key to a bacterium? How do they work?

A

Catalase and superoxide dismutase

39
Q

Define parasitic

A

Derive nutrients from the cells or living tissues of a host

40
Q

Define saprobic

A

Free-living microorganisms that feed primarily on organic detritus from dead organisms

41
Q

Define commensal

A

Receives benefits

42
Q

Define mutualistic relationships

A
  • Obligatory, dependent

- both members benefit

43
Q

Define pathogen

A

Can damage tissues and cause death

44
Q

What is generation time?

A
  • 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
Q

What is the phases of the bacterial growth curve?

A
  • Lag Phase
  • Exponential growth or log phase
  • Stationary growth phase
  • Death phase
46
Q

What is the process for the viable plate count method? What do the results indicate?

A
  • the total number of cells is counted over a given time period
  • the results indicate growth
47
Q

Know about the environment in which methanogen bacteria are found.

A

anaerobic, hydrogen-containing microenvironments such as ocean vents and hot springs

48
Q

what occurs in each phase?

Lag phase

A
  • flat period on the graph
  • population appears not to be growing
  • newly inoculated cells require a period of adjustment, enlargement, and synthesis
48
Q

what occurs in each phase?

Log Phase

A
  • Growth curve increases dramatically

- phase will continue as long as cells have adequate nutrient and the environment is favorable

49
Q

what occurs in each phase?

Stationary growth phase

A
  • population enters survival mode

- cells stop growing or grow slowly

50
Q

what occurs in each phase?

Death phase

A
  • Limiting factors intensify
  • cells begin to die at an exponential rate
  • curve dips downwards

BIO 204 Microbiology (12 decks)

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