Chapter 9 objectives Flashcards
Quiz
Organisms called _____ live on or in the body of a host, and cause some degree of harm.
Pathogens
The toxic superoxide ion is converted to harmless oxygen by two enzymes,
superoxide dismutase and oxidase.
catalase and hydrogen peroxidases.
superoxide dismutase and catalase.
superoxide dismutase and catalase
An organism that can use gaseous oxygen in metabolism and has the enzymes to process toxic oxygen products is a/n
aerobe
E. coli bacteria that normally live in the human large intestines and produce vitamin K that the body uses would be best termed a _____ relationship.
mutualistic
An organic nutrient that cannot be synthesized by the organism and must be provided is called a/n
growth factor
In _____ conditions, the cell wall will help prevent the cell from bursting.
hypertonic
mesotonic
isotonic
hypotonic
hypotonic
The process by which a cell uses ATP to enclose a substance in its membrane, by forming a vacuole and engulfing it, is called:
endocytosis
Cultures of a bacterial species were incubated in a standard incubator, in an anaerobic jar, and in a candle jar. After incubation, there was moderate growth of cultures in the candle and anaerobic jars, but heavy growth of the culture in the incubator. This species is a/n
microaerophile.
aerobe.
anaerobe.
facultative anaerobe.
facultative anaerobe
Facilitated diffusion is limited by
carrier proteins in the membrane
A microorganism that has an optimum growth temperature of 37° C, but can survive short exposure to high temperatures is called a/n
thermoduric microbe
The phase of the bacterial growth curve in which newly inoculated cells are adjusting to their new environment, metabolizing but not growing at an exponential rate, is the
lag phase
An organism with a temperature growth range of 45° C to 60° C would be called a/n
thermophile
Contractile vacuoles are
used to expel excess water from cells
Microorganisms require large quantities of ______ for use in cell structure and metabolism:
macronutrients
What is the difference between mutualism and synergism?
In a synergistic relationship the organisms cannot survive without each other.
In a synergistic relationship both organisms benefit, but in a mutualistic relationship both organisms are harmed.
In a mutualistic relationship the organisms are dependent upon each other.
in a mutualistic relationship the organisms are dependent upon each other
What type of media is used to demonstrate oxygen requirements of microbes?
thioglycollate
All of the following could find a location in or on body tissues suitable for growth except:
mesophiles.
anaerobes.
psychrophiles
psychrophiles
The milk that you bought from a grocery store a month ago got pushed to the back of the refrigerator hidden by other objects. Finding it a month later, unopened, you would like to now use it. Which statement is true?
The milk will still be fresh since it is a sterilized product.
The milk will still be fresh since the lactose sugar prevents the growth of any microorganisms.
Only thermoduric bacteria will be thriving in the milk.
Only thermoduric bacteria will be thriving in the milk.
The methanogens, producers of methane gas, require environments that:
are extremely cold.
are anaerobic with hydrogen gas and CO2.
have abundant oxygen and CO2.
are anaerobic with hydrogen gas and CO2.
An important mineral ion that is a component of chlorophyll, and stabilizer of membranes and ribosomes is:
potassium.
zinc.
magnesium.
magnesium.
The term facultative refers to:
the ability to exist in a wide range of conditions.
using chemicals for energy production.
using light for energy production.
the ability to exist in a wide range of conditions.
A microaerophile:
grows with or without oxygen.
needs normal atmospheric levels of oxygen.
requires a small amount of oxygen but won’t grow at normal atmospheric levels of oxygen.
requires a small amount of oxygen but won’t grow at normal atmospheric levels of oxygen.
A loopful of bacteria containing 1000 bacterial cells is inoculated into a nutrient broth and incubated. The culture was in lag phase for 10 minutes and then went into exponential log phase growth for 5 hours. The generation time for the bacterium is 15 minutes. Which equation set up is the correct one to determine how many cells at the end of the 5 hours of log phase growth.
1000 X 2(4)
1000 X 2(20)
1000 X 5 X 2 X 15
1000 X 40
1000 X 2(20)
Aerobic respiration is an example of:
photoautotrophy.
methanoheterophy.
chemoheterotrophy.
photoheterotrophy.
chemoheterotrophy.
Organisms that feed on dead organisms for nutrients are called:
phototrophs.
parasites.
autotrophs.
saprobes.
saprobes.
Nutrient absorption is mediated by the:
cell membrane.
peptidoglycan layer.
cell wall.
nuclear membrane.
cell membrane.
When microbes live independently but cooperate and share nutrients, it is called:
synergism.
symbiosis.
mutualism.
synergism.
The phase of the bacterial growth curve in which the rate of multiplication equals the rate of cell death is the:
stationary phase.
log phase.
death phase.
stationary phase.
After using the jelly on a sandwich, you close the jar and inadvertently place it on a room temperature shelf instead of in the refrigerator. When looking for the jelly a couple of weeks later and finding it on the shelf, you notice growth of a microorganism on the top of the jelly. What type of organism is likely to grow in this environment?
a fungus
a bacterium
a virus
a fungus
A bacterium is inoculated into a tube of nutrient broth and incubated. After incubation, it appears turbid throughout, top to bottom, with the most amount of turbidty at the very top. This bacterium would be called a:
aerotolerant
facultative anaerobe
psychrotroph
facultative anaerobe
Calcium is required for bacteria because it:
maintains cellular pH.
stabilizes the cell wall.
makes strong cell walls.
stabilizes the cell wall.
Microorganisms require small quantities of ______ for enzyme function and maintenance of protein structure:
trace elements
growth factors
macronutrients
trace elements
An organism that uses CO2 for its carbon needs and sunlight for its energy needs would be called a:
saprobe.
heterotroph.
photoautotroph.
photoautotroph.
Which of the following is not a major element of a microbial cell?
copper
nitrogen
oxygen
copper
Which of the following environmental conditions would be inappropriate for isolation of extremophilic microorganisms?
a yogurt container, pH 4.7
seawater, NaCl content of 3.5%
a compost pile with decaying vegetables and grass, temperature of 55 degree celsius
a compost pile with decaying vegetables and grass, temperature of 55 degree celsius
An organism that can exist in both oxygen and oxygen-free environments is a/n:
facultative anaerobe.
obligate anaerobe.
obligate aerobe.
facultative anaerobe.
The term obligate refers to:
the ability to exist in a wide range of conditions.
using light for energy production.
existing in a very narrow niche.
existing in a very narrow niche
The movement of substances from lower to higher concentration across a semipermeable membrane that must have a specific protein carrier and cell expenditure of energy is called:
facilitated diffusion.
diffusion.
active transport.
active transport.
Cultures of a bacterial species were incubated on the shelf of a refrigerator (5°c), out on a lab bench top (22°c), on the shelf of a 37° C incubator, and on the shelf of a 50° C incubator. After incubation, there was no growth at 37° C and 50° C, slight growth in the refrigerator, and abundant growth on the lab bench top. What term could be used for this species?
mesophile
halophile
psychrotroph
psychrotroph
When microbes are in a close nutritional relationship, and one benefits but the other is not harmed, it is called:
synergism.
mutualism.
commensalism.
commensalism.
An organism that cannot grow without oxygen is a/n:
obligate anaerobe.
facultative anaerobe.
obligate aerobe.
obligate aerobe.
When whole cells or large molecules in solution are engulfed by a cell, this endocytosis is specifically termed:
exocytosis.
pinocytosis.
phagocytosis.
phagocytosis.
A microorganism that does not have catalase or superoxide dismutase would find it difficult to live in an environment with:
carbon dioxide.
high salt.
oxygen.
oxygen.
Which of the following microorganisms would find hypotonic conditions most detrimental?
bacteria
fungi
protozoa
protozoa
You inoculate the bacterium into 3 tubes of nutrient broth medium containing salt–0.5% NaCl, 5% NaCl, and 15% NaCl. After incubation, you notice that the organism is growing very well in the 15%, and somewhat in the 5%. There is no growth in the third tube. This organism would be called:
barophilic
osmophobic
halophilic
halophilic
An organism that grows slowly in the cold but has an optimum growth temperature of 32° C is called a/n:
psychrophile.
extremophile.
facultative psychrophile.
facultative psychrophile.
Which of the following require the cell to use ATP?
facilitated diffusion
osmosis
diffusion
endocytosis
endocytosis
Which organism below has a problem in maintaining cellular electrolyte and fluid balance in its environment?
a protozoan in a fresh-water lake
a bacterium in Great Salt Lake
a bacterium in a fresh-water lake
all of the above
all of the above
An organism that cannot tolerate an oxygen environment is a/n:
facultative anaerobe.
obligate anaerobe.
obligate aerobe.
obligate anaerobe
An important mineral ion of the cytochrome pigments of cellular respiration is:
potassium.
iron.
magnesium.
iron.
This bacterium is photosynthetic, but without light it can use organic compounds to make energy. Its carbon source is a organic compound. The appropriate classification for this organisms would be:
photoautotroph
photoheterotroph
chemoautotroph
photoheterotroph
The movement of molecules from an area of high concentration to an area of lower concentration is called:
facilitated diffusion.
osmosis.
diffusion.
diffusion.
Diffusion of water through a semipermeable membrane is called:
osmosis.
diffusion.
endocytosis.
osmosis.
Human pathogens fall into the group called:
halophiles.
mesophiles.
thermophiles.
mesophiles.
The phase of the bacterial growth curve in which the rate of multiplication equals the rate of cell death is the:
lag phase.
stationary phase.
log phase.
stationary phase.
The production of antibiotics is a form of antagonism called:
symbiosis.
mutualism.
antibiosis.
antibiosis.
The termite requires the protozoan Trichonympha in its gut to provide the enzyme cellulase for the termite’s use of cellulose in wood products. The protozoan uses the end products of the cellulose breakdown. This would be a _____ relationship.
mutualistic
commensualistic
parasitic
mutualistic
You have inoculated your Clostridium species into a tube of media. After incubation, you find that it is not growing and you then realize that this organism is an obligate anaerobe. What is the best explanation for this lack of growth?
There is not enough oxygen for use when hydrogen peroxide is present.
Oxygen in the medium destroys the enzymes needed by Clostridium to undergo aerobic respiration.
Clostridium does not have enzymes to break down hydrogen peroxide.
Clostridium does not have enzymes to break down hydrogen peroxide.
Bacteria living in a freshwater stream that are moved to salty seawater would:
become dehydrated due to the loss of water.
be in a hypotonic solution.
be in an isotonic solution.
become dehydrated due to the loss of water.
A halophile would grow best in:
acid pools.
salt lakes.
hot geyser springs.
salt lakes.
In the viable plate count method, a measured sample of a culture is evenly spread across an agar surface and incubated. Each _____ represents one _____ from the sample.
colony; cell
cell; colony
generation; cell
colony; cell
Mediated transport of polar molecules and ions across the plasma membrane utilizes a/n _____ carrier that will bind to the substance, effecting a conformational change that allows movement across the membrane.
protein
porin
enzyme
protein
When it is important to count the number of cells, determine cell size, and differentiate between dead and live cells, a/n ___ is used.
turbidity counter
flow cytometer
coulter counter
flow cytometer
Microorganisms that live in severe habitats, such as very hot, acidic, or salty environments, are called:
psychrophiles.
extremophiles.
thermophiles.
extremophiles.
The time interval from parent cell to two new daughter cells is called:
death phase.
growth curve.
generation time.
generation time.
The type of photosynthesis that does not produce oxygen:
does not require CO2 as a reactant.
occurs in cyanobacteria.
occurs in purple and green sulfur bacteria.
occurs in purple and green sulfur bacteria.
Which of these terms describes a microorganism that grows at human body temperature (37°C)?
Thermophile
Psychrophile
Hyperthermophile
Mesophile
Mesophile
favors moderate temps -20° to 40°C
Which of these terms describes microbes that do not use oxygen, but can grow if it is present?
Obligate aerobe
Obligate anaerobe
Facultative anaerobe
Aerotolerant anaerobe
Aerotolerant anaerobe - tolerate oxygen but don’t use it in metabolism
Facilitated diffusion _____________?
Requires a carrier and energy
Requires a carrier but not energy
Requires neither a carrier nor energy
modifies the substrate during transport
Requires a carrier but not energy
A cell exposed to a hypertonic environment will _______ by osmosis.
gain water
lose water
neither gain nor lose water
burst
lose water
Psychrophiles would be expected to grow__________.
in hot springs
on the human body
at refrigeration temperatures
at low pH
at refrigeration temperatures. (Psychos like cold 0° to 20°C)
Organisms such as Clostridium lack oxygen-detoxifying enzymes, thus they are:
Obligate aerobes
Obligate anaerobes
Facultative anaerobes
Aerotolerant anaerobes
Obligate anaerobes
What sort of microbe only grows in the presence of oxygen?
Anaerobe
Facultative anaerobe
Aerobe
Halophile
Aerobe
Sugars and salts are used to preserve foods because they:
inhibit cell wall biosynthesis
cause plasmolysis of cells
change the pH of the food
cause plasmolysis of cells
The advantage of the direct counting method (slide) over the pour plate method is that direct counting:
counts both live and dead cells
counts only living cells
does not require incubation time
does not require incubation time. (fast method)
Organism that obtains carbon in organic form and is nutritionally dependent on other living things:
Heterotroph
Autotroph
Heterotroph
Organism that uses inorganic carbon sources and can convert them into carbon compounds, not nutritionally dependent on other living things:
Heterotroph
Autotroph
Antagonism
Autotroph
microbial growth needs ______ for structure and energy source:
Carbon
Sulfur
Nitrogen
Carbon
microbial growth needs _______ for proteins, amino acids, and ATP fixation. (used in DNA, RNA)
sulfur
nitrogen
phosphorus
nitrogen
microbial growth needs _____ for amino acids (cystine and methionine) and B vitamins.
sulfur
nitrogen
carbon
sulfur
which bacteria favors the cold, can’t grow above 0° to 20°c, lives in lakes, rivers, snow, ice, deep ocean.
psychrophile
thermophile
mesophile
psychrophile
which bacteria favors moderate temps: -20° to 40°c, most human pathogens are in this group.
mesophile
thermophile
psychrophile
mesophile
which bacteria favors the heat optimum temp: 45° - 80°c.
mesophile
thermophile
psychrophile
thermophile
which bacteria favors optimum temp: 15° – 30°c, grows slowly in the cold.
psychrotolerant
psychrophile
mesophile
psychrotolerant
Important temps to know:
boiling water is 100°c
body temp is 37°c
room temp is 25°c.
memorize these
which organism can grow slowly in the fridge slowly, prefers to grow at body temp ( 37°c) mild or no symptoms in adults, but pregnant women are more susceptible, and it can cause stillbirths and miscarriages. Soft cheeses, hot dogs, cold lunch meats, and unpasteurized milk carry it.
Listeriosis monocytogenes
its falls under the psychrotolerant group
an enzyme that converts superoxide radical into molecular oxygen (O₂) or hydrogen peroxide (H₂O₂). (2O₂⁻ + 2H⁺ > H₂O₂ + O₂):
superoxide dismutase
catalase
peroxidase
superoxide dismutase
an enzyme that neutralizes hydrogen peroxide (H₂O₂) during aerobic respiration by converting it into water (H₂O) and oxygen (O₂). (H₂O₂ > 2H₂O + O₂):
peroxidase
superoxide dismutase
catalase
catalase
what is used to stabilize pH of culture media
buffers
acidophiles
neutrophiles
buffers
what is a mixed cultures of microbes that are bound to a surface. Medically and environmentally important due to constant source of bacteria.
buffers
biofilm
binary fission
biofilm
which phase of bacteria growth phase is most susceptible to antibiotics and disinfectants:
lag phase
log phase
death phase
log phase
aka exponential growth
which phase has flat growth, newly inoculated cells adjust, grow synthesize, cells not multiplying at max. rate:
log phase
stationary phase
lag phase
lag phase
which phase does the growth curve increase exponentially, cells reach max rate of cell division, continues when cells have adequate nutrients and favorable environment, phase most sensitive to antimicrobials, maximum rate of cell division:
log phase
death phase
lag phase
log phase
which phase is survival mode, death rate balances growth rate, cells stop growing or grow slowly, depleted nutrients and oxygen, excretion of biochemical pollutants:
log phase
lag phase
stationary phase
stationary phase
in which phase do cells die at exponential rate. (note: antibiotics speed up death phase)
stationary phase
lag phase
death phase
death phase
which can use O₂ and has enzymes to process toxic oxygen products. (all growth at top)
aerobe
obligate aerobe
anaerobe
aerobe
which can’t grow without oxygen. (ex. humans)
aerobe
anaerobe
obligate aerobe
obligate aerobe
which grows best with oxygen but can also grow without oxygen. (heavy growth at the top of tube, lighter growth on the bottom)
aerobe
anaerobe
facultative anaerobe
facultative anaerobe
which one doesn’t grow at normal oxygen levels but requires a small amount of oxygen for metabolism.
facultative anaerobe
aerotolerant anaerobe
microaerophile
microaerophile
which one lacks metabolic enzyme for using O₂ in respirations. (all growth on bottom, away from oxygen):
aerobe
anaerobe
obligate anaerobe
anaerobe
which one can not tolerate oxygen exposure, lack enzymes for processing toxic oxygen. (no catalase enzyme):
obligate aerobe
obligate anaerobe
anaerobe
obligate anaerobe
which doesn’t use oxygen but can survive and grow in its presence to limited extent:
aerobe
microaerophile
aerotolerant anaerobe
aerotolerant anaerobe
which occurs when external solute concentration is higher than internal solute concentration; water diffuses out of cell = plasmolysis occurs; “high osmotic pressure”
hypotonic
isotonic
hypertonic
hypertonic
which occurs when external solute concentration is lower than internal solute concentration. Cells without cell walls swell and can burst. (hypo – outside):
hypotonic
isotonic
hypertonic
hypotonic
which occurs when environment is equal in solute concentration to the cells internal environment (solutes: E = C):
hypotonic
hypertonic
isotonic
isotonic
Diffusion of water across a membrane. (no energy needed):
active transport
osmosis
diffusion
osmosis
Particles move from areas of higher concentration to lower concentration; limited to small nonpolar molecules or lipid soluble molecules, ex. oxygen (no energy needed):
facilitated diffusion
passive diffusion
active transport
passive diffusion
Molecules bind to a specific protein carrier that changes shape to carry the molecule to the other side. Moves high to low (no energy needed) :
passive diffusion
osmosis
facilitated diffusion
facilitated diffusion
facilitates is to help
Large substrates engulfed by eukaryotic cells (active transport) types of phagocytosis where the cell eats solids. Pinocytosis where cell drinks liquids.:
phagocytosis
endocytosis
exocytosis
endocytosis
endocytosis - (IN)
Type of endocytosis; pseudopods wrap around target and separate it from the environment, forming a vacuole within the cell. ( cell eating solids):
pinocytosis
phagocytosis
active transport
Phagocytosis
(cell eating solids)
(active transport)
Molecules transported against the concentration gradient or in the natural gradient at a faster rate than by diffusion alone. Low to high (requires specific membrane proteins and energy from ATP):
phagocytosis
group translocation
active transport
active transport
Substrate is modified into a metabolically useful substance as it passes the boundary. (active transport):
active transport
group translocation
endocytosis
group translocation
Expulsion of substrate (active transport) reverse of endocytosis:
phagocytosis
exocytosis
osmosis
exocytosis
(exo - EXIT)
An organic compound that cannot be synthesized by an organism and must be externally sourced / provided as a nutrient:
growth curve
growth factor
generation time
growth factor
(examples: amino acid, nitrogenous base, or vitamins)
The time required for a complete fission cycle:
generation time
name the microbe that can grow in the refrigerator that pregnant women need to avoid.
Listeria monocytogenes
which of the following microbes would find hypotonic conditions most detrimental?
fungi
bacteria with a cell wall
protozoa without a contractile vacuole
protozoa without a contractile vacuole
(protozoa have no cell walls, cell will burst)
If a bacteria cell is low on nitrogen, the cell may not be able to perform biosynthesis on which of the following macromolecules?
Amino acids
DNA
RNA
All of the above
All of the above
The optimal number of colonies per plate for standard plate count is:
30 - 300
300 - 400
12 - 25
30 - 300
