Deck 7: Microbial Nutrition and Growth

Question 1

Most of the dry weight of a microbial cell is from ______.

A) inorganic compounds
B) water
C) organic compounds
D) salts
E) minerals

Answer 1

organic compounds

Question 2

This microbe is photosynthetic, but in the absence of light it can use organic compounds as an energy source. Its carbon source is an organic compound. The appropriate classi?cation for this organism would be ______.

A) chemoautotroph
B) photoheterotroph
C) lithotroph
D) photoautotroph

Answer 2

photoheterotroph

Question 3

The methanogens, producers of methane gas, require environments that _______.

A) are extremely cold
B) are very acidic
C) have abundant oxygen and CO?
D) are directly exposed to sunlight
E) are anaerobic with hydrogen gas and CO?

Answer 3

are anaerobic with hydrogen gas and CO?

Question 4

An organic nutrient that cannot be synthesized by the organism and must be provided is called a/an ______.

A) macronutrient
B) growth factor
C) element
D) trace element
E) compound

Question 5

Whether an organism is a phototroph or a chemotroph depends on its source of energy.

Question 6

Lithoautotrophs use inorganic nutrients for carbon and energy sources.

Question 7

Calcium is required for bacteria because it _______.

A) makes strong cell walls
B) maintains cellular pH
C) stabilizes the nucleoid
D) stabilizes the cell wall
E) stabilizes the ribosomes

Question 8

Growth factors _______.

A) are inorganic
B) are synthesized by the organism
C) contain elemental oxygen
D) cannot be synthesized by the organism
E) All of the choices are correct.

Question 9

An organism that uses CO? for its carbon needs and sunlight for its energy needs would be called a ______.

A) saprobe
B) chemoheterotroph
C) photoautotroph
D) heterotroph
E) halotroph

Question 10

Microorganisms require small quantities of ______ for enzyme function and maintenance of protein structure.

A) macronutrients
B) trace elements
C) growth factors
D) water
E) electrolytes

Question 11

Phosphorus is one of the major elements needed in larger quantities by microorganisms.

Question 12

An important mineral ion found in the cytochrome pigments of cellular respiration is ______.

A) iron
B) magnesium
C) potassium
D) zinc
E) calcium

Question 13

Many lakes in the United States are suffering from periodic algae blooms, which can be thought of as an infection of the lake. Although the algae are naturally-occurring in the lake, when adjacent farm ?elds are over-fertilized with diammonium phosphate, the run-off deposits these nutrients in the lake, allowing the algae to grow without limit. Which of the following statements is incorrect regarding the overgrowth of algae?

A) The algae are heterotrophs.
B) Lakes have su?cient micronutrients for algae to grow.
C) The phosphorus in the fertilizer is in the phosphate form, the preferred phosphorus source of most microbes.
D) The carbon source for these algae is not limiting in lakes.
E) The nitrogen in the fertilizer is in the ammonium form, the preferred nitrogen source of most microbes.

Question 14

Which of the following is not a major element of a microbial cell?

A) Nitrogen
B) Oxygen
C) Carbon
D) Hydrogen
E) Copper

Question 15

Following the Deepwater Horizon accident in the Gulf of Mexico in 2010, bioremediation was used to eliminate much of the oil from the contaminated water. To encourage the growth of oil-degrading microbes, "fertilizer" including iron and nitrogen was added to the water. Which of the following
Statements regarding the growth of these microbes is incorrect?

A) The oil-degrading microbes used oil (hydrocarbons) as their carbon source.
B) Large amounts of iron were needed, as iron is a macronutrient for oil-degrading microbes.
C) Nitrogen gas (N2) present in air is not in a form that can be used by oil- degrading microbes.
D) The concentration of sulfate in the Gulf of Mexico is su?cient for the growth of oil- degrading microbes.

Question 16

Which compound has the highest concentration in a cell?

A) NH?
B) CH?
C) H?O
D) CO?
E) Glucose

Question 17

Inorganic nitrogen must be converted to ammonia to be used by a cell.

Question 18

An important mineral ion that is a component of chlorophyll and serves as a stabilizer of membranes and ribosomes is ______.

A) magnesium
B) calcium
C) potassium
D) zinc
E) iron

Question 19

Whether an organism is an autotroph or heterotroph depends on its source of nitrogen.

Question 20

Microorganisms require large quantities of ______ for use in cell structure and metabolism.

A) trace elements
B) growth factors
C) electrolytes
D) water
E) macronutrients

Question 21

Facilitated diffusion is limited by _______.

A) carrier proteins in the membrane
B) osmotic pressure
C) the size of the cell
D) the size of the pores in the membrane
E) the substrate concentration

Question 22

Which of the following microorganisms would ?nd hypotonic conditions most damaging?

A) Bacteria
B) Protozoa
C) Cyanobacteria
D) Fungi
E) Algae

Question 23

Which organism has a challenge to maintain cellular electrolyte and ?uid balance in its environment?

A) A protozoan in a fresh water lake
B) A bacterium in a fresh-water lake
C) A bacterium in Great Salt Lake
D) All of the choices are correct.

Question 24

The movement of substances from higher to lower concentration across a semipermeable membrane via a speci?c protein carrier but without energy expenditure is called ______.

A) osmosis
B) diffusion
C) facilitated diffusion
D) endocytosis
E) active transport

Question 25

Bacteria living in a freshwater stream that are transferred to ocean water would _______.

A) become dehydrated due to the loss of water
B) gain water
C) be in an isotonic solution
D) be in a hypotonic solution

Question 26

Which of the following require the cell to use energy?

A) Diffusion
B) Endocytosis
C) Facilitated diffusion
D) Osmosis

Question 27

A saprobe with a cell wall will utilize extracellular digestion.

Question 28

A saprobe differs from a parasite in that _______.

A) a saprobe derive nutrients from dead plants and animals, but a parasite derives nutrients from living plants and animals
B) a saprobe cannot infect a human, but a parasite is always infectious
C) a saprobe does not harm a host that it lives on, whereas a parasite does harm a host
D) a saprobe is a fungus, but a parasite can be any type of microbe

Question 29

Nutrient absorption is mediated by the ______.

A) cell membrane
B) peptidoglycan layer
C) cell wall
D) nuclear membrane
E) proteins in the periplasmic space

Question 30

The movement of molecules from an area of high concentration to an area of lower concentration is called ______.

A) osmosis
B) endocytosis
C) active transport
D) facilitated diffusion
E) diffusion

Question 31

The cell wall will help prevent the cell from bursting in ______ conditions.

A) mesotonic
B) hypotonic
C) isotonic
D) hypertonic

Question 32

Organisms that feed on dead organisms for nutrients are called ______.

A) parasites
B) saprobes
C) autotrophs
D) phototrophs
E) lithoautotrophs

Question 33

Saprobes do not need a carbon source for growth and metabolism.

Question 34

The process by which a cell uses ATP to enclose a substance in its membrane, by forming a vacuole and engul?ng it, is called ______.

A) facilitated diffusion
B) diffusion
C) active transport
D) endocytosis
E) osmosis

Question 35

The movement of substances from lower to higher concentration across a semipermeable membrane via a speci?c protein carrier and cell expenditure of energy is called ______.

A) endocytosis
B) active transport
C) facilitated diffusion
D) osmosis
E) diffusion

Question 36

Diffusion of water through a semipermeable membrane is called ______.

A) diffusion
B) endocytosis
C) facilitated diffusion
D) active transport
E) osmosis

Question 37

Obligate saprobes can adapt to a living host.

Question 38

When whole cells or large molecules in solution are engulfed by a cell, this endocytosis is speci?cally termed ______.

A) exocytosis
B) facilitated transport
C) phagocytosis
D) pinocytosis
E) facilitated diffusion

Question 39

Contractile vacuoles are _______.

A) used to expel excess water from cells
B) found in bacterial cells
C) important to certain organisms in hypertonic environments
D) protein carriers in cell membranes
E) used to bring solutes into a cell

Question 40

You want to experiment with microbial growth in various nutrients, so you inoculate a loopful of E. coli into a tube of honey. Which statement best describes what you expect to happen and why?

A) E. coli does grow because it has been dehydrated by the honey.
B) E. coli do not grow because there is only sugar in the honey and no other nutrients.
C) E. coli grows well in the honey because fructose is a good carbon source.
D) E. coli will not grow because the excessive sugar is toxic.

Question 41

Human pathogens fall into the group called ______.

A) thermophiles
B) psychrophiles
C) halophiles
D) acidophiles
E) mesophiles

Question 42

Facilitated diffusion and active transport require a carrier protein to mediate the movement across the plasma membrane.

Question 43

A microorganism that does not have catalase or superoxide dismutase would ?nd it di?cult to live in an environment with ______.

A) carbon dioxide
B) high salt
C) high acidity
D) oxygen
E) temperatures above 37° C

Question 44

Cultures of a bacterial strain were incubated in a refrigerator (5°C), on a lab bench (22°C), in a 37°C incubator, and in 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. Which term best describes
This organism?

A) Capnophile
B) Psychrotolerant
C) Anaerobe
D) Halophile
E) Mesophile

Question 45

The toxic superoxide ion is converted to harmless oxygen by two enzymes, _______.

A) superoxide dismutase and catalase
B) catalase and hydrogen peroxidase
C) superoxide dismutase and hydrogen peroxidase
D) superoxide dismutase and oxidase
E) catalase and oxidase

Question 46

Cultures of a bacterial strain 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/an ______.

A) anaerobe
B) microaerophile
C) facultative anaerobe
D) capnophile
E) obligate aerobe

Question 47

An organism that can use gaseous oxygen in metabolism and has the enzymes to process toxic oxygen products is a/an ______.

A) facultative anaerobe
B) aerobe
C) microaerophile
D) obligate anaerobe

Question 48

A microaerophile _______.

A) requires a small amount of oxygen but won't grow at normal atmospheric levels of oxygen
B) grows best in an anaerobic jar
C) grows with or without oxygen
D) needs normal atmospheric levels of oxygen

Question 49

An organism that can exist in both oxygen and oxygen-free environments is a/an ______.

A) aerobe
B) microaerophile
C) facultative anaerobe
D) obligate anaerobe
E) obligate aerobe

Question 50

An organism that grows slowly in the cold but has an optimum growth temperature of 30°C is called a/an ______.

A) thermoduric microbe
B) extremophile
C) psychrophile
D) psychrotolerant microbe
E) thermophile

Question 51

A microorganism that has an optimum growth temperature of 37°C, but can survive short exposure to high temperatures is called a/an ______.

A) extremophile
B) thermoduric microbe
C) psychrophile
D) facultative psychrophile
E) thermophile

Question 52

All of the following could ?nd a location in or on human body tissues suitable for growth except ______.

A) psychrophiles
B) anaerobes
C) capnophiles
D) facultative anaerobes
E) mesophiles

Question 53

The term obligate refers to _______.

A) using light for energy production
B) the ability to exist in a wide range of conditions
C) using oxygen for metabolism
D) using chemicals for energy production
E) existing in a very narrow niche

Question 54

Which statement is correct regarding microbial growth on food at refrigeration temperatures?

A) The growth of microbes in food depends on their optimal growth temperature; some grow slowly and others faster.
B) There is no growth of microbes in food in the refrigerator; the cold temperature kills or inactivates microbial cells.
C) The absence of light in the refrigerator greatly reduces the growth of most microbial pathogens.
D) Most food does not have enough oxygen content for microorganisms to thrive.

Question 55

An organism that cannot tolerate an oxygen environment is a/an ______.

A) obligate aerobe
B) microaerophile
C) facultative anaerobe
D) aerobe
E) obligate anaerobe

Question 56

An organism with a temperature growth range of 45°C to 60°C would be called a/an ______.

A) extremophile
B) facultative psychrophile
C) psychrophile
D) thermoduric microbe
E) thermophile

Question 57

An organism that cannot grow without oxygen is a/an ______.

A) microaerophile
B) aerobe
C) facultative anaerobe
D) obligate aerobe
E) obligate anaerobe

Question 58

What type of medium is used to demonstrate oxygen requirements of microbes?

A) Sul?te polymyxin sulfadiazine
B) Sodium chloride
C) Thioglycollate
D) Blood agar

Question 59

Mediated transport of polar molecules and ions across the plasma membrane utilizes a/an _____ carrier that binds to the substance and causes a conformational change to allow its movement across the membrane.

A) protein
B) enzyme
C) porin
D) lipid

Question 60

The term facultative refers to _______.

A) the ability to exist in a wide range of conditions
B) using light for energy production
C) using oxygen for metabolism
D) using chemicals for energy production
E) existing in a very narrow niche

Question 61

You inoculate a bacterium into three tubes of nutrient broth medium containing added salt: 0.5% NaCl, 5% NaCl, and 15% NaCl. After incubation, you notice signi?cant turbidity in the 15% NaCl medium and modest turbidity in the 5% NaCl medium. There is no growth in the third tube. This organism would be termed ______.

A) barophilic
B) osmophobic
C) halophilic
D) haloduric

Question 62

In a close relationship, a change in one partner that results from a change in the other partner is termed ______.

A) coevolution
B) antibiosis
C) synergism
D) mutualism
E) symbiosis

Question 63

In a commensal relationship, the commensal bene?ts but the cohabitant is neither harmed nor bene?ted.

Question 64

Organisms called _______ live on or in the body of a host and cause some degree of harm.

A) halophiles
B) mesophiles
C) aerobes
D) commensals
E) pathogens

Question 65

Which of the following properties is likely to be found in a pioneer colonizer of a bio?lm on an arti?cial joint implant?

A) No susceptibility to reactive oxygen species like peroxides
B) The ability to grow at thermophilic body temperature (37 ºC)
C) The ability to use the titanium from the implant as an energy source
D) Surface structures for attaching to tissue

Question 66

What is the difference between mutualism and synergism?

A) In a synergistic relationship, both organisms bene?t, but in a mutualistic relationship both organisms are harmed.
B) In a mutualistic relationship, both organisms bene?t, but in a synergistic relationship both organisms are harmed.
C) In a mutualistic relationship, the organisms are dependent upon each other.
D) In a synergistic relationship, the organisms cannot survive without each other.

Question 67

A halophile would grow best in ______.

A) arid, desert soil
B) fresh water ponds
C) acid pools
D) salt lakes
E) hot geyser springs

Question 68

The bio?lm that forms in your shower ("shower curtain scum") can tolerate exposure to hot water when you shower and is resistant to desiccation between showers. The microbes in the bio?lm are not endospores, so what is the best explanation for their survival under these conditions?

A) Bio?ms are composed of diverse microbes, and within each bio?lm, there are certain to be endospore-formers and thermophiles.
B) Although some microbes will be killed, those embedded deeply within the bio?lm are protected from environmental challenges.
C) The shower hasn't been thoroughly cleaned in a while, and when I really scrub it, the microbes will all be killed.
D) Dead skin cells continuously replenish the bio?lm, and organic soaps provide a continuous carbon source.

Question 69

When microbes are in a close nutritional relationship and one bene?ts but the other is not harmed, it is called ______.

A) symbiosis
B) commensalism
C) mutualism
D) synergism

Question 70

The majority of microbes live and grow in habitats between pH 7 and 9.

Question 71

You have inoculated a Clostridium species into a tube of media. After incubation, you observe that there is no growth, and you remember that Clostridium is an obligate anaerobe. What is the best explanation for the observed lack of growth?

A) There is not enough water in the environment for Clostridium to grow.
B) Oxygen in the medium destroys the enzymes needed by Clostridium to undergo aerobic respiration.
C) Clostridium does not have enzymes to process toxic oxygen.
D) There is not enough oxygen for use when toxic oxygen is present.

Question 72

Termites are insects that require the protozoan Trichonympha in their gut to synthesize the enzyme cellulase to degrade the cellulose in wood. The protozoan uses the end products of the cellulose breakdown (glucose). This is a/an ______ relationship.

A) mutualistic
B) parasitic
C) commensualistic
D) antagonistic

Question 73

Microorganisms that live in severe habitats, such as very hot, acidic, or salty environments, are called ______.

A) psychrophiles
B) thermophiles
C) barophiles
D) extremophiles
E) halophiles

Question 74

When microbes live independently but cooperate and share nutrients, it is called ______.

A) synergism
B) symbiosis
C) antibiosis
D) mutualism

Question 75

A barophile would grow best in ______.

A) salt lakes
B) arid, desert soil
C) deep oceans
D) hot geyser springs
E) acid pools

Question 76

A bacterium is inoculated into a tube of thioglycollate and incubated. After incubation, turbidity appears throughout, top to bottom, with the greatest turbidty at the very top. This bacterium would be called a(n) ______.

A) obligate aerobe
B) facultative anaerobe
C) aerotolerant microbe
D) microaerophile
E) psychrotroph

Question 77

Most microorganisms can only grow in habitats that are similar to human body conditions.

Question 78

After using jelly on a sandwich, you close the jar and place it on a room temperature shelf instead of in the refrigerator. When you open the jar several weeks later, you notice microbial growth on the surface. What type of organism is likely to grow in this environment?

A) Virus
B) Bacteria
C) Protozoa
D) Fungus

Question 79

Anaerobes can be cultured in a CO₂ environment.

Question 80

The production of antibiotics is a form of antagonism called ______.

A) synergism
B) symbiosis
C) antibiosis
D) mutualism