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Microbiology > Chapter 9 > Flashcards

Chapter 9 Flashcards

1
Q

In which type of symbiotic relationship do both members benefit?

A) Commensalism
B) Mutualism
C) Parasitism
D) Antagonism

A

B) Mutualism

Explanation: Mutualism is a type of symbiotic relationship where both organisms benefit from the association.

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2
Q

The large intestine is commonly colonized by which type of bacteria due to its relatively oxygen-free environment?

A) Obligate aerobes
B) Facultative anaerobes
C) Obligate anaerobes
D) Microaerophiles

A

C) Obligate anaerobes

Explanation: The large intestine provides a habitat with low oxygen levels suitable for the colonization of obligate anaerobes.

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3
Q

Fill in the Blank: An organism that does not grow at normal atmospheric concentrations of oxygen but requires a small amount of it in metabolism is called a ______________.

A

Microaerophile

Explanation: Microaerophiles require lower levels of oxygen than are present in the atmosphere and are adapted to live in environments with these conditions.

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4
Q

Which type of organism obtains energy from inorganic compounds?

A) Photoautotroph
B) Chemoautotroph
C) Photoheterotroph
D) Chemoheterotroph

A

B) Chemoautotroph

Explanation: Chemoautotrophs obtain energy by oxidizing inorganic substances and typically use carbon dioxide as a carbon source.

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5
Q

Which method is a non-culture-based method for analyzing bacterial growth?

A) Plate counting
B) Flow cytometry
C) Serial dilution
D) Spread plate technique

A

B) Flow cytometry

Explanation: Flow cytometry is a non-culture-based method that counts and analyzes bacteria by passing them through a laser.

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6
Q

True or False: In commensalism, one organism is harmed while the other benefits.

A) True
B) False

A

B) False

Explanation: In commensalism, one organism benefits, and the other is not significantly harmed nor benefited.

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7
Q

Carbon, nitrogen, oxygen, and hydrogen are considered _________ because they are required in relatively large quantities, whereas manganese, zinc, and copper are considered _________ because they are required in very small quantities.

A) nonessential; essential
B) micromolecules; macromolecules
C) macronutrients; micronutrients
D) elements; atoms

A

C) macronutrients; micronutrients

Explanation: Essential nutrients can be divided into two classes depending on the relative quantities required by an organism. Macronutrients are nutrients that are required in relatively large quantities and include carbon, hydrogen, oxygen, and nitrogen. Micronutrients are required in very small quantities and there is a lengthy list of these, including manganese, zinc, and copper.

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8
Q

What is an organism called that must have oxygen because it uses gaseous oxygen in its metabolism and possesses the enzymes to process toxic oxygen products?

A) Anaerobe
B) Facultative anaerobe
C) Microaerophile
D) Obligate aerobe

A

D) Obligate aerobe

Explanation: Obligate aerobes require oxygen for their metabolism and have the necessary enzymes to deal with toxic by-products of oxygen use.

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9
Q

Fill in the Blank: Iron is a ____________ nutrient for bacterial cells because it is required in smaller amounts.

A

micronutrient

Explanation: Iron is a micronutrient; it is required in trace amounts and often serves as a cofactor in enzymes.

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10
Q

What is the doubling time in the context of bacterial growth?

A) Time taken for the bacterial population to increase by 50%
B) Time taken for the bacterial population to double
C) Time taken for the bacterial population to reach stationary phase
D) Time taken for one bacterial cell to divide

A

B) Time taken for the bacterial population to double

Explanation: Doubling time is the time required for a bacterial population to double in number.

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11
Q

True or False: Simple diffusion requires energy input from the cell.

A) True
B) False

A

B) False

Explanation: Simple diffusion does not require energy as it is a passive process driven by the concentration gradient.

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12
Q

Fill in the Blank: ___________ is a type of relationship where the parasite benefits at the expense of the host, which is harmed.

A

Parasitism

Explanation: Parasitism is a symbiotic relationship in which the parasite derives benefit while the host is negatively affected.

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13
Q

Fill in the Blank: The movement of molecules from an area of higher concentration to an area of lower concentration is known as ____________.

A

diffusion

Explanation: Diffusion is the process where molecules move from an area of higher concentration to one of lower concentration until equilibrium is reached.

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14
Q

Fill in the Blank: In ___________, members cooperate and share nutrients.

A

Synergism

Explanation: Synergism is a type of association where members work together cooperatively, often sharing nutrients for their mutual benefit.

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15
Q

Select the term that refers to a microbe able to survive very low pH conditions.

A) Halophile
B) Osmophile
C) Alkalinophile
D) Acidophile

A

D) Acidophile

Explanation: Acidophiles thrive in low pH environments.

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16
Q

In active transport, molecules are moving across the membrane from an area of ______ concentration to an area of ______ concentration.

A) low; high
B) high; low

A

A) low; high

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17
Q

A majority of medically important microbes are classified as

A) mesophiles.
B) psychrophiles.
C) endotherms.
D) thermophiles.

A

A) mesophiles.

Explanation: The majority of pathogens are mesophilic microbes, with optimal temperatures at or near body temperature.

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18
Q

Another two-word term for micronutrients is

A) limited nutrients.
B) trace elements.
C) essential elements.
D) nonessential nutrients.

A

B) trace elements.

Explanation: Micronutrients are nutrients required in very small quantities. They are also known as trace elements.

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19
Q

The time required for one complete cycle of binary fission is known as the _________, or generation time.

A) mitotic
B) mating
C) doubling
D) meiotic

A

C) doubling

Explanation: This division is referred to as doubling time, because each generation involves one bacterial cell dividing into two daughter cells.

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20
Q

True or False: Selenium is a major essential nutrient required by all bacterial cells for survival.

A) True
B) False

A

B) False

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21
Q

What factors can affect the doubling time of a bacterial cell?

A) Temperature
B) Moisture
C) pH
D) Oxygen levels
E) All of these factors can affect growth rates.

A

E) All of these factors can affect growth rates.

Explanation: There are many physical and chemical factors that can affect growth, including temperature, oxygen and carbon dioxide levels, water activity, pressure, pH, availability of nutrients, and several other factors.

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22
Q

Which term describes an organism that can switch between aerobic and anaerobic metabolism depending on whether oxygen is available?

A) Obligate aerobe
B) Facultative anaerobe
C) Obligate anaerobe
D) Microaerophile

A

B) Facultative anaerobe

Explanation: Facultative anaerobes can metabolize either by aerobic respiration when oxygen is present or by anaerobic methods such as fermentation when it is not.

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23
Q

Which is FALSE regarding binary fission?

A) Division involves the formation of a band of proteins resembling actin and tubulin of eukaryotes.
B) It is a type of asexual reproduction.
C) Like meiosis in eukaryotes, it specifically produces daughter cells with genetic variation.
D) Daughter cells are identical to each other.

A

C) Like meiosis in eukaryotes, it specifically produces daughter cells with genetic variation.

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24
Q

Which term describes the length of time of a microbial species needs to divide?

A) Binary fission
B) Growth time
C) Generation time
D) Mitosis time

A

C) Generation time

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25
Q

Bacterial cells placed in a solution where the concentration of solute within the cytoplasm is less than that of the extracellular solution would undergo ______.

A) swelling
B) no change
C) plasmolysis
D) lysis

A

C) plasmolysis

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26
Q

What is the primary active transport?

A) Movement of molecules against the concentration gradient using ATP
B) Movement of water across a membrane
C) Movement of molecules with the concentration gradient without ATP
D) Transport of molecules that involves changing their chemical structure

A

A) Movement of molecules against the concentration gradient using ATP

Explanation: Primary active transport involves the direct use of metabolic energy (ATP) to move molecules against their concentration gradient.

27
Q

True or False: A facultative anaerobe requires oxygen for its metabolism.

A) True
B) False

A

B) False

Explanation: Facultative anaerobes do not require oxygen for their metabolism as they are capable of aerobic respiration when oxygen is present and anaerobic metabolism in its absence.

28
Q

What type of microbial association is depicted in this figure?

A) Parasitism
B) Synergism
C) Commensalism
D) Antagonism

A

A) Parasitism

Explanation: Bacteriophages are destructive to their bacterial host cells. Therefore, the phage benefits by using the host cell for replication, but the host cell is harmed in the process. This is an example of parasitism, a symbiotic relationship.

29
Q

True or False: ATP is only found in animal cells.

A) True
B) False

A

B) False

Explanation: ATP is found in all types of living cells, including animal, plant, and microbial cells.

30
Q

True or False: Obligate anaerobes have the enzymes to detoxify oxygen and can survive in its presence.

A) True
B) False

A

B) False

Explanation: Obligate anaerobes lack the enzymes for processing toxic oxygen and will die if exposed to it.

31
Q

In a hypertonic solution, a cell will typically:

A) Swell
B) Stay the same
C) Shrink
D) Divide

A

C) Shrink

Explanation: In a hypertonic solution, water leaves the cell, causing it to shrink.

32
Q

True or False: A saprobe is an organism that obtains its nutrients from living hosts.

A) True
B) False

A

B) False

Explanation: A saprobe is an organism that derives its nutrients from dead or decaying organic matter, not from living

33
Q

Fill in the Blank: The process of converting ADP to ATP is known as ____________.

A

phosphorylation

Explanation: The conversion of ADP (adenosine diphosphate) to ATP is known as phosphorylation, where a phosphate group is added to ADP.

34
Q

True or False: During the stationary phase of bacterial growth, the number of bacteria decreases due to nutrient depletion and waste accumulation.

A) True
B) False

A

B) False

Explanation: During the stationary phase, the number of live bacteria remains constant; it is during the death phase that the number decreases.

35
Q

True or False: Microaerophiles can grow under normal atmospheric oxygen levels.

A) True
B) False

A

B) False

Explanation: Microaerophiles require oxygen for growth, but at lower concentrations than that of the atmosphere.

36
Q

True or False: Budding is a form of asexual reproduction where a new organism develops from an outgrowth due to cell division at one site.

A) True
B) False

A

A) True

Explanation: Budding is indeed a process where a new organism develops from an outgrowth, and it’s a form of asexual reproduction used by some bacterial species.

37
Q

Fill in the Blank: ____________ are organisms that use light as an energy source and obtain carbon from organic compounds.

A

Photoheterotrophs

Explanation: Photoheterotrophs are organisms that use light for energy and organic compounds for their carbon source.

38
Q

Pathogens usually have _________ doubling times.

A) short
B) moderate
C) long

A

A) short

Explanation: Pathogens usually have short doubling times, allowing the population to grow quickly before it is eliminated from the body.

39
Q

Choose the phase of the bacterial growth curve during which a bacterial population has the shortest doubling time.

A) Lag phase
B) Exponential growth phase
C) Stationary growth phase
D) Death phase

A

B) Exponential growth phase

Explanation: A bacterial population would have its shortest doubling time when it is growing at its most rapid rate, which would occur during the exponential growth phase.

40
Q

A particular microorganism produces a substance that kills another microorganism in its environment. This is an example of ______________.

A

antagonism.

41
Q

True or False: Selenium is a major essential nutrient required by all bacterial cells for survival.

A) True
B) False

A

B) False

Explanation: Selenium is not an essential nutrient of bacterial cells. The essential nutrients are C, H, O, N, P, and S.

42
Q

_________________ are a large number of bacterial pathogens that fall into the category of facultative anaerobes.

A

Gram-negative intestinal bacteria and staphylococci

Explanation: Many bacterial pathogens, including gram-negative intestinal bacteria and staphylococci, are facultative anaerobes, using aerobic respiration when oxygen is available and switching to anaerobic metabolism when it is not.

43
Q

You ingest 20 cells of Salmonella. This bacterium has a doubling time of 30 minutes. After 4 hours, how many of these bacteria would be present in the body (assuming no immune system responses or other biological activities affect its growth)?

A) 160
B) 320
C) 2,560
D) 5,120

A

D) 5,120

Explanation: Four hours represents 8 generations (or 8 doubling times of 30 minutes each). A starting population of 20 cells would become 5,120 after four hours. You can use this equation to solve the problem: Nf = (Ni)2n

44
Q

Fill in the Blank: During the ___________ phase of bacterial growth, bacteria are adapting and preparing for active division.

A

Lag

Explanation: The lag phase is a period of adaptation where bacteria prepare for growth but do not divide immediately.

45
Q

True or False: Antagonism is a type of symbiotic relationship where both organisms are harmed.

A) True
B) False

A

B) False

Explanation: Antagonism is a relationship where one organism is inhibited or destroyed by another, but it does not necessarily harm both.

46
Q

True or False: After binary fission, daughter cells will differ genetically.

A) True
B) False

A

B) False

47
Q

What type of anaerobes can survive and even grow to a limited extent in the presence of oxygen?

A) Obligate anaerobes
B) Facultative anaerobes
C) Microaerophiles
D) Aerotolerant anaerobes

A

D) Aerotolerant anaerobes

Explanation: Aerotolerant anaerobes do not utilize oxygen but can survive and grow to a limited extent in its presence because they have alternative mechanisms for breaking down toxic oxygen products like peroxides and superoxide.

48
Q

An aerobic bacterium that requires oxygen at a concentration less than that in the atmosphere is a(n) ___________.

A

microaerophile.

49
Q

If human red blood cells are placed in a vial of pure water,

A) the net water movement is into the cell.
B) an isotonic gradient is created.
C) a hypertonic gradient is created.
D) the net water movement is out of the cell.

A

A) the net water movement is into the cell.

50
Q

Fill in the Blank: The _______________ is an important site for anaerobic infections due to the anaerobic pockets that can occur there.

A

Oral cavity

Explanation: The oral cavity, specifically the pockets between gums and teeth, can be anaerobic and may foster the growth of microbes that cause infections like gingivitis.

51
Q

Which organism lacks the metabolic enzyme systems for using oxygen in respiration?

A) Obligate aerobe
B) Facultative anaerobe
C) Obligate anaerobe
D) Microaerophile

A

C) Obligate anaerobe

Explanation: Obligate anaerobes lack the enzymes required for processing oxygen and cannot tolerate its presence in their environment.

52
Q

During binary fission, one bacterial cell becomes _________ cells.

A) four genetically unique
B) two genetically identical
C) two genetically unique
D) four genetically identical

A

B) two genetically identical

Explanation: Binary fission involves one bacterial cell dividing into two genetically identical cells.

53
Q

True or False: Osmosis is the diffusion of solutes across a membrane.

A) True
B) False

A

B) False

Explanation: Osmosis is specifically the diffusion of water across a semipermeable membrane, not solutes.

54
Q

Which term describes a relationship where organisms are free-living and do not require associations with others for survival?

A) Symbiotic
B) Nonsymbiotic
C) Mutualism
D) Commensalism

A

B) Nonsymbiotic

Explanation: Nonsymbiotic relationships are those where organisms are free-living, and their survival does not depend on a close association with another organism.

55
Q

True or False: Carbon is considered a micronutrient for bacterial cells.

A) True
B) False

A

B) False

Explanation: Carbon is a macronutrient for bacterial cells as it is required in large amounts for building cellular components.

56
Q

If human red blood cells are placed in a vial of pure water,

A) the net water movement is into the cell.
B) an isotonic gradient is created.
C) a hypertonic gradient is created.
D) the net water movement is out of the cell.

A

A) the net water movement is into the cell.

Explanation: Cellular cytoplasm is not 100% water, so this creates a hypotonic condition and results in a net movement of water into the cell over time.

57
Q

What does ATP stand for?

A) Adenosine triphosphate
B) Advanced triprotein
C) Amino trisaccharide phosphate
D) Angular triphasic particle

A

A) Adenosine triphosphate

Explanation: ATP stands for adenosine triphosphate, which is the energy currency for the cell.

58
Q

If a cell is in a solution that is hypotonic relative to the cytoplasm, how will water move?

A) Neither into nor out of the cell
B) Out of the cell by osmosis
C) Into the cell by osmosis

A

C) Into the cell by osmosis

59
Q

A microbe’s nutritional type (e.g., chemoheterotroph) is determined by its sources of ______ and ______.
Select two.

A) nitrogen
B) carbon
C) energy
D) sulfur

A

B) carbon
C) energy

60
Q

An organism that grows at pH levels below 7 is called a(n) _________.

A

acidophile.

61
Q

The solute concentration in the environment is equal to the solute concentration within the cell under _________ conditions.

A

isotonic

62
Q

True or False: Exponential growth in bacteria is unsustainable for long periods in a closed system due to limited resources.

A) True
B) False

A

A) True

Explanation: Exponential growth is usually unsustainable because resources become limited and waste products accumulate, eventually leading to the stationary and death phases.

63
Q

Which component is not part of an ATP molecule?

A) Ribose
B) Adenine
C) Glucose
D) Phosphate group

A

C) Glucose

Explanation: Glucose is not a part of an ATP molecule. ATP consists of ribose, adenine, and three phosphate groups.

Microbiology (12 decks)

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