Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Microbiology > Unit 1 > Flashcards

Unit 1 Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

What are the 4 types of bacterial cell organization?

A
  1. individual
  2. pairs = diplo
  3. chains = strepto
  4. three-dimensional clusters = staphylo
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Why is it beneficial for bacterial cell organization to be disrupted and for cells to be broken apart?

A

It allows them to initiate new groupings

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the 4 general shapes found among bacteria?

A
  1. round = coccus
  2. rod-shaped = bacillus
  3. slightly curved = vibrio
  4. spiral = spirillum
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

To which kingdom do all bacteria belong?

A

Kingdom Monera

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is quorum sensing?

A

The manner in which bacteria monitor their population. When the bacterial population goes up the concentration of signature molecules goes up and the bacteria respond by slowing down their metabolism.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the twofold purpose of quorum sensing?

A
  1. survival depending on nutrients

2. defense mechanism against antibiotics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What does antibiosis mean?

A

It means competition, that is where the word antibiotic comes from.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is symbiosis?

A

It is when bacteria work together in a way that helps each other out

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What percentage of bacteria has actually been studied (cultured and observed)?

A

1%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Generally, what size are eucaryotic cells?

A

10-20 micrometers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Generally, what size are procaryotic cells?

A

1-2 micrometers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the 4 primary

distinguishing characteristics between procaryotic and eucaryotic cells?

A
  1. size
  2. nucleus
  3. organelles
  4. cell wall
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

If procaryotic cells do not have a nucleus, what is the region where the DNA is located called?

A

It is called the nucleoid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Which type of cell does not have organelles?

A

procaryotic cells do not have membrane bound organelles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is contained inside of the nucleoid?

A

a single (unpaired), single (just one), circular chromosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What 3 things are contained in the cytoplasm of a procaryotic cell?

A
  1. plasmids
  2. enzymes
  3. cytoskeleton
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are plasmids?

A

smaller circles of DNA, they are polyploid with 10-20 genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What types of things are enzymes used for?

A

metabolism, replication, transcription

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What does the cytoskeleton provide to a cell?

A

It used for internal movements, for example it partitions the chromosome and plasmids during duplication

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the shape of the cytoskeleton?

A

It is shaped like a figure 8 or like a two-headed arrow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are exonucleases?

A

They are enzymes that cut the ends off of linear DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Why do procaryotic cells have exonucleases?

A

As protection against viruses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Why are ribosomes differences between eucaryotic and procaryotic cells so important?

A

Because they have the essential function of translating mRNA to proteins, the difference in structure allows for antibiotics to exploit ribosomes in procaryotic cells without causing any damage to the host

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is a plasma membrane made up of?

A

It is made up of a phospholipid bilayer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What are two are the primary differences between the plasma membrane of a eucaryotic and procaryotic cell?

A
  1. procaryotic do not have cholesterol in their membranes

2. the sodium channels are different

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What are pili (fimbrae) made up of?

A

They are made up of chains of proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What 3 components make up a flagella?

A

basal body, hook, and filament

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

How does the molecular motor of a flagella work?

A

It is powered via a hydrogen ion electrochemical gradient.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is a flagella made up of?

A

proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What is hypotonic lysis?

A

It is when water diffuses into a cell in order to equilize conc. and too much water entering leads to hydrostatic pressure pushing out on the plasma membrane and the bacteria exploding

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What is the primary function of a cell wall?

A

It holds the PM in, preventing hypotonic (osmotic) lysis, but still allow nutrients to enter the cell. It can do this because it is both strong and porous.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What is a cell wall composed of?

A

peptidoglycan which is: glycan -> two alternating sugars linked by glycoslytransferase enzymes and peptido -> 4-5 amino acids covalently connecting the sugar chains, these are linked by transpeptidase enzymes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What are teichoic acids?

A

Phosphate-glycerol polymers with amino acid or sugar side chains.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What type of bacteria have teichoic acid?

A

gram positive bacteria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What function do teichoic acids serve?

A

Because they are negatively charged, teichoic acids attract essential positively charged ions and the positive poles of water molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What is different about the walls of gram negative walls?

A

They only have a few PG layers and they do not have teichoic acid. They do however have an outer membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What is an outer membrane?

A

It is similar to a plasma membrane containing many channels, lipoproteins, and liposaccharides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What does the word ‘glycocalyx’ mean?

A

sugar coat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

What is a glycocalyx?

A

It is a layer on the outside of a bacterial cell wall made up of usually polysaccharides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

What is the function of a glycocalyx?

A

clumps of bacteria sharing glycocalyces make up a biofilm, it also allows for surface adhesion, h20 absorption and it shields against phagocytosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What is a thin glycocalyx layer called?

A

a slime layer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

What is a think glycocalyx layer called?

A

a capsule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

What is the name of the smallest known bacteria?

A

Mycoplasma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

What is significant about the structure of Mycoplasma?

A

They do not have a cell wall, but they do have lipoglycans in an outer membrane like plasma membrane. Since they do not have a cell wall they can only live in isotonic environments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

How is the outer membrane attached to the peptidoglycan layer in a gram negative bacteria?

A

via lipoproteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

Most bacteria constantly progress through cycles of growth and division and most are eventually killed by?

A

drying out (desiccation)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

What does it mean to say that a bacteria is able to become dormant?

A

That it is able to slow down its growth rate all the way to zero when conditions are unfavorable and are capable of staying alive that way for indefinite periods of time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

What does it mean to say that dormant forms of bacteria are resistant?

A

That they are not susceptible to harsh environmental conditions, they can even resist desiccation

49
Q

What is the dormant pattern of the bacterial genus Chlamydia?

A

It does not have peptidoglycan and it is capable of condensing into a dormant, resistant form called an elementary body

50
Q

What is the dormant pattern of the bacterial genus’ Bacillus and Clostridium (both gram +)?

A

They form endospores which are resistant to UV light, desiccation, heat, and chemicals. They are capable of surviving centuries in this form. When conditions improve they germinate into vegitative cells.

51
Q

How are endospores formed? What are endospores made up of?

A

When the environmental conditions become unfavorable the parent cell creates a copy of the chromosome that is even more condensed and it is placed inside of a PM that is surrounded by PG and also surrounded by a protein spore coat. When the parent cell dies, the resistant endospore is released into the environment.

52
Q

What are 5 endospore producing bacteria that commonly cause human diseases?

A
  1. Clostridium tetani
  2. Clostridium botulinum
  3. Clostridium perfringens
  4. Clostridium difficile
  5. Bacillus anthracis
53
Q

Where are Clostridium tetani endospores commonly found? What effect do they have?

A

In dry soil (dust), causes rigid paralysis = tetanus

54
Q

Where are Clostridium botulinum endospores commonly found? What effect do they have?

A

In fruit or vegetable canning. Produce an extremely potent toxin which causes flaccid paralysis

55
Q

Where are Clostridium perfringens endospores commonly found? What effect do they have?

A

In dry soil, are capable of causing gangrene

56
Q

Where are Clostridium difficile endospores commonly found? What effect do they have?

A

They can be found in the GI tract of humans and they produce a potent diarrhea-producing toxin when body defenses are weakened

57
Q

What are the effects of Bacillus anthracis endospores?

A

They cause anthrax

58
Q

Why is bacterial metabolism medically important?

A

Because knowing about it allows us to exploit the enzymes and this can control bacterial growth (and bacterial growth is what causes infections so….)

59
Q

Do bacteria have mitochondria?

A

No, they do not. But they essentially act like a mitochondria all on their own and they are capable of performing glycolysis and the electron transport system

60
Q

What is the endosymbiant hypothesis?

A

That a long time ago, bacteria were endocytosed into eucaryotic cells and became mitochondria

61
Q

Why are some bacteria able to survive without oxygen?

A

Because they are able to oxidize both organic and inorganic molecules. They are able to use other atoms as a final electron acceptor in the final electron transport system

62
Q

What are two ways in which glucose can be broken down in pyruvic acid?

A
  1. glycolysis

2. Entner-Doudoroff pathway (unique to certain bacteria; Pseudomonas)

63
Q

Give three examples of final electron acceptors that are not oxygen?

A
  1. N2
  2. S04 -2
  3. CO3 -2
64
Q

If they don’t get their energy from glucose -> pyruvic acid -> final electron acceptors; How else can bacteria get energy?

A

Fermentation

65
Q

Fermentation

A

Uses the products of glycolysis (pyruvic acid and NADH2) and yields ATP as well as lactic acid and 2NAD+

66
Q

Generally what is the effect of an increase in temperature on enzymatic activity?

A

Heat generally increases enzymatic activity because it increases the rate of diffusion of enzymes and their substrates

67
Q

However, if heat increases beyond a certain maximum what is the effect on enzymatic activity?

A

It decreases dramatically because the enzymes become denatured and bonds are not able to be formed with substrates

68
Q

What are the effects of slightly higher or lower pH values than optimum on enzymes?

A

It causes them to lose their affinity for their substrates, so the rate of reaction is reduced. Because OH- and H+ ions bind to the enzyme

69
Q

What are the effects of much higher or lower pHs than is optimum on enzymes?

A

The enzymes become denatured

70
Q

How does substrate/nutrient concentration affect metabolism?

A

If there is little to react with, ATP production will be slowed

71
Q

What are the two types of enzyme inhibitors?

A
  1. competitive

2. non-competitive

72
Q

What is a competitive inhibitor?

A

It is a molecule which competes with the normal substrate by binding to the active site on the enzyme. This results in no products or reactions

73
Q

What is a non-competitive inhibitor?

A

It is a molecule which inhibits an enzyme’s activity by binding to an allosteric site, this causes a conformational change to the active site, preventing the substrate from binding

74
Q

What effect does the release of haptoglobin from the liver have on an infection?

A

Haptoglobin binds to Fe, which is an essential molecule for bacteria, bacterial growth is slowed as a result.

75
Q

Why do bacteria require an acceptable temperature range in order to grow?

A

Because of the effects of temp on enzymatic activity

76
Q

What is an acceptable temperature range for a mesophile?

A

25-40 degrees C

77
Q

What is an acceptable temperature range for a psycrophile?

A

-5-20 degrees C

78
Q

What is an acceptable temperature range for a thermophile?

A

40-70 degrees C

79
Q

What is an acceptable temperature range for an extreme thermophile?

A

70-105 degrees C

80
Q

What is the effect of refrigeration on mesophiles?

A

It limits their growth

81
Q

What is the effect of freezing a mesophile?

A

It stops their growth, and if the ice crystals puncture their cell walls than it kills the mesophiles

82
Q

What is the acceptable pH range for most bacteria?

A

6.5 - 7.5

83
Q

Why is an acceptable pH so important for bacterial growth?

A

Because it alters enzymatic activity otherwise

84
Q

Why can bacteria tolerate hypotonic environments?

A

Because they have their cell walls to protect them from osmotic lysis

85
Q

Why can most bacteria not tolerate hypertonic (more than .9% ) environments?

A

Because all of the water inside of the cell would diffuse out of the cell causing the cell to die

86
Q

What are halophiles?

A

Bacteria that are able to survive in hypertonic environments (literally means “salt-lovers”)

87
Q

What salt conc. are facultative halophiles able to tolerate?

A

up to 10 %

88
Q

What salt conc. do extremem halophiles require?

A

approximately 30 %

89
Q

What are the 3 major physica/environmental requirements for bacterial growth?

A
  1. acceptable temperature range
  2. acceptable pH
  3. tolerable osmotic pressure
90
Q

What are the 5 major chemical requirements for bacterial growth?

A
  1. source of energy
  2. source of carbon
  3. source of mineral nutrients
  4. source of vitamins
  5. source of oxygen
91
Q

What 2 things can bacteria use as a source of energy?

A

They can use either organic or inorganic molecules when oxidizing

92
Q

What are the 2 main sources of carbon for bacteria?

A
  1. other organic molecules - recycling

2. photogenic bacteria use CO2 and the energy from the sun

93
Q

What mineral nutrients does bacteria need for growth?

A

N, S, P

94
Q

Where do bacteria get their mineral nutrients?

A

They get N from things like N2, NO3- and NH4+ and they get S and P from recycling host cell molecules

95
Q

Where do bacteria get vitamins?

A

Most bacteria synthesize their own, those that can’t get them from their environment

96
Q

For what two purposes might a bacteria need oxygen?

A
  1. organic synthesis

2. as a final e- acceptor in cellular respiration

97
Q

What are obligate anaerobes?

A

They are bacteria which require oxygen in order to produce ATP. They are able to deal with the byproducts of this : superoxide dismutase and hydrogen peroxide because they have these two enzymes : 1. superoxide 2. catalase ( or peroxidase)

98
Q

What are facultative anaerobes?

A

They are bacteria that can use oxygen because they can express the necessary enzymes, but they are also able to do fermentation instead.

99
Q

What are obligate anaerobes?

A

They are bacteria that lack superoxide dismutase, catalse, and peroxidase, and are therefor unable to use oxygen as a final e- acceptor becuse the by-products would be too toxic

100
Q

What is the mechanism of bacterial growth by binary fission?

A
  1. cell elongates as cytoplasmic components are duplicated
  2. chromosome is replicated and copies move to opposite ends of the cell
  3. wall forms between the now two cells which may or may not spontaneously break apart
101
Q

What the 4 main characteristics regarding

bacterial growth?

A
  1. growth is exponential as a power of 2
  2. generation time varies
  3. exponential growth cannot be maintained
  4. bacteria must adjust to a new environment before exponential growth can occur
102
Q

Why is bacterial growth exponential?

A

Because of binary fission. After each division the number of cells doubles

103
Q

What is generation time?

A

The amount of time it takes for a bacterial population to double

104
Q

What 2 factors cause a generation time to vary?

A
  1. the species of bacteria

2. how well it’s growth requirements are being met (temperature, pH, O2 supply etc.)

105
Q

Why can exponential growth not be maintained? (5 reasons)

A
  1. acidic waste products accumulate
  2. nutrient supplies diminish
  3. quorum sensing
  4. host cell’s defenses counter-attack in an infection
  5. host may take antibiotics
106
Q

What is the name of the time during which bacteria adjust to their environment before growing at exponential rates?

A

Lag phase

107
Q

Why does a lag phase occur in bacterial growth?

A

Because many times in a new environment the different nutrients that are present require different enzymes to be broken down than are currently being expressed.

108
Q

What are the 4 stages on a bacterial growth curve?

A
  1. lag phase
  2. log phase
  3. stationary phase
  4. decline phase
109
Q

What is occurring during the log phase?

A

Cells are dividing exponentially

110
Q

What is occurring during the stationary phase?

A

The number of cells being produced is equal to the number of cells dying

111
Q

What is occurring during the decline phase?

A

The number of cells dying is greater than the number of cells being produced.

112
Q

What are 5 important things to take into consideration when observing the growth of a bacterial colony?

A
  1. daughter cells will be able to divide more times than parent cells and will last loner
  2. bacteria in the colony are being exposed to different environments depending on their location
  3. differences in populations can occur due to mutations
  4. recycling of nutrients (cannibalism) can occur in a bacterial population
  5. endospores will allow a bacterial colony to survive longer
113
Q

How is the low dose risk of something determined?

A

By testing fewer animals at much higher doses and than extrapolating to low doses

114
Q

What is hormesis?

A

exposure to extremely low doses of toxic substances induces the up-regulation of body defense mechanisms, yielding less disease than no exposure at all

115
Q

What is homeopathy?

A

the claim that diseases can be treated or prevented by exposure to extremely low doses of toxins that cause similar symptoms (law of similars)

116
Q

What is the law of infintesimals?

A

That less is better, more dilute is better

117
Q

What are 4 reasons why homeopathy might work?

A
  1. natural course of disease
  2. placebo effect
  3. drugs relieve anxiety
  4. some pseudoscience drugs release endorphin’s
118
Q

What are three categories of treatment for bacterial growth control?

A
  1. pharmaceuticals - FDA approved
  2. dietary supplements - not FDA approved but must have disclaimers
  3. homeophathic - not FDA approved & no disclaimers

Microbiology (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions