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Microbiology > Ch4 Study Guide > Flashcards

Ch4 Study Guide Flashcards

0
Q

What is the major function of the cell wall?

A

To prevent bacterial cells from rupturing when the water pressure inside the cell is greater than the outside

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1
Q

Why is an endospore called a resting structure? Of what advantage is an endospore to a bacterial cell?

A

An endospore is called a resting structure because it provides a method for one cell to “rest,”or survive, as opposed to grow and reproduce. The protective endospore wall allows a bacterium to withstand adverse conditions in the environment.

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2
Q

A group of bacteria that have unique structure and motility

A

Spirochetes

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3
Q

How do Spirochetes move?

A

By means of axial filaments, or endoflagella

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4
Q

Bundles of fibrils that arise at the ends of the cell beneath an outer sheath and spiral around the cell
-structure for motility found in Spirochetes

A

axial filaments/endoflagellum

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5
Q

Occur at the poles of bacterial cell or can be evenly distributed over the entire surface of the cell

A

Fimbriae

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6
Q

What are the three basic shapes of bacteria?

A
  • cocci(berry shaped/spherical)
  • bacillus (rod-shaped)
  • spiral
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7
Q

many prokaryotes secrete on their surface a substance called

A

Glycocalyx

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8
Q

Where is glycocalyx produced?

A

Inside the cell and secreted to the cell surface

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9
Q

If the substance is organized and is firmly attached to the cell wall, the glycocalyx is described as a

A

Capsule

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10
Q

The presence of a capsule can be determined by using which staining technique?

A

Negative staining

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11
Q

If the substance is unorganized and only loosely attached to the cell wall, the glycocalyx is described as a

A

Slime layer

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12
Q

The degree to which a pathogen causes disease is called?

A

Virulence

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13
Q

In certain species, capsules are important in contributing to?

A

Bacterial virulence

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14
Q

By the cells of the host, capsules often protect pathogenic bacteria from?

A

Phagocytosis

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15
Q

A glycocalyx that helps cells in a biofilm attach to their target environment and to each other is called an

A

Extra cellular polymeric substance (EPS)

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16
Q

Long filamentous appendages that propel bacteria are called

A

Flagella

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17
Q

Bacteria that lack flagella are referred to as

A

Atrichous (without projections)

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18
Q

The movement of a bacterium toward or away from a particular stimulus is called

A

Taxis

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19
Q

What flagellar protein is useful for distinguishing among serovars, or variations within a species, of gram-negative bacteria?

A

H antigen

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20
Q

Hairlike appendages that are shorter, straighter, and thinner than flagella and are used for attachment and transfer of DNA rather than for motility are called

A

pili

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21
Q

used for attachment and transfer of DNA.

A

pili

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22
Q

Gram-_______ bacteria contain pili.

A

negative

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23
Q

Peptidoglycan consists of a repeating ______ attached by _______ to form a lattice that surrounds and protects the entire cell.

A

disaccharide, polypeptides

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24
Q

Is it gram-positive or gram-negative bacteria, that contain teichoic acid?

A

Only gram-positive bacteria contain teichoic acid

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25
Q

The two classes of teichoic acids are: _____, which spans the peptidoglycan layer and is linked to the plasma membrane, and ______, which is linked to the peptidoglycan layer

A

lipoteichoic acid, wall teichoic acid

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26
Q

Teichoic acids, which consist primarily of an ______ (such as glycerol or ribitol) and ____.

A

alcohol, phosphate

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27
Q

Some pili are used to bring bacteria together allowing the transfer of DNA from one cell to another, in a process called _________.

A

conjugation

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28
Q

The major function of the cell wall is to prevent bacterial cells from ________

A

rupturing

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29
Q

The dissaccharide portion is made up of monosaccharides called ______ and _______.

A
  1. N-acetylglucosamine (NAG)

2. N-acetylmuramic acid (NAM)

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30
Q

Penicillin interferes with peptidoglycan in what way?

A

Interferes with the final linking of the peptidoglycan rows by peptide cross-bridges

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31
Q

The lipopolysaccharide (LPS) of the outer membrane is a large complex molecule that contains lipids and carbohydrates and consists of three components:

A
  1. Lipid A
  2. A core polysacharride
  3. O polysacharride
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32
Q

When gram-negative bacteria die, they release ______, which functions as an ______.

A

lipid A, endotoxin

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33
Q

What is responsible for the symptoms associated with infections by gram-negative bacteria such as fever, dilation of blood vessels, shock, and blood clotting?

A

Lipid A

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34
Q

The O polysaccharide functions as an ______ and is useful for distinguishing species of gram ____ bacteria.

A

antigen, negative

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35
Q

The role of O polysaccharide is comparable

to that of ______ _____ in gram-positive cells.

A

teichoic acids

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36
Q

When essential nutrients are depleted, certain gram-_____ bacteria, such as those of the genera Clostridium and Bacillus, form specialized “resting” cells called _____.

A

positive, endospores

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37
Q

The major structures in the cytoplasm of prokaryotes are a _____ (containing DNA), particles called ______, and reserve deposits called ______.

A

nucleoid, ribosomes, inclusions

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38
Q

What is the endosymbiotic hypothesis?

A
  • explains the origin of eukaryotes from prokaryotes
  • both mitochondria and chloroplasts used to be independent living external organisms, used to be bacteria, that were engulfed by bigger cells by phagocytosis
39
Q

Why do we consume fiber?

A
  • adds regularity to bowel movements
  • lowers cholesterol LDL
  • acts as a sponge that removes toxic materials, and decreases chance of colon cancer
40
Q

thick peptidoglycan layer, 60-90% of cell wall

Teichoic and lipoteichoic acid

A

Gram-positive

41
Q
  • thin peptidoglycan layer; 10-20% of cell wall
  • no teichoic acid
  • lipopolysaccharide that has three components: lipid A, a core polysaccharide, and an O polysaccharide
A

Gram-negative

42
Q

-component of gram-negative outer membrane; endotoxin

A

Lipid A

43
Q
  • Role is to provide stability

- it is attached to Lipid A and contains unusual sugars

A

Core polysaccharide

44
Q
  • extends outward from the core polysaccharide
  • composed of sugar molecules
  • functions as an antigen and is useful for distinguishing species of gram-negative bacteria
A

O polysaccharide

45
Q
  • the fluid component inside the plasma membrane

- mostly water, with inorganic and organic molecules, DNA, ribosomes, and inclusions

A

Cytoplasm

46
Q

The fluid portion of cytoplasm

A

Cytosol

47
Q

the region in a bacterial cell containing the chromosome

-contains the DNA of bacterial chromosome

A

Nucleoid

48
Q

a small circular DNA molecular that replicates independently of the chromosome

A

Plasmid

49
Q

Endospores contain a large amount of organic acid called

A

Dipicolinic acid

50
Q

protects the endospore DNA against damage

A

Dipicolinic acid

51
Q

protects bacteria from boiling, acids, and bases

A

Calcium dipicolinate

52
Q

3 germs are known for undergoing endospore formation

A
  • clostridium
  • bacillus
  • sporosaraina
53
Q

The process of endospore formation within a vegetative cell takes several hours and is known as

A

sporulation or sporogenesis

54
Q

Vegetative cells of endospore-forming bacteria begin sporulation when?

A

a key nutrient, such as carbon or nitrogen source, becomes scarce or unavailable

55
Q

an endospore can remain dormant for how long?

A

thousands of years

56
Q

an endospore returns to its vegetative state by a process called

A

Germination

57
Q

how is germination triggered?

A

By physical or chemical damage to the endospore’s coat

58
Q

Metabolism resumes when?

A

the Endospores enzymes then break down the extra layers surrounding the endospore

59
Q

Sporulation in bacteria is not a means of reproduction because?

A

one vegetative cell forms a single endospore, which, after germination, remains one cell

60
Q

Vegetative cells are killed by temperatures above?

A

70C

61
Q

Endospores can survive in what type of environment?

A

In boiling water for several hours

62
Q

Thermophilic (heat-loving) Endospores can survive in boiling water for?

A

19 hours

63
Q

describe lysozyme?

A
  • natural source, found spit
  • breaks down peptidoglycan
  • cuts the bond of NAM and NAG
64
Q

One way the cell can be damaged is by exposure to the digestive enzyme

A

Lysozyme

65
Q

Where is the lysozyme particularly active?

A

On the major cell wall components of most gram-positive bacteria, making them vulnerable to lysis

66
Q

A gram-positive bacteria or plant cell treated to remove the cell wall
*no specific, shape all that is left is the plasma membrane

A

Protoplast

67
Q

A gram-negative bacterium treated to damage the cell wall, resulting in a spherical shape

A

Spheroplast

68
Q

Three types of of osmotic solutions

A
  • isotonic solutions
  • hypotonic solution
  • hypertonic solution
69
Q

a medium in which the overall concentration of solutes equals that found inside a cell,

A

Isotonic solution

70
Q

Water enters and leaves the cell at the same rate (no net change); the cell’s contents are in equilibrium with the solution outside the cell wall

A

Isotonic solution

71
Q

Outside the cell is a medium whose concentration of solutes is
lower than inside the cell

A

hypotonic solution

72
Q

Most bacteria live in what kind solution?

A
  • hypotonic solution

* the cell wall resists further osmosis and protects cells from lysis

73
Q

A medium having a higher concentration of solutes than inside the cell has

A

Hypertonic solution

74
Q

What happens to bacterial cells in hypertonic solution?

A

*the bacterial cells placed in a hypertonic solution shrink and collapse or plasmolyze because water leaves the cells by osmosis

75
Q

Is the plasmolysis of red blood cells when exposed to a hypertonic solution

A

Crenation

76
Q

Describe penicillin

A
  • a betalactum antibiotic
  • only works if the bacteria is actively dividing
  • inhibits the synthesis of peptidoglycan
77
Q

If you treat a gram (+) bacterial cell with lysozyme, then it breaks down the cell wall (peptidoglycan) leaving the cell without a cell wall is called?

A

Protoplast

78
Q

If you treat a gram (-) bacterial cell with lysozyme, then it breaks down the cell wall (peptidoglycan) by breaking down the glycocytic bonds between NAM & NAG leaving the bacterial cell without a cell wall is known as?

A

Spheroplast

79
Q

Difference between a spheroplast and a protoplast?

A

spheroplast—> gram (-) bacterial cell without cell wall

protoplast—-> gram (+) bacterial cell without cell wall

80
Q

Most prokaryotes range between

A

0.5-2.0 micrometers

81
Q

Human blood cells range between

A

7.5 micrometers in diameter

82
Q

Spiral bacteria are how long?

A

60 micrometers long

83
Q

Typically bacteria displays 3 basic shapes which are?

A
  • coccus(cooci)—-> spiral shaped bacteria
  • bacillus—–> rod-liked shape bacteria
  • coccobacilli——> short rod intermediate between a cocci and a bacillus
84
Q

A common shape bacteria

A

Vibria

85
Q

A rigid, wavy-shaped bacteria

A

Spirillum/ spirilla

86
Q

A corkscrew-shaped bacteria

A

Spirochete

87
Q

What is pleomorphism?

A

Pleomorphic bacteria that have no specific shape

88
Q

How does bacteria divide?

A

By binary fission, but sometimes bacteria divide and remain stuck together

89
Q

How long does it take for E. coli to divide?

A

20 mins

90
Q

Bacteria that lack flagella

A

Atrichous

91
Q

Having flagella distributed over the entire cell

A

Peritrichous

92
Q

Having a single flagellum

A

Monotrichous

93
Q

Having flagella at both ends of a cell

A

Amphitrichous

94
Q

Kills bacteria

A

Bactericidal

95
Q

Kills microbes and inactivates viruses

A

Germicide

Microbiology (7 decks)

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