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Microbiology > Micro - Midterm > Flashcards

Micro - Midterm Flashcards

1
Q

Name the four major biological groups of microorganisms that Microbiologists study

A

Bacteria
Fungi
Protozoa
Algae

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2
Q

What is Mycology?

A

The fungi- a group of organisms that includes both microscopic forms like mold and yeast and larger forms like mushrooms

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3
Q

What is a protozoa?

A

Animal-like and mostly single celled organisms.

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4
Q

What is a parasite?

A

Microorganisms which need to live on other living organisms.

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5
Q

List the Characteristics of Microorganisms

A
  1. Small Size
  2. Unicellular Simplicity - single celled, very simple
  3. Growth Rate - usually very high, makes it easy for us to grow large amounts of microorganisms in a short amount of time.
  4. Adaptability - very important! Allows microbes to cause disease in humans.
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6
Q

T or F

Microbes can do harm to our bodies but our bodies cannot harm them because they are less adaptable than we are.

A

False

They are more adaptable!!

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7
Q

What microorganism adapts the fastest?

A

Viruses

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8
Q

T or F

The largest virus is the size of the largest bacteria

A

False

The largest virus is the size of the smallest bacteria

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9
Q

The smallest virus can be compared in size to what small molecule in the body?

A

Amino Acid

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10
Q

T or F

Bacteria are smaller than RBC

A

True

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11
Q

What is the range of vision of the human eye compared to the range of a light microscope?

A

Human eye: 1-2mm & we cannot see objects smaller than 2mm with the naked eye
Light Microscope: 100mm

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12
Q

What type of microscope contains two magnifying lenses, a visible light source, and a condenser?

A

Compound Microscope - what we use today

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13
Q

What are the names of the two lenses in a compound microscope?

A

Ocular & Objective

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14
Q

What does the condenser do?

A

A special lense to converge (focus) the rays of light to a single point on the object.

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15
Q

T or F

The condenser in the compound microscope functions in magnification.

A

False

This condenser lens does NOT function in magnification, it just collects the light toward the object.

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16
Q

Define magnification

A

Capacity of an optical system to enlarge small objects.

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17
Q

What lens is the one that we look through and what is its magnification?

A

The ocular - 10X

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18
Q

How many different objective lenses are there and what are their magnifications?

A 
4
4X
10X
40X
100X
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19
Q

What is known as the product of the separate power of magnification of each lens?

A

Total Magnification

Ocular lens mag x objective lens mag

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20
Q

T or F
The capacity of an optical system to distinguish or separate two adjacent objects or points from each other is known as Clarity

A

False

Known as Resolution

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21
Q

What type of microscopes do we use in lab? How many different types are there?

A

Bright-field light microscope

4

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22
Q

What is the best type of microscope is the best scope to see dead bacteria fixed on a slide?

A

Bright-Field Light Scope

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23
Q

What scopes are good for looking at the living state of microbes?

A

Dark Field
Phase Contrast
Differential Interference

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24
Q

What is the highest magnification for all four light microscopes? What will be the resolution?

A

2000X

.2um (200nm)

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25
Q

What type of scope has a magnification about 1 000 000X and a resolution of .5nm? What is it good for viewing

A

Transmission Electron Microscope

- Viewing viruses.

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26
Q

What is the mag and reso for a scanning electron microscope?

A

100 000X

10nm

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27
Q

Name the appendages of bacteria cellular structure

A

Flagella/Axial Filaments
Pilli
Fimbriae

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28
Q

The cell envelop is composed what 3 structures/ components?

A

Glycocalyx, cell wall, cell membrane

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29
Q

What is a prokaryotic cell?

A

Bacteria

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30
Q

Name some different types of eukaryotic cells

A

Fungi, algae, protozoans, helminth worm, animal cells, and plant cells.

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31
Q

What is the proper name for common bacteria?

A

Eubacteria

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32
Q

What type of bacteria live in extreme environments such as high temp, high salt, or low pH?

A

Archebacteria

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33
Q

T or F

The appendages are attached to the bacteria on both sides and are present on all species.

A

False

Only on one side. The other side is free, and not present in all species.

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34
Q

What are the appendages of motility?

A

Flagella and axial filaments

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35
Q

What is the function of the flagella?

A

To confer motility or self propulsion

Provides capacity of a cell to swim freely through an aqueous habitat.

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36
Q

In what type of bacteria do we mostly find flagella?

A

Gram negative

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37
Q

Name the three distinct parts of Flagella

A
  1. The Filament - out of the bacteria
  2. The hook - attached to the bacteria
  3. Basal body - inside the bacteria
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38
Q

What is the unique characteristics of the Basal body of the Flagella that allow it to move forward?

A

4 rings and a rod
- the rings rotate counter-clockwise and the bacteria rotates clockwise, the two opposite rotations cause the forward movement of the bacteria.

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39
Q

What is an aka for the Axial Filament?

A

Fiber endoflagella

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40
Q

How do Flagella and the Axial Filaments differ?

A
  • Axial filament is a modified flagellum with only 2 parts a long thing microfibril, inserted into a hook.
  • endoflagella is also made of protein but it is entirely inside the bacteria.
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41
Q

Is the movement caused by the Axial filaments jerky or smooth?

A

Jerky

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42
Q

T or F

Fimbriae are long appendages of attachment?

A

False!

Short appendages!

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43
Q

T or F

Pili are found in gram negative bacteria?

A

True

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44
Q

What is a second function besides attachment of Pili?

A

They are involved in the mating process (conjugation)

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45
Q

T or F

Every bacteria has a glycocalyx

A

False

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46
Q

Name the two forms of gylcocalyx

A
  1. Slim Layer - protects bacteria from loss of water and nutrient. Loosely bound this layer can be washed off
  2. Capsule - this layer has a thick, gummy consistency, and cannot be washed off easily.
47
Q

What is the name of the layer underneath the glycococalyx?

A

Cell Wall

48
Q

T or F

Almost all bacteria have a cell wall, the cell wall is essential for the survival of the bacteria.

A

True!

49
Q

Name the substance that provides a relatively rigid protective quality of the cell wall.

A

Peptidoglycon

50
Q

All of the following correctly describe gram positive microbes except:
Small amount of peptidogylcon
Acidic polysaccharides
Purple colour

A

Small amount of peptodoglycon! This is true for gram negative not gram positive.

51
Q

What colour will gram positive stain?

A

Purple

52
Q

What is unique about gram negative cell wall compared to gram positive?

A

The cell wall contains an outer membrane - two layers of lipopolysaccharide.

53
Q

What is the name of the purple stain used for gram staining?

A

Crystal Violet

54
Q

What does the crystal violet react with to form the purple colour?

A

Both + and - will stain purple because the crystal violet reacts with the peptidoglycon forming the purple precipitate.

55
Q

T or F

Gram’s Iodine is a stain

A

False! It is an agent that works to increase the binding between the crystal violet and peptidoglycon.

56
Q

What happens if you miss the Gram’s Iodine step?

A

You will loose the crystal violet, which has precipitated but not bound.

57
Q

How long do you have to put your slide in alcohol for when doing gram staining?

A

7 seconds.

58
Q

What is the name of the red/pink stain?

A

Safranin

59
Q

How does Safranin affect gram + and - microbes?

A

The gram + won’t take the new stain and change its colour because it is already purple but the - that is now colourless after step three will pick up the red or pink stain.

60
Q

Why doesn’t the outer membrane associated with the Gram negative bacteria prevent the alcohol from washing off the crystal violet?

A

Because the outer layer is made of lipids, and alcohol can dissolve the lipids and was the stain off of the peptidoglycon.

61
Q

T or F
The Gram - bacteria picks up the primary stain.
The Gram + picks up the secondary stain.

A

False! It is the opposite + picks up primary and - picks up the secondary.

62
Q

T or F

If you use the stains in the wrong order your results will be reversed

A

True!

Gram + will be pink and Gram - will be purple

63
Q

What is the major component of protoplasm?

A

Cell Pool: composed of water, sugar, amino acids, and salts

64
Q

Name the major components found scattered throughout the cell that were discussed in class.

A 
Chromatin Body
Plasmid
Ribosomes
Mesosome 
Granules
65
Q

Some bacteria contain a piece of circular DNA called _______

A

The plasmid

66
Q

What structure confers protective traits upon bacteria?

A

Plasmids

67
Q

All of the following are true regarding Mesosomes except:

  • areas of the cell membrane that fold up into the cytoplasm and increases internal surface area.
  • Storage
  • functions in DNA replication
  • functions in division and secretion
A

Storage! This is a job for the Granules not the mesosome.

68
Q

Name the two different types of granules on bacteria and their function

A
  1. Membrane-bound Granules - for storage of organic compounds such as glycogen or starch
  2. Non-membrane-bound Granules - for storage of inorganic compounds such as iron and other metals, sulfur or iodine.
69
Q

All of the following are related to Bacterial Nucleus except:

  • no surrounded by a nuclear membrane
  • does not contain mitotic apparatus
  • contains ribosomes
  • may be observed in stained cells
A

Contains Ribosomes - this is in the bacterial cytoplasm not in the nucleus.

70
Q

What type of bacteria will form endospores?

A

Only Gram +

71
Q

T or F

When favourable conditions arise, the endospore can germinate and give rise to an active vegetative cell of bacterium

A

True!

72
Q

When are Endospore’s formed/created?

A

Formed when conditions are unfavourable for continued growth of the bacteria.

73
Q

Are coccus bacteria spherical or rod shaped?

A

Spherical or ball shaped! Bacillus are rod shaped

74
Q

T or F
Spirilum = thin, flexible spiral shape
Spirochetes = thick, rigid spiral

A

False!! Opposite is true.

75
Q

T or F

Bacilli can form a palisade structure

A

True!!

irregular pair, where bacteria join each other 2 x 2 in different directions

76
Q

T or F

Procaryots do not have a membrane surrounding the chromosomes.

A

True

77
Q

What are the methods in which bacteria reproduce?

A
  1. Binary Fission

2. Transvere Fission

78
Q

What is the most common way for bacteria to reproduce?

A

Binary Fission

79
Q

Describe Transverse Fission

A

Refers to the position of the division plane forming across the width of the cell. Division starts in mesosome.

80
Q

What is budding?

A

A process in which a small protuberance develops at one end of the cell. The protuberance enlarges and eventually develops into a new cell that separates from the parent cell.

81
Q

How is bacterial growth measured?

A

By how many there are in a population, not how big each individual is.

82
Q

What is meant by generation time or doubling time?

A

time required for a complete fusion cycle from parent to two daughter cells.

83
Q

What is the doubling process when the population increases by a factor of 2?

A

Generation

84
Q

How long does the Lag Phase last in bacterial growth?

A

5 hours

85
Q

What is the name of the phase during which the cells are dividing rapidly and how long does it last?

A

Exponential Growth Phase - 5-16 hours

86
Q

In what phase of bacterial growth does the patient begin to feel uncomfortable and the 1st clinical manifestations occur?

A

Exponential Growth Phase

87
Q

How long does the Stationary Phase last?

A

16-33 hours

88
Q

What phase in bacterial growth lasts the longest?

A

Death Phase 33-45 hours

89
Q

What are the two ways to measure bacterial growth?

A

Spectrophotometer

Viable Colony Count

90
Q

What does the Spectrophotometer do?

A

As the bacteria grow in a solution it makes the solution more cloudy, the spectrophotometer is a machine that can measure the approximate colour or cloudiness of the water.

91
Q

What is a way that you can determine the exact number of bacteria and how?

A

Viable Colony Count - you make a serial dilution 10x10 of the solution and by taking the time you can determine the exact amount.

92
Q

What is a genome?

A

Total genetic materials of a cell. The size of the genome vary from 4-5 genes (virus) to more than 100,000 (in humans and plants)

93
Q

A gene has different meanings based on what 3 different levels?

A
  1. Organismic
  2. Cellular
  3. Molecular
94
Q

Name the 4 basic steps in DNA Replication

A
  1. Uncoiled
  2. Unzipped
  3. Biosynthesis
  4. Zipped and Coiled
95
Q

What operon controls catabolism?

A

Lactose Operon

96
Q

T or F

The Lac Operon is normally ON and can be turned OFF by certain substrates

A

False

Normally OFF and can be turned ON

97
Q

What is an Operon?

A

A cluster of genes responsible for gene regulation.

98
Q

Name the 3 segments or loci of the Lac Operon

A

Regulator
Control Locus
Structural Locus

99
Q

What is the function of the Regulator?

A

To make a protein which will repress the function of the operon.

100
Q

T or F

The Control Locus is made up of 3 genes eating coding for a different enzyme

A

False!

The structural Locus is made up of the 3 genes. The Control Locus is only made of 2 the promoter and the operator.

101
Q

Name the 3 enzymes that the Structural Locus codes to catabolize lactose

A

Beta-galactosidase
Permease
Tranacetylase

102
Q

T or F

As long as there is no lactose in the body the Lac Operon is off

A

True

When lactose is present the operon begins to function.

103
Q

What is the name of the operon that controls anabolism or biosynthesis

A

The Repressible Operon

104
Q

T or F

The Repressible Operon is normally in the ON mode and will be turned OFF only when this nutrient is not required.

A

True

105
Q

Using Arginine as an example describe what will happen to the repressible operon when there is enough Arginine

A
  • Arginine will bind to the repression protein making it active.
  • The newly active repression protein sits on the operator gene blocking transcription which prevents enzyme production and blocks arginine from being made.
  • When arginine is used up the one bound to the repression protein will break free making the repressor inactive.
106
Q

T or F

The repressor protein binds to the operator gene

A

True

107
Q

Find the mismatch:
Spontaneous mutation : random change in DNA
Induced mutation: exposure to mutagens
Point mutation: a change in the code that leads to a different aa
Nonsense mutation: changes in normal codon into stop codon that does not code for an amino acid.

A

Point mutation is not a change in the code that leads to a different amino acid.

Point mutation = change in a few bases (addition, removal, or substitution)

108
Q

T or F

A nonsense mutation always results in a non-functional protein

A

True

109
Q

Give an example of negative effects of mutation

A

Human Gene Mutation - alteration in a single protein is responsible for more than 400 diseases. E.g. sickle cell

110
Q

Give an example of a positive effect of mutation

A

Microbial gene mutation - certain microorganisms bearing protective mutation can adapt to the new environment.

111
Q

What is Genetic recombination?

A

A mechanism which bacteria have developed for increasing their adaptive capacity.

112
Q

How does Genetic recombination work?

A

1 bacterium donates DNA to another (inter microbial transfer) and the end product is a new strain different from both.

113
Q

What is another name for an extrachromosomal DNA? What is it?

A

Plasmid - a small genetic elements capable of independent replication in bacteria.

114
Q

T or F

Plasmids are found in the protoplasm

A

True

Microbiology (3 decks)

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