Micro - Midterm Flashcards
(114 cards)
1
Q
Name the four major biological groups of microorganisms that Microbiologists study
A
Bacteria
Fungi
Protozoa
Algae
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
3
Q
What is a protozoa?
A
Animal-like and mostly single celled organisms.
4
Q
What is a parasite?
A
Microorganisms which need to live on other living organisms.
5
Q
List the Characteristics of Microorganisms
A
- Small Size
- Unicellular Simplicity - single celled, very simple
- Growth Rate - usually very high, makes it easy for us to grow large amounts of microorganisms in a short amount of time.
- Adaptability - very important! Allows microbes to cause disease in humans.
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!!
7
Q
What microorganism adapts the fastest?
A
Viruses
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
9
Q
The smallest virus can be compared in size to what small molecule in the body?
A
Amino Acid
10
Q
T or F
Bacteria are smaller than RBC
A
True
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
12
Q
What type of microscope contains two magnifying lenses, a visible light source, and a condenser?
A
Compound Microscope - what we use today
13
Q
What are the names of the two lenses in a compound microscope?
A
Ocular & Objective
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.
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.
16
Q
Define magnification
A
Capacity of an optical system to enlarge small objects.
17
Q
What lens is the one that we look through and what is its magnification?
A
The ocular - 10X
18
Q
How many different objective lenses are there and what are their magnifications?
A
4 4X 10X 40X 100X
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
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
21
Q
What type of microscopes do we use in lab? How many different types are there?
A
Bright-field light microscope
4
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
23
Q
What scopes are good for looking at the living state of microbes?
A
Dark Field
Phase Contrast
Differential Interference
24
Q
What is the highest magnification for all four light microscopes? What will be the resolution?
A
2000X
.2um (200nm)
25
What type of scope has a magnification about 1 000 000X and a resolution of .5nm? What is it good for viewing
Transmission Electron Microscope
| - Viewing viruses.
26
What is the mag and reso for a scanning electron microscope?
100 000X
| 10nm
27
Name the appendages of bacteria cellular structure
Flagella/Axial Filaments
Pilli
Fimbriae
28
The cell envelop is composed what 3 structures/ components?
Glycocalyx, cell wall, cell membrane
29
What is a prokaryotic cell?
Bacteria
30
Name some different types of eukaryotic cells
Fungi, algae, protozoans, helminth worm, animal cells, and plant cells.
31
What is the proper name for common bacteria?
Eubacteria
32
What type of bacteria live in extreme environments such as high temp, high salt, or low pH?
Archebacteria
33
T or F
| The appendages are attached to the bacteria on both sides and are present on all species.
False
Only on one side. The other side is free, and not present in all species.
34
What are the appendages of motility?
Flagella and axial filaments
35
What is the function of the flagella?
To confer motility or self propulsion
| Provides capacity of a cell to swim freely through an aqueous habitat.
36
In what type of bacteria do we mostly find flagella?
Gram negative
37
Name the three distinct parts of Flagella
1. The Filament - out of the bacteria
2. The hook - attached to the bacteria
3. Basal body - inside the bacteria
38
What is the unique characteristics of the Basal body of the Flagella that allow it to move forward?
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.
39
What is an aka for the Axial Filament?
Fiber endoflagella
40
How do Flagella and the Axial Filaments differ?
- 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.
41
Is the movement caused by the Axial filaments jerky or smooth?
Jerky
42
T or F
| Fimbriae are long appendages of attachment?
False!
| Short appendages!
43
T or F
| Pili are found in gram negative bacteria?
True
44
What is a second function besides attachment of Pili?
They are involved in the mating process (conjugation)
45
T or F
| Every bacteria has a glycocalyx
False
46
Name the two forms of gylcocalyx
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
What is the name of the layer underneath the glycococalyx?
Cell Wall
48
T or F
| Almost all bacteria have a cell wall, the cell wall is essential for the survival of the bacteria.
True!
49
Name the substance that provides a relatively rigid protective quality of the cell wall.
Peptidoglycon
50
All of the following correctly describe gram positive microbes except:
Small amount of peptidogylcon
Acidic polysaccharides
Purple colour
Small amount of peptodoglycon! This is true for gram negative not gram positive.
51
What colour will gram positive stain?
Purple
52
What is unique about gram negative cell wall compared to gram positive?
The cell wall contains an outer membrane - two layers of lipopolysaccharide.
53
What is the name of the purple stain used for gram staining?
Crystal Violet
54
What does the crystal violet react with to form the purple colour?
Both + and - will stain purple because the crystal violet reacts with the peptidoglycon forming the purple precipitate.
55
T or F
| Gram's Iodine is a stain
False! It is an agent that works to increase the binding between the crystal violet and peptidoglycon.
56
What happens if you miss the Gram's Iodine step?
You will loose the crystal violet, which has precipitated but not bound.
57
How long do you have to put your slide in alcohol for when doing gram staining?
7 seconds.
58
What is the name of the red/pink stain?
Safranin
59
How does Safranin affect gram + and - microbes?
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
Why doesn't the outer membrane associated with the Gram negative bacteria prevent the alcohol from washing off the crystal violet?
Because the outer layer is made of lipids, and alcohol can dissolve the lipids and was the stain off of the peptidoglycon.
61
T or F
The Gram - bacteria picks up the primary stain.
The Gram + picks up the secondary stain.
False! It is the opposite + picks up primary and - picks up the secondary.
62
T or F
| If you use the stains in the wrong order your results will be reversed
True!
| Gram + will be pink and Gram - will be purple
63
What is the major component of protoplasm?
Cell Pool: composed of water, sugar, amino acids, and salts
64
Name the major components found scattered throughout the cell that were discussed in class.
```
Chromatin Body
Plasmid
Ribosomes
Mesosome
Granules
```
65
Some bacteria contain a piece of circular DNA called _______
The plasmid
66
What structure confers protective traits upon bacteria?
Plasmids
67
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
Storage! This is a job for the Granules not the mesosome.
68
Name the two different types of granules on bacteria and their function
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
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
Contains Ribosomes - this is in the bacterial cytoplasm not in the nucleus.
70
What type of bacteria will form endospores?
Only Gram +
71
T or F
| When favourable conditions arise, the endospore can germinate and give rise to an active vegetative cell of bacterium
True!
72
When are Endospore's formed/created?
Formed when conditions are unfavourable for continued growth of the bacteria.
73
Are coccus bacteria spherical or rod shaped?
Spherical or ball shaped! Bacillus are rod shaped
74
T or F
Spirilum = thin, flexible spiral shape
Spirochetes = thick, rigid spiral
False!! Opposite is true.
75
T or F
| Bacilli can form a palisade structure
True!!
| irregular pair, where bacteria join each other 2 x 2 in different directions
76
T or F
| Procaryots do not have a membrane surrounding the chromosomes.
True
77
What are the methods in which bacteria reproduce?
1. Binary Fission
| 2. Transvere Fission
78
What is the most common way for bacteria to reproduce?
Binary Fission
79
Describe Transverse Fission
Refers to the position of the division plane forming across the width of the cell. Division starts in mesosome.
80
What is budding?
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
How is bacterial growth measured?
By how many there are in a population, not how big each individual is.
82
What is meant by generation time or doubling time?
time required for a complete fusion cycle from parent to two daughter cells.
83
What is the doubling process when the population increases by a factor of 2?
Generation
84
How long does the Lag Phase last in bacterial growth?
5 hours
85
What is the name of the phase during which the cells are dividing rapidly and how long does it last?
Exponential Growth Phase - 5-16 hours
86
In what phase of bacterial growth does the patient begin to feel uncomfortable and the 1st clinical manifestations occur?
Exponential Growth Phase
87
How long does the Stationary Phase last?
16-33 hours
88
What phase in bacterial growth lasts the longest?
Death Phase 33-45 hours
89
What are the two ways to measure bacterial growth?
Spectrophotometer
| Viable Colony Count
90
What does the Spectrophotometer do?
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
What is a way that you can determine the exact number of bacteria and how?
Viable Colony Count - you make a serial dilution 10x10 of the solution and by taking the time you can determine the exact amount.
92
What is a genome?
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
A gene has different meanings based on what 3 different levels?
1. Organismic
2. Cellular
3. Molecular
94
Name the 4 basic steps in DNA Replication
1. Uncoiled
2. Unzipped
3. Biosynthesis
4. Zipped and Coiled
95
What operon controls catabolism?
Lactose Operon
96
T or F
| The Lac Operon is normally ON and can be turned OFF by certain substrates
False
| Normally OFF and can be turned ON
97
What is an Operon?
A cluster of genes responsible for gene regulation.
98
Name the 3 segments or loci of the Lac Operon
Regulator
Control Locus
Structural Locus
99
What is the function of the Regulator?
To make a protein which will repress the function of the operon.
100
T or F
| The Control Locus is made up of 3 genes eating coding for a different enzyme
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
Name the 3 enzymes that the Structural Locus codes to catabolize lactose
Beta-galactosidase
Permease
Tranacetylase
102
T or F
| As long as there is no lactose in the body the Lac Operon is off
True
When lactose is present the operon begins to function.
103
What is the name of the operon that controls anabolism or biosynthesis
The Repressible Operon
104
T or F
| The Repressible Operon is normally in the ON mode and will be turned OFF only when this nutrient is not required.
True
105
Using Arginine as an example describe what will happen to the repressible operon when there is enough Arginine
- 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
T or F
| The repressor protein binds to the operator gene
True
107
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.
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
T or F
| A nonsense mutation always results in a non-functional protein
True
109
Give an example of negative effects of mutation
Human Gene Mutation - alteration in a single protein is responsible for more than 400 diseases. E.g. sickle cell
110
Give an example of a positive effect of mutation
Microbial gene mutation - certain microorganisms bearing protective mutation can adapt to the new environment.
111
What is Genetic recombination?
A mechanism which bacteria have developed for increasing their adaptive capacity.
112
How does Genetic recombination work?
1 bacterium donates DNA to another (inter microbial transfer) and the end product is a new strain different from both.
113
What is another name for an extrachromosomal DNA? What is it?
Plasmid - a small genetic elements capable of independent replication in bacteria.
114
T or F
| Plasmids are found in the protoplasm
True
