Exam 1 Flashcards
1
Q
What is microbiology?
A
The study of living things that are too small to be seen without any magnification
2
Q
What are some microorganisms? (7)
A
Bacteria Archea Fungi Protists Algae Viruses Helminth warms
3
Q
Why are microbes important? Give 2 examples
A
Microbes are important for nutrients and energy cycling
Ex: 1) Photosynthesis, light energy converted into chemical energy
2) Decomposition, break down complex molecules
4
Q
What are some ways in which humans use microorganisms? (3)
A
1) Industry, food and chemical production
2) Biotechnology, drug and vaccine production
3) Bioremediation, use of microbes to break down unwanted or harmful waste products
5
Q
What are the three most important diseases caused by microorganisms in the US?
A
Influenza
Pneumonia
Septicemia (bloodstream infection)
6
Q
What are the four most common diseases caused by microorganisms world wide?
A
Respiratory infections
HIV/AIDS
Diarrheal
TB
7
Q
Describe Prokaryotes
A
Unicellular organisms
Lack nucleus and other membrane bound organelles
Include bacteria and archea
8
Q
Describe eukaryotes
A
Unicellular OR multicellular
Contain nucleus and membrane bound organelles
9
Q
What are viruses?
A
Acellular particles composed of nucleic acid packaged in a protein coat
10
Q
Who was Robert Hooke?
A
Used microscopes to examine surfaces and living things
First description of organisms and cells
11
Q
Who was Antony Van Leeuwenhoek?
A
Made his own lenses
Observed organisms
12
Q
Who was Edward Jenner?
A
Investigated reports that those who developed cowpox did not com down with small pox
First vaccine
13
Q
Who were Oliver Wendell Holmes and Ignaz Semmelweis?
A
They made the link between doctors not washing their hands and hospital infections. They noticed that puerperal fever was a common infection during child birth. Semmelweis insisted that doctors washed their hands with calcium chloride solution between patients. Deaths on maternity wards fell from 12% to 1%. Holmes noticed similar link, and also between work on cadavers and subsequent infections.
14
Q
Who was Joseph Lister?
A
Developed aseptic technique. He noticed that patients who survived surgery often died soon afterwards of “ward”fever. He suggested to use phenol to sterilize surgical instruments. Death rates fell from 45% to 15%
15
Q
What is the spontaneous generation hypothesis?
A
Vital forces in non living matter produced living things
16
Q
What is the biogenesis hypothesis?
A
Living things arise from preexisting living cells
17
Q
Who was Louis Pasteur?
A
Disproved spontaneous generation. Studied fermentation and food spoilage. Developed pasteurization. Made links between microbes and diseases. Developed vaccines for anthrax and rabies
18
Q
Who was the “Germ Theory King”?
A
Robert Koch
First to link a disease to a microbe and outline germ theory. 21 diseases were identified as caused by microbes
19
Q
What are the Koch’s postulates?
A
1) The microorganisms must be present in every case of the disease
2) The microorganism must grow in pure culture from diseased hosts
3) The same disease must be produced when a pure culture of the microorganism is introduced into susceptible hosts
4) The same microorganisms must be recovered from experimentally infected hosts
20
Q
Who was Alexander Fleming?
A
He discovered the first modern antibiotic penicillin. He also discovered lysozyme, a protective digestive enzyme
21
Q
Who was Selman Waksman?
A
Discovered streptomycin and coined the term antibiotic
22
Q
What is a scientific method?
A
Deductive reasoning process to investigate the world around us.
23
Q
What are the five “I”’s of culturing microbes?
A
1) Inoculation
2) Isolation
3) Incubation
4) Inspection
5) Identification
24
Q
What is inoculation?
A
Introduction of a sample into a container of media to produce a culture of observable growth
25
What is isolation?
Separating one species from another
26
What is incubation?
Placing a sample under conditions that allow growth. Cells divide and provide observable growth. Different organisms have different temperature preferences.
27
Inspections and identifications
Make macroscopic and microscopic observations of the growth, biochemical test etc..
28
What are two isolation methods developed by Robert Koch?
1) Streak plate technique
| 2) Pour plate technique
29
What is the difference between a “pure culture” and “mixed culture”?
One type of organism vs. more than one type of organism
30
How disposal of cultures happen?
Potentially hazardous cultures and specimen are usually disposed of by: steam sterilization or incineration
31
What is the general purpose of media?
Support growth of many different types of organisms
32
What are some common examples of media?
Nutrient agar and tryptic soy agar
33
What is selective media?
One type of organism can grow
34
What is differential media?
Two types of organisms can grow, but they will difference in appearance
35
What is complex media?
Exact chemical composition is unknown, contain break down product of yeast, animal or plant material
36
What is defined media?
We know the exact chemical compostion
37
What are two key characteristics of a reliable microscope?
Magnification, the ability to enlarge objects
| Resolving power, the ability to show details
38
What is resolution?
The ability to distinguish two objects as separate objects
39
What is light microscopy bright field?
Standard lab microscope
| Light source is visible light, can be used for live, fixed or stained samples.
40
What is light microscopy dark field?
Light directed as sample from an angle. Better visual contrast between cells and background. Can view living, mobile cells, no staining is required
41
What is staining?
Stains enhance difference between cells and background, increase contrast.
42
Simple stain vs. differential stain
Simple, uses only one stain
| Differential, uses at least two stains
43
Positive stain vs. negative stain
Positive, stains cells
| Negative, stains background
44
Why are electron microscopes better In resolution?
They have shorter wavelength, which means greater resolution. Can examine viruses and internal structures.
45
What is TEM?
Transmission Electron Microscopy
| Electrons pass through the sample, you can view internal structures
46
What is SEM?
Scanning Electron Microscopy
| Electrons are aimed at surface of the structure, being reflected and detected, this will result in a 3D image
47
What is the functional definition of species?
A group of organisms that interbreed to produce viable offspring
48
What are the 8 levels of classification?
1) domain
2) kingdom
3) phylum or division
4) class
5) order
6) family
7) genus
8) species
49
What are the domains of life and who determined them?
Bacteria
Archea
Eukarya
Carl Woese
50
What is taxonomy?
A group of organisms based on similarities
51
How can you determine taxonomy?
```
Look at sequences of RNA sequences/genes
Cell morphology colony appearance
Bacterial physiology
Serological analysis
Genetic and molecular analysis
```
52
What is the bacterial physiology based on?
Bergy’s manual of the systematic bacteriology
53
What is the definition of species for bacteria?
Collection of bacterial cells sharing overall pattern of traits that differ from the pattern in other bacteria.
54
What is a strain or variety?
A culture obtained from a single parent that differs in structure or metabolism from other cultures of the species
55
What is a “type”?
A subspecies that can show differences in antigenic makeup (serotype or serovar). Susceptibility to bacterial viruses (phage type) and in phatogenicity (phatotype)
56
How is phenotypical qualities used for identification in clinical diagnosis?
Divide bacteria based on cell wall structure, shape, arrangement, and physiological traits. Used for clinical identification of pathogens not taxonomy
57
What are the types of coccus (sphere) bacteria?
1) Diplococci: pairs of cells
2) Streptococci: chains of cells
3) Tetrads: four cells
4) Sarcinae: cubes or packets of cocci
5) Staphylococci: grape-like bunches
58
What are the types of bacillus (rod) bacteria?
1) Diplobacilli: pairs of bacilli
2) Streptobacilli: chains of cells
3) V-shape and palisade arrangement
59
Vibrio
Curved
60
Spirillum
Rigid curved spiral
61
Spirochete
Flexible cork screw
62
What is a pleomorphic bacteria?
A bacteria that lack a cell wall in varied cell shapes
63
What is the outer coating membrane of a bacteria called? What are some characteristics of this membrane?
The outer membrane is called Glycocalyx.
It is made of polysaccharide, protein or both
It functions for attachment and protection
64
There are two types of glycocalyx, what are they?
1) Slime layer, loosely associated with cell surface
| 2) Capsule, more organized structure, more tightly associated with a cell, it is a key virulence trait
65
What are biofilms? Give 1 example
3D communities of microorganisms. Cells are embedded in extra cellular polymetric substance of carbohydrate rich. Difficult to remove all cells
Ex. Dental plaque
66
What are 3 external appendages?
1) Flagella
2) Pili
3) Fimbriae
67
What are flagella properties/ characteristics?
A molecular motor
3 part structure:
1) filament (propeller), made of flagellin (protein)
2) hook, connect filament and basal body
3) basal body (motor), anchored to a wall and membrane
68
What is the function of the flagella?
Movement, motility, whip-like movement of the filament propels bacteria
69
What are the 4 arrangements of the flagella?
1) monotrichous, one flagellum at the end
2) lophotrichous, bunches of flagella at the end
3) amphitrichous, flagella at both ends
4) peritrichous, flagella all over the cell
70
What is “taxis” and what are the two types of it?
Taxis is the movement towards or away the stimuli
- chemotaxis: in response to chemical
- phototaxis: in response to light
71
What are the 2 flagella movements?
Run: counter clockwise flagellar rotation propels bacteria forward
Tumbling: clockwise rotation
72
What are spirochetes? Give 2 examples
Helical cells with axial filaments, located between cell wall andouter sheath. Rotation leads to a corkscrew motion
Ex.
1) Treporema pallidum: syphilis
2) Borrelia burgdorferi: Lyme disease
73
What is fimbriae? Give 2 examples
Short rods, appendages made of protein used for attachment.
Ex.
1) Neisseria gonorrhoeae: gonorrhea
2) Escherichia Coli: food poisoning
74
What are pili (plural) pilus (singular)?
Long rigid tubular structure, used for DNA exchange.
75
What is a cell envelope?
Cell membrane and cell wall, maintains cell integrity.
76
What are the two groups of envelope and their characteristics?
1) Gram positive: thick peptidoglycan layer and cell membrane
2) Gram negative: outer membrane, thing peptidoglycan layer and cell membrane
77
What is a peptidoglycan?
A disaccharide polymer made of
- N-acetylmuramic acid (NAM)
- N-acetylglucosamine (NAG)
- peptide crosslinks
78
What is the difference peptidoglycan in Gram Positive and Gram Negative?
- Gram Positive: there is indirect peptide interbridge between tetrapeptides
- Gram negative: there is direct connections between tetrapeptides
79
What are the characteristics of a Gram negative cell wall?
Thin peptidoglycan layer
| Outer membrane is a barrier to antibiotics
80
What are the characteristics of a mycobacterium? Give 2 examples
Provide resistance to many chemicals and dyes. Identified using acid fast stain. Gram positive cell wall structure.
Ex. 1) mycobacterium tuberculosis
2) mycobacterium leprae
81
What are the characteristics of mycoplasma? Give one example
No cell wall, cell membrane reinforced by sterols, very small
Ex. Mycoplasma pneumoniae
82
What are the 5 internal contents of the cell?
1. Cytoplasm
2. DNA
3. Ribosomes
4. Inclusions
5. Endospores (not all bacteria)
83
What are 3 characteristics of bacterial chromosome?
1. Single, circular double stranded protein
2. Contains information for synthesizing proteins
3. Not surrounded by a membrane
84
Which region in the cell is the chromosome found?
Nucleoid
85
What type of DNA do bacteria have? What are some characteristics of it?
```
Plasmids:
Extrachromosomal, circular double stranded
Replicate on their own
Transferable
Carry advantageous genes
```
86
What are inclusions?
They do accumulation of nutrients (storage), vary in size, number and content
87
What are some types of inclusions? (5)
1. Poly b-hydroxybutarate (PHB): energy
2. Metachromatic granules: phosphate storage
3. Sulfur granules: energy
4. Gas vesicles: buoyancy
5. Magnetosomes: magnetotaxis
88
Name the innermost layer to the outermost of an endospore:
Core-> cortex -> spore coat -> exosporium
89
How is endospore generated?
Sporulation, stimulated by the lack of nutrients. Endospore formation happens inside of the mother cell, DNA must be replicated.
90
What are endospore structures?
Survival structures that are metabolic innactive, formed when cells run out of nutrients. Very resistant to heat, chemicals, etc. contains DNA, ribosomes and RNA, which are the essential components for resuming metabolism and growth
91
What are the 4 steps of sporulation cycle?
1. Activation
2. Germination
3. Outgrowth: new vegetative cell
4. Not reproduction
92
Eukaryotic cell wall are rich in....
Carbohydrates
93
What defines fungi cell walls?
Chiatin
94
What are some characteristics of eukaryotic cell membrane?
Phospholipid bilayer, stabilized by sterols, for example cholesterol in animals
95
DNA is __________ into RNA
Transcribed
96
RNA is _________ into proteins
Translated
97
What is an endomembrane system? Give some examples
Series of single membranes bound organelles.
| Ex. Endoplasmic reticulum, Golgi apparatus, vesicles, lysosomes, vacuoles....
98
What is an endoplasmic reticulum?
Network of sacs and tubules made of membrane
99
What are two forms of endoplasmic reticulum?
Rough ER and smooth ER
100
Rough ER synthesizes.....
Protein
101
Smooth ER synthesizes......
Lipids
102
What are vesicles responsible for?
Transport, move material around the cell from the ER to golgi
103
What is the Golgi apparatus composed of and what is its function?
Golgi is a stack of membranous sacs responsible for protein folding, packing, modification and sorting.
104
What are lysosomes composed of and what are their function?
Lysosomes contain enzymes that lyse substances, digest complex molecules , break down damaged cell components (autophagy) and ingested material
105
What are mitochondria responsible for?
Site of energy, production and biosynthesis
106
What do chloroplasts do and where are they found?
They convert light energy into chemical energy and they are found in plants and protists
107
What is the endosymbiosis theory?
Chloroplasts and mitochondria appear to have originated as free living bacteria. Because they contain their own genome, replicate separate from cell cycle and have double membrane.
108
What is the cytoskeleton composed of?
Microtubules (largest)
Microfilaments (smallest)
Intermediate filaments
109
What is the microtubule function?
Move eukaryotic cells: flagella and cilia
110
What are two types of microscopic fungi and their morphologies?
1. Yeast: round, ovoid cells
| 2. Hyphae: long filaments
111
What are some characteristics of yeast?
Form loose colonies with uniform texture and appearance. Cells may divide by fission or budding
112
What are some filamentous fungi characteristics?
Grow in mass of hyphae called mycelium. Have a hairy texture. Hyphae may be divided by cross walls
113
What are the types of fungal reproduction and their characteristics?
1. Asexual: hyphae can elongate, fragments can form a new colony. Scores formed by mitosis and released, mitotic division of yeast cells
2. Sexual: meiosis to reproduce haploid cells
114
What is the fungal classification based on?
Mating structures
115
What are the different types of protists?
Sarcondina
Mastigophora (flagellates)
Ciliophora (ciliates)
Sporozoa (apicomplexa)
116
What are viruses?
Acellular pathogens
117
What is the only way that viruses can replicate?
Inside host cells, intracellular parasites
118
What is the structure of a virus?
Capsid (protein coat) protects nucleic acid genome
| Capsid + DNA called the nucleocapsid
119
Some virus have a membrane coating, what is it called?
Viral envelope
120
What are the three types of viruses?
Helical
Polyhedral
Complex
121
What is the viral genome?
DNA: ds or ss, linear or circular
OR
RNA: usually ss, may be ds
122
Function of nucleic acid
Carries genes necessary for host cell invasion and for directing host machinery to assemble new viruses
123
What may be present in the virus particle? Give some examples
Some pre-formed enzymes may be present in the virus particle:
Polymerase: DNA or RNA
Replicate: copy RNA
Reverse transcriptase: synthesis of DNA from RNA
124
What does reverse transcriptase do?
Synthesis of DNA from RNA
125
Replicase
Copy of RNA
126
How the replication of animal viruses happen?
1. Attachment
2. Entry
3. Synthesis
4. Assembly
5. Release
127
Explain attachment and entry
It is the interaction between the virus surface and the host cell surface (adsorption)
Genome enters the host cell
Genome is released from capsid (uncoating)
128
How does the host range of a virus work?
Adsorption depends on a virus happening to interact with the surface of a cell with appropriate surface receptors
129
Hepatitis B infects.....
Liver cells
130
Polio virus infects....
Primate intestinal and nerve cells
131
Rabies infects....
Various mammalian cells
132
HIV infects....
Certain blood cells CD4 + T cells
133
Synthesis
Viral components produced
134
Assembly
New viral particles constructed
135
Release
Exocytosis or cell lysis
136
What is the cytopathic effect that the viruses cause to the host cells?
Virus induced damage to cells
Changes cell in size and shape. Cytoplasmic inclusions bodies. Cell fusion into mutinucleated cells. DNA alterations and cancerous transformation. Cell lysis
137
What are the two types of viral infection?
Persistent infection and latent infection
138
Persistent infection
Host cell not immediately lysed
| Can shed viruses for an extended period
139
Latent infection
Viral genetic information incorporated into host genome. Can be reactivated later.
Ex. Measles virus in brain cells
Herpes simplex virus: cold sores and genital herpes
Herpes zoster: chickenpox and shingles
140
What are the medical importance of viruses?
Most common causes of acute infections
Some infections have a high mortality rate
Possible connection of viruses to chronic afflictions of unknown cause
141
How does replication of bacteriophage happens?
Only DNA enters the cell, so no uncoating necessary
