Microbiology 6-10 Flashcards
1
Q
Define Virus
A
- Obligate intracellular paracites not cells
- piece of nucleiod acid in a caspid
2
Q
isocahedral shape
A
- polyhedral like soccer ball
- 20 faces, each equilateral triangles, forms hollow sphere
- nucleic acid inside
- amount of capsomeres depend on viral type
3
Q
Helical Shape
A
- Viral nucleoid acid and capsomeres helically coiled together to form hollow rod
- all animal helical viruses are RNA
4
Q
Viral Envelope
A
- outer lipid membrane surrounding virion
- acquired as virion buds through host cell membrane
5
Q
What are viral spikes?
A
- Viral spikes are glycoprotein on the outer surface of a virus
6
Q
What happens if the virus has a spike protein on the surface?
A
If the virus has a spike protein on its surface, it plays the major role to the attachment of the virus. Binding.
7
Q
What are the functions of Viral Spikes?
A
- Attachments to host cell receptors; initiate entrance
- Host makes antibodies specific for spikes.
- Virus evades immune response
8
Q
virus measurement
A
- nanometers
- 1nm= 1/1000000 mm
9
Q
3 major methods to study disease
A
-animal models: disease process and immune response
-chick or duck embryo: grow viruses for vaccines
-cell culture: most common
10
Q
5 phases of interaction of animal viruses with its host cell
A
- attachment
- penetration
- uncoating
- assembly
- releases
11
Q
Attachment phase
A
- virus attaches to specific receptors on host cell surface
- most important stage for stopping viral infection
12
Q
Penetration phase
A
- virus penetrated into host cell
- 1 of 2 ways endocytosis or membrane fusion
13
Q
endocytosis
A
- without envelope
- engulfment of virions by host cell membrane
14
Q
Membrane fusion
A
- envelope fuses with host cell membrane
- nucleocapsid moves into host cells
15
Q
Uncoating phase
A
- Caspid is enzymatically removed in the host cell and viral nucleic acid is mass produced
- replication, transcription and translation
16
Q
Assembly phase
A
- DNA assembles in nucleus
- RNA assembles in cytoplasm
17
Q
Release phase
A
- release virions by lysis if without envelope
- release through budding if with envelope
18
Q
define bacteriophage
A
- viruses that infect bacterial cell
19
Q
lytic cycle
A
- phage attaches to host cell and penetrates and injects dna
- phage dna directs synthesis of viral components by host cell which are assembled into virions
- cell bursts and virions released
20
Q
Lysogenic cycle
A
- phage attaches to host cell and infects dna which integrates within bacterial chromosome: prophage
- many cell divisions occur
21
Q
Plasmid
A
- extrachromosomal
- non viral
- many contain genes for toxin production
- increase virulence
22
Q
Prophage
A
- inserted into dna of host cell
- viral in origin
- may contain genes for toxin production
- increase virulence
23
Q
Protooncogenes
A
- protroncogones = proteins/stimulate proliferation
- transformation if altered or amount of proteins increase
24
Q
TSG
A
- TSG =
proteins/suppress proliferation - transformation if TMG mutated, deleted or proteins altered or removed
25
Cancers from DNA viruses
- epstein barr
- hepatitis b
- HPV
- Human Herpes Virus 8
26
Cancers from RNA viruses
- retrovirus
- HIV
- Aids
- hepatitis c
27
Retroviruses
- viral rna-dna-integration
- virion bonded to host cell receptors
- penetration of virion into host cell
- uncoating of viral capsid
- reverse transcriptase: RNA- DNA
- viral dna integrated into host cell dna
- biosynthesis: replication of DNA
- assembly of viral particles
- release croons through budding
28
Viral latency
Virus enters host cell but does NOT go through replication
29
Cytopathic effect
virus-induced damage to cells
30
Chemical Requirements for growth
- carbon
- hydrogen
- oxygen
- nitrogen
- phosphorus
- sulfur
31
Carbon purpose
make all of the macromolecules that cells need
- Autotroph: uses CO2 to make organic compounds
-Heterotroph: obtains carbon from organic sources
32
hydrogen
make macromolecules and form hydrogen bonds
33
oxygen
make macromolecules and metabolism (aerobic respiration)
34
nitrogen
make amino acids, nucleic acids, ATP
35
Phosphorus
Make ATP, nucleic acids, phospholipids
36
sulfur
make amino acids, vitamins, disulfide bonds
37
Transport mechanisms
- Passive Transport
- Active transport
38
Passive transport
- does NOT require energy
- simple diffusion
- facilitated diffusion
39
Diffusion
- molecules move from area of higher concentration to lower concentration
40
simple diffusion
- movement of particles from higher concentration to lower concentration
-limited, lipid soluble molecules
41
facilitate diffusion
-carrier protein bonds substances and changes shape that facilitates transport
42
Active transport
- Against concentration gradient or with but at a faster rate
(lower concentration to higher)
- carrier-mediated
- group translocation
- endocytosis
43
cell mediated transport
- Need carrier protein
44
group translocation
- Molecules transported altered in the process
45
endocytosis
phagocytosis and pinocytosis
46
phagocytosis
- engulfment of whole cells/ large solids
47
Pinocytosis
- vesicles of liquid are taken into cell
48
Physical requirements for growth
- temperature
- gas
- ph
- osmotic pressure
49
temperature requirements
- most at 37 degrees celsius
- minimum-optimum-maximum curve
50
gas requirement
- CO2 and O2
- Not all need oxygen
51
pH requirements
- grow best in range 6-8
- bacteria: 7-7.2
- yeast/molds: 5-6
52
Osmotic pressure requirements
- prefer isotonic conditions
- concentration is the same inside and outside of the cell
53
what is binary fission
- cell division and reproduction
- with each round, cells double in number
54
Process of binary fission
- cell elongates/DNA replication of bacterial chromosome
- invagination of cell membrane and -- cell wall at midpoint
- cross walk formation
- cells separate
55
generation time
- amount of time required for one bacterial cell to divide into two cells
56
Bacterial growth phases
- lag
- log
- stationary
- death
57
Lag phase of growth
cells adapting and little to no cell division
58
Log phase of growth
Rapid cell division, nutrients available, cells most vulnerable
59
Stationary growth phase
decreasing nutrients, increasing toxic products, cell death rate= cell production rate
60
Death growth phase
Nutrients depleted, increase toxic products, cell death rate exceeds cell production
61
3 measurements of bacterial growth
- turbidity
- direct microscopic count
- standard plate count
62
turbidity measurement
- Turbidity measures the amount of light going through a sample
- uses a spectrophotometer
- measures living and dead bacteria
63
direct microscopic count
- bacterial cells within specific area counted using specialized slide
- Liquid per millimeter
-Solid per gram
64
standard plate count measurement
- bacterial sample diluted over and over again
- (# of bacteria/ml) colony count multiplied by dilution factor/ml of the dish
ONLY COUNTS LIVING BACTERIA
65
Define Microbial Metabolism
All chemical and physical workings in a cell
66
Microbial Metabolism has two major categories.
What are those two categories?
1- Catabolism
2- Anabolism
67
Describe and explain the Catabolism category
- The break down of larger molecules into smaller molecules to release energy
68
Describe and explain Anabolism
- Smaller molecules are joined together to form larger molecules and in this process energy ATP is needed
69
ATP
- Is the universal energy storage in the cell.
- Can be produced, saved, spent, replenished
70
ATP has three parts, what are they
- Nitrogen (Adenine)
- Ribose
- Phosphate
71
Biological catalyst
- speeds up biological reaction without being altered in the process
- lower the activity
72
Lock and key model
enzymes are very specific for the substrates they bind
73
Co factors
- multiple metals
-activate enzymes: help to bring active site and substrate together
74
Co enzymes
- organic molecules (vitamins)
- removes a chemical group from 1 substrate molecule and add it to another substrate
75
Exoenzymes
-synthesized inside and transported outside of the cell
76
Exoenzymes function
- breakdown large food molecules, harmful chemicals
- hydrolysis
77
Endoenzymes
Enzymes production and retained inside the cell
78
Endoenzymes functions
- important for the synthesis of major macromolecules
- required the input of ATP
- dehydration synthesis
79
pH
-neutral at 7
-extreme pH denature the enzyme
80
Temperature
-increase in temp: increase in enzyme activity
- function between 30-40 C
81
Substrate Concentration
-increase in substrate concentration
-increase in enzyme activity
82
In process of photosynthesis what are the reactants ?
carbon dioxide + water
83
In process of photosynthesis what are the products ?
glucose + oxygen
84
Organisms that carry out the process of photosynthesis
- green plants
- algae and photosynthetic bacteria
85
Define sterilization
destruction of all forms of microbial life
86
Define disinfection
destruction of pathogenic microorganims
87
Define Antiseptic
chemical substance applied to skin or mucous membrane
88
Define Disinfectant
chemical substance used on non-living or inanimate objects
89
what does contact rate of killing mean
the same percentage of cells die per time interval of treatment
90
7 factors affecting control methods
- size of microbial population
- amount of time agent used
- concentration of agent
- greater temperatures
- Ph extremes
- special protection
- presence of organic matter
91
4 mechanisms of action
- disruption of cell wall
- disruption of plasma membrane
- denaturation of proteins
- damage to nucleic acids
92
Disruption of cell wall
fragile cell that can result in lysis
93
Disruption of plasma membrane
- agent damages lipids/proteins in cell membrane
- content leakage
94
denaturation of proteins
- alcohols, acids, heat damage proteins and enzymes
95
damage to nucleic acid
- inhibits replication/transcription/translation
96
7 physical methods of control
- heat
- pasteurization
- dedication
- filtration
- radiation
- osmotic pressure
- low temps
97
Heat method of control
- superior method
- inactivates proteins
98
Pasteurization method of control
mild heat destroys pathogens
99
desiccation method of control
dehydration inhibits bacterial growth
100
filtration method of control
physical separation of microbe form liquid or gas using membrane filter
101
radiation method of control
damage to proteins and DNA
102
Osmotic pressure method of control
highly concentrated solutions dehydrate microbes
103
Low temp method of control
temperature (0-6 C) decreases bacterial enzyme activity
104
Why is moist heat superior to dry heat
penetrates better, denatures proteins
105
How does an autoclave work?
- destroys all form of life, even endospores
106
Chemical Methods:
Antiseptic/Disinfectants
- work by the disruption of the plasma membrane and the denaturation of proteins
107
-static
inhibit
108
-cidal
kill
109
High resistance of microbial forms
- Prions
- Bacterial endospores
110
moderate resistance of microbial forms
- protozoan cyst
- some fungal sexual spores (zygospores)
- some viruses (non enveloped)
- some bacteria
111
Low resistance of microbial forms
- most bacterial vegatative cells
- fungal spores and hyphae
- enveloped viruses
- yeast
- protozoan trophozoites
112
True or False:
Most of the antimicrobial chemicals do not sterlize
true
113
Superior Chemical Methods:
Kills Everything
- Halogens
- Aldehydes
- Hydrogen peroxide
- Gaseous Sterilants
114
What is the filter paper method?
- paper disk is soaked in a chemical and placed on an agar plater inoculated with test organism
- zone of inhibition = clear area where chemical onhibited microbial growth
