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Microbiology Flashcards

1
Q

Viruses

A

Obligate intercellular parasites (obligated/only able) that reproduce within cells (intracellularly)

Incapable of common chemical reactions of life outside of a cell -> therefore not cells or living organisms

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2
Q

Exterior Protein Shell

A

Rigid structure of fixed size (*limiting factor) that cannot expand to incorporate a larger genome (evolved to be extremely economical to rely on host encoded proteins for transcription/translation/replication).

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3
Q

Adaptation of Multiple Proteins

A

Virus can utilize more than one reading frame within a piece of DNA so that genes can overlap

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4
Q

Capsid

A

Protein coat surrounding viral nucleic acid genome -> made from repeating pattern of few protein building blocks

Helical (rod shaped)
Polyhedral (multiple sided geometric figures)

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5
Q

Capsid Heat

A

Within which the genome is located

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6
Q

Tail Fibers

A

Attach to the surface of the host cell

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7
Q

Base Plate

A

Attached to surface of host cell (connected to the tail fibers, connected to central shaft/sheath)

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8
Q

Sheath

A

Contracts using energy of stored ATP injecting genome into the host

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9
Q

Envelope

A

In animal viruses that surrounds capsid (containing phospholipids, proteins, and carbohydrates) -> derived from host cell

Budding through host cell membrane

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10
Q

Naked Virus

A

Virus without envelop (phages and plant viruses)

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11
Q

Bacteriophage

A

Viruses that use bacteria as host (bind to exterior of bacterial cell). Can then enter lytic or Lysogenic cycle

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12
Q

Penetration

A

AKA eclipse, injection of viral genome into host cell

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13
Q

Lytic Cycle

A
  1. Attachment of phage to E. coli and injection of phage chromosome
  2. Breakdown of bacterial chromosome by phage-specific enzyme
  3. Bacterial chromosome totally broken down
  4. Replication of Phage chromosome using bacterial materials + phage enzymes
  5. Expression of phage genes to produce phage structural components
  6. Assembly of progeny phage particles
  7. Release of progeny phage by lysis of bacterial wall
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14
Q

Early Gene

Ex. Hydrolase

A

Genes that are immediately expressed after infection

Hydrolytic enzyme that degrades the entire host genome

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15
Q

Late Gene

Ex. Lysozyme

A

Created later

Destroys bacterial cell wall -> host bacterium bursts (‘lyses’)

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16
Q

Lysogenic Cycle

A
  1. Phage binds to bacterium
  2. Phage DNA enters host cell
  3. The phage DNA integrates and becomes noninfective prophage
  4. Chromosome with integrated prophage (phage genome incorporated into bacterial genome) replicates
  5. In rare cases the prophage may separate and then cell is induced to lyse
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17
Q

Lysogen

A

Host of lysogenic virus

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18
Q

Excision

A

Removal of prophage from host genome that enters lytic cycle

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19
Q

Transduction

A

When excision occurs, prophage takes part of the bacterial genome with it; giving the new host a new ability

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20
Q

Animal Viruses

A
  • have specific proteins on the surface of plasma membranes that serve as specific receptors (typically play a role in regular cellular function)
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21
Q

Endocytosis

A

Method by which animal host cell engulfs virus and internalizes it

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22
Q

Uncoated

A

Viral genome after entering host being released from its capsid

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23
Q

Productive Cycle

A

Similar to lytic cycle but doesn’t destroy the host cell

Enveloped viruses exit host cell by budding (cell doesn’t lyse) the lipid bilayer can reseal as the virus leaves

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24
Q

Provirus

A

animal virus form of a prophage (in lysogenic cycle)

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25
Viral Genomes
Determined by uniqueness of each virus (can be many factors)
26
(+) RNA viruses
has ss-RNA gene, gene is infective (injection will result in viral production) ENCODE for RNA-dependent RNA polymerase that allows RNA to be replicated by RNA
27
(-) RNA viruses
Complementary genome to the piece of RNA that encodes viral mRNA production/proteins (creates useful polypeptides) ENCODES for and CARRIES RNA-dependent RNA polymerase
28
Retroviruses
(+) RNA viruses that undergo lysogeny (integrate as proviruses) In order to integrate into our DNA, must be composed of double stranded DNA as well. Need to make DNA from an RNA template: RNA-dependent DNA polymerase
29
Main Retroviral Genes
Gag (codes for viral capsid proteins) Pol (codes for reverse transcriptase) Env (codes for viral envelope proteins)
30
Double Stranded DNA Viruses
Have large genomes that include genes for enzymes involved in deoxyribonucleotide synthesis (done whenever we make DNA) and DNA replication Encode enzymes required for dNTP synthesis/DNA replication
31
Subviral Particles
Infectious agents smaller and simpler than viruses
32
Prions
Self replicating proteins (do not follow Central Dogma), misfolded proteins that can alter shapes of normal protein Causes transmissible spongiform encephalopathies (TSEs) but also can be genetically linked
33
Central Dogma
States that information flows in its nucleotide form from DNA to RNA then amino acid from RNA to protein
34
TSE
transmissible spongiform encephalopathies that result in degeneration of the nervous system (always fatal - Mad cow disease, etc.)
35
Viroid
Consist of short, circular ss-RNA - does not code for proteins Mostly found in plants except Hepatitis D (enter hepatocytes, liver cells)
36
Prokaryotes
Do not contai membrane-bound organelles: include bacteria, archae and blue-green algae
37
Prokaryotic Cytoplasm Contents
- Genome is a single ds-DNA circular chromosome - Translation/Transcription occur simultaneously in the ribosomes (polyribosomes = multiple ribosomes translating single mRNA) - plasmids are extrachromosomal genetic elements (circular ds-DNA, contain things like antibiotic resistance) - plasmids important in conjugation (bacterial exchange of information)
38
Shapes Round Rod-shaped Spiral Shaped
Cocci/Coccus Bacilli/Bacillus Spirilla/Spirillum
39
Cell Membrane
Lipid Bilayer binds cytoplasm
40
Cell Wall
Outside the cell membrane, wall composed of peptidoglycan (provides structure, target of antibiotics) Prevents osmotic lysis (explosion)
41
Protoplast
Bacteria with degraded cell wall (lysozyme degraded peptidoglycan) that is osmotically fragile
42
Gram Staining
Classification type according to cell wall, derived from bacteria's ability to change color
43
Gram Positive
Strong purple color, thick peptidoglycan layer after cell membrane
44
Gram Negative
Light pink staining Thinner layer of peptidoglycan (in periplasmic space, sometimes where enzymes that degrade antibiotics is found) in cell wall but have additional outer layer containing lipopolysaccharide
45
Endotoxins
Normal components of outer membrane of Gram-negative bacteria that aren't inherently poisonous - but cause immune system to have extreme reaction (leads to septic shock)
46
Exotoxins
Toxic substances secreted by both gram neg/pos bacteria into surrounding medium. Compete with other bacterial species (ex. normal inhabitants of mammalian gut) cause disease like tetanus
47
Capsule
AKA glycocalyx, sticky layer of polysaccharide goo surround bacterial cell and makes it more difficult for immune cells to eradicate Allows it to adhere to surfaces (i.e. lining of digestive tract)
48
Flagella
Whip-like, long filaments that help with motility
49
Flagellar Locations/Number Monotrichous Amphitrichous Peritrichous
Flagella at one end Flagella at each end Multiple flagella
50
Components of flagella
Filament, hook, and basal structure
51
Pili
long projections involved in attaching to different surfaces in bacteria.
52
Fimbriae
Smaller structures not involved in locomotion but help adhere to surfaces
53
Temperature
Mesophiles - favor mild temperature Thermophiles - high temperatures Psychrophiles - cold temperatures
54
Nutrition
Chemoautotroph - build organic molecules from CO2 using energy of chemicals (inorganic molecules) Chemoheterotroph- require organic molecules lie glucose made by other organisms as their carbon source/for energy Photoautotroph - use CO2 as carbon source and obtain energy from sun Photoheterotroph - are odd in that they get energy from sun but require organic molecule from another organism as carbon source
55
Growth Media
Bacteria grow in agar on petri dishes through a process called plating, eventually forming colonies (minimal media contains nothing but glucose and agar)
56
Bacterial Lawn
Dense growth of bacteria (plaque is clear area in the lawn)
57
Auxotrophs
Bacteria not capable of surviving on minimal medium because can't synthesize a molecule which they need to live (requires auxiliary trophic substance to live)
58
Doubling time
Amount of time required for a population of bacteria to double its number
59
Obligate Aerobes
Bacteria which require oxygen
60
Anaerobes
Do not require oxygen
61
Facultative Anaerobes
Will use oxygen when it's around but don't need it
62
Tolerant Anaerobes
Can grow in the presence or absence of oxygen but do not use it in their metabolism
63
Obligate Anaerobes
Poisoned by oxygen (lack the enzymes necessary for the detoxification of free radicals which form spontaneously when oxygen is around) - commonly infect wounds
64
Fermentation
Glucose catabolism uses final production of lactate
65
Respiration
Glucose catabolism with oxygen as an electron acceptor
66
Anaerobic Respiration
Respiration without oxygen as final electron acceptor (S, CO2, etc.)
67
Binary Fission
Asexual bacterial reproduction - growing in size until synthesizing enough cell components for two cells then divides into two
68
Conjugation
Exchange of genetic information of bacteria
69
Phases of Bacterial Cycle
Lag phase - biosynthetic pathways pathways are creating items needed for bacterial growth (no increase in # cells) Log/Exponential Phase - Exponentially grows Stationary Phase - Cells cease to divide for lack of nutrients (maximum population at this stage is referred to as carrying capacity) Death Phase: Exponential decrease in number of living bacterial cells
70
Endospore Formation
Some gram-positive bacteria form endospores (thick external shells of peptidoglycan) that form under unfavorable growth conditions) under unfavorable growth conditions (Ex.high temp)
71
Germination
Metabolic reactivation of an endospore
72
Transduction
Transfer of genomic DNA between bacteria in the lysogenic phage
73
Transformation
When pure DNA is added to bacterial culture, bacteria internalizes DNA under certain conditions
74
Conjugation
- most related to normal bacterial function Physical contact (bridging between cellls) wherein one cell copies DNA and copies this information through bridge to other cell
75
F (fertility) factor
Bacteria with F+ are considered male, and transfer F factor to female cells. A circular DNA molecule that contains genes
76
Hfr
High frequency recombination, F factor can get incorporated into the cellulary environment (these characteristics can be transferred into the F cell
77
Conjugate Mapping
Hfr conjugation stopping at various time points can help determine the order of genetic transfer
78
Archaebacteria
nontypical (not Eukaryotic bacteria) that live typically in extreme environments. Cell wall lacks peptidoglycan and reproduce via fission/budding Genetically more similar to eukaryotes (introns, similar mRNA sequences, etc.)
79
Parasitic Bacteria
Damage host cell; modulate course of damage to ensure they have materials to survive and reproduce Obligate - must be inside host cell to replicate Facultative - can live and replicate inside or outside of a host cell
80
Symbiotic Bacteria
Coexist with host where both host and cell derive benefit Ex. bacterial flora in human gut

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