Lecture 1 Flashcards by S C.

What are the 6 infectious microorganisms?

-HIV
-Influenza
-STAPHYLOCOCCUSAUREUS
-STREPTOCOCCUSPNEUMONIAE
-SALMONELLAENTERITIDIS
-MYCOBACTERIUM TUBERCULOSIS

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What are the sizes of microorganisms?

-Viruses (0.03-0.3uM)
-Bacteria (0.1-10uM)
-Microscopic protozoa and fungi (4-10uM)

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Naked Viruses contains what?

Capsid & Nucleic acid

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Enveloped Viruses contain what?

-Envelope
-Spike
-Capsid
-Nucleic acid

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T/F: Viruses are not cells

True

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Slide 13 review differences between prokaryotes and eukaryotes

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T/F: Bacteria are prokaryotes

True

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Fungi and parasites are what?

eukaryotic organisms represented by single-cell and complex organisms

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Sources and Sites of Infection

-Direct vs Indirect (contact)
-Horizontal vs Vertical (mother to fetus)

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Slide 17 memorize

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What are the classes of microorganisms?

Microbiome (normal flora)

Commensal (resident, symbiotic, core microbiome)

Transient colonization (transients, secondary microbiome)

Opportunistic (carrier state)

Pathogenic

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Commensal Microorganisms ??

Endogenous flora
> 1000 species in the human body; billions of organisms
Microbiota – cohorts of microbes in specific body regions

Provide many benefits
Process digested food
Provide essential vitamins/growth factors
Protect against invasion of pathogens

In a constant state of flux dependent on age, diet, health
Microbial populations change in response to illness or treatment with antibiotics (dysbiosis)

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What are Virulence?

Circumstances that allow a microorganism to achieve infection and cause disease with varying degrees of severity

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Virulence factors are…

gaining access to the body
avoiding multiple host defenses
colonization of the host
parasitizing host resources
inducing toxicity and damage

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Influences on the Microbiome

-Host physiology
-Environement
-Immune System
-Host genotype
-Lifestyle
-Pathobiology

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Human Microbiome Project is

Effort to sample and analyze the genome of microbes from five sites on the human body

Nose
Oral cavity
Skin
Gastrointestinal tract
Urogenital tract

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Viral Classification

All viruses are intracellular pathogens

All viruses must use some components of the hosts cellular biosynthetic machinery

All viruses are nucleic acid based

All viruses replicate by assembly of components

All viruses are composed of the viral genome, a protective coat & associated enzymes/proteins

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All viruses are composed of

the viral genome, a protective coat & associated enzymes/proteins

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Nucleic Acids consist of

DNA or RNA
single or double stranded
linear or circular
continuous or segmented genome

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Outer layer consist of

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capsid (naked)
envelope
VAPs (viral attachment proteins)

Capsid shape

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spherical
icosahedral (icosadeltahedral)
filamentous
brick-shaped
bullet-shaped

+RNA

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(N)-Picorna Calici
(E)-Toga Flavi Corona

-RNA

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(E)- Rhabdo Filo Orthomyxo Paramyxo Bunya Arena

+/-RNA

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(Double Capsid)- Reo

+RNA via DNA

(E) Retro

slide 45

Enveloped

Pox Herpes Hepadna

Naked Capsid

Polyoma Papilloma Adeno Parvo(ss)

Slide 48

Viral Replication steps

1) Recognize target cell 2) Attachment 3) Penetration/Fusion 4) Uncoating of virion 5) Transcription 6) Protein synthesis 7) Replication 8) Assembly 9) Release

Viruses can be

-Productive: Lyse the infected cell (lytic response) Non-productive Lysogenic– integration of viral genome into host genome or formation of extrachromosomal plasmid Oncogenic transformation Persistent – latent or chronic

Cells can be

Permissive Allow viral replication or integration Non-permissive Do not allow replication but may be transformative Abortive – no replication but cause cell death

Target recognition & attachment

VAPs, host range, tissue tropism

Penetration

receptor-mediated endocytosis (viropexis), membrane fusion

Uncoating

remove coat, deliver to site of replication

Synthesis

early gene products – non-structural proteins, replication late gene products – structural proteins

T/F: Most DNA Viruses generate mRNA thru splicing

TRUE From the same DNA, many different mRNA transcripts are translated into proteins

Segmented RNA genomes

one segment encodes one proteins

Some viruses have one long RNA(-) genomic strand from which mRNA can be directly transcribed

just know this

Protein synthesis

requires host ribosomes, tRNA & post-translational machinery

At Ribosomes:

produce giant, genome-spanning polyprotein produce smaller polypeptides produce individual proteins

achieve preferential translation by

block mRNAs degrade host DNA & mRNA decrease cellular transcript access/concentration

Assembly

recognition sequences allow protein:protein, protein:nucleic acid and protein:membrane interactions for budding, viral membrane proteins (like spike proteins) inserted into plasma membrane

Release

bud from plasma membrane bud through ER/Golgi (remain intracellular) pass through ER & transported to surface (endosomes) cell lysis cell-cell bridge

DNA viruses do what?

Uses the host cell DNA-dependent, RNA polymerase to make mRNA Uses freshly made DNA-dependent, DNA polymerase to copy DNA

(+) RNA VIRUSES do what?

(+)RNA viruses can begin translation by ribosomes as soon as the genome is uncoated Will still encode for a viral polymerase to copy the genome for replication (RNA-dependent, RNA polymerase)

(-) RNA VIRUSES

(-)RNA viruses must carry a viral RNA-dependent, RNA polymerase to transcribe the negative strand into mRNA *L PROTEIN*

Viral genetics are

Parental (wild-type) Mutants (change in coding sequences) viruses have terrible polymerases; lots of errors Lethal mutations Deletion mutants Plaque mutants Host range mutants Attenuated mutants Conditional mutants

Antigenic Drift

Codon should be UUU translated to AAA (Lysine); mutation created CUU which is translated to GAA (Glutamic acid

Lecture 1 Flashcards

(49 cards)