Viruses and Eukaryotes Flashcards by Deandra Williams

Extracellular form of a virus

Virus particle

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Infectious virus particle

virion

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Viral genomes can have either

DNA or RNA genomes/ circular or linear

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Can viruses have SsRNA/dsRNA same for DNA?

Yes

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Viruses are grouped based on

the hosts they infect

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capsid

protein shell around genome

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capsomer

subunit of the capsid

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Nucleocapsid and enveloped virus

-complete complex of nucleic acid

virus that has additional layers around nucleocapsid

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Helical symmetry vs icosahedral symmetry

Rod shaped viruses, length determined by length of nucleic acid.
Spherical viruses

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Enveloped viruses have

lipid bilayer with embedded proteins ad glycoproteins are encoded by the viral genome

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Glycoproteins make ? with host cells

Initial contact

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Name the enzymes critical to infection

Lysozymes, nucleic acid polymerases (Reverse transcriptase), and neuraminadases (enzymes that cleave glycosidic bonds to free the virus.)

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What is analogous to the bacterial colony and used to measure virus infectivity?

Plaque assays

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Plaques?

Clear zones that develop on lawns of host cells, result from infection by a single virus

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Phases of rial replicatio

Attachment
Entry
Synthesis
Assembly
Release

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Example the phases of the one-step growth curve

Eclipse- genome is replicated and proteins are translated
Maturation-packaging of nucleic acid in capsids
Latent Period- eclipse + maturation
Release - cell lysis, budding, or excretion

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Burst size

of virons released.

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Attachment of virion to host is

highly specific and requires complementary receptors on the surface.

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Receptors? What are they

carry out normal functions for cell,

include proteins, carbs, glycoproteins, lipids, lipoproteins, or complexes.

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What bacteria effects E. Coli?

Bacteriophage- T4

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Name the viral defenses of eukaryotes/bacteria/

Eukaryotes- RNA interference/immune defense
Bacteria- restriction-mod system, DNA destruction system (only effective against DNA virus)
, restriction enzymes (cleave DNA) at specific sequences.
AND CRISPR- against viruses,

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Once a host has been infected, what must happen?

Virus-specific proteins must be synthesized and new copies of the viral genome must be made.
mRNA first.

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Viral genome is the template for

the viral mRNA

in some viruses, viral RNA genome itself is the mRNA.

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What are in the virion

Essential transcriptional enzymes such as RNA replicase.

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Genome replication

many different schemes.

single stranded DNA/RNA virus

mRNA is in the plus configuation while its complement is in its minus config.

+ strand RNA virus

single strand RNA GENOME with sam orientation as its mRNA

- strand RNA virus

single stranded RNA GENOME WITH COMPLEMENTARY orientation to its mRNA.

Neg strand RNA and doubled stranded RNA viruses need

RNA-dependents RNA polymerase to make mRNA

Smalll DNA viruses use ?

DNA polymerase

t4 encodes? | is first replicated as?

primases, helicases, and 8-protein DNA replisome complex. | as a unit then forms concatemer (several genomic units combined)

circular permuation

feature of many virus genomes where same genes are arranged in differrent orders.

Terminally redundant

some DNA sequences duplicated on both ends.

How long does virion synthesis take? What does it release?

- 30min | - new virions lysed from cell.

Early, middle, late proteins of T4 genome

see notes

During transcription and translation of T4 bacteriophage, what happens?

The early, middle/late proteins and the T4-specific proteins modify host RNA polymerase specificity to recognize only phage promoters. Host transcription gets shut down.

explain the three stages of packaging the t4 genome | THE VIRION ASSEMBLY and the release

see notes

The genome is pumped into the head under pressure using what

ATP

the best-studied bacteriophages infect what bacteria | and most contain what genomes?

enteric | most contain dsDNA genomes

Virulent mode

lyse and kill host

Temperate mode

Replicate their genome wihtout killing

Temperate viruses can undergo a

a different life cycle resulting in the stable genetic relationship within the host, but can also kill sounds through lytic cycle

Lysogeny

state where most virus genes not expressed and virus genome (prophage) is replicated along with host chromosome

Lysogen

bacteria containing a prophage

ANIMAL viruses contain...

all known modes of viral genome replication

There are more kinds of ? animal viruses than bacterial viruses.

Enveloped

as animal viruses leave host cell,

they can remove part of host cells lipid bilyar for their envelope.

What are the consequences in virus infection of animal cells.?

lysis of cells, persistent infections, latent infections, transformation (normal to tumor)

Retroviruses

RNA viruses, that replicate via a DNA intermediate | are an enveloped and have enzymes: reverse transcriptase, integrase, protease

Process of replication of retroviruses

entrance into the cell and removal of viron envelope reverse transcription of one of the two RNA genomes integration of retroviral DNA into host genome using integrase enzyme transcription of virus mRNA from viral DNA assembly and packaging of genomic RNA after its transcribed then budding of envelopes virions, released from cell

Prions

infectious proteins causes DNA in animals Host cell has native form of prion protein found in healthy animals mad cow disease

infectious prion disease

transmitted between animals or humans

sporadic prion disease

random misfolding in uninfected indv

inherited prion disease

mutation in the prion gene yields a protein that changes more often into a disease-causing form.

Mitochondria and Hydrogenosome

specialize in chemotrophic energy metabolism the mitochondria is for respiration in oxidative phosphorylation hydrogenosome lack the CAC cycle AND HAS NO GENOME OF ITS OWN oxidizes pyruvate to hydrogen carbon dioxide in acetate and is found in trichomonas

Thylakoids

flattened membrane disks

Stroma

Lumen of chloroplast

Stroma contains LARGE AMOUNTS

RubisCO

Key enzime in calvin cycle?

Rubisco

the relationship between the 18s rRNA genes is

LESS strong for eukaryotes then 16s RRNA genes are for prokaryotes

Diplomonads

have two nuclei of equal size, have my toes ohms that degenerate mitochondria, Giardia is the cause of giardiasis a common waterborne disease

Parabasalids

Lack mitochondria but have hydrogenosomes for anaerobic metabolism living intestinal and urogenital tract trichomonas vaginalis

The two key genera refer diplomonads and parabasalids are

Giardia and trichomonas

Euglenozoans key genera

Trypanosoma and Euglena

Group of euglenozoans are

Kinetoplastids