Microbiology chapter 13 viruses viroids and prions

When two different strains of segmented virus enter the same cell resort many of the gene segments can occur resulting in

Antigenic shift

During the ____ Or maturation step in viral multiplication capsids and genetic material or packaged into curious

Assembly

The ____ or maturation stage of T4 phage Lytic cycle is marked by the formation of new phage particles inside the host cell

Assembly

Replication of temperance phages& lytic phages have which steps in common

Assembly, attachment, genome entry, release, biosynthesis of viral components

In order to infect an animal cell virus must

Attached to receptors on the host cytoplasmic membrane

List the steps of animal virus infection cycle in the correct order

Attachment penetration and uncoding synthesis of viral proteins & replication Genome assembly release

____ Phages have the option of entering the prophage state, while ____ phases always burst the host cell shortly after injection

Temperate; lytic

What mechanisms the newly assembled viruses use to leave their host cell

Triggering apoptosis & budding

After a virus enters a cell the nucleic acid separates from the protein coat a process called

Uncoating

The process by which the viral nucleic acid is released from the protective protein coat is called

Uncoating

Single virus particle is referred to as a

Virion

A_____is a infectious agent that lacks a capsid and consist only of RNA

Viroid

What are true about viruses

Viruses contain RNA or DNA but not both the viral capsid is composed of proteins

What are two types of transduction

generalized and specialized

Because they are dependent on who sells viruses are classified as

obligate intracellular parasites

The phage DNA that is latently incorporated into the bacterial host genome is called a

prophage

Which of the following are cytopathic effects of viruses

Inclusion bodies & syncytia

Which of the following directs incorporation of phage DNA into bacterial chromosome

Intergrase

- strand genome

Is the complement to mRNA

The typical symptoms of cold sores can be caused by

Latent HSV 1 that has reactivated; And initial infection with HSV one

The term _____is used to describe a rupture a personal cell

Lysis

Consequences of lysogeny include

Lysogenic conversion and immunity to superinfection

Which type of infection does the virus remain in the host for years sometimes without symptoms

Persistent

In A ____viral titer can be determined by counting clear zones in a monlayer of cells

Plaque assay

Transmissible Spongiform Encephalopathies are Caused by

Prions

Which of the following describes a type of relationship that bacteriophages skin have to host

Productive Lytic infections, latent Infection or host cell genotype is changed

The phage DNA that is latently incorporated into the bacterial host genome is called a

Prophage

A ____is a animal virus Gyno residing silently in a host cell Gynome

Provirus

The Virally encoded polymerase needed for replication of RNA viruses is called a

Replicase

The enzyme of RNA viruses that lack of proofreading ability in this makes many mistakes compared to polymerases of DNA viruses is

Replicase

_____Proteins is essential for maintenance of lysogenic state

Repressor

Specialized transduction

Results from errors in excision of the prophage; Transfers phage DNA and adjacent n host cells; Produces defective phage particals

HIV is described as a ___ because it uses reverse transcriptase to make DNA copy from its RNA genome

Retrovirus

An enzyme that uses RNA molecule as a template to make a complementary copy of DNA is called

Reverse transcriptase

+ strand genome Viral reverse transcriptase is packaged in virion, which reverse transcribes viral RNA into DNA, which eventually is fully incorporated into host as DNA

Serves as mRNA

____Transduction is the result of excision errors made as a temperate phages transition from a lysogenic to a Lytic cycle

Specialized specialized

In ____transduction only bacterial genes adjacent to the prophage can be transferred ;whereas in ___transduction any bacterial gene can be transferred

Specialized; generalized

Viral proteins that stick out from the virus in the world like acid and attach to host cell receptors are termed

Spikes

Some viruses cause an infected cell to form a distinct region call day_____ body which is the site of viral replication

Inclusion

____ viral release methods may not initially destroy the cell

Budding

Envelope viruses exit host cells by____; non-envelope viruses are released upon______ of the host cell

Budding; death

The number of phage particles released from a host cell is the

Burst size

Hepatitis B virus sometimes causes an infection that results in a continuous and low level production of virus particles this type of infection pattern specifically describes a

Chronic viral infection

Double stranded Genome

Consist of both positive and negative strand

Viral genomes can be

DNA or RNA, single or double stranded, linear or circular

The methods by which an envelope viruses can gain entry into animal cells

Endocytosis of the virus by the host ;cell fusion of the viral envelope and the cell membrane

The phospholipid by layer surrounding the captain of some viruses is the

Envelope

True or false envelopes in non-envelope viruses all mature fully in the cytoplasm of a host cell

False Non-envelope virus is mature fully in host cell cytoplasm ;for envelope viruses some mature as the virion leaves the host cell

Bitch which form of transduction results from packing errors during phage assembly

Generalizedc

Which are the two main criteria used in classifying viruses

Genome structure and host range

____Viruses that have captured that is composed of 20 flat triangles

Icosahedral