Microbiology assignment 4
How does lysogeny affect humans? The phage can be released from an infectious bacterial cell and infect human host cells instead. Bacteria can become virulent due to phage genes, causing greater damage to infected human host . The phage causes significant changes to host cell divisionleading to cancer.
Bacteria can become virulent due to phage genes, causing greater damage to infected human host .
Which of the following is NOT a transmission method for Norwalk virus? Contaminated food Aerosols Biological vectors Direct contact Undercooked shellfish Contaminated water
Biological vectors
Rabies virus has a ________________ host range as compared to hepatitis B virus. narrow broad restricted medium
Broad
Enveloped viruses are usually released from the host cell by _______________. Budding Lysis of the host cell Endocytosis Phagocytosis
Budding
Choose the statement that indicates how cytopathic effects are detected. Examine infected cells with a microscope Perform biochemical test on infected cells Grow infected cells in a variety of different media Perform immunological test on infected cells
Examine infected cell with a microscope
T/ F: Viral nucleic acid is made inside the bacterium and is combined with viral protein coat already present outside.
False
T/ F: a positive sense strand lytic RNA phage attaches to the cell wall of an E. Coli bacterium
False
T/ F: enveloped viruses are usually released from the host cell by exocytosis
False
T/F: All viruses leave a cell by exocytosis.
False
T/F: Animal viruses always kill cells they infect
False
T/F: The causative agent could be cultured from a patient's stool specimen and a Gram- stained to determine specific identity
False
T/F: Viruses can be grown on culture media like bacteria.
False
T/F: viruses belong to the Domain Archaea
False
True or false. The patients in the opening case file were diagnosed with viral gastroenteritis and were treated with antibiotic drugs to clear the infection.
False
True/ False: a naked virus fuses with the host cell membrane
False
Why are CD4 counts related to HIV infection? HIV can only bind to cells with CD4 receptors. HIV destroys CD4 molecules found on cells. HIV needs CD4 molecules for replication .
HIV can only bind to cells with CD4 receptors.
Some viruses may also possess an external membraneous covering that comes from the _________________. Penetration Environment Naked Uncoating 12 Capsid Absorption 8 Host cell Phospholipid 36 DNA Assembly Release Protein Synthesis Enveloped
Host cell
The polio vaccine currently used in the United States, the Salk vaccine, consists of pollovirus that been treated with chemical so that they can no longer reproduce within host cells and thus cannot establish an infection. They are referred to as _______________, rather than dead, viruses. Active Inactive Abiotic Inattentive
Inactive
The activation of a prophage to enter the lytic cycle is called __________________ induction repression maturation conversion adsorption
Induction
The negative (-) sense strand of RNA ________________. -Plays no role -Acts as mRNA to make viral proteins -Is used to synthesize more + strands -Makes RNA replicase
Is used to synthesize more + strands
This is the six days in the prices were Vairo enzymes digest the host cell envelope
Lysis of weakened cell
This is the fifth stage in the process where fully formed by virons are ready for release
Maturation
Simplest viral from that consists of only a nucleocapsid
Naked nucleocapsid virus
Choose the answer that best completes the blanks this sentence in the correct order. Viruses are usually ______________In size and their structure is best viewed through the use of _________________ microscopy Micrometers; electron Micrometers; bright- field Nanometers; electron Nanometers; bright-field
Nanometers; electron
Which drug targets can be found on both bacterial cells and viral particles? Cell wall Protein synthesis machinery Metabolic pathways None of the choices are possessed by bacteria . None of the choices are possessed by viruses .
None of the choices are possessed by viruses .
Genetic material within the virus
Nucleic acid
Of all infectious agents, which group has the most variety of drugs designed to treat infections? Helminths Fungi Protozoans Bacteria Viruses
Bacteria
In phage replication, __________________. -Only the phage nucleic acid enter the bacterial cell -multiple phage particles enters the same host bacterial cell at the same time -only the phage protein enters the bacterial cell -the whole phage particle enters the cell and the protein outer coat is removed
Only the phage nucleic acid enter the bacterial cell
This is the second step in the process where the viral genetic material only is injected into the bacterium through the rigid tube and eliminating the need for uncoating.
Penetration
A viral infection in which the virus can remain latent in the host cell for weeks to years is described as an _______________infection and may lead to cancer if host DNA is altered. Cytopathic Syncytial Persistent Acute
Persistent
Viral capsids are composed of ______________ nucleic acids lipids protein carbohydrates
Proteins
When present, what is the viral envelope composed of? Carbohydrates Peptidoglycan Proteins and lipids Nucleic acid
Proteins and lipids
Choose the statement that best describes the role of viral surface proteins or spikes. Provide means for virus to exchange nucleic acid Enable replication of the viral nucleic acid Provide means of attachment to host cell surface Inject viral nucleic acid into host cell Allow virus to bind to each other
Provide means of attachment to host cell surface
An envelope is acquired during which step of the viral life cycle? Penetration Synthesis Adsorption Release
Release
This is the final stage of this process, where lysis occurs expelling the mature bacteriophage particles
Release of Virus
An infection in animals similar to a lysogeny in bacteria is called a(n)___________________ infection. cytopathic transforming persistent oncogenic
persistent
A positive (+) strand of RNA ___________. 1) can directly act as mRNA 2) makes a minus (-) strand of RNA, which can then act as mRNA 3) cannot function 4) must be double stranded
1
The viral capsid ______________. 1) becomes completely enclosed by the region of the cell membrane intro which the spikes and matrix proteins are embedded 2) is dissolved 3) surrounds the viral matrix protein 4) engulfs the viral spikes
1
Describe and classify Viral Genome 1. Maybe positive sense RNA 2. May be DNA 3. May be single stranded 4. Less than 3000 genes 5. May be RNA 6. Always DNA 7. May be negative sense RNA 8. More than 3000 genes 9. Always double stranded
1 2 3 4 5 7
Unique characteristics of viruses: 1. Well viruses are not considered living things because they cannot direct their own multiplication they are more than simple an aggregate of macromolecules since they can direct the behavior of living cells. 2. Viruses are considered living things because they can direct their own multiplication as well as the behavior of living cells 3. Viruses are species specific infect cells from all five kingdoms 4. Viruses have a nucleic acid genome; however it may be either DNA or RNA in the nucleic acid may be single or double stranded 5. Some viruses are parasitic but others carry ribosomes in their capsid allowing them to translate their own proteins
1 3 4
Which answers are correct 1) the majority of food borne illness is caused by bacteria 2) the majority of food borne illness is caused by virus 3) four of these five agents are bacterial pathogens 4)antibiotics would be effective in less than half cases of food borne illness 5) antibiotics would be effective in the more than half of these cases of food borne illness
2 3 4
The correct order of the stages for phage replication are ______________. 1 = assembly 2 = attachment 3 = transcription/replication 4 = release 5 = penetration
2 5 3 1 4
Order the following choices to demonstrate your understanding of the life cycle of an animal virus. 1. Release from host cell 2. Adsorption (attachment ) host cell surface 3. Assembly of viral particle 4. Synthesis of viral nucleic acid and proteins 5. Penetration and uncoating
2 5 4 3 1
In the attachment step of phage replication, _________________. 1) carbohydrate receptors in the phage tail attach to specific receptors on the bacterial cell wall 2) attachment is nonspecific 3) protein fibers in the phage tail attach to specific receptors on the bacterial cell wall 4) phage DNA exits the protein coat and attaches to the receptors on the bacterium
3
This is the fourth step in the process where the bacteriophage components are put together
Assembly of new virons
For replication of the positive (+) sense strand of the lytic RNA phage, _______________. 1) the (+) RNA strand must code for the synthesis of RNA polymerase (replicase) 2) the RNA replicase uses the (+) sense RNA as a template to make (-) strand RNA 3) the (-) sense strand RNA is used to make (+) strands 4) the (+) RNA strand must code for the synthesis of RNA polymerase ( replicase), the RNA replicase uses the (+) sense RNA as a template to make (-) strand RNA, and (-) sense strand RNA is used to make more (+) strands
4
The first event to occur ________________. 1) the inside of the host cell membrane becomes coated with viral matrix protein 2) the viral capsid becomes enclosed by the cell membrane 3) the inside of the host cell membrane becomes coated with capsid 4) viral spikes proteins are inserted into the host cell membrane
4
Describe and classify Cellular Genome 1. Maybe positive sense RNA 2. May be DNA 3. May be single stranded 4. Less than 3000 genes 5. May be RNA 6. Always DNA 7. May be negative sense RNA 8. More than 3000 genes 9. Always double stranded
6 8 9
This entire cycle can range from ____________ hours to _____________ hours in some viruses. Penetration Environment Naked Uncoating 12 Capsid Absorption 8 Host cell Phospholipid 36 DNA Assembly Release Protein Synthesis Enveloped
8 36
If you could design a drug to "hideor block acid on respiratory cells, what stage of the life cycle of influenza would be directly impacted ? Synthesis Assembly Adsorption Release
Absorption
This is the first step of the process which requires specific receptors on the bacterial surface
Absorption
Following _______________and then _______________ into the host cell, the genomic + strand of RNA acts directly as _________________ and is immediately translated into the ________________ necessary to further viral proliferation, such as replicative __________________. Absorption Genome Template Ribosomes Enzymes Capsids Progeny mRNA Envelope — ssRNA Proteins Penetration
Absorption penetration mRNA proteins enzymes
Place the steps the correct order to assess your understanding of lysogenic and Infections exhibited by bacteriophage 1: This is the first step of the process, which requires specific receptors on the bacterial surface 2: This is the second step in the process, where the viral genetic material only is injected into the bacterium through the rigid tube eliminating the need for uncoating 3: this is the third step in the process, where the host cell shuts off its own DNA replication and protein synthesis 4: this is the fourth step in the process, where immature bacteriophage particles are assembled 5: this is the fifth stage in the process, where fully- formed curious are ready for release 6: this is the sixth stage in this process, where viral enzymes digest the host cell envelope
Absorption penetration replicationassemby maturation release
The general phases in the life cycle of animal viruses are _______________, ________________, ________________, _________________, ________________, and _________________. Penetration Environment Naked Uncoating 12 Capsid Absorption 8 Host cell Phospholipid 36 DNA Assembly Release Protein Synthesis Enveloped
Absorption penetration uncoating synthesis assembly release
Place the steps in the correct order to assess your understanding of the life cycle exhibited by animal viruses. Assembly: Viral spike proteins are inserted into the cell membrane for the viral envelope nucleocapsid is formed from RNA and capsomers Adsorption : The virus attaches to its host by specifie binding of its receptors Release: Envelope viruses bud off of the membrane carrying away an envelope the complete virus or is ready to Infect another cell Synthesis (Replication and Protein Production): under the control of viral genes the seal synthesize is the basic components of new viruses RNA molecules capsomers spikes Penetration: The virus is engulfed in to the vesicle. Uncoating: The viral envelope and capsid are dissolved, thereby freeing the viral RNA into the cell.
Absorption penetration/ uncoating synthesis assembly release
Norwalk virus belongs to which family of viruses? Picenaviridae DNA viruses Adenoviridae. DNA viruses Caliciviridae DNA viruses Picornaviridae , RNA viruses Caliciviridae RNA viruses
Caliciviridae RNA viruses
Geometric structure assembled around the nucleic acid strand or strands
Capsid
All viruses are composed of a _______________ made of ______________ which surrounds the inner core containing _______________ or RNA. Penetration Environment Naked Uncoating 12 Capsid Absorption 8 Host cell Phospholipid 36 DNA Assembly Release Protein Synthesis Enveloped
Capsid proteins DNA
Additional + ssRNA strands are made from the - ssRNA to serve as the mRNA for synthesis of late stage proteins such as _________________ and spiked. All protein synthesis takes place in the host's ____________since viruses lack these structures. Absorption Genome Template Ribosomes Enzymes Capsids Progeny mRNA Envelope — ssRNA Proteins Penetration
Capsids ribosomes
This is the third step in the process where the host cell shit off its own DNA replication and protein synthesis
Duplication of phage components; replication of virus genetic material
Order these steps of the lytic cycle A. Assembly B. Penetration C. Lysis D. Synthesis E. Adsorption
EBDAC
Every virus particle contains _______________ ribosomes DNA and RNA either DNA or RNA DNA
Either DNA or RNA
Exit from the host cell occurs in one of two ways. If the cell is lysed when the virus matures, then the virus will not acquire an _____________. If the virus buds out of a membrane-bound organelle, the membrane surrounds the capsid and pinches off, enveloping the virus as it leaves the cell. Absorption Genome Template Ribosomes Enzymes Capsids Progeny mRNA Envelope — ssRNA Proteins Penetration
Envelope
Structure that possesses bits of the membrane system of past host cell
Envelope
These viruses are known as _________________, whereas viruses without this outer covering are called ______________ viruses. Penetration Environment Naked Uncoating 12 Capsid Absorption 8 Host cell Phospholipid 36 DNA Assembly Release Protein Synthesis Enveloped
Enveloped naked
Choose the term that describes a vrus that has a membranous outer covering over its capsid, partially derived from a host cell. Icosahedral Virus Coated Virus Naked Virus Enveloped Virus Encapsulated Virus
Enveloped virus
Group comprised of mostly animal viruses that possess an additional outermost covering
Enveloped virus
In general viruses are______________ than bacterial or protozoan pathogens and are most often measured in units called _______________ larger-nanometers smaller-nanometers smaller-picometers
Smaller- nanometer
Molecules that play a role in virus attachment to a host cell
Spike
Enveloped viruses use glycoproteins called ___________________ to specifically bind with their host cells. capsids spikes capsomers tail fibers
Spikes
In addition to acting as mRNA, the + RNA genomic strand is also used as a ______________ to make ______________ which in turn acts as a template to make many copies of genomic + strand RNA for packaging into the _______________ viruses Absorption Genome Template Ribosomes Enzymes Capsids Progeny mRNA Envelope — ssRNA Proteins Penetration
Template —asRNA progeny
How are temperate phages replicated ? The phage uses its replication enzymes to create new particles. The phage is replicated along with the host cell's genome . The phage takes over the replication machinery of the host cell . The phage moves from host cell to host cell .
The phage is replicated along with the host cell's genome .
Both lytic and lysogenic cycles eventually lead to bacterial host cell damage True False
True
Cellular inclusions, cell enlargement fusion cell and formation are all examples of cytopathic demonstrated by viral-cells True or False
True
T/ F: A phage induced lysozyme lyses the host cell releasing the newly made phage.
True
T/ F: Viral lysozyme digests the host cell wall, releasing the newly made phage, and losing the host cell in release step
True
T/F: a portion of the viral envelope comes from the cell membrane of the host cell
True
True/ False: Almost immediately upon entry, the viral nuclele acid the genetic expression of the host cell
True
True/ False: both enveloped and naked viruses can enter a cell by endocytosis
True
Rather than developing more antiviral medications, what is a more common focus for researchers when it comes to viral disease? Designing bacteriophages Reducing induction triggers for persistent infections Vaccine development Designing drugs to minimize CPES
Vaccine development
Virus X can infect rodents and birds, whereas Virus Y infects humans. Which has a broader host range? Virus X Virus Y
Virus X
Why do antiviral medications often have side effects? Viruses are intracellular pathogens, and therefore, there is often host cell damage with antiviral treatments Most antiviral target cell membranes, a structure found on both virus particles and human When viral metabolism is restricted, the host cell will die
Viruses are intracellular pathogens, and therefore, there is often host cell damage with antiviral treatments
Antibiotics would be effective against which of these infections? Whooping cough Chickenpox Syphilis Cholera Cold sores Genital warts
Whooping cough syphilis cholera
Viral spikes ____________. are made of lipids attach specifically to host cell receptors attach nonspecifically to host cell receptors are present in all viruses
attach specifically to host cell receptors
In viral entry by endocytosis: -viral spikes fuse with the host cell's plasma membrane to form a vesicle -the host cell's plasma membrane surrounds only the viral protein acid coat and forms a vesicle -the host cell's plasma membrane surrounds only the viral nucleic acid coat and forms a vesicle -the host cell's plasma membrane surrounds the whole virion and forms a vesicle
the host cell's plasma membrane surrounds the whole virion and forms a vesicle
What will happen once a virus has entered a host cell and uncoated? -the virus will kill the cell - the genetic material of the virus will disintegrate - a new envelope will surround the nucleic acid - the synthesis of new virions will occur
the synthesis of new virions will occur