Micro Chap 6 - An Intro To Viruses

Viruses have all the following except A. Definite shape B. Metabolism C. Genes D. Ability to infect host cells E. Ultramicroscopic size

Host cells of viruses include A. Human and other animals B. Plants and fungi C. Bacteria D. Protozoa and algae E. All of the choices are correct

Viruses A. Cannot be seen in a light microscope B. Are prokaryotic C. Contain 70S ribosomes D. Undergo binary fission E. All of the choices are correct

Virus capsids are made from subunits called A. Envelopes B. Spikes C. Capsomeres D. Prophages E. Peplomers

Helical and icosahedral are terms used to describe the shapes of a virus A. Spike B. Capsomere C. Envelope D. Capsid E. Core

A _____ is the protein shell around the nucleic acid core of a virus. A. Capsomere B. Capsid C. Spike D. Envelope E. Monolayer

One of the principal capsid shapes is a 20-sided figure with 12 evenly spaced corners referred to as a(n) _____ capsid. A. Spiked B. Complex C. Icosahedral D. Helical E. Buckeyball

A naked virus only has a(n) A. Capsid B. Capsomere C. Nucleocapsid D. Envelope E. Antigenic surface

Which of the following is not a typical capsid shape? A. Tetrahedral B. Complex C. Helical D. Icosahedron E. All of the choices are capsid shapes

All of the following pertain to virus envelopes except A. Gained as a virus leaves the host cell membrane B. Gained as a virus leaves the nuclear membrane C. Contain special virus proteins D. Help the virus particle attach to host cells E. Located between the capsid and nucleic acid

Viral spikes A. Are always present on enveloped viruses B. Bind viral capsid and envelope together C. Allow bacteria to evade host defenses D. Are derived from host proteins E. All of the choices are correct

The core of every virus particle always contains A. DNA B. Capsomeres C. Enzymes D. DNA and RNA E. Either DNA or RNA

Which of the following is not associated with every virus? A. Envelope B. Capsomeres C. Capsid D. Nucleic acid E. Genome

Viral nucleic acids include which of the following A. Double stranded DNA B. Single stranded DNA C. Double stranded RNA D. Single stranded RNA E. All of the choices are correct

Reverse transcriptase synthesizes A. The positive RNA strand from a negative RNA strand B. A negative RNA strand from a positive RNA strand C. Viral RNA from DNA D. Viral DNA from RNA E. None of the choices are correct

A negative RNA virus must first A. Synthesize a DNA copy of its genome B. Synthesize a negative RNA copy of its genome C. Synthesize a positive RNA copy of its genome D. Transcribe reverse transcriptase E. Transcribe RNA polymerase

Viruses with _____ sense RNA contain the correct message for translation, while viruses with _____ sense RNA must first be converted into a correct message. A. Positive, negative B. Negative, positive C. Primary, secondary D. Secondary, primary E. None of the choices are correct

Classification of viruses into families involves determining all the following characteristics except A. Type of nucleic acid B. Type of capsid C. Presence of an envelope D. Biochemical reactions E. Number of strands in the nucleic acid

Which of the following represents a virus family name? A. Herpes simplex virus B. Herpesviridae C. Picornavirus D. Enterovirus E. Hepatitis B virus

Which of the following is not a viral order in the classification system? A. Caudovirales B. Vaccinia virus C. Nidovirales D. Mononegavirales E. All of the choices are viral orders

The correct sequence of events in viral multiplication is A. Penetration, uncoating, synthesis, adsorption, assembly, release B. Uncoating, penetration, synthesis, assembly, absorption, release C. Adsorption, penetration, uncoating, synthesis, assembly, release D. Assembly, synthesis, uncoating, release, penetration, adsorption E. Adsorption, release, synthesis, uncoating, assembly, penetration

Viruses acquire envelopes around their nucleocapsids during A. Replication B. Assembly C. Adsorption D. Release E. Penetration

In general, most DNA viruses multiply in the host cell's _____, while most RNA viruses multiply in the host cell's _____. A. Nucleus, cytoplasm B. Cytoplasm, cell membrane C. Cell membrane, cytoplasm D. Cytoplasm, nucleus E. Nucleus, endoplasmic reticulum

Host range is limited by A. Type of nucleic acid in the virus B. Age of the host cell C. Type of host cell receptors on cell membrane D. Size of the host cell E. All of the choices are correct

Oncogenic viruses include all the following except A. Hepatitis B virus B. Measles virus C. Papillomavirus D. HTLVI and HTLVII viruses E. Epstein-Barr virus

Which of the following is a type of cytopathic effect? A. Inclusions in the nucleus B. Multinucleated giant cells C. Inclusions in the cytoplasm D. Cells round up E. All of the choices are correct

The envelope of enveloped viruses is A. Identical to the host plasma membrane B. Only compose of host endomembrane C. Always includes spikes D. Is obtained by viral budding or exocytosis E. None of the choices are correct

Viruses attach to their hosts via A. Host glycoproteins B. Host phospholipids C. Viral phospholipids D. Viral flagella E. All of the choices are correct

Viral tissue specificities are called A. Ranges B. Virions C. Receptacles D. Tropisms E. Uncoating

The process of dissolving the envelope and capsid to release the viral nucleic acid is A. Adsorption B. Penetration C. Uncoating D. Synthesis E. Assembly

Which of the following occurs during assembly? A. Nucleocapsid is formed B. New viral nucleic acid is formed C. Viral spikes insert in host cell membrane D. All of the choices occur E. Only choices A and C occur

Mammalian viruses capable of starting tumors are A. Chronic latent viruses B. Oncoviruses C. Syncytia D. Inclusion bodies E. Cytiopathic

Persistent viruses that can reactivate periodically are A. Chronic latent viruses B. Oncoviruses C. Syncytia D. Inclusion bodies E. Cytiopathic

Which of the following is not a characteristic of a transformed cell? A. Viral nucleic acid integrated into host DNA B. Decreased growth rate C. Alterations in chromosomes D. Changes in cell surface molecules E. Capacity to divide indefinitely

New, nonenveloped virus release occurs by A. Lysis B. Budding C. Exocytosis D. Both lysis and budding E. Both budding and exocytosis

What structures are used by bacteriophages to attach to host cell receptors? A. Sheath B. Tail fibers C. Nucleic acid D. Capsid head E. None of the choices are correct

Which of the following is incorrect about prophages? A. Present when the virus is in lysogeny B. Formed when viral DNA enters the bacterial chromosome C. Replicated with host DNA and passed on to progeny D. Cause lysis of host cells E. Occur when temperate phages enter host cells

T-even phages A. Include the poxviruses B. Infect Escherichia coli cells C. Enter host cells by engulfment D. Have helical capsids E. All of the choices are correct

The event that occurs in bacteriophage multiplication that does not occur in animal virus replication is A. Adsorption to the host cells B. Injection of only the viral nucleic acid into the host cell C. Host cell synthesis of viral enzymes and capsid proteins D. Assembly of nucleocapsids E. Replication of viral nucleic acid

Viruses that cause infection resulting in alternating periods of activity with symptoms and inactivity without symptoms are called A. Latent B. Oncogenic C. Prions D. Viroids E. Delta agents

Uncoating of viral nucleic acid A. Does not occur in bacteriophage multiplication B. Involves enzymatic destruction of the capsid C. Occurs during penetration in the multiplication cycle D. Occurs before replication E. All of the choices are correct

In transduction, the viral genome A. Initiates lysis of the host B. Includes DNA from the previous host C. Is replicated in the cytoplasm D. Is replicated in the nucleus E. None of the choices are correct

Lysogeny refers to A. Altering the host range of a virus B. Latent state of herpes infections C. Virion exiting host cell D. Viral genome inserting into bacterial host chromosome E. None of the choices are correct

Viruses that infect bacteria are specifically called A. Viroids B. Prions C. Bacteriophages D. Satellite viruses E. All of the choices infect bacteria

During lysogeny, an inactive prophage state occurs when the viral DNA is inserted into the A. Host cytoplasm B. Host nucleus C. Host nucleolus D. Host DNA E. Host cell membrane

What type of phage enters an inactive prophage stage? A. Primary B. Secondary C. Temperate D. Temporary E. Transformed

The activation of a prophage is called A. Activation B. Lysogeny C. Transformation D. Induction E. Adsorption

When a bacterium acquires a trait from its temperate phage, it is called A. Transformation B. Lysogenic conversion C. Viral persistence D. Transcription E. Translation

In which stage of the multiplication cycle of T-even phages are the phages developing and are not yet infectious? A. Virion B. Induction C. Eclipse D. Conversion E. None of the choices are correct

Which of the following will not support viral cultivation? A. Live lab animals B. Embryonated bird eggs C. Primary cell cultures D. Continuous cell cultures E. All of the choices will support viral cultivation

Visible, clear, well-defined patches in a monolayer of virus-infected cells in a culture are called A. Lysogeny B. Budding C. Plaques D. Cytopathic effects E. Pocks

Viral growth in bird embryos can cause discrete, opaque spots in the embryonic membranes called A. Lysogeny B. Budding C. Plaques D. Cytopathic effects E. Pocks

Cells grown in culture form a(n) A. Monolayer B. Bilayer C. Aggregate D. Plaque E. None of the choices are correct

Diagnosis of viral infections sometimes involves analyzing the patient's blood for specific _____ that the immune system produced against the virus. A. Glycoproteins B. Antibodies C. Complement proteins D. Antigens E. None of the choices are correct

Freshly isolated animal tissue that is placed in a growth medium and allowed to produce a cell monolayer is referred to as a _____ cell culture. A. Initial B. Primary C. Secondary D. Continuous E. Positive

A common method for cultivating viruses in the lab is to use in vitro systems called _____ cultures. A. Embryo B. Cell C. Plaque D. Bacteriophage E. Egg

Infectious protein particles are called A. Viroids B. Phages C. Prions D. Oncogenic viruses E. Spikes

Infectious naked strands of RNA that affect plants are called A. Viroids B. Phages C. Prions D. Oncogenic viruses E. Spikes

Creutzfeld-Jacob disease is A. Caused by a chronic latent virus B. Initiated by an oncogenic virus C. Caused by a viroid D. A spongiform encephalopathy of humans E. Also called "mad cow disease"

Satellite viruses are A. Also called viroids B. Dependent on other viruses for replication C. The cause of spongiform encephalopathies D. Significant pathogens of plants E. All of the choices are correct

Two noncellular agents, smaller than viruses, are the infectious proteins called _____ and the infectious RNA strands called _____. A. Prions, capsomeres B. Virions, prions C. Viroids, phages D. Prions, phages E. Prions, viroids

Who developed a rabies vaccine by separating bacteria from virus using a filter? A. Leewonhoek B. Koch C. Pasteur D. Cohn

The primary purposes of viral cultivation are: A. to isolate and identify viruses in clinical specimens B. to prepare viruses for vaccines C. to do detailed research on viral structure, lifestyle, genetics and effects on host cells D. All of these

When a virus enters a host cell, the viral genes redirect the genetic and metabolic activities of the host cell. True or False

Viruses are used to produce vaccines for prevention of certain viral infections. True or False

Viruses are ultramicroscopic because they range in size from 2 mm to 450 mm. True or False

A fully formed virus that can cause an infection in a host cell is called a virion. True or False

Spikes are glycoproteins of the virus capsid. True or False

Each virus is assigned to genus status based on its host, target tissue and type of disease it causes. True or False

A specific animal virus has the ability to attach to and enter almost any animal host cell. True or False

Viral spikes are inserted into the host cell membrane before budding or exocytosis. True or False

Prophages can be activated into viral replication and enter the lytic cycle. True or False

Bacteriophages do not undergo adsorption to specific host cell receptors prior to penetration. True or False

Viruses are the most common cause of acute infections that do not result in hospitalization. True or False

The adeno-associated virus (AAV) and the delta agent are prions. True or False

Viruses are simple, non-cellular and lack mRNA. True or False

Viruses mutate and some have not been discovered. True or False

Viruses are not filterable. True or False

Viruses are unable to multiple outside of a host cell. True or False