BIO201 Exam 3

When a bacterium acquires a trait from its temperate phage, it is called _____.

lysogenic conversion

The activation of a prophage to enter the lytic cycle is called ______.

Activation of a prophage to progress into viral replication and the rest of the lytic cycle is called induction.

Order the lytic cycle

Adsorption, Penetration, Synthesis, Assembly, Lysis

If you could design a drug to "hide" or block sialic acid on respiratory cells, what stage of the life cycle of influenza would be directly impacted? Synthesis Release Adsorption Assembly

Adsorption: Sialic acid is the cell receptor used by influenza for attachment to host cells. Blocking this would block adsorption of the virus to host cells.

Which of the following is a type of cytopathic effect? Multinucleated giant cells All of the choices are correct. Cells change shape Inclusions in the nucleus Inclusions in the cytoplasm

All choices are correct

Host cells of viruses include ________.

All choices correct:bacteria,plants and fungi,protozoa and algae,humans and other animals

2. Identify what types of organisms may become infected by a virus.

Animals, humans, plants, microorganisms, bacteria, and archaea

7. Explain to a parent why antibiotics are not prescribed for viral infections.

Antibiotics are not prescribed for viral infections because viruses are not bacteria, meaning it is hard to find an antibiotic to kill the virus that would not kill the good cells for us

4. Identify the structures that make up a virus.

Capsid, envelope, nucleic acids, envelope proteins, RNA/DNA

18. Be able to discuss symptoms and causative agents of the following diseases: Chickenpox

Chickenpox: (symptoms) Fever, abundant rash appears after an incubation period of 10 to 20 days.Skin lesions progress quickly from macules and papules to itchy vesicles filled with a clear fluid, encrust and drop off after several days, heal completely or may leave a small scar, lesion can number from a few to hundreds more abundant in adolescents and adults. Causative agents: varicella virus (herpes zoster)

Chronic latent viruses

Chronic latent viruses: ability of a pathogenic virus to lay dormant (latent) within a cell denoted as the lysogenic part of the viral cycle: Latent viral is a persistent viral not a chronic viral

Select characteristics exhibited by viral capsids.

Composed entirely of protein May be an icosahedral shape May be helical in shape Protect the viral nucleic acid Composed of subunits called capsomers May bind to the surface of the host cell Viral capsids are composed entirely of protein subunits called capsomers, and form a covering which protects the nucleic acid core. Two very common shapes are helical and icosahedral. In addition to protecting the nucleic acid core, the capsid of some viruses binds to the surface of a host cell in the initial stages of establishing an infection. Viral capsids are composed entirely of protein subunits called capsomers, and form a covering which protects the nucleic acid core. Two very common shapes are helical and icosahedral. In addition to protecting the nucleic acid core, the capsid of some viruses binds to the surface of a host cell in the initial stages of establishing an infection. Viral capsids are composed entirely of protein subunits called capsomers, and form a covering which protects the nucleic acid core. Two very common shapes are helical and icosahedral. In addition to protecting the nucleic acid core, the capsid of some viruses binds to the surface of a host cell in the initial stages of establishing an infection. Viral capsids are composed entirely of protein subunits called capsomers, and form a covering which protects the nucleic acid core. Two very common shapes are helical and icosahedral. In addition to protecting the nucleic acid core, the capsid of some viruses binds to the surface of a host cell in the initial stages of establishing an infection. Viral capsids are composed entirely of protein subunits called capsomers, and form a covering which protects the nucleic acid core. Two very common shapes are helical and icosahedral. In addition to protecting the nucleic acid core, the capsid of some viruses binds to the surface of a host cell in the initial stages of establishing an infection. Viral capsids are composed entirely of protein subunits called capsomers, and form a covering which protects the nucleic acid core. Two very common shapes are helical and icosahedral. In addition to protecting the nucleic acid core, the capsid of some viruses binds to the surface of a host cell in the initial stages of establishing an infection. Viral capsids are composed entirely of protein subunits called capsomers, and form a covering which protects the nucleic acid core. Two very common shapes are helical and icosahedral. In addition to protecting the nucleic acid core, the capsid of some viruses binds to the surface of a host cell in the initial stages of establishing an infection. Viral capsids are composed entirely of protein subunits called capsomers, and form a covering which protects the nucleic acid core. Two very common shapes are helical and icosahedral. In addition to protecting the nucleic acid core, the capsid of some viruses binds to the surface of a host cell in the initial stages of establishing an infection.

Be able to discuss symptoms and causative agents of the following diseases genital warts

Genital warts: symptoms include small flesh colored swellings on genital parts and itching around those areas. The causative agent is the human papillomavirus and it is transmitted sexually.

18. Be able to discuss symptoms and causative agents of German measles (rubella)

German Measles/ Rubella: The symptoms in postnatal Rubella include: rash of pink macules and papules, appears first on face and progresses down to the trunk toward the extremities, advanced and resolves with in three days, mildose than measles rash, and adult rubella characterized by joint inflammation and pain rather than rash. Symptom of prenatal Rubella: Teratogenic, Virus is transmitted from the mother to fetus in utero, even if the mom is asymptomatic. When infection occurs during the first trimester, it can result in misscariage or multiple lasting birth defects. Most common include: deafness, cardiac abnormalities, ocular lesions, mental/ physical retardation. These individuals are more prone to get anemia, hepatitis, pneumonia, carditists, and bone infection. Transmitted by: contact with respiratory secretions and sometimes urine, virus shed during prodromal stage, carditis, and bone infection.Influenza: symptoms include nausea, fever, cough, fatigue, sore throat, runny nose. Causative agents are RNA viruses of the Orthomyxovirus genus. Transmission is spread person to person through droplets by sneezing or coughing or talking.

Be able to discuss symptoms and causative agents of the following diseases Hepatitis A and B:

Hepatitis A and B: symptoms may include fatigue, nausea, loss of appetite, and a low-grade fever. The causative agent for hepatitis A is the hepatitis A virus and hepatitis B is caused by the hepatitis B virus

6. Identify the location of replication within a host cell for a DNA virus, RNA virus.

In DNA virus replication occurs in the nucleus, in RNA virus replication occurs in the cytoplasm

18. Be able to discuss symptoms and causative agents of the following diseases: influenza,

Influenza: symptoms include nausea, fever, cough, fatigue, sore throat, runny nose. Causative agents are RNA viruses of the Orthomyxovirus genus. Transmission is spread person to person through droplets by sneezing or coughing or talking.

10. Discuss prophages.

Inserted into bacterial chromosome, reminiscent of the provirus state in animal viruses

What happens to the viral capsid?

It becomes completely encolosed by region of the cell membrane into the spike and matrix protein are embedded

7. Describe what limits host range.

It can be restrictive in cases like hepatitis B, poliovirus, rabies. Cells that lack receptors are resistant to some viruses

12. Why is it difficult to develop antiviral drugs?

It is difficult because viruses are not bacteria and antibiotics would not work on viruses. Viruses "borrow" host proteins and functions to help themselves, and it is hard to find drugs that wouldn't hurt the host cells.

Latent viruses

Latent viruses: virus remains asymptomatic on host cell for long periods

Lysogenic conversion

Lysogenic conversion: bacterium acquires a new genetic trait due to the presence of genetic material from an infecting phage

When phage nucleic acid is incorporated into the nucleic acid of its host cell and is replicated when the host DNA is replicated, this is considered part of which cycle?

Lysogenic cycle

9. Identify the major characteristics of a transformed cell.

They have an increased rate of growth, have changes in their chromosomes, changes in cell's surface molecules, and capacity to divide for indefinite period

Tropism

Tropisms: growth toward or away from stimulus

Uncoating

Uncoating: process of removal of viral coat and release of viral genome by its newly invaded host cell

Enveloped viruses are usually release from host cell by ?

budding

Which of the following is not associated with every virus? Genome Nucleic acid Capsomeres Envelope Capsid

Envelope This membranous covering is called an envelope, and viruses which have such a covering are called "enveloped" viruses. A virus which lacks this covering is referred to as a "naked" virus. Please refer to section 5.2 in the textbook for additional information.

Viruses that cause infection resulting in alternating periods of activity with symptoms and inactivity without symptoms are called _____.

latent

Viral Genome

less than 3000 genes may be negative sense RNA may be positve sense RNA may be single stranded may be RNA maybe DNA

Oncovirus

mammalian virus capable of causing malignant tumors

Oncoviruses include all the following except ________. measles virus papillomavirus HTLV I Epstein-Barr virus hepatitis B virus

measles virus:

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

metabolism

A negative-sense RNA virus ________.

must synthesize a positive RNA copy of its genome.

A naked virus has only a(n) _____.

nucleocapsid

HPV can cause cellular changes that lead to the development of cervical cancer. The virus is said to cause transformation as it changes the growth rate and properties of the host cells. Because of this, HPV can be referred to as a(n) __________ virus.

oncogenic : HPV can cause cellular changes that lead to the development of cervical cancer. The virus is said to cause transformation as it changes the growth rate and properties of the host cells. This is referred to as a transforming infection, and HPV can be referred to as an oncogenic virus.

Mammalian viruses capable of starting tumors are _____.

oncoviruses

viral infection in which the virus can remain latent in the host cell for weeks to years is described as a(n) _________ infection, and may lead to cancer if host DNA is altered.

persistent

Viral spikes ________.

protrude from the envelope.

The host cells that viruses can infect are determined by the ____________.

receptors on the host cells

Reverse transcriptase

replication of AIDS virus and other retroviruses

Enveloped viruses use glycoproteins called _______ to specifically bind with their host cells.

spikes: Glycoprotein spikes are used by enveloped viruses for attachment to host cell receptors. This is a specific interaction, limiting the host range of the virus.

A virus that undergoes lysogeny is a/an A. temperate phage B. intemperate phage C. T-even phage D. animal virus E. DNA virus

temperate phage

For replication of the positive (+) sense strand of lytic RNA phage, _______.

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 the (-) sense strand RNA is used to make more (+) strands

What percentage of human DNA is thought to consist of viral DNA sequences?

8

How does lysogeny affect humans?

Bacteria can become virulent due to phage genes, causing greater damage to infected human host. Some bacteria become pathogenic because they carry phage genes that code for toxins or enzymes that affect the human host. Examples include the bacteria that cause cholera, botulism, and diphtheria.

16. Discuss the effect on bacteria that have become infected with a bacteriophage. How can this impact human health?

Bacteriophage often makes the bacteria more pathogenic to humans, they can help human health because they can decrease the amount of bacteria on the host.

Bacteriophages

Bacteriophages: a virus that specifically infects bacteria

Rabies virus has a _______ host range as compared to hepatitis B virus.

Broad: Rabies can infect all mammals whereas hepatitis B is restricted to human hosts.

Reverse transcriptase synthesizes ________.

DNA from RNA

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

Decreased growth rate

5. Describe the stages of virus replication.

During the early phase, viral DNA enters the nucleus, where several genes are transcribed into messenger RNA, where it then moves into the cytoplasm to be translated into viral proteins that are needed to replicate. During late phase other parts of the genome are transcribed and translated into proteins required to form capsid and other structures. New genomes and capsids assembled and released by budding or cell disintegration.

Be able to discuss symptoms and causative agents of the following diseases Ebola:

Ebola: symptoms include fever, pains, aches, weakness, and fatigue. Causative agent is filoviridae and the order mononegavirales. Transmission is through wild animals such as bats then can be transmitted from person to person in close contact.

18. Be able to discuss symptoms and causative agents of the following diseases: encephalitis (meningoencephalitis),

Encephalitis: Symptoms include headache, mild flu-like symptoms, sensitivity to light, and neck stiffness. Causative agent is the herpes simplex virus which causes cold sores and genatil herpes. Transmission is normally spread through a mosquito where it gets into the bloodstream

What isthe term that describes a virus that has a membranous outer covering over its capsid, partially derived from a host cell?

Enveloped virus This membranous covering is called an envelope, and viruses which have such a covering are called "enveloped" viruses. A virus which lacks this covering is referred to as a "naked" virus. Please refer to section 5.2 in the textbook for additional information.

Be able to discuss symptoms and causative agents of the following diseases mono:

Epstein Barr (Mono): Symptoms include extreme fatigue, fever, sore throat, swollen lymph nodes, rash. Causative agent is a human lymphotropic virus. Transmission is through saliva and possibly the uterine cervix.

Choose the statement that indicates how cytopathic effects are detected.

Examine infected cells with a microscope Cytopathic effects (CPE) indicate viral damage to a cell and change the microscopic appearance of the infected cell. In order to detect CPE, the infected cells must be examined microscopically.

T or F:Enveloped viruses are usually release from host cell by exocytosis.

F:

Choose the term that describes a bacteriophage infection in which the bacteriophage DNA isinserted into the host cell DNA as a prophage, and the infected bacteria can continue to grow and divide.

Lysogentic A lysogenic infection occurs when a bacteriophage infects bacteria, inserting its DNA into the bacterial genome as a prophage. The bacteria is not lysed, but instead continues to grow and divide, though some of its properties may be altered.

Lysogeny

Lysogeny: Indefinite persistence of bacteriophage DNA in a host without bringing about the production of virions

Choose the term that describes a bacteriophage infection in which the host bacteria are lysed and killed by the infection.

Lytic

15. Identify several viral diseases that become latent in the human body. Identify which tissues will harbor the virus during latency.

Measles : Pathogenesis• Implants in the respiratory mucosa Travels to lymphatic system where it multiplies and spreads to the bloodstream Polimyelitis: Virus Carried to CNS by blood supply, specific path ways to brain and spinal cord, Neurotropic: Infiltrates motor neurons of the anterior horn of the spinal cord. aeotrrior horn of the spmis RAbies: 1-2 months at the wound sight Hepatitis: Inflammation of liver cells Mumps: 2-3 weeks incubation Viral multiplication in the salivary glands

18. Be able to discuss symptoms and causative agents of the following diseases: measles (rubeola)

Measles/ Rubeola: (symptoms) sore throat, cop like spots, dry cough, headache, conjunctivitis, lymphadenitis, fever, red maculopapular exanthem that erupts on the head and progresses to the trunk and extremities. Transmitted by : Respiratory droplets, human to human, Infectious during incubation, prodromal, and skin rash stages, not contagious during convalescence, only dense populations of non-vaccinated individuals can sustain transmission.

13. Discuss the structure and function of viral spikes?

Molecules that allow viruses to dock with their host cells, they are on the outside of the structure of virus

Cellular Genome

More than 3000 genes Always DNA Always double standed

18. Be able to discuss symptoms and causative agents of the following diseases: C mumps

Mumps: symptoms include fever, headache, muscles aches, and tiredness. Causative agent is paramyxovirus. Transmission

1. Identify the characteristics of viruses.

Non cellular particles with a definite size, shape, and chemical composition, are obligate intracellular parasites that cannot multiply unless they invade a specific host cell.

8. Identify some of the major oncoviruses discussed in lecture.

Papillomavirus, herpesviruses, hepatitis B virus

Be able to discuss symptoms and causative agents of the following diseases Polio

Polio: symptoms include fever, sore throat, headache, vomiting, fatigue, and possible back pain. Causative agent is the human enterovirus of the picornaviridae family. Transmission occurs in fecal to oral, droplets from a sneeze or cough from an infected person.

Which of the following is not true regarding the structure and function of viral spikes? They are coded for by the host genome They are coded for by the viral genome They mediate the docking process of virus to host cell They consist of proteins and carbohydrates They are found on both enveloped and naked viruses

They are coded for by the host genome

Select the infectious agents that are noncellular.

Prions,Satellite viruses,Viroids In addition to viruses, there are several other noncellular infectious agents. These include prions, satellite viruses, and viroids. In addition to viruses, there are several other noncellular infectious agents. These include prions, satellite viruses, and viroids. In addition to viruses, there are several other noncellular infectious agents. These include prions, satellite viruses, and viroids. In addition to viruses, there are several other noncellular infectious agents. These include prions, satellite viruses, and viroids. In addition to viruses, there are several other noncellular infectious agents. These include prions, satellite viruses, and viroids.

Choose the statement that best describes the role of viral surface proteins or spikes.

Provide means of attachment to host cell surface Many viruses have surface proteins that project outward from the capsid or envelope. These proteins provide a means for the virus to attach to a host cell, the first step in establishing an infection.

14. Discuss what happens to the respiratory cells during a case of RSV.

RSV causes intense inflammation inside the bronchi and bronchioles. RSV irritates the epithelium and makes it swell up destroying the cells including the cells that clear mucus from the lungs

Be able to discuss symptoms and causative agents of the following diseases RSV :

RSV: symptoms include runny nose, decrease in appetite, coughing, sneezing, fever, and wheezing. Causative agent is rhinovirus, and enteroviruses that cause an infection in the respiratory tract and lungs. Transmission occurs if you get sneezed or coughed on with someone with rsv, you can also get it from other droplets on doorknobs or other items that they have touched, coughed or sneezed on.

18. Be able to discuss symptoms and causative agents of the following diseases: shingles

Shingles: Symptoms include: Characteristic of asymmetric distribution in the skin of the trunk or the head. Develops abruptly after reaction by stimuli such as psychological/ stress, x ray treatments, immunosuppressive, and other drug therapy, surgery, and developing malignancy. Virus enters the sensory ending of the dermatomes after recovery from chicken pox. Regions of the skin supplied by cutaneous branches of the thoracic and trigeminal nerves.

Select the terms that describe the possible configurations of viral nucleic acids.

Single-stranded DNA,Double-stranded DNA, linear,Double-stranded DNA, circular,Single-stranded RNA, positive sense,Single-stranded RNA, negative sense,Double-stranded RNA Viral nucleic acids display a large variety of configurations. Among DNA viruses, the DNA may be typical double-stranded DNA, either linear or circular, or it may be single-stranded DNA. RNA viruses may have double-stranded RNA genomes, or single-stranded RNA. Depending on whether the single RNA strand is immediately ready for translation or has to be converted into the proper form, it will be known as positive sense RNA or negative sense RNA, respectively. Viral nucleic acids display a large variety of configurations. Among DNA viruses, the DNA may be typical double-stranded DNA, either linear or circular, or it may be single-stranded DNA. RNA viruses may have double-stranded RNA genomes, or single-stranded RNA. Depending on whether the single RNA strand is immediately ready for translation or has to be converted into the proper form, it will be known as positive sense RNA or negative sense RNA, respectively. Viral nucleic acids display a large variety of configurations. Among DNA viruses, the DNA may be typical double-stranded DNA, either linear or circular, or it may be single-stranded DNA. RNA viruses may have double-stranded RNA genomes, or single-stranded RNA. Depending on whether the single RNA strand is immediately ready for translation or has to be converted into the proper form, it will be known as positive sense RNA or negative sense RNA, respectively. Viral nucleic acids display a large variety of configurations. Among DNA viruses, the DNA may be typical double-stranded DNA, either linear or circular, or it may be single-stranded DNA. RNA viruses may have double-stranded RNA genomes, or single-stranded RNA. Depending on whether the single RNA strand is immediately ready for translation or has to be converted into the proper form, it will be known as positive sense RNA or negative sense RNA, respectively. Viral nucleic acids display a large variety of configurations. Among DNA viruses, the DNA may be typical double-stranded DNA, either linear or circular, or it may be single-stranded DNA. RNA viruses may have double-stranded RNA genomes, or single-stranded RNA. Depending on whether the single RNA strand is immediately ready for translation or has to be converted into the proper form, it will be known as positive sense RNA or negative sense RNA, respectively. Viral nucleic acids display a large variety of configurations. Among DNA viruses, the DNA may be typical double-stranded DNA, either linear or circular, or it may be single-stranded DNA. RNA viruses may have double-stranded RNA genomes, or single-stranded RNA. Depending on whether the single RNA strand is immediately ready for translation or has to be converted into the proper form, it will be known as positive sense RNA or negative sense RNA, respectively. Viral nucleic acids display a large variety of configurations. Among DNA viruses, the DNA may be typical double-stranded DNA, either linear or circular, or it may be single-stranded DNA. RNA viruses may have double-stranded RNA genomes, or single-stranded RNA. Depending on whether the single RNA strand is immediately ready for translation or has to be converted into the proper form, it will be known as positive sense RNA or negative sense RNA, respectively.

An infection in animals similar to a lysogeny in bacteria is called a(n) ______ infection.

Some animal viruses are harbored by their host cells for several weeks or up to a lifetime. These are called persistent infections.

3. What can make up the genome of a virus?

Sum total of the genetic information, either made up of DNA or RNA not both, poses only genes to invade host cells

Syncytia

Syncytia: a multinucleated protoplasmic mass formed by consolidation of individual cells

T or F: Both lytic and lysogenic cycles eventually lead to bacterial host cell damage.

T: Both are forms of parasitism, with the lysogeny representing a less deadly form.

What structures are used by bacteriophages to attach to host cell receptors?

Tail fibers

11. Discuss lysogeny.

The host chromosome carries bacteriophage DNA, viral particles are not produced and bacterial cells carrying temperate phages do not lyse and are appear entirely normal

How are temperate phages replicated?

The phage is replicated along with the host cell's genome Temperate phages insert into the bacterial chromosome as a prophage. As the bacterium divides, its replicates its genome including the prophage. Therefore, all daughter cells of the original infected bacterium carry a copy of the prophage.

18. Be able to discuss symptoms and causative agents of the following diseases: viral meningitis,

Viral Meningitis: symptoms include fever, headache, stiff neck, sleepiness, and vomiting. Causative agent are enteroviruses, other viruses like herpes simplex virus or HIV mumps virus can cause this also. Transmission is direct saliva, nasal mucus, or feces and also easily spread through coughing or sneezing.

What is the first event to occur in the mechanism for releasing enveloped viruses?

Viral spike proteins are inserted into the host cell membrane

Virus X can infect rodents and birds, whereas Virus Y infects humans. Which has a broader host range? Virus X Virus Y

Virus X has a broader host range because it can infect many types of animals rather than just a human host.

Capsid

all proteins have this, shell surrounds nucleic acid in the central core

Why are CD4 counts related to HIV infection? a) HIV needs CD4 molecules for replication. b)HIV can only bind to cells with CD4 receptors. c)HIV destroys CD4 molecules found on T cells.

b)HIV can only bind to cells with CD4 receptors. HIV glycoproteins bind to CD4 receptors on certain white blood cells to cause infection and eventual destruction of those cells.

A positive (+) strand of RNA _______.

can directly act as mRNA

A(n) _______ is the protein shell around the nucleic acid core of a virus.

capsid

Helical and icosahedral are terms used to describe the shapes of a virus _____.

capsid

Virus capsids are made from subunits called _____.

capsomeres

Persistent viruses that can reactivate periodically are _____.

chronic latent viruses

One of the principal capsid shapes is a 20-sided figure with 12 evenly spaced corners referred to as a(n) _______ capsid.

icosahedral

An infection in animals is similar to lysogency in bacteria is called what kind of infection?

induction Some animal viruses are harbored by their host cells for several weeks or up to a lifetime. These are called persistent infections.

The envelope of enveloped viruses ________.

is obtained by viral budding or exocytosis

The negative (-) sense strand of RNA _______.

is used to synthesize more + strands

Respiratory syncytial virus (RSV) is a common respiratory virus that causes mild cold-like symptoms in most individuals, but can be more serious in infants and the elderly. RSV is so-named because ________.

it causes the fusion of damaged host cells, forming a large, multinucleated cell

Viral tissue specificities are called _____.

tropisms

T of F: the portion of the viral envelope that comes from the cell membrane of the host cell

true

The presence of viruses in the blood is called ________.

viremia