Chapter 13: Case Study

Viruses that infect bacterial cells are called

bacteriophages

When the defective phage enters a new bacterial cell

both phage DNA and bacterial DNA integrate into the chromosome of the new cell host

After entry of the bacteriophage into the host cell, a phage enzyme

breaks the host DNA into fragments

A positive (+) strand of RNA

can directly act as mRNA

When the bacteriophage transfers bacterial DNA into a recipient bacterial cell, this DNA

can integrate into the chromosome

Anemia

deficiency of red blood cells

Oncolysis

destruction of tumor cells

Every virus particle contains _______

either DNA or RNA

Fatigue

extreme tiredness

all viruses can infect any cell type or tissue type

false

Intubate

inserting a tube into the trachea to assist breathing

The negative (-) sense strand of RNA

is used to synthesize more (+) strands

In transduction, bacterial DNA is transferred to a new cell when

it is injected by the virus

Arthralgia

joint pain

Anorexia

loss of appetite

Thrombocytopenia

low blood platelet count

The final step in T2 bacteriophage infection results in

lysis of the bacterial cell and release of new viral particles

The final step in T2 bacteriophage infection results in:

lysis of the bacterial cell and release of new viral particles

Bacteriophages involved in generalized transduction are ________ phages.

lytic

Viral cycles that end in release of the new phages and immediate destruction of the host bacterial cell are referred to as ________

lytic

myalgia

muscle pain

Once inside the host cell, viral DNA directs production of _______

new viral particles

Once inside the host cell, viral DNA directs production of ________

new viral particles

In the process of specialized transduction

only a few specific genes from one bacterial cell are transferred to the second bacterial cell by a phage

In specialized transduction

only bacterial genes near the site of integration of the phage DNA can be transduced

Bacteriophages absorb or attach

only to members of the same bacterial species

A major difference in the replication of animal viruses and bacteriophages is the ______ step

penetration

After host cell DNA is broken down by a viral enzyme

phage DNA is replicated and phage coat proteins are produced

A difference between plasmids and fragments of DNA that have been transferred between cells is

plasmids can replicate independently

Viral capsids are composed of

protein

Obtund

reduced consciousness

Immunosuppression

reducing the immune response

Phage DNA encodes or the proteins of the viral capsid and

regulatory proteins that direct the production and assembly of the capsid proteins

During viral infection of a host cell, which is the third step of the process?

release of nucleocapsid into host cytoplasm

Rehydration

restoring lost water

A bacteriophage initially associates with which bacterial structure?

the bacterial cell wall

In viral entry by endocytosis

the host cell's cytoplasmic membrane surrounds the whole virion and forms a vesicle

The genetically engineered adenoviruses are oncoselective in that

they kill cells expressing high levels of CPEB4 but not cells with high levels of CPEB1

Bacteriophage DNA directs the degradation of the bacterial host cell's DNA

true

In order for viruses to enter host cells, they must bind to receptors on the host cytoplasmic membrane

true

More than one mechanism of viral entry into a host cell exists

true

Giloma

type of brain tumor

Removal of the capsid to release the virus nucleic acid into the host cytoplasm is called

uncoating

Oncoselective viruses

viruses that select cancer cells

Select the TRUE statements regarding CPEB4

- CPEB4 is highly expressed in a number of type of cancer cells - CPEB4 belongs to a family of 4 proteins - CPEB4 is a regulatory protein

The general steps in viral replication (in order) are

- adsorption - penetration - synthesis - assembly - release

In the lytic phage infections, the early viral proteins are important for initial steps of phage multiplication. Which of the following are functions of these proteins?

- degrade host cell's DNA - modify host cell's RNA polymerase so that it doesn't recognize bacterial promoters

The advantageous genes that can be transferred by transduction are genes for

- sugar fermentation - toxin production - drug resistance

Select all the reasons that likely led to the patient in this case becoming dehydrated

- vomiting - diarrhea - fever

The patient's platelet count doubled between his first blood test and his second blood test.

False

A bacteriophage can infect many different types (strains) or bacterial cells.

False Reasoning: Bacteriophages have a limited host range, which means that they are limited in the types of cells they can infect. This makes phage typing an effective method of bacterial identification when more than one strain within a species exists.

What are the two entry mechanisms used by enveloped viruses?

Fusion and endocytosis

Select the false statement regarding using oncolytic viruses for treating cancer

Genetically engineered viruses such as adenoviruses have been shown to cure people of cancer that previously were untreatable

Febrile

Having a fever

How does bacteriophage DNA get into the host cell?

It is injected

When present, of what is the viral envelope composed?

Many lipids

Bacteriophage DNA directs the synthesis of an enzyme which degrades the bacterial host cell's DNA

True

Both enveloped and non-enveloped (naked) viruses can enter a cell by endocytosis

True

Certain cancer cells express high levels of CPEB4 and low levels or no CPEB1, while normal cells express high levels of CPEB1

True

Sometimes a piece of bacterial DNA near the specific site of insertion stays attached to the phage DNA, and a piece of phage DNA remains behind.

True

The enzyme lysosome is used by the T4 phage to assist in the injection of its DNA into the target cell

True

The lambda phage DNA always integrates into the host DNA in the same specific site

True

The researchers are hopeful that oncolytic viruses could be used to treat people with a variety of different cancers, including colorectal cancer, pancreatic cancer, and a type of brain cancer.

True

Which of the following can cause a phage in the lysogenic stage to revert to he lytic stage?

Ultraviolet light

Generalized transduction occurs when

a bacteriophage packages a piece of bacterial DNA during replication

During maturation or formation of phage particles

a few phage heads may surround fragments of host bacterial DNA

The capsid of a virus is

a protein shell that surrounds the nucleic acid

Lymphopenia

abnormally low number of lymphocytes in the blood

Leukopenia

abnormally low number of white blood cells

The basic parts of a bacteriophage are

an isohedral head, tail pins and fibers

Viral spikes

attach specifically to host cell receptors

The stage of T4 replication that involves interaction between the protein fibers on the phage and receptors on the bacterial cell wall is the

attachment stage

Place the steps of T4 phage replication into the correct sequence

1. Attachment - phages attach to receptors on bacterial surface 2. Genome entry - phage tail contracts and phage DNA is injected into bacterial cell 3. Synthesis - phage genome is transcribed and translated phage DNA is replicated 4. Assembly - newly synthesized phage components are assembled into mature virions 5. Release - bacterial cell lyses, releasing new infectious virions

Assume that the patient's normal level of AST should have been 20 U/L. How much higher was his level at the time of the first blood test?

6.9-fold

Which of the following is required to maintain a lysogenic state?

A repressor protein

In animal virus replication, an uncoating step is needed to release the nucleic acid from the capsid. Why is this step not needed in bacteriophage replication?

Bacteriophages inject their DNA into the host cell

The cases reported from the community were the same strain of Salmonella enterica serotype Enteritidis as the cases in the vaccine production facility.

False

Which of the patient's blood test results could be considered normal?

Creatinine

Which tests indicate a person's kidney function?

Creatinine and BUN

What bacterial enzyme is used by the virus for replicating its nucleic acid?

DNA polymerase

What bacterial enzyme would the phage need to use to replicate their genome?

DNA polymerase

Why was the patient given doxycycline by his physician, even though the doctor had not diagnosed his illness?

Doxycycline is the standard antibiotic given to treat tick-borne diseases, and then patient had developed his illness following a tick bite

The T-even bacteriophages such as T2 and T4 infect

Escherichia coli

Everyone that was exhibiting signs and symptoms of salmonellosis in this should immediately be given antibiotics to treat their illness.

False

Generalized transduction involves the transfer of phage genes from one bacterial cell to another

False

Generalized transduction is so called because specific bacterial genes are transferred during this process

False

In the lysogenic stage of phage replication, the host cell is lysed.

False

Once a phage becomes lysogenic, it will remain lysogenic and never be lytic again.

False

T-even phages can replicate independently of a host cell

False

The specific serotype of Salmonella enterica causing the infection was determined by

Phage typing

Three or more watery stools within a 24-hour period of time describes infection with

Salmonella

Why do you think cases of salmonellosis are often underreported?

Symptoms are not severe enough to necessitate a trip to the doctor

Working together for greater effect

Synergism

A bacteriophage initially associates with which bacterial structure?

The bacterial cell wall

People with cancer who get conventional chemo drugs often experience side effects such as nausea, vomiting, diarrhea, and hair loss because

The drugs cause the death of any rapidly dividing cells and the digestive tract and hair follicles have fast-growing cells

What did all of the vaccine production factory workers who contracted the illness have in common?

They all worked in the room where the spill occurred

Chemotherapy

Treating cancer with medicaitons

All of the employees who reported symptoms of salmonellosis had entered the room where the spill of SE occurred.

True

Almost immediately upon entry, the viral nucleic acid alters the gene expression of the host cell

True