microbio hw 3

Which of the following Escherichia coli cells did NOT produce colonies on the growth medium containing tetracycline?

Cells that did not pick up a plasmid

Which of the following descriptions fits a chronic viral infection?

Characterized by continuous production of low levels of viral particles, potentially even in the absence of active symptoms of disease. The organism is usually still highly infectious during this time.

1. Plasmids are made of ______.

DNA

The entire set of cloned fragments of the complete human genome is termed a

DNA library

The single-stranded ends of DNA molecules can be joined together by

DNA ligase

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

DNA polymerase

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

DNA polymerase

PCR requires all of the following EXCEPT ______.

DNA template primers DNA polymerase DNA ligase. Correct deoxyribonucleotides

In 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 gene for human insulin has been successfully cloned in

E. coli

3. The T-even bacteriophages such as T2 and T4 infect

Escherichia coli.

Which of the following is NOT true of CRISPR-Cas technology?

Gene editing using CRISPR is widely used to cure genetic diseases.

4. Why is the DNA heated to over 90 degrees Celsius to start the process?

Heat denatures the DNA, meaning it separates the two strands

2. For which of the following can PCR be used?

Identification of individuals. Crime scene investigation. Paternity testing. Recombinant DNA technology. All of the given choices. Correct

6. What is the role of Taq polymerase?

It catalyzes the synthesis of the new DNA chains.

2. How does bacteriophage DNA get into the host cell?

It is injected.

1. Why is a selective marker (such as drug resistance) important in recombinant DNA technology?

It makes it possible to easily identify recombinant cells.

Which of the following is NOT given as an advantage of using CRISPR-Cas in diagnosing infections in kidney transplant patients?

It will protect the patient's kidney from invading DNA.

The family to which the Rhinovirus belongs is the

Picornaviridae

1. A bacteriophage initially associates with which bacterial structure?

The bacterial cell wall

3. How are mini-STRs different from SNPs?

The mini-STRs are a few chromosomal regions that vary between individuals

1. Why do plasmids work well as vectors for the insertion of foreign DNA?

They can replicate independently of the chromosome. They usually contain an identifiable selection marker. They contain an origin of replication. All of the choices are correct. Correct

5. Why is the DNA cooled slightly after it is denatured?

To allow the primers to anneal to their complementary sequence on the target DNA. Correct

1. What is the general purpose of the PCR process?

To make many copies of a small target piece of DNA

What is the function of the reporter molecule in CRISPR diagnostics?

When Cas binds to and cleaves target DNA, the reporter molecule on the enzyme is activated and emits a detectable signal.

The experiment involved the transfer and expression of ______ DNA into bacterial cells.

frog

5. What are the two entry mechanisms used by enveloped viruses?

fusion and endocytosis

Select the INCORRECT statement regarding CRISPR-Cas technology.

gRNA contains guanisine in place of uracil.

The primer used in Sanger (dideoxy chain termination) sequencing

has a nucleotide sequence complementary to the 3' end of the region to be copied.

4. In order for insertional inactivation of a gene to occur, the restriction site must be

in the middle of the gene

6. In insertional inactivation, if foreign DNA is inserted into the beta-galactosidase gene, the gene is

inactivated, and the colonies are white.

Which of the following BEST describes the protein coat of a virus? It

is called a capsid, protects the nucleic acid, AND is involved in the recognition of host cell receptors by non-enveloped viruses.

The negative (-) sense strand of RNA

is used to synthesize more (+) strands

What is the function of gRNA in CRISPR-Cas technologies?

it ensures the Gas enzyme cuts at the correct place in the target DNA

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

it is injected by the virus.

Resistance of some animals to certain viral diseases is based on

lack of specific receptors on the host cell.

5. The final step in T2 bacteriophage infection results in

lysis of the bacterial cell and release of new viral particles

5. The final step in T2 bacteriophage infection results in:

lysis of the bacterial cell and release of new viral particles.

3. Bacteriophages involved in generalized transduction are ______ phages.

lytic

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

lytic

3. When present, what is the viral envelope composed?

mainly lipids

Outside of living cells, viruses are

metabolically inert

Blood tests at the time of Patient A's admission showed that his white blood count was high (>70,000 cells/ mm3). What is another way of expressing mm3?

microliter

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

new viral particles

1. Bacteriophages adsorb or attach

only to members of the same bacterial species.

1. What component of DNA is different from one person to the next?

order of nitrogenous bases

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

penetration

advantages of using rpcr rather than the traditional culture-based methods in diagnosing imd

performed on samples from people after death, even from preserved tissues; used to differentiate between different bacterial serotypes; detect microbial dna, even if patient has received antibiotics and bacteria are no longer growing

1. After host cell DNA is broken down by a viral enzyme

phage DNA is replicated and phage coat proteins are produced.

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

phage typing

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

plasmids can replicate independently.

2. Viral capsids are composed of ______.

protein

Select all the signs and symptoms that are associated with meningitis.

rash fever vomiting diarrhea weepy eyes (maybe)

1. Phage DNA encodes for the proteins of the viral capsid and

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

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

release of nucleocapsid into host cytoplasm

cDNA used in microarrays is synthesized using the enzyme

reverse transcriptase

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

salmonella

3. Primers are used for

showing the polymerase enzyme where to begin building the new DNA chain. Correct

2. If people have a different base at one point in their DNA sequence, this is referred to as a ______.

single nucleotide polymorphism

A gene chip has on it tens or hundreds of thousands of spots containing ______.

single-stranded DNA

To carry out Sanger (dideoxy chain termination) sequencing a mixture is needed containing

single-stranded DNA. DNA polymerase. four deoxyribonucleotides A, T, C, G. RNA polymerase. All of the answer choices are correct. CORRECT

Agarose gel electrophoresis separates nucleic acid fragments according to

size

The genome of retroviruses is made of

ssRNA

7. Taq polymerase is specifically used in this process because it is

stable at high temperatures.

standard culture-based methods used to identify a microorganism

staining such as gram stain and capsule stain; next-generation sequencing; 16s rdna sequencing; biochemical tests such as oxidase and catalase tests

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

sugar fermentation. toxin production. drug resistance. All of the answer choices are correct. Correct

2. Why do you think cases of salmonellosis are often underreported?

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

1. A bacteriophage initially associates with which bacterial structure?

the bacterial cell wall

2. Contamination of the sample is a serious concern when doing PCR because

the contaminant may also be amplified, causing a false-positive result.

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.

Determine what alerted the pathologist to the possibility that Patient A was likely misdiagnosed, and that he had a bacterial illness rather than cancer.

the fact that a second family member developed the same signs and symptoms as Patient A.

2. In viral entry by endocytosis

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

8. A ______ is used to automatically expose the polymerase chain reaction to repetitive steps, yielding large amounts of DNA in a short period of time.

thermal cycler

1. 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

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

true

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

true

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

true

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

true

2. If host cells are ampicillin-sensitive and are plated on a medium containing ampicillin, only cells that have taken up the ampicillin-resistant vector can grow.

true

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

true

2. Plasmids are naturally found in some bacteria.

true

3. All viruses can infect any cell type or tissue type.

true

3. Genetic engineering involves the intentional manipulation of an organism's genetic material.

true

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

true

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

true

4. The primary purpose of recombinant DNA technology is to deliberately remove genetic material from one organism and combine it with that of a different organism.

true

DNA microarrays may be used to study how a cell responds to specific environmental conditions.

true

Examining the electrophoresis gel and reading from bottom to top, one base at a time, gives the sequence of DNA.

true

PCR is carried out in machines termed thermocyclers (also known as thermal cyclers).

true

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

true

The host range of a virus depends on the presence of host receptor molecules.

true

Three PCR cycles are required to generate the first double-stranded target fragment.

true

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

ultraviolet light

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

uncaring

5. All of the following are desirable features of a cloning host except

well-mapped genome. keeps foreign genes intact. pathogenicity. Correct fast growth rate. easy to culture.

Plant viruses may be transmitted by

worms. contaminated seeds. humans. insects. All of the choices are correct. CORRECT

You make two different cDNA probes to analyze a gene chip. One probe is labeled with a red fluorescent dye, and the other is labeled with a green fluorescent dye. The gene chip contains DNA to which both of your probes hybridize. When the gene chip is analyzed, the DNA spots to which both probes hybridize appear ______ .

yellow

Select two ways that viruses can infect plants.

- By contaminated insects feeding on plant cells and disrupting the cell wall. - Through grafting infected plant tissue onto healthy tissue.

Select the TRUE statements regarding the use of CRISPR in biotechnology.

-Cas9 and dCas9 use double-stranded RNA sequences to guide them to a target DNA sequence. -Cas9 and dCas9 use single-stranded RNA sequences to guide them to a target DNA sequence. -Cas9 blocks transcription, turning a gene off and preventing expression. -dCas9 can be used to understand the function of a particular gene by blocking transcription of that gene. -Cas9 has nuclease function and can be used to change the nucleotide sequence at specific target sites

Calculate the percentage of blood samples that tested positive for N. menigitidis by culture-based methods versus the percentage that tested positive by rPCR.

24.3% (culture) vs. 89.7% (rPCR)

Arrange the following in the proper sequence in which they occur during a single PCR cycle. 1. Addition of DNA nucleotides by Taq DNA polymerase. 2. Complementary base pairing between primers and target DNA. 3. Heat separation of strands of target DNA.

3, 2, 1

9. How many copies of the DNA segment of interest would there be after 3 cycles of the polymerase chain reaction?

8

2. Which of the following can serve as selective markers for identifying recombinant bacterial cells?

Antibiotic resistance AND differences in colony phenotype.

Place the steps of T4 phage replication into the correct sequence.

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

During PCR, which primer anneals to DNA with its 3' end?

Both the forward and reverse primers

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

false

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

false

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

false

4. T-even phages can replicate independently of a host cell.

false

5. 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

6. Bioengineered hormones, enzymes, and vaccines are easier to produce but not as safe as their natural equivalents.

false

If you were to use CRISPR diagnostics to check for infection in your kidney transplant patient, what critical information woud you need?

Which pathogen(s) you suspect has/have infected your patient.

2. Generalized transduction occurs when

a bacteriophage packages a piece of bacterial DNA during replication.

3. During maturation or formation of phage particles

a few phage heads may surround fragments of host bacterial DNA. Correct

Taq polymerase is

a heat-stable DNA polymerase from Thermus aquaticus.

1. The capsid of a virus is

a protein shell that surrounds the nucleic acid

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

a repressor protein

2. The general steps in viral replication (in order) are

adsorption, penetration, synthesis, assembly, release.

genetic engineering

allows the use of bacteria as production factories for a number of molecules AND relies on recombinant DNA technology.

2. The basic parts of a bacteriophage are

an isohedral head, tail, tail pins, and fibers.

1. 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

The correct order for the stages of a phage infection is

attachment, penetration, transcription, replication of nucleic acid and protein, assembly, release.

Which does not refer to the shape of a virus?

bacillus

Human DNA cut with restriction enzyme A can be joined to

bacterial DNA cut with restriction enzyme A.

1. Viruses that infect bacterial cells are called ______.

bacteriophages

Viruses that infect bacteria are referred to as

bacteriophages

6. 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

5. The lac z gene codes for ______.

beta-galactosidase

Which part of the body is affected with meningitis?

brain and spinal cord

2. 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

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

can integrate into the chromosome.

Expression of viral oncogenes in infected animal cells

can mimic proto-oncogenes, causing an imbalance in cell cycle control towards unchecked proliferation, leading to tumor formation.

1. A sample being tested in the polymerase chain reaction will be mixed with a primer, Taq polymerase, and ______.

deoxyribonucleotides

When CRISPR is used in diagnostics, a positive result would be indicated by

detention of color or a fluorescent signal

1. Every virus particle contains ______.

either DNA or RNA

The energy to separate fragments during agarose gel electrophoresis is supplied by

electricity

3. Restriction enzymes are naturally found in eukaryotic cells.

false

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

false

3. When foreign DNA and plasmid are both cut with the same restriction enzyme and then mixed together, all molecules will form recombinants.

false

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

false

4. An endonuclease will cut DNA only at the ends of the molecule.

false