micro test 3

Compare the three stages of sewage treatment process: TERTIARY

removal of inorganic materials achieved through chemical means and not with microbes

beta-lactamase (aka penicillinase)

resistant to the effects of penicillin an enzyme that destroys the beta-lactam ring and therefore neutrilizes the imoact of penicillin

trimethoprim

synthetic antimetabolite that interferes with folic acid production later in the metabolic pathway

Sulfa drugs

target folic acid synthesis (metabolic pathways)

Macrolides

target protein synthesis

Macrolides, tetracyclines, and many more

target ribosome and protein synthesis

Beta-lactam

target the cell wall synthesis (PG) and inhibit transpeptidases

Ciprofloxacin, monofloxacin, nalidixic acid (Quinoione antibiotics)

target topoisomerase and DNA gyrase

Rifampicin

targets RNA polymerase

Amoxicillin

targets transpeptidases involved in PG synthesis

vancomycin is one of the only drugs left that will attack drug res. gram + bacteria but it is some what toxic to the kidneys and must be used with care

true

beta-lactamases are able to inactivate the pennicillins and cephylasporins but not the macrolids

true???

Transduction

type of HGT (horizontal gene transfer) that involves the transfer of genetic info from one bacteria to another via a virus (phage)

Lytic cycle

phage replication cycle resulting in the release of new phages by lysis (and death) of the host cell. the host dies and new phages are produced

Lysogenic cycle

phage replication cycle where the viral genome becomes incorporated into the bacterial host chromosome as a prophage and doesn't kill the host

Envelope

piece of organelle membrane or cell membrane covering capsid. (Not called a membrane because no cytoplasm)

Genes carried on plasmids. How plasmids are transferred between cells? what i

plasmids carry genes that cause diseases or convey antibiotic resistance genetic info is directly transferred btwn cells via a bridge-like structure called a *pilus* during conjugation

Size of ribosomes

30nm

Carbon to Nitrogen ratio of bacteria

5C:1N

Difference in prokaryotic and eukaryotic ribosome

80S= Eukaryotic (mitochondria will contain 70S) 70S= Prokaryotic

T/F To best isolate mutant bacteria that are threonine auxotrophs from a larger population, threonine-rich media should be inoculated and any colonies that form are presumptive auxotrophic mutants

False

T/F Transduction in this case is specialized rather than generalized.

False

T/F Transposable elements have been found only in prokaryotes and do not appear to play a major role in eukaryotes.

False

T/F Transposons are frequently used as cloning vectors.

False

T/F When a eukaryotic gene is expressed in a bacterium, the eukaryotic regulatory sequences should be maintained in order to achieve maximum expression of the gene.

False

The CDC has its Headquarters in Washington DC

False

The thermostable enzyme most commonly used in PCR is reverse transcriptase.

False

Transposons are frequently used as cloning vectors.

False

When a eukaryotic gene is expressed in a bacterium, the eukaryotic regulatory sequences should be maintained in order to achieve maximum expression of the gene.

False

True or False..The larger the surface/volume creates nutrient supply problems to the cell's interior.

False Smaller cells are more easily maintained. A larger surface/vol means its a smaller cell and diffusion in faster.

Some plasmid vectors have incorporated the regulatory sequences of the lactose operon so that the expression of the recombinant gene can be induced at the appropriate time.

True

T/F . Approximately half of known animal carcinogens can be detected by the Ames test.

True

T/F A microbial ecologist who is interested in studying how gene expression is influenced by different species of bacteria in a biofilm would most likely find a metagenomic library more useful than a genomic library.

True

T/F Cosmids are plasmids that can be packaged into capsids of the bacteriophage lambda; therefore, they can be transmitted like phages, but they can exist and replicate in a cell like plasmids.

True

T/F Genes for antibiotic resistance can be found in antibiotic-producing bacteria as well as in non-antibiotic-producing bacteria.

True

T/F If 5-bromouracil was added to a culture of actively dividing bacterial cells, resulting mutations could eventually become a stable part of the cellular genome.

True

T/F In an HFR F+ mating, the conjugation bridge usually breaks before chromosomal transfer is complete. Therefore, the recipient remains F-.

True

T/F In the mechanics of conjugation, exclusive of gene transfer, Hfr and F+ strains behave the same.

True

T/F Photoreactivation repairs thymine dimers by splitting them back into separate thymines.

True

T/F Regardless of the exact approach taken to recombinant DNA technology, one of the keys to successful cloning is choosing the right vector.

True

T/F Some plasmid vectors have incorporated the regulatory sequences of the lactose operon so that the expression of the recombinant gene can be induced at the appropriate time.

True

T/F When assessing the role of conjugative bacteria in the spread of antibiotic resistance genes, it is fair to say that Hfr cells contribute most while F- cells contribute least

True

The Southern blotting technique for transferring DNA from an agarose gel to a piece of nitrocellulose membrane is named for E. M. Southern, the person who developed the procedure.

True

True or False..Pure cultures are only found in the lab

True

True/False..Every type of organism has a virus that infects it.

True

When two drugs enhance each other this is called drug synergism

True

Genetic material for viruses, DNA or RNA, single stranded or double stranded?

can be DNA or RNA (but not both) can be single or double stranded

target: amoxycillin

cell wall target

What antibiotics target

cell wall, topoisomerase and DNA gyrase, RNA polymerase, ribosome and protein synthesis, metabolic pathways, and membrane function

Interon vs Exon

coding regions (exons) are interrupted by noncoding regions (introns).

Clavulanate (found in augmentin) is the most powerful broad spectrum penicillin ever produced

false

HAART stands for human anti-aids reverse transcriptase

false

If all of the PCR products of a DNA sequence are 4000 bp, then the DNA sequence that was amplified must have been 8000 bp.

false

Promoters for genes that code for proteins can be isolated from a cDNA library.

false

The thermostable enzyme most commonly used in PCR is reverse transcriptase.

false

Transposons are frequently used as cloning vectors.

false

When a eukaryotic gene is expressed in a bacterium, the eukaryotic regulatory sequences should be maintained in order to achieve maximum expression of the gene.

false

a fomite is an insect that can transmit diseases to humans

false

about the only drug left that will still treat most cases of MRSA is methicillin

false

all communicable diseases are contagious

false

bacterial fibrolysins such as streptokinase (produced by group A streptococci) are being used in medicine to treat strokes caused by hemorrhaging in the brain

false

collagenase is an enzyme produced by some pathogens that breaks down hyaluronic acid (the ground substance or intracellular matrix)

false

commensalism is the type of symbiosis where both organisms benefit

false

endotoxins are normally proteins

false

erythromycin is an example of an aminoglycoside

false

fleming discovered the first true antibiotic, salvarsan, in 1906

false

if the microbe causing a patients nosocomial infection comes from the normal flora it is exogenous

false

main antiviral drug used to treat HIV infections is acylovir (zovirax)

false

morbidity rate is normally expressed as # of deaths per 100,000 population

false

more bacteria live on the skin than any other site in the human body

false

most common STD in the U.S. is syphilis

false

one mechanism by which bacteria become resistant to antibiotics is that the bacteria become immune by producing antibodies against the drugs

false

one of the first symptoms of botulism is the tightness of the muscles of the jaw (lockjaw)

false

pregnant women should avoid cats bc they can get histoplasmosis if bitten by fleas and transmit this to their unborn baby

false

the TB skin test involves injecting a PPD, from mycobacterium tb, in the skin and then three hours later checking for redness

false

the great majority of the normal flora of the human body reside on the skin

false

the incubation period is the period during which the infected person cannot transmit the agent to others (noncommunicable)

false

universal precuations are regulations published by OSHA to protect the patient from nosocomial infections

false

bacterial endotoxins are easily destroyed by heating (boiling)

false, heat stable

most dangerous fluid is feces

false. blood

amoxycillin is a semi-synthetic pennicillin that is much more resistant to the beta-lactamases than regular penicillin

fasle

Adsorption

following contact, molecules on surface of virus bind to particular molecules on host

Injury to Plasma Membrane

-Fatty acid synthesis attracts new antibiotics -Weakness -Polymyxin B (against gram(-))

Reisistance to Antimicrobial Drugs

-Persister Cells: variant of regular microbial cells in a population that are dormant and resistant to antibiotics -Superbugs: bacteria resistant to a large number of antibiotics

Industrial microbiology define fermentation? Compare Chemostat vs batch growth

Fermentation: the mass culture of microorganisms Chemostat: bioreactor in which the volume is kept constant by continuously adding fresh medium while removing the culture liquid Batch culture: technique for growing bacteria, bacteria grow until the limited supply of bacteria is used up

Two-dimensional gel electrophoresis. What is it used for?

It uses electrophoretic gel to separate proteins based on 2 dimensions: charge and molecular mass pH gradient separates proteins by charge using isoelectric focusing, and gravity is used to separate based on mass *Process* Mix of proteins is loaded into an isoelectric focusing tube gel. (the gel consists of a pH gradient that separates proteins by charge) Proteins move around in the gel until their net charge is zero The isoelectric fell is laid on its side and the proteins move around until they're arranged by mass (small proteins travel farther down into the gel)

Atazanavir (Reyataz)(antivirus drugs)

Inhibit HIV protease targets HIV INHIBITOR OF VIRON MATURATION/RELEASE

Lopinavir (Kaletra)(antivirus drugs)

Inhibit HIV protease targets HIV INHIBITOR OF VIRON MATURATION/RELEASE

Saquinavir (Invirase)(antivirus drugs)

Inhibit HIV protease targets HIV INHIBITOR OF VIRON MATURATION/RELEASE

Augmentin

-amoxicillin and Beta-lactamase inhibitor

Complete transfer in an Hfr F- mating takes approximately __________

100

If chromosomal DNA from a host is the only type of DNA carried by a transducing particle, what can be concluded regarding transduction in this case?

Transduction in this case is generalized rather than specialized. -General transduction for pure DNA

A DNA molecule used to carry a foreign gene into a host organism is called a

vector

If chromosomal DNA from a host and phage DNA are carried by a transducing particle, what can be concluded regarding transduction in this case?

Transduction in this case is specialized rather than generalized.

Transduction

Transfer of DNA from one cell to another by a virus. Requires donor and recipient be related.

Horizontal gene transfer.

Transfer of genes from one mature independent organism to another

Conjugation

Transfer of genetic information via direct cell-cell contact is called

T/F The Southern blotting technique for transferring DNA from an agarose gel to a piece of nitrocellulose membrane is named for E. M. Southern, the person who developed the procedure.

True

The selective toxicity (therapeutic index) of the antimicrobic is very important of it is to be taken internally

True

Viruses can grow in..

Whole organism or eggs or organ/tissue/cell culture

Which cloning vector should be used to express a 500-kb DNA fragment in Saccharomyces cerevisiae?

YAC

Lysogen definition

a bacterium that contains a virus

Missense

a point mutation in which a *single nucleotide change results in a codon that codes for a different amino acid.* It is a type of nonsynonymous substitution. Often non-lethal and are the *driving force behind evolution*

transition mutation

a point mutation that changes a purine nucleotide to another purine (A ↔ G) or a pyrimidine nucleotide to another pyrimidine (C ↔ T). Usually due to base analogous

target: polymyxins

cell membrane

Selective toxicity. It is a term used to describe action of which molecules

ability of chemotherapeutic agents to exploit differences in the structures or metabolisms of microbes and of the host cells and inhibit or kill the pathogens w/o harming the host cells this is a key characteristic of useful microbial agent and describes the action of antibiotics

Pathogenesis

do not produce important molecules too soon to top off immune system. Multiply slowly until enough to make a difference

Reverse Transcriptase

enzyme that turns single-stranded RNA into double-stranded DNA

the limmulus ameobocyte assay test uses blood from the king cobra to test IV fluid for the prescence of LPS

false

the sulfanomides compete with DNA polymerase to prevent the bacteria from carrying out transcription

false

static agents

inhibit their growth

In order to express eukaryotic genes in a bacterium, the __________ must first be removed.

introns

hybridoma(immortal)

mix primary culture with cancer cells

___________ is a bacterial plasmid vector.

pUC19

The order of gene transfer in an Hfr F- mating is best represented by

part of the plasmid followed by the chromosome followed by the rest of the plasmid.

Which of the following components of PCR ensures amplification of the target DNA sequence only, despite the presence of many other DNA sequences?

primers

target: erythromycin

protein synthesis

Cloning vector

provides a mean for transferring genes of interest to a host organism during cloning.

A microbial ecologist who is interested in studying how gene expression is influenced by different species of bacteria in a biofilm would most likely find a metagenomic library more useful than a genomic library.

true

Regardless of the exact approach taken to recombinant DNA technology, one of the keys to successful cloning is choosing the right vector.

true

a pandemic is generally more dangerous than an endemic disease

true

diseases that animals can transmit to humans are called zoonoses

true

every year in the U.S. about 100,000 patients die of nosocomial infections or their complications

true

plague toxin causes tissue necrosis

true

the beta-lactams antibiotics will only kill dividing bacteria

true

Reverse vaccinology works?

use of bioinformatics to screen the entire genome of a pathogen in order to identify genes that are good vaccine targets

Which of the following effects may be mediated by transposable elements

-A mutation may result from insertion into a gene. -Activation of nearby genes may occur. -Genetic deletions may form. (All the above)

MRSA

-Increase in cell wall material -Resistant to many antibiotics including vancomycin which is "the antibiotic of last resort" -Health Care Associated MRSA: transmitted by bed linens, bed rails, medical equip, hands of doctors, nurses, etc -Community Associated MRSA: transmitted by direct contact in crowded areas

General Starvation Response (not a modulon)

-Increase surface volume (become smaller) -Induction of low km uptake systems -Release scavenging molecules -Become spores (low metabolic activity)

mRNA in bacteria

-Short upstream (5') and downstream (3") untranslated regions. -Purine-rich regions (Shine Delgarno sequence) immediately upstream from AUG start codons, bind to 16S rRNA -No introns (except in Archaea), no 5' cap or poly-A tail -No transport from a nucleus, rather immediate initiation of translation while transcription is still in progress.

Broad Spectrum

-Spectrum of microbial activity that affects a broad range of both gram (-) and gram (+). -Usually used when identity of pathogen is unknown. -Ability of a drug to be effective against a wide range of microorganisms

Narrow Spectrum

-Spectrum of microbial activity that affects gram-positive but few gram-negative (Ex: Penicillin G) -active against only a select group of microbes -narrow range of microbes -ex. Penicillin G

Genomic Island

-Stretch that has a composition that is different from the rest of the genome. -Not found in all members of species. -Contain one or more genes that assist bacterium -Flanked by direct repeats

several possible mechanisms by which viruses causes cancer

-virus may alter cell-cycle regulation. Ex....34 -may directly insert the oncogene into the host -virus may insert a promoter or enhancer close to an existing cellular oncogene

Gene cloning

1 Isolate plasmid DNA from bacterial cell 2 Isolate DNA of interest 3 Insert gene of interest into plasmid DNA, which forms recombinant DNA 4 Insert recombinant DNA into bacterium such as Ecoli 5 Culture the bacteria, growing many identical copies

Bacteria can sense..

1. Availability of nutrients 2. Concentration of specific nutrients 3. O2, Temp, Osmolarity, Stress 4. Population Size 5. If they are floating or attached

Plasmid Types:

1. F-Type 2. R-Type 3. Catabolic 4. Bacteriocin 5. Virulence 6. Tumor-Inducing 7. Cryptic

Action Modes of Antibacterial Drugs

1. Inhibition of cell wall synthesis (penicillins, cephalosporins, bacitracin, and vancomycin) 2. Inhibition of protein synthesis (chloramphenicol, erythromyocin, tetracyclines, streptomycin) 3. Inhibition of nucleic acid replication and transcription (quinolones, rifampin) 4. Injury to plasma membrane (polymyxin B) 5. Inhibition of essential metabolite synthesis (suflanilamide, trimethoprim)

Translation steps

1. Initiation (while transcription in progress) 2.Elongation 3.Termintation (loops)

Viruses are specific

1. Some can't cross species barrier 2. Cell type 3. Tissue Type

Smallest *bacteria* are around what size?

200nm

Viruses range in size from ____nm-____nm

20nm-300nm

sex pilus

A plasmid that can be spread by conjugation codes for a ____ _____.

Restriction endonucleases were discovered by A. Arber and Smith. B. Jackson, Symons, and Berg. C. Boyer and Cohen. D. Temin and Baltimore.

A. Arber and Smith

Possible fates for an exogenote

A. integration into the host chromosome. B. independent replication and functioning. C. degradation to nucleotides. (All the above)

Genomic Island

Abrupt change in %G-C content means..

Transforming infections? List Viruses that cause cancer? Oncogenic Viruses?

Affects the host's genetic makeup, causing some kind of mutation in the host chromosome Often involves the integration of a viral genome at a point in the genome called an *oncogene*

Which type(s) of mutation might lead to a threonine auxotrophic revertant? A. All of the choices are correct. B. Base substitution C. Missense mutation D. Point mutation

Alltheabove

Allels

Alternate forms of genes resulting from mutations

Generalized Transduction

Chopped up bacterial DNA is incorporated into a capsid Phage binds to new host bacterium, but injects donor bacterial DNA instead

List factors influencing effectiveness of antimicrobial drugs.

Amount that's administered Speed of uptake Rate of clearance from body Susceptibility of the pathogen Other hurdles such as: necrotic tissue/blood clots that prevent the drug from reaching its target

In silico analysis and annotation

Analysis carried out by a computer Annotation- used to determine where genes start and end, allows you to locate genes on the genome identifies ORF

Plasmid vectors often contain __________ genes that can be used to screen for recombinants

Antibiotic resistance

Describe ETest

Antibiotic sensitivity test manual in vitro diagnostic device used in labs to determine the MIC (minimum inhibitory concentration) and whether or not a specific strain of fungus or bacterium is susceptible to a particular antimicrobial agent

Plasmid cloning vector DNA is usually introduced into bacterial hosts by A. ligation. B. transformation. C. transduction. D. plasmolysis.

B. transformation

Lytic cycle

Bacteriophages multiply then lyse the host cell (most common)

Valacyclovir (Virazole)(antivirus drugs)

Base analog (mimics guanine) Inhibiting DNA polymerase targets Herpesviruses INHIBITION OF GENOME REPLICATION

Ribavirin (Virazole)(antivirus drugs)

Base analog (mimics guanine) inhibiting viral replication targets Hepatitis B and C INHIBITION OF GENOME REPLICATION

Shape change can lead to increased or decreased binding...aka transcription?

Both

Autonomous replication?

Being able to replicate independently of the bacterial chromosome. Plasmids are capable of this.

The polymerase chain reaction (PCR) can be used to produce __________ of copies in a few hours.

Billions

Negative Control

Binding of protein to DNA *prevents* transcription (Lactose)

Positive Control

Binding of protein to the DNA promotes transcription

Raltegravir (Isentress)(antivirus drugs)

Block provirus integration targets HIV INHIBITION OF GENOME REPLICATION

HIV is an example of what release technique?

Budding

The polymerase chain reaction (PCR) can be used to produce __________ of copies in a few hours. A. hundreds B. thousands C. millions D. billions

D. billions

Which of the following was first produced commercially using recombinant DNA technology? A. Human growth hormone. B. Interleukins. C. Hepatitis B vaccine. D. Human insulin.

D. human insulin

Which of the following PCR procedures includes all of the others?

DNA is amplified for one cycle.

A public health microbiologist plans to screen a particular bacterial species that was isolated from several patients in an intensive care unit to detect if any of the cells are penicillin-resistant mutants. What is the first step in conducting this experiment? A. Determine whether or not wild type cells of the same bacterial species are susceptible to penicillin.

Determine if wild type (un-mutated)cells are penicillin resistant to begin with

Conjugation

Direct cell-cell transfer of DNA

Transformation

Direct uptake of genetic material ("naked") from the surroundings

Temin and Baltimore.

Discovered reverse transcriptase

Regulon

Dispersed genes or operons controlled by the same signal (Controlled together but not next to each other)

Components of a virus. Name the two that every virus must have

EVERY virus must have a nucleic acid and a capsid SOME also have an envelope and spikes

Reverse Transcriptase

Enzymes that virus needs but the host can't provide

Which is the most frequently chosen prokaryotic host for use in cloning techniques?

Escherichia coli

In an F+ F- conjugation, the donor is the __________ strain.

F+

After an F+ F- mating, the donor is __________ and the recipient is __________.

F+ , F-

Cosmids are so named because they can be used to express foreign genes in a variety of different hosts.

FALSE

As a Health Care worker, your chances of getting stuck with a needle is very low. Only about 2,000 workers get stuck each year

False

Cholera toxin is an example of a neurotoxin

False

Endospores

Form within a cell and have a thick coat. Are for survival NOT for reproduction. Will go back to normal cell when survival is easier. IRREVERSIBLE at a certain point.

A mutation from the most prevalent form of a gene to a mutant form is called a

Forward Mutation

Why are immunosuppressed individuals given antifungal agent?

Fungal infections are hard to diagnose in immunocompromised individuals- they can cause immortality Given as a preventative measure

Mutations that result in the death of an organism when expressed are called __________ mutations.

Leathal

Prevents the activation of CRP/CAP

Glucose

Tumor

Growth or lump of tissue benign tumor remains in place

Genetic Diversity

Horizontal gene transfer provides _______ ________.

Credited with demonstrating unidirectional and nonreciprocal transfer of DNA between two mating E. coli cells

Hayes

A reciprocal exchange in which a pair of DNA with the same nucleotide sequence break and rejoin in a crossover is called __________ recombination.

Homologus (similar in position, structure)

When an F plasmid integrates into the host chromosome, the strain is referred to as

Hfr

Which situation(s) might warrant the removal of a histidine tag when purifying a recombinant protein?

Histidine residues inhibit protein folding, thereby decreasing the functionality of the protein.

Two classification techniques of viruses using how the pathways they use to get to mRNA..

ICTV (Int. Committee on Taxonomy of Viruses) and The Baltimore System

Tools used in biotechnology and genetic engineering

In Silico analysis, DNA microarray analysis, gel electrophoresis, PCR, and RFLP analysis.

Specialized transduction can be carried out

Only those temperate bacteriophages that integrate into the host chromosome.

Biofilm problems

Industrially -plug pipes Medically -Heart valves; seed infections elsewhere in body -Hard for antibiotics to completely get rid of

Prokaryotes- Injection or endocytosis?

Injection

Insertion Sequences

Insert itself somewhere else. Codes for enzyme that cuts this sequence and moves it, as well as a repressor to prevent too much movement.

Which of these transposable elements do not carry genes for functions other than those needed for transposition?

Insertion Sequence

Siderophores

Iron scavenging molecules

Role of reverse transcriptase in formation of provirus?

It converts the single stranded RNA to double stranded DNA. This enzyme is necessary for retroviruses to integrate into the host chromosome

Role of RNA in origin of life.

It has the ability to replicate and act as a catalyst for chem rxns it could have been the nucleic acid used in Earth's earliest life forms and RNA could have eventually given rise to DNA

Prokaryotes have more or less non-coding genes compared to eukaryotes?

Less

Prokaryotes have more or less repeated sequences compared to eukaryotes?

Less

Trench Fever

Lice

Niche

Location and role in that location

Microbial ______ is the basis for ecology

Metabolism

Malaria

Mosquito

St.Louis Encephalitis

Mosquito

Yellow Fever

Mosquito

Are effectors like light switches? (Are they all or nothing)

No

Viruses are ________ __________ ___________ (three words)

Obligate intracellular parasites

Presence of glucose prevents or allows positive regulation?

Prevents (Not the same as inhibiting though)

Genetic Regulation

Prevents the synthesis of the enzymes that make the small molecules. Results in energy savings.

What is composting? Do microbes have any role in this?

Process of decomposing organic matter and recycling it as fertilizer Soil is added to the organic matter in the compost to add microorganisms which help break down the organic matter

Recombinant DNA technology does not rely on which of the following enzymes? A. restriction endonucleases B. RNA methylase C. DNA ligase D. reverse transcriptase

RNA methylase

Lethal mutations can be maintained in diploid organisms if they are

Recessive

Which is a true statement regarding the size of PCR products?

Since the number of DNA products ending exactly between both primers increases with each cycle, when PCR is completed, the majority of products are of similar size.

Viral pathogenicity

The ability to: penetrate host cells grow within the cell fight against host cell's defense mechanisms damage the host

Chemotaxis

The most common type of bacterial taxis

Which of the following best describes the basis for separation of DNA fragments during agarose gel electrophoresis?

The smallest fragments will migrate fastest.

Transforming infection

The virus affects the host's genetic makeup, causing some kind of mutation in the host chromosome

The utility of the strains of Salmonella typhimurium used in the Ames reversion assay because

They are highly permeable to test substances

Which of the following is not true of cloning vectors?

They contain at least two replication origins.

A molecular biologist treats a 600-kb length of linear DNA with HindIII restriction endonuclease. Following gel electrophoresis, the biologist observes that there is only one band on the gel corresponding with the migration distance of the 200-kb molecular weight marker. Assuming that no procedural errors were made, what can be concluded from these results?

Three HindIII recognition sequences were present in the original DNA.

Plasmid cloning vector DNA is usually introduced into bacterial hosts by

Transformation

Diauxic

Two phased growth

type: TB

acid-fast

An F' plasmid results when

an integrated F plasmid is incorrectly excised, bringing host genes with it.

type: trachoma, psittacosis

chlamydia

pUC19

common cloning plasmid vector

Aerobes oxidizing to CO2 which autotrophs use is an example of _______ ________

complementary pathways

Composite Transposons

composed of insertion sequences and original DNA. Flanked- either side. Middle dna has antibiotic resistance

syncytia

coommon cytopathic effect caused by paramyxovirus

What is Beta-Lactam ring? Which group of antibiotics contain beta-lactam ring?

crucial feature of penicillins,essential for their bioactivity consists of 3 C atoms and one N atom it binds to and inhibits enzymes responsible for the final step of bacterial cell wall synthesis (transpeptidation)

Exogenote

donor DNA that enters the bacterium by one of several mechanisms

An enzyme that cleaves internal phosphodiester bonds of a DNA molecule is a (n)

endonuclease.

A (n) __________ vector contains promoters that result in high-level transcription of the gene cloned within a multicloning site

expression

A (n) __________ vector contains promoters that result in high-level transcription of the gene cloned within a multicloning site.

expression

Repression

genes normally in use are shut off when no longer needed

tissue viral technique

growing viruses in individual cells. however viruses can also be grown in entire organism, including bacteria, plants, and laboratory animals. in additiopn, researchers can inject a virues into various parts of an embryonated chicken egg to culture and propagate it. this tech is commonly used to propagate the influenza virus

type: pinworm

hemlithic

amphotericn B

is an antifungal drug antiviral drug polyene HIV protease

cidal agents

kill microbes

A genomic __________ is a sufficiently large collection of recombinant DNA molecules in which the inserted sequences together represent the entire genome of an organism.

library

Matrix Proteins

link core to a viral envelope

Conjugative transpons

may be involved in the spread of antibiotic resistance in bacteria.

type of b: rabies

none its a virus

type of b: herpes

none, its a virus

Therapeutic index definition

ratio of the toxic dose to the therapeutic dose = toxic dose/therpeutic dose it's better for a drug to have a high therapeutic index bc it means overdosing is less likely to have negative consequences

A (n) __________ vector is a plasmid that can be replicated in several different organisms because it has at least one origin of replication that will function in each host.

shuttle

Fluoroquinolones

target DNA structure/replication

Generalized Transduction

transfer of any bacterial gene to a recipient bacterium using a phage

Conjugation

transfer of genetic material between bacteria through direct contact

type: polio

viral

How many domains of supercoiled DNA exist?

~50

Transduction

bacterial genes are transferred to another bacterium by a virus

Azidothymidine (AZT; Retrovir)(antivirus drugs)

base analog (mimics adenine) Terminating DNA chain elongation targets HIV INHIBITION OF GENOME REPLICATION

Idoxuridine (Stoxil)(antivirus drugs)

base analogs (mimics thymidine) causing replication errors (mutations) targets herpesviruses INHIBITION OF GENOME REPLICATION

Trifluridine (Viroptic)(antivirus drugs)

base analogs (mimics thymidine) causing replication errors (mutations) targets herpesviruses INHIBITION OF GENOME REPLICATION

Lac Z is the gene for..

beta-galactosidase (converts lactose--> Allolactose)

Competitive Inhibition of Essential Metabolites

-Sulfonamides (sulfa drugs) -Folic acid necessary -Bacteriostatic -Doesn't harm human cells

Antibiotics effective against protein synthesis. Describe their modes of action

*Aminoglycoside* - binds to the 30S ribosomal subunit - directly inhibits protein synthesis, causes misreading errors - Ex: Streptomycin, gentamycin, erythromycin -resistance and toxicity are 2 common problems *Tetracyclines* - bind to the 30S ribosomal subunit - inhibits tRNA from binding to the ribosome a site -broad-spectrum drugs -bacteriostatic - treat acne *Macrolides antibiotics* - bind to the 50S -ex: erythromycin(broad spectrum, bacteriostatic; inhibit elongation of peptides) -pt allergic to penicillin *Chloramphenicol* -toxic compound -similar to erythromycin - bind to the 50S - interferes w/ peptidyl transferase rxn -synthesis this in the lab

Antifungal and antiviral drugs

*Antiviral:* Acyclovir (herpes) ribovirin (influenza) Amantadine (prevents virus from penetrating and uncoating) Tamiflu (shortens flu and prevents contagiousness) *Antifungal:* (targets ergosterol(acts like a chloestrol and can be effective target of antifungal medications)) azoles polyenes

Bio-Conversion, Biosensors, Biopolymers, Bio-Surfactants, and Biofuels

*Bio-conversion* AKA biotransformation Use of live organisms to facilitate a chemical reaction that converts a substance to a chemically modified form *Biosensors* Uses microorganisms, enzymes, or organelles and a physical transducer to detect the presence of a substance *Biopolymers* serve as gelling agents and modify the flow of liquids (ex: dextran or PHB) adding this to a fluid can slow it's movement through a system- industrial applications *Bio-surfactants* emulsify other substances such as oil useful in oil recovery, dispersing oil spills, bioremediation *Biofuels* microbial fermentation of crop residues consisting of cellulose and hemicellulose produces ethanol (a biofuel) which is widely used to power cars. Microbes also produce methane gas and hydrogen which can be used as biofuels.

Biocatalysts, bio-pesticides, GMOs

*Biocatalysts* microorganisms that facilitate changes to a substrate molecule but they aren't used up or changed as a result of the rxn Important to bioconversion! *Bio-pesticides* Naturally produced agents that kill pests *GMOs* living organisms whose genetic material has been artificially manipulated in a lab through genetic engineering

Bioprospecting and high-throughput screening (HTS)

*Bioprospecting*- the search for species that have medical and commercial use for humans (search in remote places like oil fields, rainforests, volcanoes, copper mines, hot springs) *HTS* allows researchers to rapidly and cheaply sequence and analyze a large amount of DNA

Sub-microscopic, obligate intracellular parasite, and host specificity characterize viruses.

*Characteristics of Viruses:* sub-microscopic: can't see them with a microscope bc they're so small obligate intracellular parasites: can't grow or produce energy on their own, they require a host host specificity: specific viruses only attack a specific range of organism

Viruses: enter, spread, and exit from the body?

*Entering:* -Mucous membranes: respiratory, genital, alimentary, or conjuctiva RESPIRATORY IS THE MOST COMMON ROUTE OF ENTRY -Skin: via wounds, scratches, insect bites *Spreading:* - Spread locally, over epithelial surfaces - Neurotropic viruses spread through nervous system (ex: rabies) - Lymphotrophic spreads through lymphatic system (most common route) - Blood stream Viremia= when viruses are present in the blood stream - penetrating the skin (uncommon) - mother to fetus during pregnancy *Exiting:* Virus shedding= the many ways a virus can leave the body - sometimes a virus remains w/in the host and never sheds - through skin, feces, respiratory secretions, oropharyngeal secretions, etc point of exit isn't always the same as the point of entry

Human microbiome and explain the role metagenomics plays in its investigation.

*Human microbiome:* the aggregation of all the microorganisms that reside on or in the human body *Metagenomics:* Study of metagenomes (genetic material recovered from environmental samples) Used to study the composition of the human gut genome through analysis of fecal samples

Icosahedra and helical structures?

*Icosahedra shape* a polyhedron with 20 traingular faces, 30 edges, and 12 vertices made of capsomers *Helical shape* helical array of proteins wrapped around the nucleic acid

Cloning vectors used in creating Recombinant DNA.

*Plasmids* The most common type of cloning vector Plasmid- a self replicating piece of extrachromosomal DNA found in prokaryotes Popular bc they can be easily transferred from one organism to another via conjugation or transformation Typically carry inserted sequence in the mid-size range (20,000 base pairs or less). Ex: pBR322 and pUC19 *Bacteriophages* A virus that infects bacteria Carries smaller fragments ~9,000-25,000 base pairs *Cosmids* Is a hybrid btwn a plasmid and a phage. Carries larger fragments of ~30,000-47,000 base pairs *Artificial Chromosomes* Synthetic chromosomes that contain fragments of DNA integrated into a hose chromosome Categories: PI artificial chromosomes (PACs), bacterial artificial chromosomes (BACs), and yeast artificial chromosomes (YACs) Carries larger fragments YACs carry fragments up to 1million base pairs Used in the Human Genome Project

PCR

*Polymerase Chain Reaction* technique for quickly and easily making many copies of even a very small amount of DNA

Compare the three stages of sewage treatment process: PRIMARY

*Primary* Physically removing solid organic materials. the sludge is transferred to a large tank called an anaerobic digester where anaerobic methanogens degrade the organic molecules PRODUCES METHANE AS A BYPRODUCT methane gas burns very clean so plants use this gas as an energy source to generate electricity

Protoplast fusion? Electroporation? Transformation (plasmids picked up by laboratory-induced competent bacterial cells)

*Protoplast fusion* Scientists use enzymes or other means to remove cell walls of multiple cells, creating protoplasts Then put protoplasts together in solution and apply an electric shock (electroporation) which makes them fuse together to form a somatic hybrid (commonly used with fungi) *Transformation* -The direct uptake of genetic material from a bacterium's surroundings -Very rare in nature, commonly used in lab

Natural Penicillins

-Penicillin G: narrow spectrum; acidity of stomach diminishes its concentration -Penicillin V: stable in the stomach -Disadvantages: narrow spectrum and susceptible to beta-lactamases

Antibiotics : inhibitors of nucleic acid synthesis. Describe their modes of action

*Quinolones* - broad spectrum, synthetic drugs - inhibits DNA gyrase and DNA topoisomerase (which supercoils the DNA) *Rifampicin* - part of tuberculosis treatment - inhibits RNA polymerase *Ciprofloxacin* is an ex of quinolones - treat anthrax pt -many had extreme sensitivity to the drug

RFLP?

*Restriction Fragment Length Polymorphism* Tool for genetic fingerprinting, genome mapping, localization of genes, paternity testing, and microbial classification Highly conserved and repetitive DNA sequences are present in nearly every genome, including genomes of humans, gram- and gram+ bacteria Uses fact that every organism has slightly different restriction sites so on the electrophoretic gel the patterns of restrictive fragments will vary Every person has a unique DNA fingerprint (useful for forensic evidence or paternity testing)

Give an example of how synergistic drug interaction between two drugs work

*Synergistic effect* 2 drugs work together to accomplish more than the additive effect of the two working separately *Trimethoprim and sulfonamides* (2 metabolic antagonists (antimetabolite drugs)) often prescribed together to make treatment more efficient aka septra - sulfonamide is a structural analog and inhibits folic acid synthesis( humans have to ingest in their food) *Augmentin* combines amoxicillin and clavulanate potassium (beta-lactamase inhibitor) *Isoniazid and Rifampin* Isoniazid= antimetabolite Rifampin= nucleic acid inhibitor treats tuberculosis these often have side effects on humans like photosensitivity and abdominal pain

Bacteria vs viruses

*Viruses* smaller than bacteria nonliving no cell walls or ribosomes not cellular requires host to replicate *Bacteria* living have cell walls have ribosomes cellular replicate on their own

Virus replication. What is the importance of un-coating step in viral infection

*attachment/adsorption* virus uses capsid or spikes to attach to receptors on host cell spikes act as ligands *penetration* virus injects genetic info into host sometimes nucleocapsid enters membrane also viral envelope is lost upon entry into the host cell *uncoating* If the viral capsid penetrates the cell, it must be shed inside the cell so as to expose the nucleic acid. After uncoating, the virus fuses with the endosome and the nucleic acid is released into the cell *synthesis/replication* viral genome is replicated and capsid proteins are produced *assembly* assembly of protein capsid around the nucleic acid core occurs within host *release* released into environment and considered virions

Microarray system. What is its purpose? Where the sample come from for this analysis (mRNA)

- Allows scientist to observe pattern of DNA expression for thousands of genes at a time. - Measure levels of specific RNA - Scan fluorescence, brightest= most RNA = most "active" genes - Monitor level of expression of every gene in a cell - DNA microarray- chips with a collection of tny DNA spots attached to a solid surface - Created by robotic machines that arrange hundreds or thousands of genes onto a single chip

antiparasite drugs

- Chloroquine: prevent a malarial infection, caused by parasite plasmodium falciparum - Metronidazole: treats infections by entamoeba( a group of anaerobiuc parasitic protoans)

Kirby-Bauer test and its purpose.

- Method for carrying out disk diffusion tests - for determining sensitivity of a bacterium to a particular antibiotic - bacterium grows on agar plate until it fills up - disk soaked in antibiotic is then placed on the plate - if bacterium is insensitive to the antibiotic, it will simply grow over the disk - if it IS sensitive, a "clear zone" will appear called a zone of inhibition (zone of no growth)

Penicillins (General)

-Structure: Beta-lactam ring (nucleus) -Prevents the crosslinking of (mostly gram(+)) of peptidoglycan during cell wall synthesis

Properties of viruses given in slide 60.

- Obligate intracellular parasites of bacteria, protozoa, fungi, algae, plants, and animals - estimated 10^31 virus particles on earth - Ubiquitous in nature and have had major impact on development of biological life - Ultramicroscopic in size - Acellular, structure is compact and economical - Don't independently fulfill characteristics of life - basic structure consists of protein shell (capsid) surrounding the nucleic acid core - molecules on virus surface have high specificity for attachment to host cell - multiply by taking control of host cell's genetic material and regulating synthesis and assembly of new viruses - lack enzymes for most metabolic processes -lack machinery for synthesizing proteins

transmission of drug resistance

- bacterial chromosome: where spontaneous mutations that convey antibiotic resistance usually occur (occurs rarely) - plasmids: (resistance plasmids) with antibiotic resistance genes -transposons: (jumoing genes) jump from a bacterial chromosome to a plasmid and back to the chromosome. composite transposon carry genes for antibiotic resistance and some have multiple resistence genes.

Antifungal Drugs

-Affect fungal sterols -Plasma Membrane -Interrupt Synthesis -Azoles (ketoconazole, clotrimazole, miconazole, fluconazole, triazole)block the biosynthesis of ergosterol and thus inhibit cell membrane synthesis -polyenes (nystatin and amphotericin B) cause leakage of cellular components when they bind to sterols in the cell membrane

Discovery of penicillin

-Alexander Fleming: inhibited grow of S. Aureus; active compound of penicillin

Polypeptide Antibiotics

-Bacitracin >effective mainly against gram (+) > topical -Vancomycin >addresses MRSA

Carbapenems

-Beta-lactam antibiotic -broad spectrum -primaxin

Metabolic plasmids:

-Catabolic plasmid: example, tol plasmid with genes for breaking down and using toluene, an organic solvent. -Bacteriocin plasmid: codes for bacteriocins, proteins that kill related bacteria. -Virulence plasmid: has genes needed for the bacterium to infect the host. -Tumor-inducing plasmid: The Ti plasmid found in Agrobacterium tumefaciens. Codes for plant growth hormones. When the bacterium infects the plant cell, the plasmid is passed to the plant cell and the genes are expressed, causing local overgrowth of plant tissue = gall. Very useful plasmid for cloning genes into plants. -Cryptic: who knows?

Treatment/Prevention

-Drainage of infected area and antibiotics -Prevention: wash hands, clean hospital rooms/med equip, contact precautions, cover wounds

Extended Spectrum Penicillin

-Effective against many gram (-) and gram (+) -ampicillin, amoxicillin, *carbenicillin, *ticarcillin (*greater act against gram (-))

Mechanisms of Resistance

-Enzymatic destruction or inactivation of the drug -Prevention of penetration to the target site within the microbe -Alteration of drugs target site -Rapid efflux of the antibiotic -Variation of mechanisms of resistance

Conjugative plasmids:

-F-plasmid: genes to make a sex pilus; replicates, and a copy is passed to another cell. -Resistance plasmid: genes that make the cell resistant to antibiotics, heavy metals.

Nucleid Acid Synthesis

-Interferes with DNA replication and transcription -Rifamycins: inhibits mRNA synthesis -Quinolones and fluoroquinolones: inhibit DNA replication

Lipopolysaccharide

-Layer of gram negative -Drugs should be small and hydrophilic -Lipophilic drugs are large and don't readily enter gram (-) cells

Antibiotic Misuse

-Less developed areas of the world -Developing world contributes too (antibiotic prescriptions for common cold are unnecessary)

Streptomyces

-More than half our antibiotics are produced by these species

RNA Polymerase

-Multi-component enzyme -Needs a template, but NOT a primer -In bacteria, a component (sigma) recognizes the promoter as the place on DNA to start synthesis -Synthesis proceeds 5' to 3', just as in DNA

Insertion sequences

-Normally relatively short (700 to 1,650 bp). -Capable of transposition. -Are discrete genetic elements bounded at both ends with inverted repeats.

Semi-synthetic Penicillins

-Overcomes the disadvantages of the natural penicillin -Created in 2 ways: 1. interrupt synthesis of Penicillum and only obtain nucleus 2. Remove side chain from natural molecule, and add new side chain to make more resistant.

viral concentration is measured in( growing in bacterial cells)

-PFUs per mill -plaque-forming units per milliliter of solution poured onto the plate ...32

Chemotherapy

-Paul Ehrlich -Selective Toxicity

Antiviral Drugs

-Targets steps in viral infection 4 majopr classes: -amantadine:prevents the influenza virus from penetrationa nd uncoating -tamiflu:acts as a neuraminidase inhibitor. does not kill influenza but does shorthen the length of illness and prevents influeza from spreading to others -acyclovir:prevents the herpes virus from replicating -ribavirin: inhibits the hepatitis virus

Diffusion Method Test

-Test guide for chemo -disk diffusion method: Kirby Bauer test -disk impregnated with known conc of agent placed on agar with organism (measured zone of inhibition)

Penicillin Resistance

-To staphylococcal infections (plasmid with gene encoding for beta-lactamase) -MRSA- methicillin resistant staphylococcus aureus

Plaque Assay

-Virus and host cell mixed -Bacteria on top & Eukaryotic cells on bottom of agar -Multiplication of virus leads to destruction of cells -Visible as holes

Broth Dilution Tests

-determines minimal inhibitory concentratiom (MIC) and minimal bactericidal concentration (MCB) of antimicrobial agent -Growth= bacteriostatic -No Growth= bacteriocidal

Antimicrobial Drug

-drug that inhibits the growth of a microorganism (Sulfa drug)

some drugs are successfully target unique asspects of pro synthesis of DNA and RNA. usually acheived by targeting enzyme involved in the process of DNA replication and transcription

-drugs that block DNA replication inhibit DNA polymerase, DNA helicase, or other enzymes involved in making the DNA supercoiled -drugs that block transcription inhibit RNA polymerase

properties of viruses

-estamated 10^31 viruses particles on earth- about 10x the number of prok -ubiquitous in nature and have major impact on development of biological life

prevent drug resistance

-give drug in high concentrations -only use drugs when necessary -give two or more drugs at the same time for synergistic effects

viruses involved in cancer

-herpes virus is associated with several cancers, including kaposi's sarcoma -epstein-barr virus is associated with several, including burkitts lymphoma -hepatitis B/C cause cancer of the liver -human papillomavirus(HPVs) cause cervival cancer -human t-cell lymphotrophic virus 1 (HTLV-1) cause leukemia

Symptoms of MRSA

-looks like spider bite -bump on skin -infected area is red swollen and painful

Clavulanates

-non-competitive inhibitor of penicillinase

mechanism of drug resistance

-preventing entrance of the drug -using efflux pumps to remove the drug before it can have an effect -inactivating the drug -modifying the enzyme or organelle that the drug targets -using an alternative pathway or increasing production of a target metabolite

spread of antibiotic resistant bacteria

-selective pressures -genetic factors

Infections of MRSA

-skin or wound -pneumonia -bloodstream infections

Antibiotics

-substance produced by microorganisms that in small amounts inhibits another microorganism

therapeutic index

-the ratio between the toxic and therapeutic concentrations of a drug -toxic dose/therapeutic dose= theraputic index - better for a drug to have a high therapeutic index becasue it means overdosing is less likely to have negative consequences

Plaque assay technique steps

1 place few drops of host cells in plate with soft agar 2 allow host cells to grow to fill the entire plate 3 infect bacteria with virus 4 count # of viral plaques (clear areas) where the virus has killed a group of cells

Life Cycle of Virus

1. Adsorption 2. Penetration 3. Synthesis/Replication 4.Assembly (spontaneous) 5. Release (spread)

What modulo's do..

1. Respond to changes in nutrients and energy supply -type of carbon available -Limitation of required N to P -Lack of AA (the stringent response) -May change shape (spores) 2.Stress response -High heat/Oxidative 3.Aggregation/Cell-cell interactions -quorum sensing

Lysogenic cycle

A not so violent death. Viral DNA inserts into the bacterial chromosome (a prophage). Damage to bacteria DNA prompts lytic cycle but its not permanent

A change in genotype, but not in phenotype, is most likely due to

A point mutation in the third position of a DNA triplet

Viral syndrome

A viral syndrome= a collection of signs and symptoms Ex of infections: oral, resp tract, skin rash, eye, hemorrhagic fevers, flu-like and systemic symptoms, gastroenteritis, hepatitis, CNS infection, STDs, congenital, perinatal, neonatal diseases

During the investigation of a convenience store robbery, witnesses report that the perpetrator exited through a main entry door without wearing gloves. The police are holding a prime suspect in custody while samples from the door are collected and analyzed for a DNA match. Since the door was handled by many people before the robbery, how will the forensics department distinguish the suspect's DNA from the DNA of others using PCR?

A- Sequence-specific primers to the suspect's DNA will be used for PCR amplification.

Which type of medium support growth of mutant bacteria that are threonine auxotrophs? A. Threonine auxotrophs only grow on media that is supplemented with threonine. B. Threonine auxotrophs only grow on media that lacks threonine. C. Since threonine is essential for growth, threonine auxotrophs do not grow on any type of media. D. Since threonine is essential for growth, threonine auxotrophs can grow on any type of media.

A- Threonine auxotrophs only grow on media that is supplemented with threonine.

30. Which of the following types of cloning vector can carry the largest amount of foreign DNA? A. bacterial artificial chromosome B. bacteriophage C. cosmid D. plasmid

A. bacterial artificial chromosome

A molecular biologist is interested in purify a recombinant protein by His-tagging, but the protein and vector both lack histidine residues. In this case, the molecular biologist could use which of the following technique(s) to acheive purification?

A. Add a 6xHis-tag to the C-terminus of the protein. B. Add a series of histidine residues to the N-terminus of the protein. C. Amplify the histidine-encoding sequence by PCR and add it to the gene of interest. D. All of the choices are correct.

Which of the following bacterial hosts would should be used to avoid degradation of DNA that is introduced via a cloning vector? A. Escherichia coli that lack endonucleases B. RecA-expressing Escherchia coli C. Escherchia coli RecA mutants D. Saccharomyces cerevisiae wild type cells

A. Escherichia coli that lack endonucleases

Which of the following types of cloning vector can carry the largest amount of foreign DNA? A. bacterial artificial chromosome. B. bacteriophage. C. cosmid. D. plasmid.

A. bacterial artificial chromosome

Which situation(s) might warrant the removal of a histidine tag when purifying a recombinant protein?

A. Histidine residues inhibit protein folding, thereby decreasing the functionality of the protein.

You and a friend are student assistants in a research laboratory that investigates the anti-cancer properties of proteins isolated from marine organisms. Your friend mentions that she is using a BAC vector to insert shark DNA into Escherichia coli, but after repeated attempts, has found that the bacterial cells fail to synthesize the encoded protein. What is your advice? A. If the shark DNA is unmodified, it contains introns that are not recognized by bacteria, therefore protein synthesis will not occur.

A. If the shark DNA is unmodified, it contains introns that are not recognized by bacteria, therefore protein synthesis will not occur.

63. Which of the following is true of the integration of a viral genome into the host chromosome? A. Integration of the viral genome is a form of site-specific recombination. B. The enzymes that are used in integration are nonspecific for the virus and its host. C. Integration begins the process of host chromosome degradation. D. All of the choices are correct.

A. Integration of the viral genome is a form of site-specific recombination.

Which of the following techniques exemplifies phenotypic rescue in a host cell? A. Introducing a genomic library from a cell that produces a particular gene product into a mutant host cell auxotroph that cannot synthesize the product. B. Introducing a genomic library from a mutant cell auxotroph for a particular gene product into a host cell that can synthesize that product constitutively. C. Removing genes that encode a particular gene product from a cell that expresses that product constitutively before creating a genomic library. D. Replacing a mutant gene with a functional gene in a DNA library from an auxotrophic mutant cell prior to introducing the library into a related host cell.

A. Introducing a genomic library from a cell that produces a particular gene product into a mutant host cell auxotroph that cannot synthesize the product.

Site-specific recombination systems

A. do not depend on extensive nucleotide sequence homology. B. depend on enzymes that are often specific for sequences within the host. C. are features of some viruses. (All the above)

What would be the hypothetical outcome if the action of RecA were inhibited during the SOS response?

A. LexA would not autolyse, and therefore the transcription of DNA repair genes would not occur.

Which of the following terms is most closely related to genetic complementation? A. Phenotypic rescue B. Naked DNA C. Reverse transcription D. SOS response

A. Phenotypic rescue

In order to express eukaryotic genes in a bacterium, the __________ must first be removed. A. introns B. exons C. enhancers D. 3' poly A sequence

A. introns

Which of the following can be used as vectors for cloning DNA fragments?

A. plasmids B. cosmids C. bacteriophages D. All of the choices are correct.

Which is a true statement regarding the size of PCR products? A. Since the number of DNA products ending exactly between both primers increases with each cycle, when PCR is completed, the majority of products are of similar size. B. Since the number of DNA products extends beyond each primer with each cycle, when PCR is completed, the majority of products are of various sizes. C. Since the length of primers increases with each cycle, when PCR is completed, the majority of products are of various sizes. D. None of the choices are correct.

A. Since the number of DNA products ending exactly between both primers increases with each cycle, when PCR is completed, the majority of products are of similar size.

Which is most analogous to the role of GFP in recombinant DNA technology?

A. Using dyes to stain and detect bacteria under light microscopy from the sputum of a patient diagnosed with tuberculosis. (GFP is green florescent protein, used to differentiate)

A transposable element composed of an antibiotic resistance gene, a recombinase gene, and inverted repeats is identified in a bacterial genome. This element can be any of the following except

A. an insertion sequence.

SOS repair

A. requires RecA protein. B. is inducible by DNA damage. C. is error prone, i.e., produces mutations (All the above)

Antibiotics incorporated into the culture medium can A. select against organisms that have not incorporated the plasmid. B. select against organisms that have incorporated a plasmid not containing the desired gene. C. enhance production of recombinant proteins. D. select against organisms that have not incorporated the plasmid and select against organisms that have incorporated a plasmid not containing the desired gene

A. select against organisms that have not incorporated the plasmid

Antibiotics incorporated into the culture medium can

A. select against organisms that have not incorporated the plasmid.

A (n) __________ vector is a plasmid that can be replicated in several different organisms because it has at least one origin of replication that will function in each host. A. shuttle B. chimeric C. expression D. phage

A. shuttle

Which of the following is not part of a yeast artificial chromosome (YAC)? A. The F factor. B. A selectable marker. C. An ARS. D. A CEN sequence.

A. the F factor

Which of the following is not part of a yeast artificial chromosome (YAC)? A. the F factor B. a selectable marker C. an ARS D. a CEN sequence

A. the F factor

Abortive infection

AKA non-productive infection virus is unable to successfully complete replication

Lytic infection

AKA permissing infection/productive infection "standard" kind of viral infection virus infects the host and hijacks the cellular machinery to make more copies of itself and destroys the host by causing lysis influenza and polio

Allolactose

Actually binds to the lac repressor protein (not lactose)

An enzyme that cleaves internal phosphodiester bonds of a DNA molecule is a (n) A. exonuclease. B. endonuclease. C. ligase. D. methylase.

B. endonuclease

Restriction endonucleases were discovered by

Arber and Smith

Three domains of microorganisms. Compare viruses with all other living things

Archaea, Bacteria, Eukarya Archaea and Bacteria include prokaryotes Eukaryotes: have diff ribosomes than prokart and lack gas vesicles mRNA contains introns and has to be further processed after transcription (prokr. mRNA doesn't) Viruses: acellular and nonliving rely on machinery and energy of their host cells to live an reproduce

Non-essential

Are plasmids essential or non-essential to the cell?

Heat Shock Proteins

Are turned on in response to elevated temperatures. Trigger protective proteins to help the cells live. Example of a modulon.

Cloning a gene involves all of the following except

expression of the vector and the gene in a cell-free environment.

The three steps that take place in each cycle during PCR occur in which order? A. DNA annealing, denaturation, and synthesis. B. DNA denaturation, annealing, and synthesis. C. DNA synthesis, denaturation, and annealing. D. none of the above.

B. DNA denaturation, annealing, and synthesis

Recombinant DNA technology does not rely on which of the following enzymes? A. restriction endonucleases B. RNA methylase C. DNA ligase D. reverse transcriptase

B. RNA methylase

Restriction endonucleases in bacteria may have evolved in order to A. carry out natural genetic engineering. B. protect the bacteria from infection by viruses. C. use nucleic acids as a food (energy) source. D. all of the choices

B. protect the bacteria from infection by viruses

The PCR method was developed by A. Boyer. B. Mullis. C. Cohen. D. Sanger.

B. Mullis

21. Which of the following is not true of cloning vectors? A. They usually contain multicloning sites or polylinkers. B. They contain at least two replication origins. C. They can be replicated within an appropriate host. D. All of these are true of cloning vectors.

B. They contain at least two replication origins

Plasmid vectors often contain __________ genes that can be used to screen for recombinants. A. metabolic activation B. antibiotic resistance C. insertion sequence D. promoter/operator

B. antibiotic resistance

Restriction endonucleases are produced by A. fungi. B. bacteria. C. protozoa. D. plants. E. all of the choices

B. bacteria

Restriction endonucleases are produced by A. fungi. B. bacteria. C. protozoa. D. plants. E. All of the choices are correct.

B. bacteria.

When a eukaryotic gene is cloned into a bacterium, the advantage of a complementary DNA (cDNA) gene being used instead of fragments of genomic DNA is that A. the promoter and terminator are found in the cDNA gene but not in the genomic fragment. B. the introns have been removed from the cDNA gene but not from the genomic fragment. C. the cDNA is made with the nucleotides found in the prokaryote but not in the eukaryote. D. there is no advantage to using a cDNA gene rather than a genomic fragment.

B. the introns have been removed from the cDNA gene but not from the genomic fragment

Which of the following is not true of cloning vectors? A. They usually contain multicloning sites or polylinkers. B. They contain at least two replication origins. C. They can be replicated within an appropriate host. D. All of these are true of cloning vectors.

B. they contain at least two replication origins

A DNA molecule used to carry a foreign gene into a host organism is called a A. plasmid. B. vector. C. probe. D. blot.

B. vector

Mechanisms by which bacteria develop resistance to different anti-microbial drugs

Bacteria could develop ways to prevent antibiotic entrance into the cell, pump the drug out of the cell, modify the drug so it's ineffective, modify the structure that the drug acts on, or use an alternate pathway than the one the drug acts on mutation on chromosomal genome produce enzyme that inactivates drugs pump drugs out of cell before they're' effective exchanging plasmids

Microbes and the sulfur cycle

Bacteria engage in a number of redox rxns which cause the reduction of sulfur oxides to hydrogen sulfides

Antibiotics

Bacteria may send these out to slow the competition from other bacteria

Acyclovir (Zovirax)(antivirus drugs)

Base analog (mimics guanine) Inhibiting DNA replication targets herpesviruses INHIBITION OF GENOME REPLICATION

Dideoxycytidine (Hivid)(antivirus drugs)

Base analogs (mimic cytosine and adenine, respectively) terminating DNA chain elongation targets HIV INHIBITION OF GENOME REPLICATION

Dideoxyinsine (Videx)(antivirus drugs)

Base analogs (mimic cytosine and adenine, respectively) terminating DNA chain elongation targets HIV INHIBITION OF GENOME REPLICATION

Water plants die and release NH4+ into the soil. Oxidized to nitrite and then to nitrate. Nitrate used by the living plants. This is an example of___________ ___________.

Biogeochemical Cycling

Bio-pesticides? Give an example.

Biopesticides = naturally produced agents that kill pests Ex: Bacillus thuringiensis (Bt) is a gram+ bacteria that produces a toxin (parasporal body). this kills a certain group of insects

Amantadine (Symmetrel) (antivirus drugs)

Block viral uncoating targets Influenza A BLOCKING OF PENETRATION/UNCOATING

Enfuvirtide (Fuzeon)(antivirus drugs)

Blocks penetration/uncoating targets HIV BLOCKING OF PENETRATION/UNCOATING

Pleconaril (Picovir)(antivirus drugs)

Blocks uncoating targets Picornavirus BLOCKING OF PENETRATION/UNCOATING

. A microbiologist is working with two genera of bacteria, A and B, to determine if cells are competent. Strains are grown under optimal conditions, and DNA fragments that carry the gene for green fluorescent protein is added to each culture at 20-minute intervals. Samples from each treatment are plated to nutrient agar and incubated, after which the plates are examined under an ultraviolet lamp. The microbiologist observes that all plates of bacteria B contain colonies that are fluorescent, while for bacteria A only the plates from stationary phase demonstrate fluorescent colonies. What can be concluded from these results?

Both bacteria A and bacteria B cells are competent.

Which of the following is true about restriction endonucleases? A. They make a blunt cut on the two DNA strands so that there are no single-strand regions. B. They make staggered cuts on the DNA so that single-strand ends are formed that can be used to insert foreign DNA cut with the same enzyme. C. Some make a blunt cut on the two DNA strands so that there are no single-strand regions and some make staggered cuts on the DNA so that single-strand ends are formed that can be used to insert foreign DNA cut with the same enzyme. D. Depending on the incubation conditions, the same enzyme can either make a blunt cut on the two DNA strands so that there are no single-strand regions OR make staggered cuts on the DNA so that single-strand ends are formed that can be used to insert foreign DNA cut with the same enzyme.

C

A (n) __________ vector contains promoters that result in high-level transcription of the gene cloned within a multicloning site. A. shuttle B. chimeric C. expression D. phage

C. expression

Movement of charged molecules in an electrical field, which is used to separate nucleic acid fragments for recombinant DNA work, is called A. iontophoresis. B. nucleophoresis. C. electrophoresis. D. plasmaphoresis.

C. electrophoresis

Cloning a gene involves all of the following except A. isolating the fragment of DNA containing the desired gene. B. insertion of the gene into an appropriate vector. C. expression of the vector and the gene in a cell-free environment. D. introducing ligated DNA into E. coli cells.

C. expression of the vector and the gene in a cell-free environment

Cloning a gene involves all of the following except A. isolating the fragment of DNA containing the desired gene. B. insertion of the gene into an appropriate vector. C. expression of the vector and the gene in a cell-free environment. D. introducing ligated DNA into E. coli cells.

C. expression of the vector and the gene in a cell-free environment.

___________ is a bacterial plasmid vector. A. Lambda B. T4 DNA ligase C. pUC19 D. SV40

C. pUC19

A __________ is a DNA molecule used in hybridization reactions to detect the presence of a particular gene in separated DNA fragments. A. plasmid B. vector C. probe D. blot

C. probe

A PCR procedure that allows a determination of the amount of a particular DNA fragment that is present in a sample is called A. quantitative PCR. B. analytical PCR. C. real-time PCR. D. reverse PCR.

C. real-time PCR

Genetic manipulation

Changing the genome of an organism to produce desired traits

Chemotherapeutic agents? Which part of cells could be used as a target for antimicrobial agents

Chemotherapeutic agents include antibiotics and synthetic drugs that control the spread of microbes, either by killing them or preventing their proliferation. Used to fight diseases

Cloning?

Cloning is the process by which DNA sequence is isolated and replicated using a cloning vector.

What is the rationale behind the combination drug therapy for HIV infections?

Combination of drugs create obstacles to HIV replication This is why treatment for HIV involves at least 3 drugs from two diff classes

Biofilms

Communities of microbes attached to a surface -use fimbriae and slime

Medical significance of comparative genomics analysis? RFLP?

Comparative genomics studies the differences among the genomes of different organisms. Gives info about what makes a pathogen virulent and gives insights into what kinds of vaccines or therapies will be useful to fight against a virulent pathogen

CPE and give examples.

Cytopathic effects (CPE)= the effects of a viral infection that can be visualized with a microscope. *Examples:* - Viral plaque- visible area where virus has destroyed infected cells in a cell culture - Enlargement of either the cell, nucleus, or both - Membrane changes (greater elasticity) - Fusion of cells which produces a syncytium (multinucleate cell) - Leaky internal organs

Which of the following can be used as vectors for cloning DNA fragments? A. plasmids B. cosmids C. bacteriophages D. All of the choices are correct.

D All the above

Which of the following is not a strategy that bacteria use to resist the action of antibiotics? A. Modification of the antibiotic by the acetylation or phosphorylation. B. Cleavage of a key structural component of the antibiotic. C. Altering cell membrane structure to prevent antibiotic influx. D. All of the choices are correct.

D- All the above

Which of the following bacterial hosts would should be used to avoid degradation of DNA that is introduced via a cloning vector?

Escherichia coli that lack endonucleases

Which of the following mutagens is most different than the others in terms of its effect on DNA? A. Acridine orange B. Intercalating agent C. Planar mutagen that inserts between stacked bases D. Base analogue

D. Base analogue

The most frequently chosen prokaryotic host in cloning techniques is A. Saccharomyces cerevisiae. B. Bacillus subtilis. C. Staphylococcus aureus. D. Escherichia coli.

D. Escherichia coli

Which is the most frequently chosen prokaryotic host for use in cloning techniques? A. Saccharomyces cerevisiae B. Bacillus subtilis C. Staphylococcus aureus D. Escherichia coli

D. Escherichia coli

The enzyme reverse transcriptase was discovered by A. Arber and Smith. B. Jackson, Symons, and Berg. C. Boyer and Cohen. D. Temin and Baltimore.

D. Temin and Baltimore

Which of the following can be used as vectors for cloning DNA fragments? A. plasmids. B. cosmids. C. bacteriophages. D. all of the choices.

D. all of the choices

Which of the following was first produced commercially using recombinant DNA technology? A. human growth hormone B. interleukins C. hepatitis B vaccine D. human insulin

D. human insulin

All of the following are appropriate strategies for overcoming drug resistance in bacteria except: A. decreasing the use of antibiotics in agriculture. B. patient compliance with dosage instructions when taking antibiotics. C. heightened infection control in health care facilities. D. prudent use of antibiotics when treating viral infections.

D. prudent use of antibiotics when treating viral infections.

Complementary DNA (cDNA) probes are produced using A. restriction endonucleases. B. RNA polymerase. C. DNA ligase. D. reverse transcriptase.

D. reverse transcriptase

Which of the following best describes the basis for separation of DNA fragments during agarose gel electrophoresis? A. The fragments with the highest percentage of G and C will migrate fastest. B. The fragments with the highest percentage of A and T will migrate fastest. C. The largest fragments will migrate fastest. D. The smallest fragments will migrate fastest.

D. the smallest fragments will migrate fastest

Recombinant DNA

DNA containing fragments from two or more different sources

cDNA

DNA copied from RNA by reverse transcriptase, lacks interons

The three steps that take place in each cycle during PCR occur

DNA denaturation, annealing, and synthesis

The three steps that take place in each cycle during PCR occur in which order?

DNA denaturation, annealing, and synthesis

If a region of DNA contained numerous mismatches due to a modifying agent that caused methylation of guanine, which of the following mutagens is most likely the cause?

DNA modifier

Probe

DNA molecule used in hybridization reactions to detect the presence of a particular gene in separated DNA fragments

If DNA were a positively charged rather than negatively charged, what change to the gel electrophoresis procedure must be made?

DNA must be loaded at the positive pole rather than at the negative pole.

Repair of an apurinic or apyrimidinic site in DNA by AP endonuclease must be completed by the action of

DNA polymerase I

Complementary DNA (cDNA)

DNA produced from an RNA template using reverse transcriptase. often used to clone eukaryotic genes in prokaryotes. *Basic Process:* Begin with single stranded RNA and apply short poly-T primer Add reverse transcriptase and four nucleotides (ACGT) Add on enzyme called RNaseH to cut up the RNA and regenerate the RNA primers Add DNA polymerase and DNA ligase to synthesize a new strand

Arber and Smith.

Discovered Restriction endonulases

History/origin of antibiotics? Why some microorganisms produce antibiotics

Discovered by Alexander Fleming in the 1920s (pencillin) Saved many thousands of lives during WWII Antibiotics are produced by bacteria and fungi as a natural defense mechanism against other bacteria ex: bacillus is a genus of bacteria that produce antibiotics and penicillium is a genus of fungi that produce antibiotics

How one may prevent the emergence of drug resistant microbes?

Doctors can prescribe antibiotics in high enough concentration and in correct combination to kill all of the bacteria (giving 2 or more drugs at a time has synergistic effects) Doctors can prescribe fewer antibiotics Researchers can develop new drugs and treatments

T/F The transformation frequency of very competent cells is about 10-6, or about 1 in 1,000,000 when an excess of DNA is used.

False

In _____________, cells are mixed with recombinant DNA and exposed to a brief pulse of high-voltage electricity to cause the membrane to become permeable and allow the uptake of DNA from its environment.

Electroporation

Eukaryotes-Injection or endocytosis?

Endocytosis

Restriction enzymes

Endonucleases that cut double-stranded DNA at specific recognition sequences. Naturally produced by bacteria as a defense against viral infection, commonly used to create recombinant DNA

Stringent Response

Ex: Rapid drop in AA triggered by empty tRNA. Alarmones are triggered. ppGpp (a modulon) turns on/off several genes and the cell stops growth. All attention goes to synthesizing AA. Will resume normal function when everything is caught up.

Cosmids are so named because they can be used to express foreign genes in a variety of different hosts.

False

Diphtheria toxin is an example of an enterotoxic exotoxin

False

Doctors should always use the most broad spectrum antibiotic available when treating an infection

False

If the prevalence of HIV in 1995 was 256 per 100,000 then this mean that of every 100,000 people in the US, 256 of them got infected with HIV in 1995

False

Promoters for genes that code for proteins can be isolated from a cDNA library.

False

T/F A cell that is Hfr and a cell that is F+ can be the same cell

False

T/F Bacterial isolates from post surgical infections of several patients on the same hospital floor demonstrate an increase in resistance to similar antibiotics. The pattern of antibiotic resistance in these cases is most likely due to vertical gene transfer among bacteria that carry resistance genes to bacteria that lack those genes.

False

T/F In an F+ F- mating, all or part of the host chromosome usually is transferred to the recipient.

False

T/F One strategy to overcome antibiotic resistance is to use the same antibiotics in animal husbandry as those that are prescribed for humans, since the potential for resistant bacteria to evolve would be limited to only a small number of drug classes

False

T/F Stable integration of foreign DNA into a bacterial host genome is generally accomplished through induced plasmid transformation than by natural uptake of free DNA fragments.

False

Operon

Genes physically adjacent and regulated together (next to each other, turned on & transcribed as a group)

Mobilome

Genes that are mobile

Horizontal Transfer

Genes transfered to others, not offspring

Essential components of viruses _____ & ______.

Genetic Material & Covering

Genomics and list the three area of genomics

Genomics= study of the organization of genomes, the info they store, and the gene products they code for *Structural* study of physical nature of genomes *Functional* study of function of genomes - paralog= 2 or more genes found alike in the same genome that likely arose from gene duplication - ortholog= 2 or more genes very similar in different organisms, predicted to have the same function *Comparative* study of the differences among the genomes of diff organisms

Lytic vs lysogenic, why would a virus choose one over the other?

If it's lytic, it can quickly replicate and spread in the population BUT it could eventually kill all host cells and be without a host. Virus might opt for lysogenic cycle so that the host can survive and the virus can remain integrated in the host. It can then undergo induction when environmental conditions are right

You and a friend are student assistants in a research laboratory that investigates the anti-cancer properties of proteins isolated from marine organisms. Your friend mentions that she is using a BAC vector to insert shark DNA into Escherichia coli, but after repeated attempts, has found that the bacterial cells fail to synthesize the encoded protein. What is your advice?

If the shark DNA is unmodified, it contains introns that are not recognized by bacteria, therefore protein synthesis will not occur.

Oseltamivir (Tamiflu)(antivirus drugs)

Inhibit viral release targets Influenza A INHIBITOR OF VIRON MATURATION/RELEASE

Zanamivir (Relenza)(antivirus drugs)

Inhibit viral release targets Influenza A INHIBITOR OF VIRON MATURATION/RELEASE

Four categories of antimicrobial drugs based on their mechanisms of action.

Inhibitors of cell wall synthesis Protein synthesis inhibitors Nucleic acid synthesis inhibitors Inhibitors of cell membrane function

Ecology

Interactions among living things and their environments

As pertaining to the spread of antibiotic resistance in bacteria, which of the following terms is not directly related to the others? A. Intercalate B. Cassette C. Integron D. Integrase

Intercalate (to insert)

A mutagen that inserts between the stacked bases of a DNA double helix, distorting the DNA to induce single-pair insertions or deletions is called a(n) __________ agent

Intercalating

In order to express eukaryotic genes in a bacterium, the __________ must first be removed.

Interons

Which of the following techniques exemplifies phenotypic rescue in a host cell?

Introducing a genomic library from a cell that produces a particular gene product into a mutant host cell auxotroph that cannot synthesize the product.

An insertion sequence is distinguishable from other mobile genetic elements because

It is smallest

When separating DNA fragments by gel electrophoresis, what is the purpose of including molecular weight markers?

Markers are used as a control to determine the relative size of restriction fragments.

Name two groups of Archaea and describe their unique characteristics

Methanogenic archaea and extremely halophilic archaea (primarily chemoorganoheterotrophs that require a sodium chloride concentration of >1.5M)

the main weapon bacterial pathogens use against phagocytosis by our WBC is to employ a capsule

true

Methanogens and what are their ecological and/or environmental impact

Methanogens produce methane as a metabolic product They live in anaerobic environments and are commonly found in the rumens of cows alongside grass Used by humans in sewage plants to digest sludge

What is the difference between methanogens and methanotrophs?

Methanotrophs- metabolize methane as their main source of carbon and energy Methanogens- produce methane as a metabolic byproduct

Microbes and the nitrogen cycle

Microbes convert one form of nitrogen to another Ex: denitrifying, nitrifying, nitrogen-fixing, and bacteria that assist in the decay of organic waste

Microbes and the phosphorus cycle

Microbes play NO role in this cycle

prototrophs

Microbes that can grow on minimal media/ synthesize own metabolites

Microbes and the carbon cycle

Microbial decomposition releases CO2 into the atmosphere Methanotrophs consume methane and methanogens produce methane

Dissimilation

Molecules *do not* require elements to grow. Releases energy. Not as limited.

Assimilation

Molecules require elements to grow. Needed for biomass. Energy is required so amount of reaction is limited.

Monolayer in virus multiplication. List other culturing methods used to propagate viruses in laboratory

Monolayer: layer of homogenized cells growing side by side. If they're exposed to cancer cells, they will become "immortal" and can be used to propagate viruses Other method: growing viruses in entire organisms or in embryonated chicken eggs

Which of the following terms is most closely related to genetic complementation?

Phenotypic rescue

The PCR method was developed by

Mulis

The PCR method was developed by . Mullis.

Mullis.

Which procedure is most associated with unsuccessful transformation and degradation of DNA?

Natural Transfomation

Is DNA negatively or positively supercoiled?

Negatively

Modulon

Network of regulons that have different regulators. Respond to environmental changes that effect the organism

Oxygen diffuses into a pond to supply aerobes. It then diffuses slightly into the soil where facultative aerobes consume it ignorer for strict aerobes to survive. This is an example of a _____.

Niche

Are viruses alive? Reasons for no:

Not made of cells--violation of cell theory, Do not grow, Cannot reproduce w/o host cell

DNA + Proteins packaged =

Nucleiod

Capsid + Nucleic Acid=

Nucleocapsid

the most common type of nosocomial infections are urinary tract infections

true

How do semisynthetic antibiotics differ from their parent molecules?

Often more effective than parent molec Ex: semisynthetic penicillin has a broader range than natural penicillin

Pasmid DNA having one EcoRI recognition sequence is treated with EcoRI restriction endonuclease. Following gel electrophoresis, how many bands should be visible on the gel?

One; plasmid is circular

Metabolic engineering? Explain DNA shuffling and whole genome shuffling.

Optimizing genetic processes in order to incr the production of a certain substance DNA shuffling: propagate beneficial mutations and incr size of a DNA library by randomly fragmenting a pool of related genes and reassembling those fragments Whole genome shuffling: use of protoplast fusion to introduce recombination throughout the entire genome

there are no normal flora of the blood

true

List the common reasons for increasing drug resistance and emergence of superbugs.

Over-prescription of antibiotics has selected against bacteria that lack resistance to drugs = leaving only drug-resistant bacteria in the population Result: greater # of bacteria is resistant to antibacterial drugs

Specialized Transduction

Part B

Lac Y is the gene for..

Permease

If the att site of Escherichia coli was dissimilar to that of lambda phage due to a mutation, how would transduction be affected?

Phage DNA would be unable to integrate into host DNA

Temperate phage? What is their role in pathogenic microbe?

Phage that is capable of establishing lysogeny and integrating into the bacterial host Viruses can carry virulence genes that convey pathogenicity and help bacteria spread For it to produce more phage, induction must occur

typhoid mary is an example of a subclinical (healthy) carrier

true

Biochemical Regulation

Prevents the synthesis of unneeded small molecules

Recombinant DNA technology does not rely on which of the following enzymes?

RNA methylase

Promoter

RNA polymerase recognizes this and binds (defined by function)

Transposons that insert at a new location while a copy remains at the original location are said to mediate _______________ transposition.

Replicative

Host __________ is the process by which some cells are capable of degrading an exogenote

Restriction

Recombinant plasmids

Restriction enzymes (cuts DNA of interest and bacterial plasmid at specific restriction sites, leaving fragments with sticky ends) cloning vectors DNA ligase (seals strands together by catalyzing phosphodiester bonds btwn single-strand breaks)

Efavirenz (Sustiva)(antivirus drugs)

Reverse transcriptase inhibitors targets HIV INHIBITION OF GENOME REPLICATION

Nevirapine (Viramune)(antivirus drugs)

Reverse transcriptase inhibitors targets HIV INHIBITION OF GENOME REPLICATION

Which of the following is the most error-prone of the repair mechanisms A. Postreplication repair B. Recombination repair C. SOS repair D. Photoreactivation

SOS repair

One of the major advantages to using plasmids as cloning vectors is that very high copy numbers can be achieved with many types of plasmid vectors.

True

Are viruses alive? Reasons for yes:

Self assemble, Steal energy form host cell, Can evolve over time, Can respond to environmental stimuli, Have a complex/Organized structure

How septic tank is compared to industrial sewage treatment process?

Septic tank= a holding tank for waste water, isn't a treatment system. Solid organic material falls to the bottom of the tank and settles, the tank has to be emptied after a few years MICROBES DON'T PLAY A ROLE IN THIS PROCESS

During the investigation of a convenience store robbery, witnesses report that the perpetrator exited through a main entry door without wearing gloves. The police are holding a prime suspect in custody while samples from the door are collected and analyzed for a DNA match. Since the door was handled by many people before the robbery, how will the forensics department distinguish the suspect's DNA from the DNA of others using PCR?

Sequence-specific primers to the suspect's DNA will be used for PCR amplification.

A (n) __________ vector is a plasmid that can be replicated in several different organisms because it has at least one origin of replication that will function in each host. A. shuttle

Shuttle

Recognizes the promoter in order for RNA Polymerase to bind..

Sigma protein

The enzyme reverse transcriptase was discovered by

Temin and Baltimore.

When an F' plasmid acts as the donor in a mating, which of the following do(es) not happen?

Some chromosomal genes not on the plasmid are transferred.

55. Which of the following is true about restriction endonucleases? A. They make a blunt cut on the two DNA strands so that there are no single-strand regions. B. They make staggered cuts on the DNA so that single-strand ends are formed that can be used to insert foreign DNA cut with the same enzyme. C. Some make a blunt cut on the two DNA strands so that there are no single-strand regions and some make staggered cuts on the DNA so that single-strand ends are formed that can be used to insert foreign DNA cut with the same enzyme. D. Depending on the incubation conditions, the same enzyme can either make a blunt cut on the two DNA strands so that there are no single-strand regions OR make staggered cuts on the DNA so that single-strand ends are formed that can be used to insert foreign DNA cut with the same enzyme.

Some make a blunt cut on the two DNA strands so that there are no single-strand regions and some make staggered cuts on the DNA so that single-strand ends are formed that can be used to insert foreign DNA cut with the same enzyme

Which of the following is true about restriction endonucleases?

Some make a blunt cut on the two DNA strands so that there are no single-strand regions and some make staggered cuts on the DNA so that single-strand ends are formed that can be used to insert foreign DNA cut with the same enzyme.

Proteomics?

Study of proteomes AKA entire collections of proteins produced by an organism

Functional genomics

Study of the function of genomes, how a genome works

Bioinformatics. What branch of science is involved in bioinformatics

Study of the genome using computers integrates computer science, biology, stats, math

Electroporation is commonly used to introduce recombinant DNA molecules into cells.

TRUE

Genetic engineering methods have been used to produce vaccines.

TRUE

If all of the restriction fragments in a DNA digest were of very low molecular weight, then all of the fragments on the electrophoretic gel will be closest to the positive pole and furthest from the negative pole.

TRUE

One of the major advantages to using plasmids as cloning vectors is that very high copy numbers can be achieved with many types of plasmid vectors.

TRUE

Some plasmid vectors have incorporated the regulatory sequences of the lactose operon so that the expression of the recombinant gene can be induced at the appropriate time.

TRUE

T/F If all of the restriction fragments in a DNA digest were of very low molecular weight, then all of the fragments on the electrophoretic gel will be closest to the positive pole and furthest from the negative pole.

TRUE

The Southern blotting technique for transferring DNA from an agarose gel to a piece of nitrocellulose membrane is named for E. M. Southern, the person who developed the procedure.

TRUE

he thermostable enzyme most commonly used in PCR

Tag Polymerase

Transformation

Taking up of "naked DNA" from solution

Blotting

Technique that combines electrophoresis and hybridization to detect specific DNA fragments Southern = DNA Western = Protein Northern = RNA

An Hfr cell and an F- cell result from conjugation between a donor cell and a recipient cell. Which statement is false regarding this event?

The donor could have been either F- or F+.

Three basic principles of antimicrobial therapy

The drug must have selective toxicity for the target microbe Drug has to be able to reach the target at the right concentration Drug must be able to bind to and penetrate the cell, avoiding inactivation and extrusion

Which of the following conclusions can be made if two identical insertion sequences are identified in separate locations on a chromosome?

The insertion sequence was transferred via replicative transposition.

When a eukaryotic gene is cloned into a bacterium, the advantage of a complementary DNA (cDNA) gene being used instead of fragments of genomic DNA is that

The introns have been removed from the cDNA gene but not from the genomic fragment.

Which of the following is not true of specialized transduction? A. It is carried out by temperate phage. B. It is restricted to those genes on either side of an integrated prophage. C. The phage genome retains the full complement of phage genes. D. All of the choices are correct.

The phage genome retains the full complement of phage genes.

Generalized Transduction

The process by which foreign DNA is introduced into a cell by a virus or viral vector. *- The host chromosome is degraded into randomly sized fragments. - Any DNA fragment of the appropriate size is packaged. - Any bacterial gene may be transferred to the subsequent host. * (All the above)

Recombination

The process in which one or more nucleic acid molecules are rearranged or combined to produce a new nucleotide sequence

The major distinction between horizontal gene transfer and vertical gene transfer?

The recipient of genes in horizontal transfer is a mature cell, whereas the recipient of genes in vertical transfer is a progeny cell.

Lyme Disease

Tick

What is the overall purpose of sewage treatment process? Why is treating sewage is necessary before releasing it in the environment?

To reduce the biological oxygen demand (BOD) = measure of amount of dissolved oxygen required by aerobic biological organisms in a body of water to break down the organic material in the water The more organic material in the water, the greater the biological oxygen demand= the more stress put on marine life Reducing BOD means sewage will support the growth of less bacteria Coliform bacteria is the most common to detect H2O contamination in the US

Under-winding of DNA is carried out by which enzyme?

Topoisomerase

When a recipient cell acquires a piece of naked DNA from the environment, it is called

Transformation

Cholera toxin causes the small intestine to secrete massive amounts of fluids and electrolytes (explosive watery diarrhea) leading to dehydration and possible death if not treated

True

Cosmids are plasmids that can be packaged into capsids of the bacteriophage lambda; therefore, they can be transmitted like phages, but they can exist and replicate in a cell like plasmids.

True

Electroporation is commonly used to introduce recombinant DNA molecules into cells.

True

Genetic engineering methods have been used to produce vaccines.

True

Regardless of the exact approach taken to recombinant DNA technology, one of the keys to successful cloning is choosing the right vector.

True

African Sleeping sickness

Tsetse Fly

Ti plasmid

Tumor-inducing plasmid (Ti) induces the formation of tumors in hundreds of plant species. Scientists found a way to take out the tumor-inducing genes and other non-essential regions. The plasmid can be used as a cloning vector

Light Production

Turn on the lights once there are enough bacteria to make a difference. ATP cost is very high

Quorum Sensing

Use this to monitor their population size

Whole genome shotgun sequencing?

Used for sequencing long DNA strands DNA is randomly broken up into numerous small segments and reassembled by computer programs by looking for regions of overlap (This was used to map the human genome!)

Which is most analogous to the role of GFP in recombinant DNA technology?

Using dyes to stain and detect bacteria under light microscopy from the sputum of a patient diagnosed with tuberculosis.

photoreactivation

Using light energy to repair thymine dimers

Sputum from a patient with a history of tuberculosis due to Mycobacterium tuberculosis bacteria is collected and sent to the microbiology lab for analysis. X-ray analysis and an acid-fast smear made from the sputum indicate that the patient has active tuberculosis. The physician has requested that the sputum be analyzed for pathogen load, but because colonies of Mycobacterium typically take between 3 to 8 weeks to appear on agar, results from traditional culture methods are often delayed. If you were the microbiologist in this case, what would you do?

Using the sputum, apply real-time PCR with primers to Mycobacterium tuberculosis DNA to estimate the pathogen load, then follow up with a traditional culture.

A DNA molecule used to carry a foreign gene into a host organism is called a

Vector

Which of the following methods of genetic recombination is common to both eukaryotic and bacterial cells?

Vertical Gene Transfer

Budding

Virus is formed by pushing through the membrane

Quantifying viruses in laboratory? Plaque assay? Hem-agglutination assay?

Virus quantification= counting the number of viruses in a specific volume to determine the concentration of viruses

Persistent infection

Virus reproduces slwoly and released by the cell slowly over a long period of time These infections don't abruptly kill the host as in a lytic infection

Bacteriophage

Virus that infects a bacterium

Explain why there are far fewer antiviral agents than there are antibacterial agents.

Viruses aren't metabolically active so they don't reproduce on their own. Drugs that fight against viruses must have their unique targets.

Virus multiplication vs growing bacteria.

Viruses require a host in order to replicate but bacterium can multiply on their own

One-Step growth cycle? What is the meaning of eclipse period?

a technique that involves exposing bacteria to viruses and then diluting the sample enough that no additional host cells will be infected by new viruses(bacteriophage virologists); measured via plaque assay Eclipse period= there are no detectable infections viruses in the cell, although the virus is using the cell's internal machinery to produce the components needed to produce more viruses

The production of large quantities of a particular DNA sequence is known as gene

amplification

The production of large quantities of a particular DNA sequence is known as gene __________________.

amplification

A microbiologist would like to use a noncompetent genus of streptococcal bacteria, Enterococcus faecalis, as a cloning host to express genes from Streptococcus pneumoniae, which is naturally competent. Is this possible?

Yes via artificial transformation (electroporation or chemical)

A microbiologist would like to use a noncompetent genus of streptococcal bacteria, Enterococcus faecalis, as a cloning host to express genes from Streptococcus pneumoniae, which is naturally competent. Is this possible?

Yes; electroporation or chemical transformation can be used to make Enterococcus competent, and then genes from Streptococcus can be introduced via a cloning vector.

Methicillin

a semisynthetic form of penicillin that is resistant to penicillinase, but less active then penicillin g commonly used to fight staph infections

Neoplasia

abnormal new cell growth and reproduction due to loss of regulation of the cell cycle. leads to the formation of tumors

drug resistance

an organisms ability to eliminate or neutralize the effect of anantimicrobial drug begins with a spontaneous mutation in the genome can be transfered via horizontal gene transfer ex: MRSA--> VRSA

Name three anaerobic environments where methanogens are found and are rich in organics.

animal rumens anaerobic sludge digesters anaerobic protozoa

target: sulfanomides

anti metabolite

Plasmid vectors often contain __________ genes that can be used to screen for recombinants.

antibiotic resistance

trans: dengue fever

arthropod

trans: malaria

arthropod

transmission: bubonic plague

arthropod

A(n)__________ __________ is a piece of DNA with all of the features necessary for chromosomal replication and which can carry large (up to 1000 kb) pieces of foreign DNA into a host organism.

artificial chromosome

Chages' disease

assassin bug

one-step growth cycle

attachment and penetration: virus binds to receptors on the host's cell membrane(virus acts like a ligand that exploits the hosts natural receptors). viruses brought into the cell via receptor-mediated endocytosis(host cell memrane invaginates and pinches off forming an endosome that contains the virus)virus the produces compounds that lower the pH inside the endosome which causes the virus to uncoat the triggers the virus fusion with the endosome. then released into the cytop[lasm. the number goes from 1 to 0 bc the virus that initally infects the cell is disassembled into its component parts Eclipse: Maturation/ yeild: (burt period/ rise period) the number of observable infectious viruses in the cell increases as the virus3s begin to assemble Release: the number of viral particles remains high. eventually liberated from the cell. may bud off or lyse the plasma membrane

Restriction endonucleases are produced by

bacteria

Which of the following types of cloning vector can carry the largest amount of foreign DNA?

bacterial artificial chromosome

The polymerase chain reaction (PCR) can be used to produce __________ of copies in a few hours.

billions

Vancomycin

binds pentapeptides (peptide tip) can't crosslink glycopeptide antibiotic that blocks transpeptidation does not have beta-lactam ring, so penicillinases don't impact its function. may be affected where penicillin is not effective against MRSA treated enterococcal and staph

Inducer

binds to repressor and causes it to fall off

Rimantadine (Flumadine) (antivirus drugs)

block viral uncoating targets influenza A BLOCKING OF PENETRATION/UNCOATING

Marviroc (Selzentry)(antivirus drugs)

blocks attachment/penetration targets HIV BLOCKING OF PENETRATION/UNCOATING

Lethal mutations can be recovered in haploid organisms if they are

conditional

trans: mono

direct contact

Compare the three stages of sewage treatment process: DISINFECTION

disinfect water to remove all microbes ex: chlorination

How metabolic antagonists (antimetabolites) work?

disrupt steps in key metabolic pathways the drugs are typically structural analogs that resemble an actual molecule in the metabolic pathway but doesn't function like that molecule drugs that block their function of metabolic pathways through competitive inhibition of those metabolites by key enzymes are often structural analogs bacterial cells use anabolic metabolic pathways to build up important cellular components like AA, they use catabolic metabolic pathways to break down other components like sugars

Sulfonamides (sulfa drugs)

disrupts the pathway by acting as a structual analog of p-aminobenzoic acid(PABA), which is a precursor involved in the pathway in the synthesis of folic acid. almost have the same structure of PABA ut do not function the same

Antimicrobial drugs: Protein synthesis inhibitors

disturb the process of protein synthesis, often targeting ribosomes(protein synthesis occurs in ribosomes) Polymyxin B Aminoglycoside Tetracyclines Macrolides Chloramphenicol

Silent Mutation

does not alter the amino acid sequence of the resulting protein

toxic dose

drug level at which drug becomes too toxic for patient (produces side effects: an undesirable effect of a drug on a host cell)

Movement of charged molecules in an electrical field, which is used to separate nucleic acid fragments for recombinant DNA work, is called

electrophoresis.

In _____________, cells are mixed with recombinant DNA and exposed to a brief pulse of high-voltage electricity to cause the membrane to become permeable and allow the uptake of DNA from its environment.

electroporation

PCR Primer

ensures amplification of the target DNA sequence only

endonuclease

enzyme that cleaves internal phosphodiester bonds of a DNA molecule

cephalosporins

functional and structually similar to penicillin have beta-lactam rinds broad sectrum for pt who are allergic to penicillin

type: histopasmosis

fungal

type: ring worm

fungal

type: thrush

fungal

Induction

genes are off until they are needed. Mostly in negative regulation

Endogenote

genome of the recipient

type of bacteria: neisseria

gram neg cocci

type of b: bubonic plague

gram neg rod

type of b: cholera

gram neg rod

type of b: e. coli

gram neg rod

type of b: pseudomonas

gram neg rod

type of b: streptococcal pneumoniae

gram pos cocci

type of b: b. cureus

gram pos rod

type of b: tetanus

gram positive rod

Hemagglutination assay technique

hemagglutinin causes red blood cells to agglutinate (clump up) exposing a solution containing viruses to red blood cells and observe how much they clump up, researchers can quantify the red blood cells in the sample

Which of the following was first produced commercially using recombinant DNA

human insulin

Antimicrobial drugs: Inhibitors of cell membrane function

impacts the assembly or proper functioning of the cell membrane Polymyxin B: binds to the plasma membrane, disrupting its structure and permeability; very toxic and has side effects like kidney damage

trans: cholera

indirect contact

Damages inflicted on host cells by viruses

inducing lysis (kills the cell) transforming the cell's genome altering nuclear or cytoplasmic structure of the hose altering gene expression int he host inhibiting RNA synthesis or synthesis of proteins using product of transcription (RNA molec) to construct new viruses rather than in normal gene expression for the host encouraging *apoptosis* (programmed cell death)

Viroid

inert version of the virus that exists outside of the host

Industrial and medical products produced via biotechnology

insulin alpha, beta, and gamma interferons alpha1-antritrypsin (treats emphysema) blood clotting factors (treats hemophilia) calcitonin (treats osteomalacia) focuses on producing primary and secondary metabolites for use as food, amino acids, antibiotics, and other purposes

Human peptide and proteins synthesized by genetic engineering

insulin (diabetes) alpha1- antitrypsin (emphysema) blood-clotting factors (hemophilia) calcitonin (osteomalacia) epidermal growth factor (wounds) erythropoietin (anemia) growth hormone interleukins (tumors and immune disorders) macrophage colony stimulating factor (cancer) relaxin (childbirth) serum albumin (plasma supplement) somatostatin (acromelagy) streptokinase and tissue plasminogen activator (anticoagulents) tumor necrosis factor (cancer)

Bacitracin

interferes with bactoprenol recycling blocks transportation of those building blocks outside the cell

Cycloserine

interferes with pentapeptide synthesis, can't synthesis amino acids, inhibits transglycosylases blocks the synthesis of the building blocks of the cell wall inside the cell

Operator

location where regulatory proteins bind (defined by function)

Why protein synthesis (translation) excellent targets against some infectious diseases, but not others?

many antibiotics work by binding to the small (30S) or alrge (50S) subunits of the prokaryotic ribosomes, preventing them from assembling or carrying out their proper functions size and composition of prok/euk ribosomes differ, so antibiotics can effectively prevent protein synthesis in prok ribosomes while leaving the euk host's ribosomes unaffected

Real-time PCR

measure gene expression levels (quantity)

administration of antimicrobial drugs

oral administration: pill topical administration:creams parenteral routes: injection via needles

Plasmid DNA having one EcoRI recognition sequence is treated with EcoRI restriction endonuclease. Following gel electrophoresis, how many bands should be visible on the gel?

one

Antimicrobial drugs: Inhibitors of cell wall synthesis

prevent cells from proliferating by preventing synthesis of cell walls. inhibit peptigoglycan sythesis (polymer made of NAM and NAG) This is the most important target for antibiotics but is useless against bacteria that do not have cell walls Penicillins( inhibits the final step in bacterial wall synthesis aka transpeptidation), cephalosporins, vancomycin, methicillin

integrase inhibitors

prevent integrase from adding the viral DNA into the host DNA.

Antimicrobial drugs: inhibitors of Nucleic acid synthesis

prevent synthesis of DNA or RNA Quinolones Ciprofloxacin Rifampicin

Products made by microbes in industrial scale (industrial microbiology)

primary and secondary metabolites plant hormones food additives biopesticides genetically modified plants

A __________ is a DNA molecule used in hybridization reactions to detect the presence of a particular gene in separated DNA fragments.

probe

carcinogenesis

process by which cancer forms, is a complex, multi step process that often involves oncogenes. some cases viruses transfer these genes to the host and in other causes the viruses transforms already exsisting proto-oncogenes into true oncogenes that lead to improper cell-cycle regulation.

fusion inhibitors

prohibits the virus from entering host in the first place

Restriction endonucleases in bacteria may have evolved in order to

protect the bacteria from infection by viruses.

target: tetracycline

protein synthesis

Spikes (peplomers)

protein used for attachment, escape. Extend from envelope

A PCR procedure that allows a determination of the amount of a particular DNA fragment that is present in a sample is called

real time PCR

Which procedure is most useful in quantifying the active transcription of botulism toxin genes in a can of food that is contaminated?

real time PCR

Merozygote

recipient cell that is temporarily diploid as result of transfer process

Phototaxis

refers to movement in response to light

Aerotaxis

refers to movement in response to oxygen gas concentration.

Complementary DNA (cDNA) probes are produced using

reverse transcriptase.

Anaplasia

reversion to a more primitive or less differentiated state loss of cell differentiation that allows the cancer to spread

Antibiotics incorporated into the culture medium can

select against organisms that have not incorporated the plasmid.

selective toxicity

selectively finding and destroying pathogens without damaging the host

Nonsense mutation

sense codon that corresponds to one of the twenty amino acids specified by the genetic code is *changed to a chain-terminating codon*

Gel electrophoresis

separates nucleic acids and proteins on the basis of their size and electrical charge, using a gel that is a polymer

Prophage definition

specifically a virus that has infected a bacterial host latent form of a virus genome that remains with the host without destroying it

type: lyme disease

spiral bacteria

type: syphilis

spiral bacteria

Metastasis

spread of cancerous cells throughout the body

Vidarabine (Vira-A)(antivirus drugs)

terminates DNA chain elongation targets Herpesviruses INHIBITION OF GENOME REPLICATION

Spectrum of activity

the # of diff pathogens a drug attacks can be narrow-spectrum or broad-spectrum

Which of the following is not part of a yeast artificial chromosome (YAC)?

the F factor

therapeutic dose

the amount of a drug taken to get the desired effect minimum drug level required for clinical treatment

When a eukaryotic gene is cloned into a bacterium, the advantage of a complementary DNA (cDNA) gene being used instead of fragments of genomic DNA is that

the introns have been removed from the cDNA gene but not from the genomic fragment.

Minimum inhibitory concentration (MIC)

the lowest concentration of a particular antibiotic that visually inhibits the growth of bacteria The smallest concentration of drug needed to visibly control microbial growth. Determine the cut-off between concentration that prevents the microbe from spreading and the concentration that do not prevents the microbe from spreading

Therapeutic dose definition

the minimum drug level required for clinical treatment the minimum dose that is effective to achieve the desired results

Penetration

the nucleic acid must get access to the machinery of the cell to replicate

Specialized Transduction

the transfer of a restricted set of only a few, specific bacterial genes to another bacterium via a phage

As a newly hired molecular biologist for a company that produces genetically modified seeds, your first project is to ensure that a GM cotton plant carrying a bacterial insecticide gene is expressed in tissues of seedlings as well as mature plants. To better understand regulation of the gene, you decide to use________ GFP fusion to detect activity of the promoter and also use_______ GFP fusion to determine the location of the protein in plants tissues at various stages of growth.

transcriptional; translational

Name one mechanism by which resistance may spread through a bacterial population.

transferring R plasmids between bacteria

Plasmid cloning vector DNA is usually introduced into bacterial hosts by

transformation

Cosmids are plasmids that can be packaged into capsids of the bacteriophage lambda; therefore, they can be transmitted like phages, but they can exist and replicate in a cell like plasmids.

true

The arthropods most responsible for mechanical transmission of disease are flies and cockroaches

true

all contagious diseases are infectious

true

all viruses are obligate intracellular parasites

true

amantadine (symmetrel) is mainly used to treat cases of influenza A

true

bactricin can only be used as a topical medicine for skin infections because it is too toxic to be taken internally

true

bubonic plague is a disease of rodents that can be spread by the rat flea

true

exotoxins are usually heat labile (sensitive)

true

exotoxins are usually secreted by living cells

true

genital herpes is an incurable infection

true

herpes and shingles are examples of recurrent diseases

true

in some infections, the damage done by the human immune system can be worse than the damage caused by the disease itself

true

lack of hand washing is still a major cause of nosocomial infections in the modern hospital

true

many extracellular pathogens such as diptheriae and cholera depend on toxins to cause disease

true

mosquito is the most dangerous animal

true

the incubation period always happens before the disease period

true

the main type of nosocomial infection that is a danger to both patients and staff is hepatitis

true

Ames Test

used to measure the mutagenicity of chemicals.

Compare the three stages of sewage treatment process: SECONDARY

uses MICROBES to remove organic material from the liquid portion of sewage three major options: trickling filtration, activated sludge processing, and use of large lagoons REMOVES MOST OF THE BOD

type: yellow fever

viral

Provirus definition

viral DNA that has been integrated into a host's chromosome

Latent infection

virus remains in the host cell in a dormant state until a trigger activates it and causes it to make more copies of itself HIV and Herpes