BIO 205 final

Explain the differences between communicable and noncommunicable infectious diseases and between contact and indirect modes of transmissions using examples.

- communicable: infectious disease can be tranmitted from person-to-person, flu, or herpes - contagious: communicable disease that is easily transmissible...like chickenpox - noncommunicable: disease is not spread from host-to-host, like tetnus 1 - Contact transmission: direct (handshaking), indirect (fomite) 2 - Vehicle transmission: airborne, waterborne, foodborne 3 - Vector transmission: biological (mosquito), mechanical (house fly)

Design an experiment using the vaccinia virus to make a vaccine against the AIDS virus (HIV).

- engineer a vaccinia virus to show HIV proteins -might express HIV spike protein and induce naturlizing antibodies

After contact with a patient's spinal fluid, a lab technician developed fever, nausea, and purple lesions on her neck and extremities. A throat culture grew Gram-negative diplococci. What is the genus of the bacteria? Explain in detail how you came to this conclusion.

-Neisseria Meningitidis Menningicoccol (meningitis) -gram stain showing gram negative dipolococci and systems of meningitis. infection of the membrane covering the brain and spinal cord

Why did the use of DNA polymerase from the bacterium Thermus aquaticus allow researchers to add the necessary reagents to tubes in a preprogrammed heating block (PCR)?

-because it is heat resistant -the cycle of pcr must be heated to a very hight temperature and taq polymerase is stabe to the heat required to denature DNA which is very high. -added to extension of DNA synthesis -can also read template strands and match to complimentary nucleotide -PCR copies DNA- allows for Aids todetected at an earlier stage

Which of the following statements about yeasts are true? (1) Yeasts are fungi. (2) Yeasts can form pseudohyphae. (3) Yeasts produce asexually by budding. (4) Yeasts are facultatively anaerobic. (5) All yeasts are pathogenic. (6) All yeasts are dimorphic.

1, 2, 3, 4

List the experimental requirements of Koch's postulates, and explain the exceptions to the requirements.

1. same pathogen must be present in every case of disease. Tetanus - unequivocal symptoms 2. The pathogen must be isolated from the diseased host and grown in pure culture Exception: Syphilis - can't be isolated and grown in lab 3. The pathogen from the pure culture must cause the disease when inoculated into a healthy, susceptible laboratory animal. Exception: HIV - only in humans 4. The pathogen must again be isolated from the inoculated animal and must be shown to be the same pathogen as the original organism. Exception: pneumonia and nephritis are caused by multiple organisms

Jury members were provided two sets of fingerprints as evidence in a homicide case. One set tested 5 markers and the other tested 10 markers. Both sets matched the defendant's profile. Which one is more reliable and why?

10 is more reliable

Discuss the connection between viruses and cancers giving possible mechanisms for viruses that cause cancer.

10% of cancers are caused by viruses and Several DNA viruses are retroviruses and oncogenic. The genetic material of oncogenic viruses become integrated into the host cells DNA. Among the RNA viruses only the retroviruses seem to be oncogenic. HTLV-1&2 have been found to cause cancer. Activated oncogenes transform normal cells into cancerous cells, but even when a virus is not the cause of cancer, the mechanisms of the disease are similar to when a virus DOES cause the cancer

1.metacercaria 2.redia 3.adult 4.miracidium 5.cercaria If a snail is the first intermediate host of a parasite with these stages, which stage would be found in the snail?

2

Place the following in the most likely order for biosynthesis o a bacteriophage. 1. phage lysozyme 2. mRNA 3. DNA 4. viral proteins 5. DNA polymerase

2, 5, 3, 4, 1

1.9 + 2 flagella 2. 70S ribosome 3.fimbria 4.nucleus 5.peptidoglycan 6. plasma membrane Which is (are) found in all three domains?

2, 6

Place the following in the order in which they are found in a host cell 1. capsid proteins 2. infective phage particles 3. phage nucleic acid

3, 1, 2

1.9 + 2 flagella 2. 70S ribosome 3.fimbria 4.nucleus 5.peptidoglycan 6. plasma membrane Which is (are) found only in prokaryotes?

3,5

How many phyla are represented in the following list of organisms:

4

1.metacercaria 2.redia 3.adult 4.miracidium 5.cercaria Put the above stages in order of development, beginning with the egg:

4, 2, 5, 1, 3

The DNA probe, 3'GGCTTA, will hybridize with DNA containing

5'CCGAAT

You have a small gene that you want replicated by PCR. You add radioactively labeled nucleotides to PCR thermalcycler. After three replication cycles, what percentage of the DNA single-strands are radioactively labeled?

87.5

Suppose you inoculated three flasks of minimal salts broth with E. coli. Flask A contains glucose. Flask B contains glucose and lactose. Flask C contains lactose. After a few hours of incubation, you test the flasks for the presence of β-galactosidase. Which flask(s) do you predict will have this enzyme?

A & B

Two daughter cells are most likely to inherit which one of the following from the parent cell?

A change in a nucleotide in DNA

Which of the following would be the first step in the biosynthesis of a virus with reverse transcriptase?

A complementary strand of DNA must be synthesized from an RNA template

Which of the following does not initiate DNA synthesis?

A single-stranded RNA virus (Togaviridae)

Which of the following statements is true? The primary goal of a pathogen is to kill the host. Evolution selects for the most virulent pathogens. A successful pathogen doesn't kill its host before it is transmitted. A successful pathogen never kills its host.

A successful pathogen doesn't kill its host before it is transmitted.

Which of the following is used to classify organisms into the Kingdom of Fungi?

Absorptive; possess cell wall; eukaryotic

Pathogenic bacteria can be

All of the above

The ability of a virus to infect an organism is regulated by

All of the above

Into which group would you place a multicellular organism that has a mouth and lives inside the human liver?

Animalla

The definitive host for Plasmodium vivax is

Anopheles

These are nonmotile parasites with special organelles for penetrating host tissue.

Apicomplexa

Plasmids differ from transposons because plasmids

Are self-replicated outside the chromosome

Antibiotics that inhibit translation have side effects

At the 70S ribosomes in eukaryotic cells

Which of the following terms is the most specific?

Bacillus

Which of the following is not a method of horizontal gene transfer?

Binary fission

Which of the following is not a portal of entry for pathogens?

Blood

What is the LD50 for the bacterial toxin in the example below?

C 25ug/kg 3 animals died 3 animals survived

Explain what it means to be a carrier of infectious disease, and describe four ways humans can be carriers. What is epidemiologically and medically important about carriers in a population?

Can pass on an infection to somebody else A symptomatic, chronic, passive, convulsive, incubation are they contagious and can they cause an epidemic

The mechanism by which the presence of glucose inhibits the lac operon is

Catabolite repression

Cell membrane damage causes death because

Cell contents leak out

A Maryland woman was hospitalized with dehydration; Vibio cholerae and Plesiomonas shigelloides were isolated form the patient. She had neither traveled outside the U.S. nor eaten raw shellfish during the preceding month. She had attended a party two days before her hospitalization. Two other people at the party had acute diarrheal illness and elevated levels of serum antibodies against Vibrio. Everyone at the party ate crabs and rice pudding in coconut milk. Crabs left over from this party were served at a second party. One of the 20 people at the second party had onset of mild diarrhea. Specimens from 14 of these people were negative for virbiocidal antibodies. The source of the disease was

Crabs

Fleas are the intermediate host for Dipylidium caninum tapeworm and dogs are the definitive host. Which stage of the parasite could be found in the flea?

Cysticerus larva

Translate the DNA code below to the correct chain of amino acids (protein). Make mention of each step of the process with an explanation of what is going on (brief explanation of each step). DNA code = T A C T T A C C G A G A T T C T T G T T T A T C mRNA code =

DNA code = T A C T T A C C G A G A T T C T T G T T T A T C mRNA code = The mRNA code is A U G A A U G G C U C U A A G A A C A A A U A G because mRNA has uracil instead of thymine for complementary base pairing! AT (at the) GC (golf course) AU (arizona university) During transcription, the enzyme RNA polymerase synthesizes a strand of RNA from one strand of double stranded DNA which serves as a template; translation begins at AUG; the region of DNA that is the end point of transcription is the terminator. Translation, or protein synthesis, is the process that used for decoding the language of nucleic acids and converting the information into the language of proteins. The process of transcription: 1. RNA polymerase binds to the promoter, and DNA unwinds at the beginning of a gene. 2.RNA is synthesized by complementary base pairing of free nucleotides with the nucleotides bases on the template strand of DNA. 3. The site of synthesis moves along DNA; DNA that has been transcribed rewinds. 4. Transcription reaches the terminator. 5. RNA and RNA polymerase are released and the DNA helix re-forms. The process of translation: 1. Components needed to begin translation come together. Needed components include: two ribosomal subunits, a tRNA with the anticodon UAC, and the mRNA molecule to be translated along with additional protein factors. 2. The first tRNA binds to the start codon, bringing with it the amino acid methionine. 3. When the tRNA that recognizes the second codon moves into position on the ribosome, the first amino acid is transferred by the ribosome. 4. After the ribosome joins the two amino acids with a peptide bond, the first tRNA molecule leaves the ribosome. 5. The ribosome the moves along the mRNA to the next codon. 6. As the proper amino acids are brought into line one by one, peptide bonds are formed between them, and a polypeptide chain results. 7. Translation ends when one of the three nonsense codons in the mRNA is reached. 8. When the ribosome arrives at the terminator codon, it comes apart in two subunits, and the mRNA and newly synthesized polypeptide chain are released. *Process goal: to produce proteins using mRNA as the source of information. DNA -----------------> mRNA ----------------> protein (transcription) (translation)

These photosynthetic organisms can cause paralytic shellfish poisoning.

Dinoflagellates

Which of the following statements is not true?

E. coli never causes disease.

Propose an explanation as to how the kingdoms Bacteria and Archaea could have collectively given rise to eukaryotes. Why would microbiologists believe the archaea are more closely related to eukaryotes than bacteria?

Eukaryotic genomes are a mixture of genes from distinct origins. Some are very similar to bacterial genes because they indeed have a bacterial origin. They were transferred to Eukaryotes from the bacterium that was engulfed by an early Eukaryote and eventually became the mitochondria (organelle responsible for energy production inside cells) [7]. But after comparing the similarity in conserved genes among the Bacteria, Archaea and Eukarya, studies found that they were more similar between Eukarya and subgroups of Archaea (TACK). This supports the archaeal-host hypothesis [6], in which important genes in the nucleus came from the host that gave rise to the Eukaryotic lineage.

Name two parasites that are transmitted in the cyst form. How must a non-cyst-forming pathogenic protozoan be transmitted? Why?

Giardia Lamblia Non-cyst forming is sexually transmitted

If you Gram-stained the bacteria that live in the human intestine, you would expect to find mostly

Gram-negative rods

Bergey's Manual of Systematic Bacteriology differs from Bergey's Manual of Determinative Bacteriology in that the former

Groups bacteria according to phylogenetic relationships

A viral species is not defined on the basis of the disease symptoms it causes. The best example of this is

Hepatitis

Ciprofloxacin, erythromycin, and acyclovir are used to treat microbial infections. Ciprofloxacin inhibits DNA gyrase. Erythromycin binds in front of the A site on the 50S subunit of a ribosome. Acyclovir is a guanine analog. What steps in protein synthesis are inhibited by each drug? Which drug is more effective against bacteria? Why? Which drug is more effective against viruses? Why? Which drugs will have effects on the host's cells? Why? Use the index to identify the disease for which acyclovir is used. Why is it more effective than erythromycin for treating this disease?

In order for the information stored within DNA to make the proteins to control the activity of our cells, a process called protein synthesis occurs. Normal protein synthesis involves two major steps, Transcription and Translation. In the first step of Transcription, genetic information in the DNA is copied (transcribed) into a complementary base sequence of RNA. In the next step, Translation, the information is then used by the cell to make specific proteins based on the transcribed instructions. Ciprofloxacin, erythromycin, and acyclovir are used to treat microbial infections. Antimicrobial drugs are either bactericidal, meaning they kill bacteria directly or bacteriostatic, which simply prevent microbes from growing. (Case et. al, 2007). Each drug has its own effect on protein synthesis and therefore, will have varying levels of success as treatments. Ciprofloxacin is a type of Quinolones, with a derivative known as Fluoroquinolone antibiotics. This drug works to inhibit protein synthesis by actually inhibiting the enzymes necessary for carrying out the process of DNA synthesis and replication. DNA gyrase is one of the major enzymes that gets targeted by this category of drug, causing it to be unable to perform its normal role in DNA synthesis. Erythromycin is also used to treat microbial infections by inhibiting protein synthesis on prokaryotic ribosomes. This belongs to a category of drugs known as Macrolides, and is used as an alternative to penicillin. Macrolides are a group of antibiotics that have a macrocyclic lactone ring. Erythromycin interferes with the process by attaching to 50s subunit and "blocking the tunnel" of protein synthesis. It is not, however, capable of penetrating cell walls of most gram-negative bacilli. (Case et. al, 2007). Since there is a difference between prokaryotic and eukaryotic ribosomes, erythromycin is capable of killing the microbe without harming the person taking the drug. Acyclovir is a type of Antiviral Drug known as Nucloeside and Nucleotide Analogs, and is used primarily against herpesviruses. Its mode of action in inhibiting protein synthesis is that is inhibits the synthesis of DNA or RNA synthesis. Acyclovir has no effect on a cell not infected by a virus, but in a virally-infected cell, the thymidine kinase is altered and coverts the acyclovir into a false nucleotide, which then causes a blockage of the process of DNA synthesis via DNA polymerase (Case et. al, 2007). When it comes to effectiveness against bacteria, Erythromycin would prove to work best. This is because Erythromycin is capable of inhibiting the protein synthesis process on prokaryotic ribosomes. By reacting with the 50S portion of the 70S prokaryotic ribosome, it inhibits the formation of peptide bonds in the polypeptide chain. While most drugs that are inhibitory to protein synthesis have a broad spectrum of activity, Erythromycin does mot penetrate the cell wall of gram-negative cells, so it will strongly affect gram-positive bacteria (Case et. al, 2007). The drug that will be most effective against viruses would be Acyclovir. Acyclovir is actually classified as an Antiviral Drug, and inhibits DNA or RNA synthesis. Acyclovir structurally resembles deoxyguanosine, a nucleoside. "An enzyme called thymidine kinase then combines phosphates with nucleosides to form nucleotides, which are then incorporated into DNA" (Case et. al, 2007). When a cell is infected with a virus, the thymidine kinase enzyme is altered and coverts the Acyclovir into a false nucleotide, which then causes DNA synthesis to be blocked by DNA polymerase. As a result of its structure and function, Acyclovir is especially effective in the treatment of viruses. Although all of these drugs knowingly come with risks and side effects, none of them should have any abnormally toxic effect on the host's cells. According to the textbook, "Acyclovir has no effect on a cell not infected by a virus" (Case et. al, 2007). This is because it will not alter the thymidine kinase enzyme or be converted into a false nucleotide. When it comes to Ciprofloxacin, DNA gyrase is one of the major enzymes that gets targeted by this category of drug, which causes it to be unable to perform its normal role in DNA synthesis. However, unlike those of microbes, our human cells possess a different enzyme instead of DNA gyrase, so it does not have the same toxic effect on us as it does on the bacteria. Erythromycin only acts on prokaryotic ribosomes. Since humans possess eukaryotic cells, this won't have the same process in a host cell. As identified in the index found in the textbook, Acyclovir is classified as an Antiviral Drug, as a Nucleoside and Nucleotide Analog, which inhibits DNA or RNA synthesis and is primarily used against herpesviruses (Case et. al, 2007). Acyclovir is more effective against herpesviruses than erythromycin because herpes is a virus. Erythromycin works best against bacterias, so would not be capable of disrupting protein synthesis in viruses such as herpesviruses. A major part of the healthcare field involves the pharmaceutical business and prescription synthetic drugs. Countless antibacterial, antifungal, antiviral, etc. drugs have been developed and are continuing to make new advancements as modern medicine grows everyday. In working as a nurse, having a strong understanding and background in how these drugs work against specific microbes will be a major part of my job. As we learned in previous lessons, prescribing an antifungal drug, for example, against a bacterial infection, can actually have very negative effects on a patient. This is why it is so important to get to know the drugs that I may be prescribing to patients. Additionally, it will be vital to patient safety to communicate if they are currently taking other prescription drugs of any kind before prescribing anything else to them, as mixing can sometimes cause harmful effects and even counteract one another. It is also important to note that while some drugs are extremely effective against microbes, they can also have very harmful side effects depending on their mode of action. It will be my job to review the side effects and possible negative outcomes when selecting an appropriate drug based on their particular needs.

What types of information do epidemiologists require to differentiate between the incidence and prevalence of infectious diseases?

Incidence is the rate of new (or newly diagnosed) cases of the disease. Prevalence is the actual number of cases alive, with the disease either during a period of time (period prevalence) or at a particular date in time (point prevalence)

The most selective antimicrobial activity would be exhibited by a drug that

Inhibits cell wall synthesis

When Legionella was newly discovered, it was classified with the pseudomonads because

It is an aerobic gram-negative rod

Which of the following does not belong with the others?

Lactobacillales

An example of lysogeny in animals could be

Latent viral infections

These are obligate intracellular parasites that lack mitochondria.

Microspora

Bacillus and Lactobacillus are not in the same order. This indicates that which one of the following is not sufficient to assign an order to a taxon?

Morphological characteristics

Which of the following is not true about scientific nomenclature?

Names vary with geographical location.

Which of the following will not affect eukaryotic cells?

None of the above

A girl developed generalized seizures. A CT scan revealed a single brain lesion consistent with a tumor. Biopsy of the lesion showed a cysticercus. The patient lived in South Carolina and had never traveled outside the state. What parasite caused her disease? How is this disease transmitted? How might it be prevented?

Parasites use humans as a host and are categorized as either Platyhelminthes (also known as flatworms) or Nematoda (commonly called roundworms) and are generally called Helminths. Parasites that invade a human host can be responsible for a number of diseases and be caused by varying factors. In the above example, a girl developed generalized seizures and after obtaining a CAT scan, the results revealed a single brain lesion consistent with a tumor. After a biopsy, the lesion showed a cysticercus. According to the Centers for Disease Control and Prevention, cysticercus is an infection caused by larvae of a specific parasite known as Taenia solium. The parasite gets into the human host via a person swallowing the eggs of the tapeworm and the larvae get into the tissues and muscles and form cysts (known as cysticerci). According to our textbook, humans are the only known host for Taenia solium. The disease is commonly transmitted in Latin America, Asia, and Africa by a human-pig cycle, when adult tapeworms already living within a human body (intestine) produce eggs, which the human passes via feces. Pigs then eat the eggs and humans again become infected when they consume the pigs in circumstances where the pork has been undercooked. In the above example, however, the patient is living within the United States, in South Carolina, and has never even travelled outside of her home state. In this case, and with most cases in the U.S., transmission is more human-to-human and virtually nonexistent in pigs. Instead, this patient likely contracted Taenia solium by consuming eggs that came from another person before the larvae find their way into the human body and cause cysticercocis, cysts in the tissue or muscle. Humans serve as intermediate hosts for Taenia solium. According to the textbook, "Approximately 7% of the few hundred cases in recent years were acquired by people who had never been outside of the United States" (Case et. al, 2007). The explanation for why this patient could have been infected was via household contact (i.e. someone not washing their hands well enough) with another individual who had travelled outside of the U.S. or had been born in a country where they were exposed to it. Unlike many other countries where the primary cause of this specific tapeworm is a human-to-pig cycle, cases in the United States are primarily spread via household human contact, which spreads the eggs of the tapeworm. The Center for Disease and Control and Prevention lists a number of preventative measures for the spread ofTaenia solium. It may seem simple, but ensuring that you are washing your hands thoroughly with the proper technique using warm water and soap after handling food, using the restroom or having any contact with feces is very important. Additionally, washing fruits and vegetables before consuming them. For those that do travel outside of the United States to countries that are at higher-risk for Taenia solium such as Latin America, Asia, and Africa, it is important to be aware of good food and water safety. For example, only drinking bottled water in areas that the water has potential for contamination and paying attention to how your food is being prepared. Clearly, once parasites find a human host, they can cause severe health issues. Sometimes, you don't even have to go out of the country or leave the state to be exposed, and it could be passed to you by simple household contact. This is why it is very important to seek medical attention at any sign of irregularity in your body. Luckily, there are often treatments available. Taenia solium, for example, can be treated by anti-parasitic drugs and/or anti-inflammatory drugs. As in the above case, where the patient was experiencing seizures, sometimes treatment instead focuses on reducing specific symptoms caused by the parasite. Working in a career as a nurse, parasites and how they interact with their human hosts will be an important part of my work. Although sometimes rare and unusual, it will be important to look beyond the symptoms and perform CAT scans and other procedures to dig deeper and understand what may be the real cause. In the case above, for example, the patient was experiencing seizures, which can be caused by many different factors. However, looking further and getting to the root of what was causing the seizures revealed the diagnosis. It is also an important lesson because it shows how someone who hasn't even traveled outside of the country, let alone her home state, was exposed to something that may have originated in someone in a country thousands of miles away. This proves that asking simple questions of a patient like "Have you travelled outside of the U.S.?" are not always reason enough to eliminate certain diseases or parasites. As a future nurse, having the ability to ask questions and keep all possibilities on the table until eliminating a cause will be imperative to proper diagnosis, treatment, and prevention in my patients.

You could identify an unknown bacterium by all of the following except

Percentage of guanine + cytosine

Restriction enzymes were first discovered with the observation that

Phage DNA is destroyed is a host cell

Spirillum is not classified as a spirochete because spirochetes

Possess axial filaments

Cyanobacteria differ from purple and green phototrophic bacteria because cyanobacteria

Produce oxygen during photosynthesis

Into which group would you place a photosynthetic organism that lacks a nucleus and has a thin peptidoglycan wall surrounded by an outer membrane?

Proteobacteria (gram-negative bacteria)

The following steps are sued to make cDNA. Which is the second step?

RNA processing to remove introns

Which of the following is an intracellular parasite?

Rickettsia

Which of the following pairs is mismatched?

Spirochete- Helicobacter

Which one of the following does not belong with the others?

Staphylococcus

Cancer patients undergoing chemotherapy are normally more susceptible to infections. However, a patient receiving an antitumor drug that inhibited cell division was resistant to Salmonella. Provide a possible mechanism for the resistance.

The antitumor drug was a genetically altered form of salmonella • Targets cancerous cells and prevents replication by binary fission • Salmonella bacteria multiply through cell division which drug inhibits - therefore no salmonella contraction. Chemo basically trashes your immune system by suppressing it. That means your immune system cannot or is very slow to respond to infection. Chemotherapy works by loading the cancer cells with toxic chemicals that fry them. Drugs that block cell division work by stopping the splitting and replication of the tumour's DNA. Incidentally this is how bacteria such as salmonella multiply. Thus the blocking medication in theory can block it as well. • The antitumor drug was a genetically altered form of salmonella • Targets cancerous cells and prevents replication by binary fission • Salmonella bacteria multiply through cell division which drug inhibits - therefore no salmonella contraction

Why can one not reliably predict the sequence of nucleotides on mRNA or DNA by observing the amino acid sequence of proteins? Provide an example demonstrating how the same protein could be synthesized by different mRNA strands.

The coding system from DNA to amino acids is redundant, meaning that some amino acids can have multiple codons (sets of 3 nucleotides) that code for them. You could get a decent idea of what it might look like, but definitely not 100%. For example if you have the amino acid serine, it could be coded for by a UCA, UCC, UCU, or UCG. Notice that they differ only in the last nucleotide. This is most likely so minor mutations in the DNA won't have that drastic of an effect on the proteins. If you have a UCA, and the A gets changed into a G, it will still code for serine. This is a silent mutation because it doesn't affect the production of the protein, which is a good thing for us.

Which of the following is not one Koch's postulates?

The disease must be transmitted from a diseased animal to a healthy, susceptible animal by some form of contact.

HIV attacks only specific types of human cells, such as certain white blood cells and nerve cells. Explain why a virus can enter some types of human cells but not others.

The first step in viral infections is adsorption which depends upon specific membrane receptors that the virus attaches to. If a cell does not have the specific receptors for a virus, it cannot attach and then penetrate the cell.

Place each phylum listed in Table 11.1, shown above in the lesson, in the appropriate category. Typical Gram-positive cell wall Typical Gram-negative cell wall No peptidoglycan in cell wall No cell wall

The phyla that belong in the category; a. Typical gram-positive cell wall, are: Firmicutes (exception of mycoplasma, see no cell wall) Actinobacteria Euryarchaeota b. The phyla listed that belong in the category; Typical gram-negative cell wall, are: Alphaproteobacteria Betaproteobacteria Gammaproteobacteria Deltaproteobacteria Epsilonproteobacteria Cyanobacteria Chlorobi Chloroflexi Spirochaetes Nonproteobacteria Bacteroidetes Fusobacteria Crenarchaeota c. The phyla listed that belong in the category; No peptidoglycan in cell wall, are: Domain Archaea, Crenarchaeota Chlamydiae d. The phyla listed that belong in the category; No cell wall, are: Mycoplasma

The wall less mycoplasmas are considered to be related to gram-positive bacteria. Which of the following would provide the most compelling evidence of this?

They share common rRNA sequences.

A Maryland woman was hospitalized with dehydration; Vibio cholerae and Plesiomonas shigelloides were isolated form the patient. She had neither traveled outside the U.S. nor eaten raw shellfish during the preceding month. She had attended a party two days before her hospitalization. Two other people at the party had acute diarrheal illness and elevated levels of serum antibodies against Vibrio. Everyone at the party ate crabs and rice pudding in coconut milk. Crabs left over from this party were served at a second party. One of the 20 people at the second party had onset of mild diarrhea. Specimens from 14 of these people were negative for virbiocidal antibodies. The description above is an example of

Vehicle transmission

A Maryland woman was hospitalized with dehydration; Vibio cholerae and Plesiomonas shigelloides were isolated form the patient. She had neither traveled outside the U.S. nor eaten raw shellfish during the preceding month. She had attended a party two days before her hospitalization. Two other people at the party had acute diarrheal illness and elevated levels of serum antibodies against Vibrio. Everyone at the party ate crabs and rice pudding in coconut milk. Crabs left over from this party were served at a second party. One of the 20 people at the second party had onset of mild diarrhea. Specimens from 14 of these people were negative for virbiocidal antibodies. The etiologic agent of the disease is

Vibrio cholerae

Which of the following statements is not true?

Viruses multiply inside living cells using viral mRNA, tRNA, and ribosomes

Discuss the arguments for and against the classification of viruses as living organisms.

When discussing arguments in support of and against classifying viruses as living organisms, the scientific community still has an ambiguous answer. Depending on who you ask, it can be considered a highly complex nonliving thing or as an extremely basic living microbes. The uniqueness of viruses, and perhaps the reason for so much debate, is that they can only survive and thrive within a living host. Viruses were first discovered because they were extremely small and therefore filterable. Since this is also a characteristic of bacteria, it is important to look further into what makes viruses even more distinctive. By looking at how viruses multiply and their various structural components, we can begin to understand the arguments for how they should be classified. By looking at the characteristics of living things, we can help make arguments for either side. The scientific community has come up with a list of things in order to more easily classify things as living or non-living, depending on whether or not they possess characteristics of movement, respiration, sensitivity, growth, reproduction, excretion, and nutrition. As far as viruses go, it can be argued that they do possess a single type of nucleic acid, which is either DNA or RNA. They also have a protein coat, which can also be enclosed by an envelope of lipids, proteins, and carbohydrates surrounding the nucleic acid (Case et. al, 2007). Viruses could also be considered living because they possess sensitivity. In other words, they will react to what is going on within the environment inside of the host cell. However, again, since they can't survive without the host, if the host dies, the virus will die along with it. As far as arguing against the classification of viruses as living organisms, there is also evidence for support. For example, viruses do not have enzymes of their own to maintain a metabolism, but instead rely on the host cell's metabolic system. As a result, they cannot independently perform protein synthesis or generate ATP as a source of energy. (Case et. al, 2007). So, in order to multiply, viruses must be inside of the living host using its "borrowed" machinery. This does not meet the criteria of growth or reproduction because it technically could not accomplish this on its own. This is why a virus will not be sustained and will be killed if it is not living within a living host. Since arguments can be made to both sides in regards to whether viruses are considered living or non-living, it truly does depend on who you ask and can even come down to how you wish to interpret the criteria for living things. For example, while you can argue that they can multiply/reproduce/grow, all characteristics of a living thing, on the other hand it could be argued that if you took away their host, this would no longer be possible. This uniqueness and these "exceptions" is why viruses have continuously been a challenge to understand, study, and definitively classify as concretely living or non-living. As humans, and more importantly, as scientists, we like to be able to explain things in black or white, in a definitive way, because that is what allows us to confidently study and make advances. However, the characteristics of viruses as living or non-living organisms may never be truly black or white, and we'll be forced to continue to learn more about the grey areas. Viruses, and how they interact with their host, will likely be a common issue that comes up with patients in working as a future nurse. Viruses can show up in patients in very common ways, such as the cold and flu viruses, which often just go away on their own with lots of rest and the drinking of fluids. Or, they can appear in much more alarming and serious ways, such as HIV, perhaps one of the deadliest types of viruses. While drugs have been developed to allow for a longer and more quality of life in patients that are diagnosed, it still continues to devastate, especially in regions of the globe where treatment is not always readily available or affordable. As a nurse, it will be important to conduct the proper tests, most commonly Serological tests, in order to properly identify a virus. Viruses can take on many different forms and new types are still being discovered and treated, so continued education will be a major part of my job. Throughout history, viral outbreaks have become epidemics and have devastated populations. Since this is always a risk to public health, with new potential for outbreaks always possible, I will always need to be prepared for the unexpected. Regardless of the answer to the often ambiguous question about whether or not viruses are to be considered living or nonliving, it will be my job to think on my feet and be able to quickly identify and advise patient treatment for the specific type of virus, no matter how common or rare it may be.

Describe the two main types of asexual fungal spores and how they are formed. Name several types of conidia.

Yeast and mold.Molds reproduce by producing small spores, which can be either sexual (reproducing using meiosis) or asexual (reproducing using mitosis). Most yeasts reproduce asexually. The most common process is known as "budding," when a small bud forms on the parent cell. The parent nucleus splits in two and the daughter nucleus moves into the bud cell, which continues to grow until it splits from the parent cell. Blastoconidia- bud of yeast cells Arthroconidia- formed from hyphal cells with fragmentation at the septal wall Aleurioconidia- develops as an expansion at the end of a hyphal branch Phialoconidia- arises from a vase shaped cell called a phialide.

Describe the mode of action of each of the following antibiotics and explain what effect each one may have on host cells. Give an example of an organism that would be effectively treated for each drug. Penicillin Indinavir Erythromycin polymyxin B

a. Penicillin inhibits synthesis of cell wall 1. Effects bacterial cells - not the host -animals and human cells - no cell wall 2. Staphylococcus aureus b. Indinavir inhibits HIV protease 1. Host cell - antiviral - protects host cells 2. Treats HIV c. Erythromycin binds to 70S ribosome inhibiting protein synthesis 1. Host cell - can kill gram negative host cells minimally 2. Treats Treponema pallidum d. polymyxin B causes membrane leakage, - cationic detergent 1. No effect on host cells 2. Treats Salmonella enterica

Bacteria can acquire antibiotic resistance by

all of the above

Which of the following events follows cell fusion in an ascomycete?

ancospore formation

Why would it be an advantage to synthesize eukaryotic genes by using reverse transcriptases to make cDNA?

cDNA is often used to clone eukaryotic genes in prokaryotes. When scientists want to express a specific protein in a cell that does not normally express that protein (i.e., heterologous expression), they will transfer the cDNA that codes for the protein to the recipient cell. cDNA is also produced naturally by retroviruses (such as HIV-1, HIV-2, simian immunodeficiency virus, etc.) and then integrated into the host's genome, where it creates a provirus.

A population of cells carrying a desired plasmid.

clone

A 40-year-old male who was seropositive for HIV experienced abdominal pain, fatigue, and low-grade fever (38 °C) for 2 weeks. A chest X-ray examination revealed lung infiltrates. Gram and acid-fast stains were negative. A viral culture revealed the cause of his symptoms: a large, enveloped polyhedral virus with double-stranded DNA. What is the disease? Which virus caused it? Why was the viral culture done after the Gram and acid-fast stain results were obtained?

disease: CMV virus: Cytomegalovirus Gram/ aid fast stains negative - not bacterial. since stains negative- virus suspected (cannot see viruses with light microscope)- viral culture to determine which virus

The mechanism by which lactose controls the lac operon is

induction

Describe the use of a DNA probe and PCR for: a. Rapid identification of an unknown bacterium. b. Determining which of a group of bacterium are most closely related.

labeled DNA probe might be bind to sequence of unknown probe therefore idetifying it • DNA Probe - give us library of known bacteria to compare unknown bacteria to on plate • PCR - allows for replication and isolation of one strand of DNA to match to DNA probe -you grab different wells of the known bacterium and add the unknown bacterium DNA and wait to see where it completely binds Describe the use of a DNA probe for rapid identification of an unknown bacterium: A labeled DNA probe may bind to sequences from an unknown, thereby identifying it. Describe the use of PCR for rapid identification of an unknown bacterium: PCR can be used to amplify unique sequences, thereby confirming an organism's identity. Describe the use of a DNA probe for determining which of a group of bacteria are most closely related: The degree of binding of a probe can be used to establish relatedness Describe the use of PCR for determining which of a group of bacteria are most closely related: the number of shared PCR targets can be used to establish relatedness

Pieces of human DNA stored in yeast cells.

library

Which of the following is the fourth basic step of genetic engineering?

ligation

What characteristics of plasmids and bacteriophages make them good cloning vectors? What characteristics of bacteria make them good cloning hosts? What is one way to determine whether a bacterial culture has received a recombinant plasmid?

must be capable of carrying a significant piece of dDNA and must be readily accepted by cloning host. protocols using E. Coli are well adapted, easy and reliable (rapid growth, grow in large numbers, nonpathogenic, well mapped genome). Purify it. Using columns. This works when you are identifying a plasmid that has been recombined with genes that will make it apparent (ie P-GLO), otherwise you will need some experience and a good lab.

The G-C content of Micrococcus is 66-75 moles %, and of Staphylococcus, 30-40 moles %. According to this information, would you conclude that these two genera are closely related? Explain your answer.

not closely related -related but not closely; belong to the same branch int he domain bacteria -66-75 mole % is high G +C gram positive bacteria & 30-40 mole% is low G+C gram-positive bacteria -the difference would come from the ratio of guanine and cytocine each one has. pers: knowing the pathogen infecting patient is an important part of treatment;allows for more effective treatments Based on the G-C content of the two genera presented I would conclude that they are not closely related. Staphylococcus, with a G-C content of 30-40 moles %, belongs to the phylum Firmicutes , or low G+C Gram Posi±ve bacteria. Micrococcus, with a G-C content of 66-75 moles %, belongs to the phylum AcTnobacteria , or high G+C Gram Posi±ve bacteria. Both of these genera are gram posi±ve bacteria and the diFerence comes in with the ra±o of Guanine and Cytosine that each of them have. Gram posi±ve bacteria are classi²ed into phyla by the ra±o of Guanine and Cytosine in their nucleic acids. The fact that they are both gram posi±ve and belong on the same branch in the domain Bacteria, as a result of the G=C ra±os, leads me to conclude that they are related, just not closely related. In health care, iden±fying the pathogen that is infec±ng a pa±ent is an important part of effective treatment. An±bio±cs that work for one strain of bacteria may not work for another. Knowing that diFerent strains of bacteria are closely related will allow for the selec±on of more eFec±ve treatment methods. Conversely, trea±ng all bacteria in the same way will only lead to more resistant bacteria, more frequent infec±ons, and illnesses that are diffcult to cure.

An encapsulated bacterium can be virulent because the capsule

resists phagocytosis.

Feedback inhibition differs from repression because feedback inhibition

stops the action of preexisting enzymes

A virus with RNA-dependent RNA polymerase

synthesizes double-stranded RNA from an RNA template

If you put a gene in a virus, the next step in genetic engineering would be

transduction

The transfer of DNA from a donor to a recipient cell by a bacteriophage is

transduction

The transfer of DNA from a donor to a recipient as naked DNA is solution is

transformaion

Self-replicating DNA for transmitting a gene from one organism to another.

vector

The molecule serving as mRNA can be incorporated in the newly synthesized virus capsids of all of the following except

− strand RNA rhabdoviruses