NEM 10V Lecture Notes - Lecture 22: Microorganism, Antigen, Edward Jenner

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6 May 2018

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Nematology

Part 1 Viruses:

• Viruses infect organisms in all three domains and exist everywhere

-non-cellular infectious agents-rely on a host for replication

-consist of a protein coat containing a DNA or RNA core

-1. virus attaches to the host cell

-2.virus injects its DNA or RNA into host

-3. viral genes instruct the host cell to make copies of the virus

-4.viral particles are assembled

-5.new virus particles build up in the host cell until the host cell ruptures.

• As they emerge, some viruses retain parts of the host cell membrane forming an envelope

around the virus. This envelope gives some protection to the virus from the immune

system of the host organism.

-capable of infecting more host cell/repeating the process of virus replication.

• Life cycle of a virus works scientists have been able to develop antiviral drugs that target

specific points in the virus life cycle and prevent the virus from replicating.

• Smallpox virus-spread through the air and attacks skin cells, bone marrow, spleen, and

lymph nodes of its victims

-Symptoms:fever, vomiting, rash, and scabs followed by scars

-1350 BC Egyptian prisoners spread smallpox to the Hittites devastating that civilization.

Smallpox made its way around the world via Egyptian merchants, then through the Arab

world with the Crusades, and all the way to the Americas with the Spanish and

Portuguese conquests.

-1022 A.D. China-Buddhist nun developed variolation-technique in which ground up

small pox scabs were blown into the nostrils of healthy people

-1796, Edward Jenner, father of immunology, used cowpox-v. similar to smallpox but

less virulent in humans-develop vaccine. It was not widely accepted until 1840. After

large vaccination campaigns throughout the 19th and 20th centuries the World Health

Organization declared smallpox’s eradicated in 1979.

• Polio-viral disease causes paralysis. To survive, victims are placed inside a breathing

machine called an iron lung.

-Franklin Delano Roosevelt (FDR) got polio in 1921 and was completely paralyzed from

the legs down. He started The March of Dimes to raise funds for rehabilitation and for

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Part 1 viruses: viruses infect organisms in all three domains and exist everywhere. Non-cellular infectious agents-rely on a host for replication. Consist of a protein coat containing a dna or rna core. 2. virus injects its dna or rna into host. 3. viral genes instruct the host cell to make copies of the virus. 5. new virus particles build up in the host cell until the host cell ruptures: as they emerge, some viruses retain parts of the host cell membrane forming an envelope around the virus. This envelope gives some protection to the virus from the immune system of the host organism. Symptoms:fever, vomiting, rash, and scabs followed by scars. 1350 bc egyptian prisoners spread smallpox to the hittites devastating that civilization. Smallpox made its way around the world via egyptian merchants, then through the arab world with the crusades, and all the way to the americas with the spanish and.

Related Questions

Class 6: Viruses (and Cells, continued)

Making connections: viruses and microbes Match the cell biology concept (on page 1) with an important application of that concept (on page 2). Then answer the follow-up questions at the bottom of page 2.

Cell Biology concepts
1. Bacteria that cannot construct new cell wall material become fragile and break down.
2. During influenza infection, the viral enzyme neuraminidase is required to release new viruses from the host cell in which they were made. Once released, the new viruses can infect many additional cells.
3. Thermus aquaticus is a bacterium found in hot springs and can live at temperatures up to ~80Â°C (175Â°F). It has adapted so that its enzymes are most functional at the elevated temperatures, compared with many organismsâ enzymes that function best ~37Â°C (98Â°F).
4. Until the isolation and investigation of retroviruses, scientists thought that RNA could be copied from DNA, but DNA could not be copied from RNA. Research on this class of viruses led to an update to this âCentral Dogmaâ of biology.
5. Some bacteria have adapted, so that the enzymes involved in making cell wall materials have a slightly different shape and can no longer be bound by certain drugs.
6. Rhizobia are bacteria that colonize the roots of certain plants (legumes, including beans and peas). The host plant benefits from the prokaryotesâ ability to âfixâ nitrogen, converting N2 from the atmosphere into a form that is usable by the plant.
7. Many species of bacteria contain the enzyme cellulase. More than 10 billion such bacteria and other symbiotic microbes may be found in a single milliliter of material from inside the digestive system of ruminant mammals.
8. Fungi, including those that cause athleteâs foot, use ergosterol to maintain healthy membranes. Animal cells do not make ergosterol, they use a similar lipid â cholesterol.
9. During retrovirus infection, a DNA copy is made of the virusâs RNA genome. A cut is made in the host cellâs DNA and the DNA copy of the viral genome is pasted into the host chromosome by a viral enzyme called integrase.
10. Prokaryotic cells contain smaller ribosomes (â70Sâ ribosomes) than eukaryotic cells (â80Sâ ribosomes). Both types of ribosomes synthesize proteins, but the macromolecules they use to do it are somewhat different.

2
Applications
_______ Oseltamivir, also called Tamiflu, binds and inhibits the viral protein neuraminidase.
_______ Clotrimazole is a drug that is used to treat certain infections. It interferes with synthesis of ergosterol, a lipid involved in phospholipid membranes.
_______ Penicillin is a drug that interferes with synthesis of peptidoglycans (these are biological molecules that are part protein and part carbohydrate) that are present in certain cell walls.
_______ HIV is often treated with several drugs that inhibit different parts of the viral replicative cycle. Raltegravir is an example of a drug that interferes with the integration of viral genes into the host cellâs chromosome.
_______ Cows, like other vertebrates, lack the ability to breakdown cellulose. Yet they are able to live on a diet of grass and other vegetation high in cellulose.
_______ Enzymes isolated from extremophiles have been very useful in laboratory research. For example, Taq polymerase facilitates PCR, a revolutionary technique for production of DNAs of particular sequences, which requires cycling reactions through high temperatures.
_______ Plants and animals require nitrogen to make biological macromolecules, however theyâre unable to convert atmospheric nitrogen (N2) into a biologically useful form.
_______ Azithromycin is a drug that binds to 70S ribosomes and blocks synthesis of any new proteins.
_______ Methicillin-Resistant Staphylococcus aureus (MRSA) can cause life-threatening infections of the skin and bloodstream. One of the reasons MRSA infections are so serious is that they are resistant to treatment by many antibiotics, including methicillin and penicillin.
_______ The enzyme reverse transcriptase, isolated from retroviruses, is an important tool in molecular biology research. Scientists interested in learning what genes are turned on in particular cells use it to make DNA copies of RNAs they are studying (The DNA copies are useful because they are more stable).

When you have completed the matching activity, answer these follow-up questions:
â¢ What types of infections can be treated with the following drugs?
o Penicillin
o Clotrimazole
o Azithromycin
o Tamiflu
o Raltegravir
â¢ Why are these drugs (above) safe for you to take? That is, why donât they kill your cells?
â¢ Cancer cells are your own human cells that have become deregulated so that they divide and pile up in an uncontrolled way. Many chemotherapy drugs treat cancer by interfering with cell division and other cell processes.
o Why are there so many more side effects for individuals undergoing chemotherapy than for individuals taking antibiotics?

NEM 10V Lecture Notes - Lecture 22: Microorganism, Antigen, Edward Jenner

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