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Biology 1001A Chapter Notes - Chapter 23.3A: Chromosome, Lysogenic Cycle, Veterinary Virology

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spectral
9 Nov 2016
School
Western University
Department
Biology
Course
Biology 1001A
Professor
Tom Haffie

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Document Summary

Virulent bacteriophages kill their host cells during each cycle of infection. Temperate bacteriophages enter an inactive phase inside the host cell and can be passed on for generations of daughter cells before they become active and kill the host. These proteins infect the dna genome into the cell. Lytic pathway: the phage attaches to a host cell, the phage injects dna into the host cell. Sometimes, during bacteriophage replication, a mistake is made, and a fragment of the host dna gets packaged into a viral capsid. The resulting phage would be able to infect another cell, but it would not have any viral genes, so it would not be able to replicate. The cell infected by this phage would survive, and would have an extra piece of bacterial dna present, which could undergo recombination with the host chromosome, and perhaps cause a gene conversion event.

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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 ~80°C (175°F). It has adapted so that its enzymes are most functional at the elevated temperatures, compared with many organisms’ enzymes that function best ~37°C (98°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 “Central Dogma” 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 prokaryotes’ ability to “fix” 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 athlete’s foot, use ergosterol to maintain healthy membranes. Animal cells do not make ergosterol, they use a similar lipid – cholesterol.
9. During retrovirus infection, a DNA copy is made of the virus’s RNA genome. A cut is made in the host cell’s 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 (“70S” ribosomes) than eukaryotic cells (“80S” 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 cell’s 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 they’re 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:
• What types of infections can be treated with the following drugs?
o Penicillin
o Clotrimazole
o Azithromycin
o Tamiflu
o Raltegravir
• Why are these drugs (above) safe for you to take? That is, why don’t they kill your cells?
• 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?

QuestionGroup: #51 Innate immune 1

Assigned as

Homework

51

What is the name of a chemical substance responsible for stimulating an immune response?

A

Pathogen

B

Rotomers

C

Antigen

D

Antibody

E

Troll receptor

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QuestionGroup: #52 Innate immune2

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52

What is the purpose of secondary metabolites produced by normal flora in your body?

A

To aid T cells in fighting local infection

B

To kill infected B cells

C

To help balance electrolytes

D

To inhibit adhesion, and growth of the certain microbes

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QuestionGroup: #53 Innate immune3

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53

The lysozyme removes most bacteria in our foods through the saliva in our mouth, how does it do this?

A

The lysozyme attacks the bacteria through the blood.

B

The lysozyme are not strong enough to get rid of bacteria.

C

The lysozyme breaks down the polysaccharide walls of different bacteria.

D

The lysozyme will tell your body to get rid of the bacteria by vomiting.

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QuestionGroup: #54 Adapt immune 1

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54

In adaptive immunology, the key component is which of the following?

A

Antigen trigger the the production of vaccines.

B

Antibodies will trigger responses in the antigen which will cause an inflamation.

C

Antigens trigger responses of the antibodies which will recognize the antigen.

D

Antibodies will be able to recognize other antibodies and destroy them.

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QuestionGroup: #55 Adapt immune2

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55

An autoimmune induced disorder is...?

A

When the body's immune system attacks a tissue or organ in the body

B

When the immune system is not present

C

When the body attacks the antigens and antibodies of the immune system

D

When the autonomic nervous system attacks the antigen and antibodies of the immune system

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QuestionGroup: #56 Adapt immune3

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56

Antibodies are also called immunoglobulins and constitute part of the blood proteins. How do antibodies work?

A

Agglutination-- they just clump with each other (blocking antigen)

B

Precipitation-- force insolubility and settled out of solution along with antigens

C

Complement fixation-- proteins attach to antigen surface (causing cell lysis)

D

Neutralization-- bind to specific sites to prevent antigen attachment

E

All of the above

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QuestionGroup: #57 Infectious disease

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57

The most deadly STD is HIV, but many other viruses can be deadly. Name the most common sexually transmitted infection.

A

Genital human parisis virus (GHPV)

B

Herpes Simplex

C

Human papilloma virus (HPV)

D

Human pappathe virus tentis (HPVT)

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QuestionGroup: #58 Infectious disease2

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58

Microbes have developed an array of weapons to be able to go from host to host. These virulent factors are divided into several groups, but one important group is the one produced by bacteria. Name the subgroups within this bacterial group.

A

Retretoxin and maitotoxin

B

Retretoxin and butotoxin

C

Endotoxins and exotoxins

D

Lipotoxin and exotoxin

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QuestionGroup: #59 Infectious disease3

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59

Sexually transmitted diseases are very successful at spreading from one person to another. Name one important reason for this fact.

A

Mucous membranes use B cells only and are resistant to antigens

B

Mucous membranes in the sex organs differ from those of the skin in that they allow certain pathogens into the body

C

STDs are transmitted through sex only

D

STDs are usually caused by viruses

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QuestionGroup: #60 HIV/ AIDS

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60

HIV has which of the following characteristics?

A

It has an enzyme called reverse transcriptase which causes the DNA to reverse the nucleotide sequence in messenger RNA.

B

It is a retrovirus meaning that it reverses the order of protein production in that the virus affects the DNA in the cell to make the protein.

C

It is an anti-retrovirus meaning that it attacks the DNA causing the development of new HIV particles.

D

It has a short incubation period which means that the symptoms show up also immediately after infection.