Microbe Mission B/C

[Nano1llus10n]

1. What are HIV's primary and secondary receptors needed for entry?
2. Which glycoprotein on HIV's surface binds to the primary receptor?
3. Which SIV from which animal host is most closely related to HIV-1? (be specific)
4. Where is HIV-2 largely confined to due to its poor capacity for transmission?
5. What rare genetic mutation (mostly found in Eurasian descent) causes the individual to be resistant to HIV?

[The48thYoshi]

This might be a little too specific
Scenario: A 28 year old man returning from a visit to the Middle East is complaining of abdominal pain, loss of appetite, fever, and intestinal blockage. Further testing reveals a palpable mass near the right Iliac fossa. It was suspected that the man had acute appendicitis and as a result, was opened up for an appendectomy. Following the incision, an unusual view lay before the doctors. A resection exam was then performed, revealing epithelioid granulomas along with necrosis as well as langerhans giant cells. The surgeons involved were immediately put into quarantine, along with the patient himself.
1. What disease did the man have?
2. What is the agent that causes the disease (domain and specific scientific name)
3. What medications should be prescribed?
4. What are some common side effects of these medications?
5. What are risk factors for this disease?
6. What risk factors are present in this specific case?
7. What signs and symptoms present helped the doctors diagnose the disease?

Maybe? (Click to Show Hidden Text)

1. Tuberculosis
2. Bacteria; Mycobacterium tuberculosis
3. tetracycline
4. dizziness, vomiting, diarrhea, sore throat
5. traveling to endemic areas
6. traveling to Middle East
7. not appendicitis but still has a palpable mass near the right iliac fossa, epitheliod granulomas w/ necrosis & Langerhans giant cells.

All correct

[fabishkf]

Here's a question since this hasn't been posted on lately:

A drop of immersion oil has been placed between the objective lens and cover slip in a compound light microscope. Given the index of refraction of the immersion oil is 1.515, the wavelength of light being used is blue (0.45um) and the resolution of the microscope is .2um, find the one-half angular aperture of the microscope.

[Alex-RCHS]

Here's a question since this hasn't been posted on lately:

A drop of immersion oil has been placed between the objective lens and cover slip in a compound light microscope. Given the index of refraction of the immersion oil is 1.515, the wavelength of light being used is blue (0.45um) and the resolution of the microscope is .2um, find the one-half angular aperture of the microscope.

this? (Click to Show Hidden Text)

2.745
it seems far too large though... maybe i should divide it in half? i'm using this equation: δ = 1.22 x wavelength / (N.A. objective + N.A. condenser)

[fabishkf]

Answer (Click to Show Hidden Text)

Not quite. How I understand it, the half numerical aperture is an angle measurement, so the max value would be 90 (180 would be the max for the angular aperture, and would occur when the cover slip is touching the objective lens). So, it'll be larger than 2.745. To solve this problem, you would first solve for the numerical aperture with the resolution equation (resolution = wavelength / 2*NA) then use that to solve for one-half angular aperture in the numerical aperture equation. So the NA is 1.125, and the one-half angular aperture is 47.95 degrees. You can also use the resolution equation resolution = 1.22*wavelength / numerical aperture, which I think is what you were using (except in this problem I was talking about the NA of the entire microscope, didn't factor in that both the condenser and the objective would have a numerical aperture; probably should've specified that). I think the formula varies based on the microscope, but I'm not sure.

[Alex-RCHS]

Answer (Click to Show Hidden Text)

Not quite. How I understand it, the half numerical aperture is an angle measurement, so the max value would be 90 (180 would be the max for the angular aperture, and would occur when the cover slip is touching the objective lens). So, it'll be larger than 2.745. To solve this problem, you would first solve for the numerical aperture with the resolution equation (resolution = wavelength / 2*NA) then use that to solve for one-half angular aperture in the numerical aperture equation. So the NA is 1.125, and the one-half angular aperture is 47.95 degrees. You can also use the resolution equation resolution = 1.22*wavelength / numerical aperture, which I think is what you were using (except in this problem I was talking about the NA of the entire microscope, didn't factor in that both the condenser and the objective would have a numerical aperture; probably should've specified that). I think the formula varies based on the microscope, but I'm not sure.

Okay, I’m pretty sure that’s called the half-angle, not the half-angle aperture. I solved for the combined numerical apertura of the condenser and the objective, which is obviously not right.

I had never heard of that equation you listed. I’ll put it in my notes — thanks. Is the NA in that equation of the whole microscope or just the objective?

[fabishkf]

It is of the whole microscope. Apologies if I used the incorrect term.

[ScandinavianBeaver]

Might as well post another question...

The following proteins are encoded by the HIV virus genome(regulatory proteins not included):
1. Reverse transcriptase
2. Integrase
3. HIV Protease
4. Spacer protein
5. Capsid protein
6. Matrix protein
7. gp120

a. What proteins are used for HIV replication?
b. What is the function of HIV protease and what happens if the protein is inhibited?
c. What protein binds to CD4 on cells, and how does this allow the virus to penetrate?

[Nano1llus10n]

Might as well post another question...

The following proteins are encoded by the HIV virus genome(regulatory proteins not included):
1. Reverse transcriptase
2. Integrase
3. HIV Protease
4. Spacer protein
5. Capsid protein
6. Matrix protein
7. gp120

a. What proteins are used for HIV replication?
b. What is the function of HIV protease and what happens if the protein is inhibited?
c. What protein binds to CD4 on cells, and how does this allow the virus to penetrate?

Answer (Click to Show Hidden Text)

1. Reverse transcriptase, Integrase, HIV Protease, Spacer protein 
2. It cleaves the large nonstructural protein precursor; inhibition prevents replication of virions 
3. gp120; it allows adhesion to the host cell and eventually the fusion of membranes