On the left is a lymph node taken from a person during an active immune response. MZ = mantle zone; LZ = light zone and DZ = dark zone. This left image tissue is stained with H and E. The right image is from an adjacent tissue section stained by an anti-CD21 antibody. CD21 can be located on follicular dendritic cells or B cells. What type of T cell is most likely to be prominent in the same region as the region that stains with the anti-CD21 antibody?

Pathogenic Streptococcus pneumoniae possess a polysaccharide capsule that prevents phagocytosis, allowing them to evade the immune system and multiple, causing pneumonia. S. pneumoniae that lack the capsule do not cause disease as they are readily destroyed by host phagocytes. When a mixture of living nonencapsulated and heat-killed encapsulated S. pneumoniae are injected into a mouse, the mouse dies, and living capsulated bacteria can subsequently be isolated from the mouse. Which of the following best explains this result?

If you could extract and quantify all the mRNA in a single cell, this would essentially be a measure of:

When sequencing DNA using the Sanger (dideoxy) sequencing method, we rely on all of the following EXCEPT ______.

You conduct an Ames test on a chemical you suspect might be a carcinogen. Following incubation, you find some colonies on your control plate. Why do you see some colonies on your control plate?

Following from the previous two questions about Anabaena, would you find mRNA that is different between these two cell types, photosynthetic and nitrogen fixing heterocyst? If so, what would it represent?

If you could extract and quantify all the mRNA in a single cell, this would essentially be a measure of:

Pathogenic Streptococcus pneumoniae possess a polysaccharide capsule that prevents phagocytosis, allowing them to evade the immune system and multiple, causing pneumonia. S. pneumoniae that lack the capsule do not cause disease as they are readily destroyed by host phagocytes. When a mixture of living nonencapsulated and heat-killed encapsulated S. pneumoniae are injected into a mouse, the mouse dies, and living capsulated bacteria can subsequently be isolated from the mouse. Which of the following best explains this result?

Janthinobacterium lividum is a Gram negative bacterium that produces a dark violet compound called violacein that possess antiviral, antibacterial, and antifungal properties. You are interested in finding gene(s) responsible for the production of violacein. You transform a culture with a plasmid containing a transposon and an ampicillin resistance gene (bla). Realizing your transformation efficiency will be low, how might you identify bacteria that have been successfully transformed?

When sequencing DNA using the Sanger (dideoxy) sequencing method, we rely on all of the following EXCEPT ______.