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TLS Online TPP Program

#Question id: 3963

To stimulate transcription, enhancer sequences:

#Unit 3. Fundamental Processes

  1. must be within a few base pairs of the gene they enhance.

  2. must be within a few hundred base pairs of the gene they enhance.

  3. can be tens of thousands of base pairs away from the genes they enhance.

  4. will not function if they are moved experimentally.

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TLS Online TPP Program

#Question id: 15843

#Unit 8. Inheritance Biology

You have isolated two temperature-sensitive mutations in phage l that you suspect may be in the same gene. These phage mutants are called ts-1 and ts-2. Each mutant will form plaques at 35˚C but not at 42˚C. You cross ts-1 to ts-2 phage by coinfecting E. coli at the permissive temperature of 35˚C. When the resulting phage lysate is plated at 35˚C you count 10,000 plaques per ml of phage lysate, but when the same phage lysate is plated at 42˚C, there are only 80 plaques per ml.           What is the distance between the ts-1 and ts-2 mutations in m.u.?
TLS Online TPP Program

#Question id: 4322

#Unit 3. Fundamental Processes

If a particular operon encodes enzymes for making an essential amino acid and is regulated like the trp operon, then
TLS Online TPP Program

#Question id: 18918

#Unit 13. Methods in Biology

Recognition Sequences for Some Type II Restriction Endonucleases 

Match them correctly
TLS Online TPP Program

#Question id: 2589

#Unit 2. Cellular Organization

Following statements are regarding to the mechanism of thick filament regulation.

A. In vertebrate smooth muscle, phosphorylation of the myosin regulatory light chain (LC) activates contraction.

B. At Ca2+ concentrations of more than 10−6 M, the regulatory light chain is not phosphorylated, and the myosin adopts a folded conformation.

C. When the Ca2+ level rises, Ca2+ binds calmodulin (CaM), which undergoes a conformational change (CaM*). The CaM*-Ca2+ complex binds and activates myosin light chain kinase (MLC kinase), which then phosphorylates the myosin LC. This phosphorylation event unfolds the myosin II, which is now active and can assemble into bipolar filaments to participate in contraction.

D. When the Ca2+ levels drop, the myosin LC is dephosphorylated by myosin light-chain (MLC) phosphatase, which is dependent on Ca2+ for activity, causing muscle relaxation.

Which of the following combination is correct?
TLS Online TPP Program

#Question id: 1954

#Unit 4. Cell Communication and Cell Signaling

What is the single best description of type 1 diabetes?