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TLS Online TPP Program

#Question id: 1033

 A research lab is trying to produce new antibiotics. They come up with drugs that detach the hydrophilic heads from the phospholipids in plasma membranes. This drug

#Unit 4. Cell Communication and Cell Signaling

  1. would be highly toxic and completely useless for human beings-we also have plasma membranes with hydrophilic head groups!

  2. would be highly toxic only to bacteria, making it an excellent drug to develop and test further. Humans have a different phospholipid structure in their cell plasma membranes than bacteria.

  3. would generally not be toxic enough to damage Gram-negative bacteria, as their plasma membranes lie under a thick layer of peptidoglycan.

  4. would be highly toxic for human beings, but might be useful as a topical antibiotic skin cream. The top layer of skin cells is dead anyway, so it wouldn't matter if this damaged those cells. It could NOT be taken internally, though, by human beings. 

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TLS Online TPP Program

#Question id: 15395

#Unit 5. Developmental Biology

Which of the following promote the synthesis of the Paired box 6 (Pax6) transcription factor in the anterior ectoderm?
TLS Online TPP Program

#Question id: 15405

#Unit 8. Inheritance Biology

You set up a mapping cross involving two genes in Aspergillus and determine the following percentages of tetrad types: parental ditype 51%, nonparental ditype 49%. What can you say about your genes?
TLS Online TPP Program

#Question id: 15406

#Unit 8. Inheritance Biology

Which method of gene transfer involves direct contact between the bacteria?
TLS Online TPP Program

#Question id: 15407

#Unit 8. Inheritance Biology

The end result of F factor mediated conjugation:
TLS Online TPP Program

#Question id: 15408

#Unit 8. Inheritance Biology

Which of the following is not a protein or group of proteins required for conjugation to occur?
TLS Online TPP Program

#Question id: 15409

#Unit 8. Inheritance Biology

 A heterozygous trihybrid corn plant is testcrossed and the following progeny are produced (all traits are recessive to their wildtype alternative);
          booster                              6
          booster, silkless                  137       
          booster, liguleless, silkless      291
          liguleless                          142
          liguleless, silkless                  3
          silkless                            30
          booster, liguleless                  34
          wildtype                            339
What is the order of the loci on the chromosome?