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TLS Online TPP Program
#Question id: 24541
#Unit 9. Diversity of Life Forms
Phylogenetic trees represent hypothesis about the evolutionary relationships among a group of organisms, these relationship based on which character?
TLS Online TPP Program
#Question id: 5608
#Unit 5. Developmental Biology
Stereoblastulae -
TLS Online TPP Program
#Question id: 33375
#Unit 1. Molecules and their Interaction Relevant to Biology
How many hydrogen bonds will be present in 20 amino acid alpha helix
TLS Online TPP Program
#Question id: 11208
#Unit 7. System Physiology – Animal
Neurotransmitters are released from axon terminals via ________.
TLS Online TPP Program
#Question id: 15619
#Unit 13. Methods in Biology
Wild type E. coli metabolizes the sugar lactose by expressing the enzyme ß-galactosidase. You have isolated a mutant that you call lac1–, which cannot synthesize ß-galactosidase and cannot grow on lactose (Lac–). During an condition isolate a mutation that constitutively expresses abnormally high levels of ßgalactosidase, which you designate lacc. Preliminary P1 transduction experiments indicate that lacc is linked to the Tn5 insertion. To map lacc relative to lac1– you set up two reciprocal crosses. In the first cross you grow P1 on a strain that carries the Tn5 insertion and the lac1– mutation. You then use this lysate to infect a lacc mutant and select for Kanr. From 100 Kanr transductants examined, 20 are Lac–, 76 express ß-galactosidase constitutively and 4 show normal ß-galactosidase expression. In the second cross you grow P1 on a strain that carries the Tn5 insertion and the lacc mutation. You then use this lysate to infect a lac1– mutant, and select for Kanr. From 100 Kanr transductants examined, 81 are Lac– and 19 express ß-galactosidase constitutively. So what will be the correct order of the Tn5 insertion and the lac1– and lacc mutations. Express any measured distances as cotransduction frequencies.