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#Question id: 2900


Which of the following statement is INCORRECT from the set of statements given below?

#Unit 2. Cellular Organization
  1. Since deamination is a common cause of DNA damage, and since the deamination of cytosine forms a product similar in structure to uracil, repair enzymes cannot repair this damage easily.

  2. In packaging the eukaryotic DNA into nucleosomes, it is thought that the requirement for histone proteins and their synthesis is a cause of the slower rate of movement of the replication fork.

  3. In photoreactivation, DNA damage caused by UV light is reversed by DNA photolyase which forms a complex with thymine dimers which absorbs visible light and reverses the dimerization.

  4. DNA is the only cell macromolecule that can be repaired.

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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 -

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#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

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#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.