TLS Online TPP Program

#Question id: 4703


Within a few weeks of treatment with the drug 3TC, a patientʹs HIV population consists entirely of 3TC-resistant viruses. How can this result best be explained?

#Unit 11. Evolution and Behavior
  1. HIV can change its surface proteins and resist vaccines.

  2. The patient must have become reinfected with 3TC-resistant viruses.

  3. HIV began making drug-resistant versions of reverse transcriptase in response to the drug.

  4. A few drug-resistant viruses were present at the start of treatment, and natural selection increased their frequency.

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TLS Online TPP Program

#Question id: 15779

#Unit 5. Developmental Biology

During stem cell regulation extracellular mechanisms leading to intracellular changes that regulate stem cell behaviour. Which of the following is not consider as extracellular mechanisms for stem cell regulation?

TLS Online TPP Program

#Question id: 15780

#Unit 5. Developmental Biology

In drosophila, the somatic cells of the hub are able to regulate stem cell proliferation by secreting the paracrine factor Unpaired onto the cells attached to them. Unpaired activates the JAK-STAT pathway in the adjacent germ stem cells to specify their self-renewal. Those cells that are distant from the paracrine factor cannot receive this signal, they begin their differentiation into the sperm cell lineage. This means hub cells act as

TLS Online TPP Program

#Question id: 15781

#Unit 5. Developmental Biology

Chemical regulation of stem cells takes the form of secreted proteins from surrounding cells that influence stem cell states and progenitor differentiation through endocrine, paracrine, or juxtacrine mechanisms. These signaling factors:

TLS Online TPP Program

#Question id: 15782

#Unit 5. Developmental Biology

Adult cells may be reprogrammed to gain pluripotency by modifying the genes namely 

TLS Online TPP Program

#Question id: 15783

#Unit 5. Developmental Biology

During the formation of induced pluripotent stem cell, what is the function of Klf-4?

TLS Online TPP Program

#Question id: 15784

#Unit 5. Developmental Biology

During the formation of induced pluripotent stem cell, what is the function of C-myc?