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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: 24449

#Unit 13. Methods in Biology

A 10-year-old boy was diagnosed with childhood absence epilepsy. His EEG showed a bilateral synchronous, symmetrical 3-Hz spike-and-wave discharge. Absence seizures
TLS Online TPP Program

#Question id: 33477

#Unit 2. Cellular Organization

Finding: Ancestry have similar organizations with conservation of the positions (of at least some) of the introns.

Example: The globin and DHFR genes are examples of a genes that share a common ancestor
TLS Online TPP Program

#Question id: 7103

#Unit 5. Developmental Biology

Patterning of the Xenopus mesoderm along the dorso-ventral axis involves an antagonistic relationship between chordin and BMP-4. Is there an analogy here to dorso-ventral patterning in the Drosophila embryo?
TLS Online TPP Program

#Question id: 11964

#Unit 7. System Physiology – Animal

 Animals cannot produce enzymes to digest cellulose, yet many termite species consume cellulose from plant material as a main part of their diet. How do termites access the nutrients contained in cellulose?
TLS Online TPP Program

#Question id: 28251

#Unit 5. Developmental Biology

the arrangement of axoneme in sperm propulsion system consist of___