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TLS Online TPP Program

#Question id: 5002

All animals with eyes or eyespots that have been studied so far share a gene in common. When mutated, the gene Pax-6 causes lack of eyes in fruit flies, tiny eyes in mice, and missing irises (and other eye parts) in humans. The sequence of Pax-6 in humans and mice is identical. There are so few sequence differences with fruit fly Pax-6 that the human/mouse version can cause eye formation in eyeless fruit flies, even though vertebrates and invertebrates last shared a common ancestor more than 500 million years ago.

The appearance of Pax-6 in all animals with eyes can be explained in multiple ways. Based on the information above, which explanation is most likely?

#Unit 11. Evolution and Behavior

  1. Pax-6 in all of these animals is not homologous; it arose independently in many different animal phyla due to intense selective pressure favoring vision.

  2. The Pax-6 gene is really not ʺoneʺ gene. It is many different genes that, over evolutionary time and due to convergence, have come to have a similar nucleotide sequence and function.

  3. The Pax-6 gene was an innovation of an ancestral animal of the early Cambrian. Animals with eyes or eyespots are descendants of this ancestor.

  4. The perfectly designed Pax-6 gene appeared instantaneously in all animals created to have eyes or eyespots.

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TLS Online TPP Program

#Question id: 10551

#Unit 6. System Physiology – Plant

plants possess a second type of immunity mediated by a set of highly specific intracellular receptors known as nucleotide binding site–leucine rich repeat (NBS–LRR) receptors. How NBS–LRRs become activated,
TLS Online TPP Program

#Question id: 12760

#Unit 10. Ecological Principles

Which of the examples below provides appropriate abiotic and biotic factors that might determine the distribution of the species in question?
TLS Online TPP Program

#Question id: 22974

#Unit 7. System Physiology – Animal

In the intestine, 1,25-dihydroxycholecalciferol induces the synthesis of 
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#Question id: 641

#Unit 1. Molecules and their Interaction Relevant to Biology

Which of the following does NOT describe a mechanism that cells use to regulate enzyme activities?

A. Cells control enzyme activity by phosphorylation and dephosphorylation.

B. Cells control enzyme activity by the binding of small molecules.

C. Cells control the rates of diffusion of substrates to enzymes.

D. Cells control the rates of enzyme degradation.

E. Cells control the rates of enzyme synthesis.

F. Cells control the targeting of enzymes to specific organelles. 
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#Question id: 19685

#Unit 13. Methods in Biology

The P-waves of ECG indicates: