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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: 27069

#Unit 1. Molecules and their Interaction Relevant to Biology

Choose the correct option regarding the stereochemistry of given compound 
TLS Online TPP Program

#Question id: 27068

#Unit 1. Molecules and their Interaction Relevant to Biology

Isoleucine and Threonine have two chiral carbons so exists in multiple RS configuration, choose the correct option regarding the given fig.
1. a is D-threonine is (2S, 3S) threonine
2. b is L-threonine is (2R,3S) threonine
3. a is L-threonine is (2S, 3R) threonine
4. b is D-threonine is (2R,3S) threonine
TLS Online TPP Program

#Question id: 27067

#Unit 1. Molecules and their Interaction Relevant to Biology

Choose the correct statement regarding the stereochemistry of amino acid
1. 16 amino acid except (Thr, Ile, Cys, Gly) L Fischer projection is equal to S and D is equal to R configuration 
2. Thr, Ile is special case because of two chiral center exist in L – Ile/Thr – 2S,3R and D-Ile/Thr–2R,3S configuration  
3. Cys exiest in L- Cys – R & D- Cys – S configuration 
4. Gly is optically inactive 
TLS Online TPP Program

#Question id: 744

#Unit 1. Molecules and their Interaction Relevant to Biology

In a DNA molecule, deoxyribonucleotides are joined into a polymer by the covalent linkage of a phosphate group. The covalent link termed as:
TLS Online TPP Program

#Question id: 745

#Unit 1. Molecules and their Interaction Relevant to Biology

The structure of RNA differs from that of DNA, as RNA contains:
TLS Online TPP Program

#Question id: 746

#Unit 1. Molecules and their Interaction Relevant to Biology

Two separate chains of DNA are wound around each other, each following a helical (coiling) path, resulting in: