Practice Questions

TLS Online TPP Program

#Question id: 288

Which does not occur during the hydrolysis of RNA by RNase A?

#Unit 1. Molecules and their Interaction Relevant to Biology

Covalent catalysis involving a bond between a pyrimidine and a lysine of RNase A.
Acid-base catalysis to cleave the phosphodiester bond.
Abstraction of a proton from the 2ʹ-hydroxyl group by histidine.
Transition-state stabilization of a pentavalent phosphorous atom.

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TLS Online TPP Program

#Question id: 8896

#Unit 9. Diversity of Life Forms

Chordate pharyngeal slits appear to have functioned first as

TLS Online TPP Program

#Question id: 8897

#Unit 9. Diversity of Life Forms

Which of the following statements would be least acceptable to most zoologists?

TLS Online TPP Program

#Question id: 8898

#Unit 9. Diversity of Life Forms

Which extant chordates are postulated to be most like the earliest chordates in appearance?

TLS Online TPP Program

#Question id: 8899

#Unit 9. Diversity of Life Forms

A new species of aquatic chordate is discovered that closely resembles an ancient form. It has the following characteristics: external armor of bony plates, no paired lateral fins, and a suspension-feeding mode of nutrition. In addition to these, it will probably have which of the following characteristics?

TLS Online TPP Program

#Question id: 8900

#Unit 9. Diversity of Life Forms

Which of the following statements about craniates is (are) correct?

1. Craniates are more highly cephalized than are non-craniates.

2. Craniatesʹ genomic evolution includes duplication of clusters of genes that code for transcription factors.

3. The craniate clade is synonymous with the vertebrate clade.

4. Pharyngeal slits that can assist in gas exchange originated in craniates,

5. The two-chambered heart originated with the early craniates.

TLS Online TPP Program

#Question id: 8901

#Unit 9. Diversity of Life Forms

The origin of the craniates occurred at roughly the same time as the