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TLS Online TPP Program

#Question id: 13018

Generalized global air circulation and precipitation patterns are caused by

#Unit 10. Ecological Principles
  1. Rising, warm, moist air masses cool and release precipitation as they rise and then at high altitude, cool and sink back to the surface as dry air masses after moving north or south of the tropics.
  2. Air masses that are dried and heated over continental areas that rise, cool aloft, and descend over oceanic areas followed by a return flow of moist air from ocean to land delivering high amounts of precipitation to coastal areas.
  3. Polar, cool, moist high pressure air masses from the poles that move along the surface, releasing precipitation along the way to the equator where they are heated and dried.
  4. The revolution of the Earth around the sun.
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TLS Online TPP Program

#Question id: 174

#Unit 1. Molecules and their Interaction Relevant to Biology

What is the net charge on the dipeptide Arg-Pro at pH 9.0? The table below gives the pKaʹs of the ionizable groups on the free amino acids.
TLS Online TPP Program

#Question id: 175

#Unit 1. Molecules and their Interaction Relevant to Biology

The ionic charges associated with a protein molecule are ________.
TLS Online TPP Program

#Question id: 176

#Unit 1. Molecules and their Interaction Relevant to Biology

A peptide has the sequence Glu–His–Trp–Ser–Gly–Leu–Arg–Pro–Gly. What is the net charge of the molecule at pH 3
TLS Online TPP Program

#Question id: 177

#Unit 1. Molecules and their Interaction Relevant to Biology

The titration curve of alanine shows the ionization of two functional groups with pKa values of 2.34 and 9.69, corresponding to the ionization of the carboxyl and the protonated amino groups, respectively. The titration of di-, tri-, and larger oligopeptides of alanine also shows the ionization of only two functional groups, although the experimental pKa values are different. The trend in pKa values is summarized in the table. Which of the following is a reason for this shift in pK values
TLS Online TPP Program

#Question id: 178

#Unit 1. Molecules and their Interaction Relevant to Biology

Given the pKa values of different acidic sites in cysteine, the principal ionic form which will never exist at any pH
TLS Online TPP Program

#Question id: 179

#Unit 1. Molecules and their Interaction Relevant to Biology

The average molecular weight of the 20 standard amino acids is 138, but biochemists use 110 when estimating the number of amino acids in a protein of known molecular weight.  Why?