Sucrose is replace by another sugar in tobacco callus medium without effecting callus growth. This sugar is an osmotic agent and is not taken into the plant cells or metabolized because of its molecular size.

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#Question id: 158

#Section 2: General Biology

At the isoelectric pH of a tetrapeptide:

TLS Online TPP Program

#Question id: 159

#Section 2: General Biology

The chirality of an amino acid results from the fact that its alpha carbon:

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#Question id: 161

#Section 2: General Biology

Two amino acids of the standard 20 contain sulfur atoms.  They are:

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#Question id: 162

#Section 2: General Biology

All of the amino acids that are found in proteins, except for proline, contain a(n):

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#Question id: 164

#Section 2: General Biology

The uncommon amino acid selenocysteine has an R group with the structure —CH2—SeH (pKa = 5).  In an aqueous solution, pH = 7.0, selenocysteine would:

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#Question id: 165

#Section 2: General Biology

Amino acids are ampholytes because they can function as either a(n):