Moderate

In an amino acid, in which the R group is hydrogen, the amino acid will be:

Correct answer: B. Glycine

  • A. Alanine
  • B. Glycine
  • C. Leucine
  • D. Valine

Explanation

The correct answer is Glycine. Glycine is the simplest amino acid because its R group is a single hydrogen atom. This makes it unique among the standard amino acids. Alanine, Leucine, and Valine all have more complex side chains with different chemical structures and properties. Alanine's side chain is a methyl group, while Leucine and Valine have branched aliphatic side chains, classifying them as branched-chain amino acids (BCAAs). Glycine, being the simplest, is essential for forming protein structures that require minimal steric hindrance.

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The chapter covers water's polarity and biological roles, carbohydrates, lipids, proteins and nucleic acids, including their monomers, bonds, structures and functions. It also distinguishes RNA from DNA and explains conjugated molecules such as glycoproteins, glycolipids and nucleoproteins, which combine organic molecules with a non-protein component.

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