Three Different Proteins, A, B, and C, from a Plant

question 237

Multiple Choice

Three different proteins, A, B, and C, from a plant were studied.In each case, a glycine residue was changed to an alanine.Changes in the biological activities of the mutated proteins were then measured, and the results are shown in the table below. Which statement about structure-function relationships in proteins is supported by the data?

• A) Each unique amino acid sequence results in a protein with a unique function.
• B) A protein's function changes only when changes in primary structure alter its tertiary structure.
• C) Substitution of a nonpolar amino acid for another nonpolar amino acid is sufficient to allow a protein to retain its biological activity.
• D) Amino acids located at the beginning of a polypeptide chain have less importance in determining biological function than amino acids in the middle or far end of the chain.
• E) Every amino acid substitution in a protein's primary structure leads to a change in the protein's function.

Understand the concept of molecular dipole moments and their determination in molecules.

Identify and explain the types of intermolecular forces present in various compounds.

Understand solubility principles, especially the concept of "like dissolves like".

Recognize and explain the presence and implications of hydrogen bonding in compounds.

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Definitions:

Bile

A digestive fluid produced by the liver and stored in the gallbladder, which helps in the digestion of fats.

Peristalsis

A series of wave-like muscle contractions that move food through the digestive tract.

Muscular Contractions

The process of muscle fibers shortening and lengthening to produce movement or maintain posture.

Incisors

The front teeth in mammals, typically characterized by their sharp edges for cutting food.