**Core Concept**
The structure of proteins is crucial for their function. Amino acids can contribute to the folding and stability of a protein by introducing bends, kinks, or turns in the primary structure of the protein, specifically in the alpha helix. These bends can be caused by the steric hindrance of certain amino acid side chains.

**Why the Correct Answer is Right**
The amino acid responsible for inducing bends in a helix is Proline (Pro). Proline has a unique side chain that forms a ring structure, which causes a steric hindrance that disrupts the hydrogen bonding pattern of the alpha helix. This leads to a kink or bend in the helix, making proline a key contributor to protein structure and function. The presence of proline can also affect the stability and flexibility of the protein.

**Why Each Wrong Option is Incorrect**
**Option A:** Glycine (Gly) is the smallest amino acid and can fit into tight spaces, but it does not typically cause bends in a helix.
**Option B:** Serine (Ser) and other polar amino acids can form hydrogen bonds with other parts of the protein, but they do not typically cause bends in a helix.
**Option C:** Aspartic acid (Asp) and other acidic amino acids can form ionic interactions with other positively charged residues, but they do not typically cause bends in a helix.

**Clinical Pearl / High-Yield Fact**
Proline is often referred to as a "helix breaker" due to its ability to disrupt the hydrogen bonding pattern of the alpha helix. This knowledge is essential for understanding protein structure and function, and is relevant to many areas of medicine, including protein misfolding diseases.

**Correct Answer:** Proline.