[ Biology ] Open Question : Biochemistry homework help?

when protein alpha helixies are formed, how can i tell where a hydrogen bond will from. Example: in a protein's alpha helix, amino acid 7 (N-termius end) forms a hydrogen bond with amino acid.. 1. 3 and 11 2. 4 and 12 3. 5 and 9 4. cis-Proline 5. 8 I already know proline cannot be answer due to its R-group arrangement, but how can i tell from from the others. (please Explain)

Source: http://answers.yahoo.com/question/index?qid=20121206125915AAtHNTI

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