Which of the following statement(s) is/are true?

1)    Proteins have glycosidic bonds.

2)    A major difference between synthetic polymers and biopolymers is their structure, the latter fold into secondary structure, tertiary structure etc. This has an impact on it’s function as well.

3)    Protein compounds are nitrogenous compounds which may contain phosphorus and sulphur .

4)    Hormone insulin is a sterol.

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