What are the levels of protein structure and what role do functional groups play?

The levels of protein structures are: PRIMARY, SECONDARY AND TERTIARY STRUCTURES.
The amino acid sequence and the bonding types between the amino acids determine the structures of proteins. Protein structures also determines the function of a protein, if a protein losses its structure it will not be able to perform its function again.
Functional groups play an important role in the formation of protein structure.Functional groups also participates in specific biochemical reactions in the body thus enabling the proteins to perform their functions. 

Twins are born minutes apart, not a year apart. fraternal twins are no more closely related genetically than ordinary siblings born a year apart. they just happen to be born at the same time. identical twins result from a single fertilized egg dividing and separating early in gestation. although identical twins are more similar to each other than other siblings, there is some research to suggest they are not 100% the same. you and your brother share very similar dna because you have the same parents, and you look the same. i'll bet you resemble one or both of your parents, and likely a grandparent or two as well.