How do social and cultural constructs impact privilege and power? What elements of social structure (e.g. norms, values, and social institutions) play a part in the construction of race?

After having read “Racial Formations” by Omi and Winant and viewing Race – The Power of an Illusion, Episode 1, explain the assertion that race is a social construct.
How do social and cultural constructs impact privilege and power?
What elements of social structure (e.g. norms, values, and social institutions) play a part in the construction of race?