The answer is May be. An investment bank may or may not provide retail banking services like checking accounts, credit cards etc. Their area of expertise is investment services, mutual funds, underwriting services etc.
An Investment is a financial institution that helps individuals, corporations etc. in raising capital by underwriting and/or acting as the clients agent in issuance of securities (Shares, bonds...
A retail bank is the building on the corner where you cash your checks, make deposits, go to the atm, etc.
An investment bank works exclusively on an institutional level with other banks, investment...
It varies from country to country. Every country has a central bank that is the bank for other banks in the country. Ex: Federal reserve system - USA Reserve Bank - India etc