Marketing major undergrad vs. grad

Hi everyone! What is the difference between an undergrad marketing program and grad program besides the difference in years of study? Is it easy to find marketing jobs after graduating from a graduate business program or will it be hard since I only study marketing for one to two years? Will the companies think I am not as knowledgeable as people in undergraduate business schools? I am not sure how it works… I am planning to major in a science-related field for undergrad btw