Generally, a resume is much shorter in length compared to a CV, usually limited to one page. It is meant to be a very brief synopsis of your career and education history. Resumes should focus on measurable accomplishments rather than soft skills or listed responsibilities. Like a CV, resumes need to be updated, but those updates should be made form specific job to which you are applying.
GPA. As mentioned above, your GPA is only necessary if you are a recent college graduate and do not have work experience to back you up. There are a few jobs that require a GPA, however, including engineering and finance.