From 46 human chromosomes, is each one from a single parent?
Yes, each single chromosome came from one parent.  However, it is not true that each chromosome came from one grandparent.  Due to crossing over in meiosis, the copy of Chr 1 that you got from your father is partially from his father, and partially from his mother.  And the same for all the rest of your chromosomes.  You will not pass on a whole chromosome as you inherited it onto your children, crossing over will happen in your gametes, so that your kid will get whole chromosomes that are part from your mother, and part from your father.  The sex chromosomes are exceptions, because in men, they can't do crossing over, since men have a mismatched pair.  (At least in biologically "normal" men.)