i haven't read the other responses so i apologize if any of this is repetitive
🙂
i was a single parent during my undergrad years, and this is what i did...
-always had flashcards in my pocket and notes for an upcoming test with me. if i had free time i would use them, whether that was for an hour or two before my next class or ten minutes during a coffee break.
-survived off of minimal sleep

i would pick up my daughter from daycare around 5PM and make sure that from then until her bedtime i was JUST dedicated to her. we would play, have dinner together, snuggle on the couch and watch a movie...you name it! she went to sleep at 730/8 and then i hit the books. sometimes i'd have to make several pots of coffee to stay awake during particularly exhausting days, like if i had two tests the next day or during my final exam weeks. designating that time for her, though, and forcing myself to step away from academics really helped me stay focused.
-if there are days where you just have TOO MUCH to do, take advantage of modern technology and pop in a movie! i would sometimes study while "watching" a movie with my daughter (this was mostly during final exam weeks). sometimes my workload was so crazy that that's just what i had to do.
-utilize the weekends! i tried to set aside a few hours each saturday and sunday day just for studying. as a single parent, this meant hiring a sitter or having one of my friends play with my daughter for a little while. she always had a blast and i got a lot done!
-make sure you have a productive place to study. sometimes i just couldn't concentrate at home, so i went to the library. that always helped me stay focused.
-what is your most "awake" time? morning? night? use it to your advantage. mine is lunch time and night time - i would often get a lot of work done during lunch hours so i could have a little free time during my "groggy" periods (ie, 3PM). then when night rolled around, i was ready again.
-audio lectures for commutes! i have Vango Notes for Anatomy and Physiology and Vango Notes for Biology...they are awesome! they are actually audio text books; i listen to those at work all the time when im doing an experiment. you could also listen when youre making dinner, cleaning, etc.
-do you have an iphone? ipad? ipod?

Apple has some cool MCAT apps!
ill try to think of some more
🙂