In teaching my course over the years, I have often been asked by students the relative importance of different topics for the MCAT. Although an opinion in terms of the explicit distribution of questions can be fairly straightforward, my answers would tend to go into somewhat greater depth because there is often more to the answer than simply 'what will be on the test'. With regard to the topics of fundamental mechanics, while the basic concepts and classic model problems do directly appear with good frequency on the MCAT, the concepts appear, even more so, indirectly as underpinnings of almost everything else in science.
With regard to Newton's Laws, for the MCAT itself, there is the fundamental core you need to come to know intuitively. You need to habitually associate net force with acceleration, for example, or be able to unpack the inclined plane or distinguish kinetic and static friction. But don't leave it at that. Take time and step back. In learning mechanics you are building a foundation for understanding all science.
Earlier in Kinematics, we described motion in terms of displacement, velocity, and acceleration. Now in Newton's Laws, we describe the changes that occur to the motion of material bodies in terms of force and mass. Force is the cause of acceleration.