And that means any type of biological reaction that you're going to come across in your study of biochemistry must obey these laws. So in this lecture, we're going to focus on the first and second law of thermodynamics, because in the study study of biochemistry, these laws essentially dictate the conditions under which a certain biological reaction is favorable and the conditions under which that same reaction is not favorable. So we have to take into consideration these two laws in essentially every biological process that takes place. So let's begin with the first law of thermodynamics. So recall that any region of space that contains the atoms or molecules that we're studying, that is our system. And all the molecules and atoms found outside the system, that is our surroundings.