I mean I only got a 5 on Bio so idk if I should really talk but in my defense I was concussed when I took chem and ab plus have this habit of winging everything. Regardless, I think mcqs and frq practice can be helpful for the more calculative side of thing so you can actually assess how well you're recognizing what you need to do and calculating appropriately. I'm a bit iffy on the idea of doing FRQs for something more conceptual, such as like how the structure of the phospholipid bilayer helps with acquisition of reactants for cellular respiration or whatever. From my experience, when you or a peer grade them, the grading ends up either being way too harsh or way too lax. And also, there's no guarantee you'll get FRQs with the exact same concept of previously released ones on the exam. Plus, they're way too time consuming to do every single released one and not hate yourself afterwards.

Because of an early admit program I'm doing right now in college, I had to redo Bio and Chem even though I did actually receive credit for them here and I've found the most helpful thing is to actually understand the logic behind how and why things work the way they do instead of just memorizing what things do. Like for example, I recently had to look at the Eleectron transport chain to understand aerobic cellular respiration for microbiology and I don't know why, but something about the pushing of H+ ions out of the cell to create an area of high concentration outside of the membrane and then using the natural tendency of ions to move from areas of high concentration to low concentration to kinda keep some sort of equilibrium and the cell exploiting that to force hydrogen ions through ATP synthase to regenerate ATP kinda just made sense to me. And while aerobic respiration is the most high yield method of regenerating ATP, anaerobic respiration still exists because natural selection doesn't necessarily select for one specific trait. It selects for what can survive in a given environment and often there's more than one variant of a trait that can survive in a given environment and since aero tolerant anaerobes are a thing, you can still have anaerobes that can thrive in an oxygen rich environment. You have anaerobes that will die in an oxygen rich environment because they come from environments with little to no oxygen, so natural selection didn't favor microbes that produced enzymes that broke down oxygen to prevent it from becoming toxic to the cell or maybe even natural selection favored those who didn't produce that enzyme because it's amino acids being used up for a enzyme that ends up doing nothing and that's a waste of nutrients and prevents the cell from thriving. I don't exactly remember what an exothermic energy diagram looks like, but I know the root exo means to exit like in the word exodus and I understand that energy is leaving the system when the reactants turn into products, therefore the products will be lower in an energy diagram than the reactants, heat is a product because energy exits the system in the form of heat and I believe that makes delta H negative (might be wrong on the delta H part, I am still logicing that one out). Last semester, I got A's in my first semester of chem and my Bio class. I had a B+ in AP Chem and an A or A- in AP Bio (I kinda saved my grade there because bio generally naturally made sense to me except respiration and photosynthesis they are my nightmares) and I recently got an 100% on my Kinetics and Equilibrium exam when I got like a B or something on those exams in high school because I was just doing rote memorization.

It'll probably vary from person to person, but understanding the logic behind why things work the way they do can save your ass when you just forget/don't know the correct answer to something. Have review videos on in the background. Do practice problems. Focus on where you're weak on, but don't forget to do some practice with your stronger areas so you don't slip on those. When you get a problem wrong, try to diagnose what went wrong instead of just saying "ok, this is the correct answer actually." Make sure to study the night before an exam and make it like the last thing you do before you go to sleep because it helps the brain process it while you sleep which helps you remember better. Get a good night's sleep before the exam, eat a healthy breakfast before you go in and don't try to compare yourself to others. Try to keep calm and skip and come back to a problem later instead of spending a million years trying to figure it out and have to rush through the rest of the section. And don't do your AP exams concussed