MCAT B/B Strategies: How I Scored 131 In MCAT Bio/Biochem

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Bio/Biochem passages are frustrating for a lot of students...

The passages are very complicated, there are acronyms everywhere, the graphs are confusing, and the list goes on. 

It was difficult for a lot of your mentors here at MCAT Mastery as well, including Aly Dwight. 

You've met Aly in other videos; she's a retaker, 520 scorer, and soon to be MS1!

Aly scored a 131 (99th percentile) in Bio/Biochem and in this video, she shares her top strategies to show you:

→ How to decipher coded messages every B/B passage gives you.

→ Why you don't need to use too much background knowledge to try and answer B/B questions.

→ How to start making connections the MCAT expects of you, to find the right answer.

→ The right way to tackle the graphs in B/B passages.

And much more

Aly is also one of our lead instructors in the Chem/Phys & Bio/Biochem Mastery Course.

Inside, she dissects over 20 AAMC B/B passages, showing you her thought process on how she analyzes the passages, the question stems, the graphs, and the answer choices.

Strategy 1: Use The Passage

  • B/B questions are often passage-based instead of standalone. And this is really empowering! Often, the answer is within the passage, you just have to be able to find it. Sometimes students use their background knowledge too much to answer B/B questions that handed you the answer in the passage.
  • Your background knowledge will often be way more specific, and sometimes this can hurt you in answering a question that you’re supposed to use the passage for. 
  • This isn’t for every B/B question, as there are of course plenty that are content based, however I started to spend more time deciphering the passage because I looked at it as my best friend.
  • These passages are often confusing when you start, but if you spend a lot of time in your practice understanding them, eventually they will start to click and you’ll see those hidden answers as you read.

Strategy 2: Know Format of The Passage

  • If you have not taken biochemistry for a long time or were never confident in that course, this section may be difficult for you because of small ways concepts are presented in the passage that look unfamiliar.
  • For example, some of my students have not known that, for example, E127A in B/B means alanine is replacing glutamate at position, or amino acid, 127. This means that, unless otherwise stated, this is the only change that has taken place. The rest of the protein is untouched and in the native state.
  • This is valuable in experiments because you can see either how important glutamate was in the original protein, or how harmful or even helpful alanine was instead as a replacement.
  • In addition, you need to be familiar with the term catalytic efficiency known as kcat.
  • There are some test prep companies that do not mention either of these concepts explicitly, and they may have been confusing to you.

Strategy 3: Interconnected Concepts

  • You need to think of every pathway and the substrates within them as interconnected. I would draw out a huge cell and write glycolysis in the cytosol, with pyruvate as the final product. Then where does pyruvate go? It feeds into the PDH. Where does it go after? Into the TCA. How do these relate to the shuttles within the mitochondria? How do these relate to gluconeogenesis and the pentose phosphate pathway?
  • I know it’s a lot of information, but the more you draw them and see them as connected, the easier they will be to understand at a high level.

Strategy 4: Mnemonics

  • Along the lines of pathways, I think mnemonics are crucial for this.
  • For the TCA, I used: Can I Keep Some Succinate For Myself?
  • For glycolysis, I used: Goodness Gracious, Father Franklin Didn’t Go Buy Perfect Pumpkins (to) Prepare Pies
  • When you are using these mnemonics for enzymes, think about what that enzyme is doing. If it’s a kinase, then we know that phosphate and ATP are involved. What should your product then look like? If it’s a dehydrogenase, then we know that our reactant will have a hydrogen removed and given to another compound, which is often NAD turning into NADH. Use the information you know about enzymes to determine what the product will be in each reaction - conceptualizing will help you WAY more than memorizing will.

Strategy 5: Graphs

  • Graphs are a huge part of B/B, and they’re usually incredibly confusing on purpose. Before you get bogged down by the details, look at the x and y axis. What is the graph even measuring? Sometimes the x and y axes are also confusing on purpose, but take the time to understand them.
  • If you don’t understand at a macro level what this graph is measuring, then you won’tbe able to figure out the information contained within it to draw conclusions. 
  • If this doesn’t come easy to you, then spend time with these graphs during your practice and review. You can’t escape them!


  • B/B gives you coded help in the passages, and you just need enough practice to know how to decipher them. Make sure you know your amino acids, kinetics, and viruses and bacteria cold for this section in terms of content. Otherwise, these strategies may be able to help you with this section.

Lastly, whenever you feel discouraged, remember that's part of the process.

The MCAT is your training grounds. It's moulding your way of thinking to be ready for med-school. 

Enjoy it. Grow with it. 

And remember...

You got this,

The MCAT Mastery Team
Your MCAT Success Mentors

The MCAT Mastery Team

About the Author

We're a team of future doctors passionate about giving back and mentoring other future doctors! All mentors on the team are top MCAT scorers and we all are committed to seeing you succeed in achieving your physician dreams 🩺  To help you increase your MCAT score to the competitive mark quickly, we have collaboratively created these self-paced MCAT strategy courses and are also available for one-on-one tutoring!

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