MCAT biology prep can be overwhelming. The amount of biologically-related content makes you question where to start. This definitive MCAT biology prep guide will outline how much biology you can expect on the test day, how to start studying for MCAT biology and give you some foolproof biology study tips. Finally, you will have access to the entire list of biology concepts you can expect on the test in one place, right here!
Disclaimer: MCAT is a registered trademark of AAMC. BeMo and AAMC do not endorse or affiliate with one another.
>>Want us to help you get accepted? Schedule a free initial consultation here <<
Listen to the blog!
Check out this video for more tips on how to ace the MCAT Biology Section!
How Much Biology is on the MCAT?
Unsurprisingly, biology is prominently featured in the MCAT. Critical Analysis and Reasoning Skills (CARS) is the only of the four MCAT sections where you should not expect your biological knowledge to be tested. The first section, Chemical and Physical Foundations of Biological System, will have about 30% of biology-related content; section 3, Biological and Biochemical Foundations of Living Systems, will have about 90%; lastly, section 4, Psychological, Social, and Biological Foundations of Behavior, will have about 5%. Each of these three sections will have 59 questions, a combination of passage-based and discrete. You will have 95 minutes to complete each section. And while there is a lot of ground to cover in your biology review, recall that you do not need to be a biologist to ace these sections of the MCAT. To be competent for the exam, we highly advise you to take a variety of biology and biochemistry classes. It might be wise to take more than just intro classes. Some colleges and universities do not cover all the MCAT biology content in intro classes. Research what kind of courses you can take at your university that will help you in preparation for this challenging MCAT topic.
A warning before you start your MCAT biology prep: do not panic when you see the entire list of biology concepts and terminology you should know for the MCAT. You might feel the need to express your frustration and ask questions of your peers on Reddit Premed or Premed101 forums, but these platforms tend to incite even more fear and panic in students. In these forums, you will encounter individuals who will claim that they have read every biology textbook under the sun, who hired multiple tutors to prepare for the MCAT, who had to memorize thousands of terms and concepts before they took the exam – all this can make you question your level of dedication, knowledge, and MCAT prep strategies. If you really need some quality advice, you should reach out to a medical school advisor to discuss your fears and concerns about your knowledge of biology. These professionals can often provide you with valuable advice about what study resources to use and where to seek help for concepts you are struggling with.
![MCAT Biology Guide infographic](data:image/svg+xml,%3Csvg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 500 493"%3E%3C/svg%3E)
How to Start Studying for MCAT Biology
The overwhelming amount of biology on the MCAT can be intimidating but try to remember that thousands of students have overcome this challenge, and so can you. If biology is not your forte, do not panic. Any MCAT prep must begin with an MCAT diagnostic test. It will help you determine how much you already know, which disciplines and concepts you need to focus on, and finally, help you prioritize which topics need your immediate attention. For example, if after the practice test you find that your biology knowledge is lacking, you should try to focus your attention on biology and biochemistry. Why? Because of their prominence on the exam. While MCAT physics takes up only 20%-25% of the second section of the MCAT, biology and biochemistry are featured in every MCAT section with the exception of CARS. So, if you are struggling with biology questions, make sure to include the topics you find challenging in your MCAT study schedule.
![MCAT diagnostic test infographic](data:image/svg+xml,%3Csvg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 500 850"%3E%3C/svg%3E)
When to start studying for the MCAT will depend on whether you have just taken all the necessary intro courses. If you have just taken all the necessary classes, your MCAT prep will be more reminiscent of review and revision. You will most likely quickly recall biology concepts and terminology as soon as you see them on the practice exam. However, if it's been a while since you have been exposed to the study of biology, you must initiate your study prep earlier. Don’t forget that in addition to reviewing biology, you must also pay some attention to MCAT chemistry questions, MCAT psychology questions, and MCAT physics equations during your preparations. In addition to reviewing these scientific and social science topics, you must also get ready for CARS. As many of you know, you cannot get ready for MCAT CARS by memorizing concepts and terminology – you must practice reading challenging texts for months (!!!) and go over MCAT CARS practice passages. This is why having a solid MCAT CARS strategy is key to tackling this challenging section.
MCAT Biology Study Tips
Let’s go over some study strategies you can implement to help you internalize MCAT biology content.
Start Early
Unlike MCAT physics, biology has a much more dominant presence on the exam. There is a large number of biology concepts and topics you will need to review before you take the test. This is why we highly advise you to begin your MCAT prep at least 6 months before your scheduled MCAT test date, especially if it's been a while since you have taken the intro biology and biochemistry courses. After you take a look at all the biology terms, topics, and themes you have to cover, you might be alarmed by how hard the MCAT is. However, if you have the right MCAT study schedule, you will be able to get ready for this challenging exam.
![What makes the MCAT challenging](data:image/svg+xml,%3Csvg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 500 1136"%3E%3C/svg%3E)
Keep the “Big Picture” In Mind
Keep in mind that the MCAT tests basic scientific knowledge, so do not get bogged down by the details of the passages, questions, and responses. Read the passages carefully but try not to panic if you find that the passage is full of words that are unknown to you. It is almost certain that you will encounter concepts and terminology that are unfamiliar to you – do not worry, the passage is aimed to see whether you can understand the underlying ideas and concepts of biological systems. As you are reading a biology passage, try to get the general gist of what the passage is about and go from there.
Try Highlighting Important Sections of the Passage
When you encounter passages that deal with biological concepts, read the passage carefully, and highlight the most important aspects of the text. Try to take no longer than 4 minutes per passage. As you are reading the passage, try to anticipate what questions they are going to ask you. If you highlight effectively, you will more-or-less have the key to answers right in front of you – you will not need to reread the passage again to find the answer.
Leave External Knowledge Behind the Exam Door
Most likely, you have heard that you should not bring in any external knowledge when you choose your answers for MCAT CARS passages. This is true for most MCAT sections. You may be tempted to choose answers based on your outside knowledge but avoid this temptation. Each question and answer options are tailored to the specific passages you are given. The MCAT is designed to test basic scientific knowledge: if you start bringing in the knowledge that is not related to the passage or the question, you may not be able to find the correct response, panic, and miss an opportunity to increase your score.
Read the Passages, Answers, and Questions correctly. Anticipate Answers Before You Read the Responses
Accurate reading and understanding of MCAT biology passages, questions, and answers are the keys to your success. Pay special attention to graphs, figures, or images you may encounter. Attention to detail may allow you to make predictions before looking at the answers. Then you can simply choose the answer that is closest to what you came up with. If you go straight to reading the responses, you may become overwhelmed – it’s like answering four or five questions instead of answering just one!
Try Skimming Though Questions Before You Read the Passage
This method won't work for everyone; however, as you start your MCAT prep, you may have time to try out different strategies. Some students have noted that skimming through questions (not the responses!) before reading the passages helps them highlight the words that correspond with the keywords in the question. So, after reading the questions, highlight any words in the passages that look familiar – this way, you will not need to reread the passage several times for each question. This kind of practice can help you get better at recognizing relevant and important information in each passage you face.
Make Notes of Weak Areas
Remember, taking as many diagnostic tests as you can during your MCAT prep is one of the best study tactics. Not only do they help you create your MCAT study schedule, but they also help you see if you are improving. As you are going over MCAT biology questions, jot down any topics that you are struggling with or topics you completely missed in your practice test. After you finish practicing with sample biology questions, add to your study plan which content areas you need to review and what kind of study strategies you will implement. For example, if you are lacking knowledge about nucleotide structure, schedule to review corresponding chapters of your textbook and your notes, draw diagrams, and watch helpful video content.
Keep a Log of Wrong Answers
This may seem counterintuitive but keeping a record of what questions you got wrong may be a useful MCAT prep practice for some. In this log, write down the passage and questions you got wrong, along with explanations of the correct answers. For example, if you chose the wrong responses with regards to the structure of a cell, draw a correct diagram of it in your log. If you review the cell structure in detail, you are less likely to get similar questions or topics wrong in the future. For some students, nothing drills the correct answers into their memory more than getting something wrong first. This prompts them to research the correct response and find a detailed explanation of why they were wrong.
Draw the Material
Some students learn quite well by reading, memorizing, and writing down material. Some students, however, learn best in a visual format. Think about drawing your notes, using different colours or highlights, or making flowcharts so you can visualize key concepts, which can make it easier to recall large amounts of information.
Active Learning
Using the study tips above may help you remember the large amount of content you need. However, a great way to know you have really understood it is to teach it to someone else. Recruit a study buddy who is also preparing for the MCAT and take turns explaining key concepts to the other person. Can you explain it so your friend understands? If so, you can be more confident that you know the material well.
Try Reading Difficult Material About Biology
Think of this study tip as killing two birds with one stone. Reading biology-related material in journal articles, newspapers, or magazines will help you become familiar with biology concepts AND practice your reading skills (which is helpful for all sections of the MCAT, but especially CARS). Try reading books written by physicians, which often discuss clinical cases and include mentions of physiology concepts, as these are often quite interesting to read and will also help you do well on the whole MCAT (including the biology section).
![MCAT biology section tips](data:image/svg+xml,%3Csvg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 500 1088"%3E%3C/svg%3E)
Appendix: What Biology Concepts Are on the MCAT?
MCAT section 1: Chemical and Physical Foundations of Biological Systems (CPBS) - first-semester biochemistry 25%, introductory biology 5%
4A. Translational motion, forces, work, energy, and equilibrium in living systems
4B. Importance of fluids for the circulation of blood, gas movement, and gas exchange
Circulatory System
- Arterial and venous systems; pressure and flow characteristics
4C. Electrochemistry and electrical circuits and their elements
Specialized Cell – Nerve Cell
- Myelin sheath, Schwann cells, insulation of axon
- Nodes of Ranvier: propagation of nerve impulse along axon
4D. How light and sound interact with matter
4E. Atoms, nuclear decay, electronic structure, and atomic chemical behavior
MCAT section 3: Biological and Biochemical Foundations of Living Systems (BBLS) – 65% introductory biology, 25% first-semester biochemistry
Category 1A focuses on the structural and functional complexity of proteins, which is derived from their component amino acids, the sequence in which the amino acids are covalently bonded, and the three-dimensional structures the proteins adopt in an aqueous environment.
Amino Acids
Description
- Absolute configuration at the α position
- Amino acids as dipolar ions
- Classifications: acidic or basic; hydrophobic or hydrophilic
Reactions
- Sulfur linkage for cysteine and cystine
- Peptide linkage: polypeptides and proteins
- Hydrolysis
Protein Structure
Structure
- 1° structure of proteins
- 2° structure of proteins
- 3° structure of proteins; role of proline, cystine, hydrophobic bonding
- 4° structure of proteins
Conformational Stability
- Denaturing and folding
- Hydrophobic interactions
- Solvation layer (entropy) (BC)
Separation Techniques
- Isoelectric point
- Electrophoresis
Non-Enzymic Protein Function
- Binding
- Immune system
- Motors
Enzyme Structure and Function
Function of enzymes in catalyzing biological reactions
Enzyme classification by reaction type
Reduction of activation energy
Substrates and enzyme specificity
Active Site ModelInduced-fit Model
Mechanism of catalysis
- Cofactors
- Coenzymes
- Water-soluble vitamins
'Effects of local conditions on enzyme activity
Control of Enzyme Activity
Kinetics
- General (catalysis)
- Michaelis–Menten
- Cooperativity
Feedback regulation
Inhibition – types
- Competitive
- Non-competitive
- Mixed (BC)
- Uncompetitive (BC)
Regulatory enzymes
- Allosteric enzymes
- Covalently-modified enzymes
- Zymogen
Category 1B focuses on the molecular mechanisms responsible for the transfer of sequence specific biological information between biopolymers which ultimately results in the synthesis of proteins. Category
Nucleic Acid Structure and Function
Description
Nucleotides and nucleosides
- Sugar phosphate backbone
- Pyrimidine, purine residues
Deoxyribonucleic acid (DNA): double helix, Watson–Crick model of DNA structure
Base pairing specificity: A with T, G with C
Function in transmission of genetic information
DNA denaturation, reannealing, hybridization
DNA Replication
Mechanism of replication: separation of strands, specific coupling of free nucleic acids
Semi-conservative nature of replication
Specific enzymes involved in replication
Origins of replication, multiple origins in eukaryotes
Replicating the ends of DNA molecules
Repair of DNA
Repair during replication
Repair of mutations
Genetic Code
Central Dogma: DNA → RNA → protein
The triplet code
Codon–anticodon relationship
Degenerate code, wobble pairing
Missense, nonsense codons
Initiation, termination codons
Messenger RNA (mRNA)
Transcription
Transfer RNA (tRNA); ribosomal RNA (rRNA)
Mechanism of transcription
mRNA processing in eukaryotes, introns, exons
Ribozymes, spliceosomes, small nuclear ribonucleoproteins (snRNPs), small nuclear RNAs (snRNAs)
Functional and evolutionary importance of introns
Translation
Roles of mRNA, tRNA, rRNA
Role and structure of ribosomes
Initiation, termination co-factors
Post-translational modification of proteins
Eukaryotic Chromosome Organization
Chromosomal proteins
Single copy vs. repetitive DNA
Supercoiling
Heterochromatin vs. euchromatin
Telomeres, centromeres
Control of Gene Expression in Prokaryotes
Operon Concept, Jacob–Monod ModelGene repression in bacteria
Positive control in bacteria
Control of Gene Expression in Eukaryotes
Transcriptional regulation
DNA binding proteins, transcription factors
Gene amplification and duplication
Post-transcriptional control, basic concept of splicing (introns, exons)
Cancer as a failure of normal cellular controls, oncogenes, tumor suppressor genes
Regulation of chromatin structure
DNA methylation
Role of non-coding RNAs
Recombinant DNA and Biotechnology
Gene cloning
Restriction enzymes
DNA libraries
Generation of cDNA
Hybridization
Expressing cloned genes
Polymerase chain reaction
Gel electrophoresis and Southern blotting
DNA sequencing
Analyzing gene expression
Determining gene function
Stem cells
Practical applications of DNA technology: medical applications, human gene therapy, pharmaceuticals, forensic evidence, environmental cleanup, agriculture
Safety and ethics of DNA technology
1C focuses on the mechanisms that function to transmit the heritable information stored in DNA from generation to generation.
Evidence that DNA is Genetic Material
Mendelian Concepts
- Phenotype and genotype
- Gene
- Locus
- Allele: single and multiple
- Homozygosity and heterozygosity
- Wild-type
- Recessiveness
- Complete dominance
- Co-dominance
- Incomplete dominance, leakage, penetrance, expressivity
- Hybridization: viability
- Gene pool
Meiosis and Other Factors Affecting Genetic Variability
Significance of meiosis
Important differences between meiosis and mitosis
Segregation of genes
- Independent assortment
- Linkage
- Recombination (single crossover, double crossover, synaptonemal complex, tetrad)
- Sex-linked characteristics
- Very few genes on Y chromosome
- Sex determination
- Cytoplasmic/extranuclear inheritance
Mutation
- General concept of mutation — error in DNA sequence
- Types of mutations: random, translation error, transcription error, base substitution, inversion, addition, deletion, translocation, mispairing
- Advantageous vs. deleterious mutation
- Inborn errors of metabolism Relationship of mutagens to carcinogens
Genetic drift
Synapsis or crossing-over mechanism for increasing genetic diversity
Analytic Methods
- Hardy–Weinberg Principle
- Testcross (Backcross; concepts of parental, F1, and F2 generations)
- Gene mapping: crossover frequencies
- Biometry: statistical methods
Evolution
Natural selection
- Fitness concept
- Selection by differential reproduction
- Concepts of natural and group selection
- Evolutionary success as increase in percent representation in the gene pool of the next generation
Speciation
- Polymorphism
- Adaptation and specialization
- Inbreeding
- Outbreeding
- Bottlenecks
Evolutionary time as measured by gradual random changes in genome
Category 1D focuses on the biomolecules and regulated pathways involved in harvesting chemical energy stored in fuel molecules, which serves as the driving force for all of the processes that take place within a living system.
Principles of Bioenergetics
Bioenergetics/thermodynamics
- Free energy/Keq (Equilibrium constant; Relationship of the equilibrium constant and ΔG°)
- Concentration (Le Châtelier’s Principle)
- Endothermic/exothermic reactions
- Free energy: G
- Spontaneous reactions and ΔG°
Phosphoryl group transfers and ATP
- ATP hydrolysis ΔG << 0
- ATP group transfers
Biological oxidation-reduction
- Half-reactions
- Soluble electron carriers
- Flavoproteins
Carbohydrates
Description
- Nomenclature and classification, common names
- Absolute configuration
- Cyclic structure and conformations of hexoses
- Epimers and anomers
Hydrolysis of the glycoside linkage
Monosaccharides
Disaccharides
Polysaccharides
Glycolysis, Gluconeogenesis, and the Pentose Phosphate Pathway
Glycolysis (aerobic), substrates and products
- Feeder pathways: glycogen, starch metabolism
Fermentation (anaerobic glycolysis)
Gluconeogenesis
Pentose phosphate pathway
Net (maximum) molecular and energetic results of respiration processes
Principles of Metabolic Regulation
Regulation of metabolic pathways
- Maintenance of a dynamic steady state
Regulation of glycolysis and gluconeogenesis
Metabolism of glycogen
Regulation of glycogen synthesis and breakdown
- Allosteric and hormonal control
Analysis of metabolic control
Citric Acid Cycle
- Acetyl-CoA production
- Reactions of the cycle, substrates and products
- Regulation of the cycle
- Net (maximum) molecular and energetic results of respiration processes
Metabolism of Fatty Acids and Proteins
Description of fatty acids
Digestion, mobilization, and transport of fats
Oxidation of fatty acids
- Saturated fats
- Unsaturated fats
Ketone bodies
Anabolism of fats
Non-template synthesis: biosynthesis of lipids and polysaccharides
Metabolism of proteins
Oxidative Phosphorylation
Electron transport chain and oxidative phosphorylation, substrates and products, general features of the pathway
Electron transfer in mitochondria
- NADH, NADPH
- Flavoproteins
- Cytochromes
ATP synthase, chemiosmotic coupling
- Proton motive force
Net (maximum) molecular and energetic results of respiration processes
Regulation of oxidative phosphorylation
Mitochondria, apoptosis, oxidative stress
Hormonal Regulation and Integration of Metabolism
- Higher level integration of hormone structure and function
- Tissue specific metabolism
- Hormonal regulation of fuel metabolism
- Obesity and regulation of body mass
MCAT section 4: Psychological, Social, and Biological Foundations of Behavior (PSBB) – 5% introductory biology
Category 6A focuses on the detection and perception of sensory information.
Sensory Processing
Sensation
- Threshold
- Weber’s Law
- Signal detection theory
- Sensory adaptation
- Psychophysics
Sensory receptors
- Sensory pathways
- Types of sensory receptor
Vision
Structure and function of the eye
Visual processing
- Visual pathways in the brain
- Parallel processing
- Feature detection
Hearing
- Structure and function of the ear
- Auditory processing (e.g., auditory pathways in the brain)
- Sensory reception by hair cells
Other Senses
Somatosensation (e.g., pain perception)
Taste (e.g., taste buds/chemoreceptors that detect specific chemicals)
Smell
- Olfactory cells/chemoreceptors that detect specific chemicals
- Pheromones
- Olfactory pathways in the brain
Kinesthetic sense
Vestibular sense
Category 6B focuses on cognition, including our ability to attend to the environment, think about and remember what we experience, and use language to communicate with others.
Category 6C focuses on how we process and experience emotion and stress.
FAQs
1. How much biology is on the MCAT?
Biology is prominently featured in the MCAT. For example, biology questions compose 90% of the second section of the MCAT, Biological and Biochemical Foundations of Living Systems. You may expect to see a biology-related question in most sections of the MCAT, perhaps with the exception of CARS. If you want to see a complete breakdown of the MCAT sections, read our “How long is the MCAT?” blog.
2. What kind of coursework should I pursue in my undergrad to get ready for MCAT biology?
Most medical school prerequisites do cover the MCAT biology content, but some do not. If you think that taking advanced undergrad biology courses will help you better prepare for the exam, you should research your school’s directory of courses and see which classes will cover topics you haven’t had the chance to learn. Advanced biology courses are not required, but they may help you.
3. How important is my knowledge of biology for the MCAT?
You must have a solid knowledge of biology for the MCAT. Notice that three out of the four MCAT sections include some biology-related concepts that you need to know for the exam. There is definitely a correlation between a solid knowledge of biology and a good MCAT score.
4. I am having trouble with biology-related passages. How can I improve my reading and comprehension of the graphs, charts, and images within the passages?
You can strengthen your reading and comprehension of experiment-based passages that often include images and graphs by joining a research lab. Getting involved in research will also expand your scientific knowledge and bolster your med school applications. When you start looking for research positions, don’t forget to accompany your job application or CV with a strong research assistant cover letter. Another way to increase your reading and comprehension of biology passages is to read scientific journals. Get used to reading an article each week and analyzing its graphs and figures. You can even try explaining the graphs and figures to others – if they understand your explanation, you are on track with your MCAT biology prep!
5. I do well with other MCAT concepts and disciplines, but biology and biochemistry are my weakness. Does it really matter?
Some medical schools pay attention to only one MCAT section during application review. For example, the McMaster medical school in Ontario, Canada only considers your CARS score during the review. However, most schools look at each section separately, and then your sum score. So, it's important to do well in all four sections, because most schools do look at the score of each section and your cumulative score. Consistency demonstrates your competence in all scientific and social science disciplines. Remember each section makes up 25% of your total MCAT score!
6. There is so much biology on the exam! How can I review all this content?
Your success will depend on your diligence and time management. Remember, ideally, you will have about 6 months to review all the MCAT disciplines. Be sure to create a thorough study schedule that includes the content you need to cover and the study strategies you will use. Additionally, don’t be afraid of changing the schedule as you begin your MCAT prep. It’s normal to rearrange and improve your study plan as you work through the concepts. If you have less than 6 months, you will need to arrange your study schedule to meet your needs and focus on content areas that need your attention, e.g. if you struggle with CARS, focus on CARS prep, if you struggle with physics, practice with physics equations and concepts, etc.
7. When should I take the MCAT?
Before you are ready to take your MCAT, take as many diagnostic tests as possible. Firstly, pay attention to whether you are improving and keep studying if you are. Remember, you are not simply trying to get a “good enough” score – you are trying to get the highest score possible! If you plateau and are happy with the score you are getting (around 90%), then you may take the test.
8. Do I have to take biology courses in university to do well?
This is recommended, as there is a lot of material to be covered. However, you must judge your own strengths. Perhaps you are very strong in biology and can review the material using textbooks on your own time. The bottom line: Leave enough time to cover the vast amount of biology material that will be on the MCAT.
9. How come the biology section does not have more anatomy and physiology?
Anatomy and physiology are covered extensively DURING medical school. Before medical school, programs want to know you have the basic science knowledge and critical thinking skills to excel at learning anatomy, physiology, and clinical medicine, so while some of this knowledge is needed for the MCAT, other concepts in biology are also important.
10. Why is active learning a good way to learn?
Active learning involves engaging with the material, whereas more passive learning involves things like listening to lectures or rote memorization. Active learning will cement concepts in your brain more than passive learning by itself can (although lectures, reading, and memorization are often required before active learning can occur). So, try drawing out concepts yourself, or teaching another student a difficult biology topic. These types of active learning will show that you have really understood the material and they are a lot more fun also!