TEAS 7 Science: The 10 Topics Students Miss Most

Our tutors tracked which science topics caused the most student struggles and how to tackle them efficiently.

The science section of the ATI TEAS 7 exam is notoriously the most difficult hurdle for aspiring nursing students. It requires an incredibly broad base of knowledge across four distinct scientific disciplines. If you are struggling to figure out exactly what to study, you are not alone. Let's dive into the ultimate ATI TEAS 7 science section breakdown for 2025, detailing exactly how the 50 questions are weighted and the specific top 10 topics where students lose the most points.

ATI TEAS 7 Science Section Breakdown 2025

Before you begin memorizing flashcards, you need to understand the structural weighting of the test. The Science section consists of 50 total questions (44 scored and 6 unscored pre-test questions). You have exactly 60 minutes to complete this section, which averages out to 1 minute and 12 seconds per question. Here is how those questions are distributed:

• Human Anatomy & Physiology (A&P): ~32 questions. This is by far the largest and most important sub-section. It covers the structures, functions, and diseases of the 11 major organ systems.
• Biology: ~9 questions. Focuses on cellular biology, genetics, macromolecules, and microorganisms.
• Chemistry: ~8 questions. Covers atomic structure, chemical reactions, balancing equations, acids/bases, and states of matter.
• Scientific Reasoning: ~1 question. Analyzes your ability to understand the scientific method, experimental design, and data interpretation.

Top 10 Most Missed Science Topics

Our expert tutors have worked with thousands of pre-nursing students, and we've tracked the data. Before diving into hundreds of flashcards, establish your baseline by taking our free TEAS practice quiz. Here are the top 10 specific scientific concepts that trip students up the mostand where you should focus your study time.

1. The Endocrine System's Hormone Cascade
Students frequently confuse which gland secretes which hormone. You must memorize the pituitary gland's hormones (TSH, ACTH, FSH, LH) versus the hormones secreted by the target organs (like the thyroid and adrenal glands). Understand the concept of negative feedback loops.

2. The Pathway of Blood Through the Heart
Rote memorization isn't enough; you need to map this out visually. Know the exact path from the Superior/Inferior Vena Cava ? Right Atrium ? Tricuspid Valve ? Right Ventricle ? Pulmonary Valve ? Pulmonary Artery ? Lungs ? Pulmonary Veins ? Left Atrium ? Mitral Valve ? Left Ventricle ? Aortic Valve ? Aorta.

3. Cellular Respiration and ATP Production
In the biology section, questions about glycolysis, the Krebs cycle, and the electron transport chain appear frequently. You need to know the basic inputs and outputs (reactants and products) and where in the cell (cytoplasm vs. mitochondria) each phase occurs.

4. Balancing Chemical Equations
For many, the chemistry section is a major stressor. Balancing equations is a common question type. Remember the Law of Conservation of Mass: the number of atoms for each element must be identical on both the reactant and product sides of the equation.

5. Mitosis vs. Meiosis
Don't just memorize the phases (PMAT); understand the end results. Mitosis results in two identical diploid somatic cells used for growth and repair. Meiosis results in four genetically unique haploid gametes (sperm and egg cells) used for sexual reproduction.

6. The Immune System: Innate vs. Adaptive
You must be able to categorize immune responses. The innate immune system includes physical barriers (skin, mucous) and non-specific responses (inflammation, phagocytes). The adaptive system includes highly specific T-cells and B-cells (antibodies).

7. Macromolecules and Their Functions
Know your carbohydrates, lipids, proteins, and nucleic acids. Be prepared to identify their monomers (e.g., amino acids for proteins, monosaccharides for carbs) and their primary functions within the human body.

8. Acids, Bases, and the pH Scale
The test expects you to understand that the pH scale is logarithmic. This means a pH of 3 is ten times more acidic than a pH of 4. Know what constitutes an acid (donates hydrogen ions) versus a base.

9. Autonomic Nervous System: Sympathetic vs. Parasympathetic
Memorize the "fight or flight" (sympathetic) versus the "rest and digest" (parasympathetic) responses. Understand what happens to heart rate, pupil dilation, and digestion during each state.

10. Punnett Squares and Mendelian Genetics
You must be comfortable writing out and interpreting monohybrid Punnett crosses. Understand the difference between dominant and recessive alleles, and heterozygous versus homozygous genotypes. Be prepared to calculate phenotypic and genotypic ratios.

How to Study for the TEAS Science Section

Because the scope of the material is so vast, blind memorization usually fails. The most successful approach is taking a strategic, active recall approach. Draw diagrams of the heart. Write out the chemical formulas on a whiteboard from memory. Create physical models or mnemonics for the biological processes.

If you are struggling to synthesize this mountain of information, working with a tutor is the most efficient way to prepare. A tutor can break down complex chemical reactions or physiological pathways into simple, digestible analogies. They can also provide you with highly realistic practice questions tailored strictly to the A&P concepts heavily featured on the 2025 exam.

Frequently Asked Questions

What science topics are on the TEAS 7?

The TEAS 7 Science section covers: human anatomy and physiology (all body systems), life science (cell biology, genetics, evolution), physical science (chemistry basics, states of matter), and scientific reasoning (scientific method, experimental design).

How many science questions are on the TEAS?

There are 44 questions in the Science section with a 60-minute time limit. Science is weighted at 31.1% of your composite score — tied with Reading as the heaviest section.

Which body systems are tested most on the TEAS?

Cardiovascular, respiratory, and nervous systems appear most frequently. Digestive and endocrine systems are also commonly tested. Focus your study time on these five systems first before covering others.

Do I need to know chemistry for the TEAS science section?

Basic chemistry only. You should know the periodic table structure, atomic structure (protons, neutrons, electrons), types of chemical bonds, states of matter, and pH scale basics. No organic chemistry or advanced concepts.

Is the TEAS science section harder than college biology?

The TEAS tests breadth across many science topics rather than depth in one area. If you have taken college-level A&P and Biology courses, most TEAS science content will be familiar. The challenge is the time pressure — about 80 seconds per question.