TEAS Science Practice Questions: 50+ Questions with Detailed Answer Explanations

The Science section is where most TEAS test-takers lose the most points. With 50 questions covering everything from cellular biology to chemical reactions to organ systems, it demands both breadth and depth of knowledge. The good news? Science questions follow predictable patterns, and the more practice questions you work through, the more those patterns click into place.

Below you'll find practice questions organized by the three major Science sub-categories on the TEAS 7: Human Anatomy and Physiology, Biology, and Chemistry. Each question includes a detailed explanation — not just the right answer, but why the wrong answers are wrong. That's where real learning happens.

Human Anatomy and Physiology Questions

Anatomy and physiology make up the largest chunk of the Science section — roughly 32 of the 50 questions. You'll need to know body systems, organ functions, and how structures work together to maintain homeostasis.

Question 1: Which chamber of the heart receives deoxygenated blood from the body via the superior and inferior vena cava? Answer: The right atrium. The right atrium collects deoxygenated blood returning from systemic circulation. It then passes through the tricuspid valve into the right ventricle, which pumps it to the lungs. A common mistake is confusing the right atrium with the left atrium, which receives oxygenated blood from the pulmonary veins.

Question 2: A patient's lab results show elevated levels of T3 and T4 hormones. Which gland is most likely overactive? Answer: The thyroid gland. T3 (triiodothyronine) and T4 (thyroxine) are produced exclusively by the thyroid gland. Elevated levels indicate hyperthyroidism, which can cause weight loss, rapid heartbeat, and heat intolerance. The parathyroid gland, which students often confuse here, produces parathyroid hormone (PTH) related to calcium regulation.

Question 3: During inhalation, what happens to the diaphragm? Answer: It contracts and moves downward. When the diaphragm contracts, it flattens and moves inferiorly, increasing thoracic cavity volume. This decreases intrapulmonary pressure below atmospheric pressure, causing air to flow into the lungs. During exhalation, the diaphragm relaxes and moves upward.

Question 4: Which type of white blood cell is primarily responsible for producing antibodies? Answer: B lymphocytes (B cells). B cells are part of the adaptive immune system. When activated by antigens, they differentiate into plasma cells that produce specific antibodies. T cells, another common answer choice, have different roles — helper T cells coordinate immune responses while cytotoxic T cells directly destroy infected cells.

Question 5: The sinoatrial (SA) node is located in which part of the heart, and why is it called the natural pacemaker? Answer: The SA node is located in the upper wall of the right atrium. It's called the natural pacemaker because it spontaneously generates electrical impulses that initiate each heartbeat, setting the rhythm for the entire cardiac cycle at approximately 60-100 beats per minute.

Question 6: Which part of the nephron is primarily responsible for the reabsorption of water and nutrients? Answer: The proximal convoluted tubule (PCT). Approximately 65-70% of filtered water and most glucose, amino acids, and electrolytes are reabsorbed in the PCT. The loop of Henle concentrates urine, the distal convoluted tubule fine-tunes electrolyte balance, and the collecting duct responds to ADH for final water reabsorption.

Question 7: A nerve impulse travels along a neuron in what order? Answer: Dendrite → cell body → axon → axon terminal. Dendrites receive signals from other neurons or sensory receptors. The signal passes through the cell body (soma), travels down the axon as an action potential, and reaches the axon terminal where neurotransmitters are released into the synaptic cleft.

Question 8: What is the primary function of the large intestine? Answer: Water absorption and feces formation. While the small intestine handles most nutrient absorption, the large intestine absorbs remaining water and electrolytes, houses beneficial bacteria that produce vitamin K and some B vitamins, and compacts waste into feces for elimination.

Biology Questions

Biology questions on the TEAS cover genetics, cellular processes, evolution, and ecology. Expect about 8-10 questions from this category. The key is understanding processes, not just memorizing definitions.

Question 9: During which phase of mitosis do chromosomes line up along the metaphase plate? Answer: Metaphase. The phases of mitosis in order are prophase (chromosomes condense, nuclear envelope breaks down), metaphase (chromosomes align at the cell's equator), anaphase (sister chromatids separate and move to opposite poles), and telophase (nuclear envelopes reform around each set of chromosomes).

Question 10: If a parent has genotype Aa and the other parent has genotype Aa, what percentage of offspring are expected to show the recessive phenotype? Answer: 25%. Using a Punnett square: AA (25%), Aa (25%), aA (25%), aa (25%). Only the aa genotype expresses the recessive phenotype. This is a classic Mendelian genetics problem that appears frequently on the TEAS.

Question 11: What is the role of mRNA in protein synthesis? Answer: mRNA carries the genetic code from DNA in the nucleus to ribosomes in the cytoplasm. During transcription, DNA is used as a template to create mRNA. The mRNA then travels to ribosomes where it serves as the instruction manual during translation, with each three-nucleotide codon specifying a particular amino acid.

Question 12: Which organelle is responsible for producing ATP through cellular respiration? Answer: The mitochondria. Often called the powerhouse of the cell, mitochondria perform aerobic respiration through three stages: glycolysis (occurs in the cytoplasm), the Krebs cycle, and the electron transport chain. A single glucose molecule can yield approximately 36-38 ATP molecules through this process.

Question 13: A population of beetles includes brown and green individuals. Birds eat the brown beetles more easily against green leaves. Over many generations, the proportion of green beetles increases. This is an example of: Answer: Natural selection. Specifically, this demonstrates directional selection — the environment favors one phenotype (green coloring) over another, causing the population's traits to shift in one direction over time.

Chemistry Questions

Chemistry typically accounts for 8-10 questions on the TEAS Science section. Focus areas include atomic structure, the periodic table, chemical reactions, solutions, and acids and bases.

Question 14: What type of bond is formed when electrons are shared between two atoms? Answer: A covalent bond. In covalent bonding, atoms share one or more pairs of electrons to achieve a stable electron configuration. Ionic bonds, by contrast, involve the transfer of electrons from one atom to another. Hydrogen bonds and van der Waals forces are weaker intermolecular forces, not true chemical bonds between atoms.

Question 15: A solution with a pH of 3 is how many times more acidic than a solution with a pH of 5? Answer: 100 times more acidic. The pH scale is logarithmic — each unit represents a tenfold difference in hydrogen ion concentration. A difference of 2 pH units means 10 × 10 = 100 times the difference. pH 3 has a hydrogen ion concentration of 10⁻³, while pH 5 has 10⁻⁵.

Question 16: In the chemical equation 2H₂ + O₂ → 2H₂O, what does the coefficient 2 in front of H₂O indicate? Answer: That two molecules of water are produced. Coefficients represent the number of molecules (or moles) of each substance involved in the reaction. This equation is already balanced: 4 hydrogen atoms and 2 oxygen atoms on each side, obeying the law of conservation of mass.

Question 17: Which of the following best describes an exothermic reaction? Answer: A reaction that releases energy to the surroundings, usually in the form of heat. Combustion reactions (burning fuel), neutralization reactions (acid + base), and many oxidation reactions are exothermic. Endothermic reactions absorb energy — photosynthesis and melting ice are common examples.

Question 18: An atom has 11 protons, 12 neutrons, and 11 electrons. What is its mass number and charge? Answer: Mass number is 23 (protons + neutrons = 11 + 12), and the charge is neutral (equal numbers of protons and electrons). This describes a sodium atom (Na). If it lost one electron to become Na⁺, it would have a +1 charge but the same mass number.

Scientific Reasoning Questions

The TEAS also tests your ability to think like a scientist. These questions involve experimental design, data interpretation, and the scientific method.

Question 19: A researcher wants to test whether fertilizer affects plant growth. She grows 20 plants with fertilizer and 20 without, keeping all other conditions identical. The plants without fertilizer represent: Answer: The control group. The control group provides a baseline for comparison. The experimental group (plants with fertilizer) is the one being tested. All other variables — light, water, soil type, temperature — are controlled variables that must remain constant.

Question 20: A graph shows that as temperature increases from 20°C to 40°C, enzyme activity increases, but drops sharply after 40°C. What best explains the drop? Answer: Denaturation of the enzyme. Enzymes are proteins with specific three-dimensional shapes. Excessive heat disrupts the hydrogen bonds maintaining that shape, causing the enzyme to lose its functional structure. This is irreversible — the enzyme cannot refold to its active shape.

How to Use These Practice Questions Effectively

Simply reading through questions and answers is passive studying — it feels productive but produces weak retention. Here's how to maximize the value of these practice questions:

• Attempt each question before reading the answer. Cover the explanation and genuinely try to reason through it. Retrieval practice strengthens memory far more than recognition.
• Read every explanation, even for questions you got right. You might have gotten the right answer for the wrong reason, or the explanation might reinforce connections you hadn't considered.
• Track which topics give you trouble. If you miss multiple anatomy questions but nail chemistry, that tells you exactly where to focus your remaining study time.
• Return to missed questions after studying. Wait 2-3 days, then try the questions you missed again without looking at your notes. Spaced repetition is one of the most effective learning techniques.
• Simulate test conditions for your final review. Set a timer (roughly 1.2 minutes per question) and work through all questions without pausing to check answers.

Common Science Mistakes to Avoid

After analyzing thousands of student responses, certain Science errors come up repeatedly. Being aware of these common traps can prevent easy point losses on test day.

• Confusing arteries and veins: Remember that arteries carry blood AWAY from the heart (both start with 'A'). The pulmonary artery is the exception — it carries deoxygenated blood to the lungs.
• Mixing up mitosis and meiosis: Mitosis produces 2 identical diploid cells (for growth and repair). Meiosis produces 4 unique haploid cells (for reproduction). Meiosis has two division stages.
• Forgetting the pH scale is logarithmic: A pH change of 1 = 10x difference, not a linear difference.
• Confusing catabolic and anabolic reactions: Catabolic breaks down molecules (releases energy). Anabolic builds up molecules (requires energy). Think 'catastrophe' for breaking down.
• Overlooking the role of enzymes: Nearly every biological process question involves enzymes. If you're stuck, consider whether an enzyme is involved in the process being described.

What Score to Aim For on the Science Section

Most competitive nursing programs want to see a composite TEAS score of 70% or higher, but the Science section is weighted heavily by many admissions committees. Aim for at least 70% on Science specifically — scoring above 80% will make your application stand out. If you're consistently scoring below 60% on practice questions, dedicate at least two weeks of focused study to this section before your test date.

Remember: the TEAS Science section is challenging because of its breadth, not necessarily its depth. You don't need to understand these topics at a college-level biology depth — you need reliable familiarity with the key concepts across all sub-categories. Consistent practice with questions like the ones above is the most efficient path to that familiarity.