TEAS science cheat sheet: the facts behind all 4 content areas
This TEAS science cheat sheet puts the facts the science questions lean on into tables you can review in one sitting: the body systems and their flows, the hormones, cells and genetics, chemistry and pH, and the rules of a good experiment. TEAS science is 50 questions in 60 minutes, 44 of them scored, and anatomy and physiology alone is 18 of the 44.
A cheat sheet is for review, not for learning a topic for the first time. Read a block, cover it, and say it back. Where a block feels new, open the full guide linked under it. You can't take notes of any kind into the exam room, so this page is for the weeks before.
What science is on the TEAS test?
ATI splits the science section into four content areas. The counts are scored questions; six more are unscored pretest questions that look the same as the rest, so treat every question as if it counts.
| Content area | Scored questions | Share of science | Full guide |
|---|---|---|---|
| Human anatomy and physiology | 18 | 41% | TEAS anatomy and physiology |
| Biology | 9 | 20% | TEAS biology |
| Chemistry | 8 | 18% | TEAS chemistry |
| Scientific reasoning | 9 | 20% | TEAS scientific reasoning |
| Total | 44 scored + 6 unscored = 50 | 60 minutes, about 72 seconds a question |
So the order of this sheet follows the points: the body first, then cells and genetics, then chemistry, then experiments. If you have only a few days, spend half of them on the first block. For a study order over two weeks, read how to study for the TEAS science section.
Anatomy and physiology cheat sheet
Directions and planes
Questions use these words to say where a structure is. Every term assumes the body in anatomical position: standing, facing you, palms forward.
| Term | Means | Example |
|---|---|---|
| Superior / inferior | Toward the head / toward the feet | The heart is superior to the diaphragm |
| Anterior (ventral) / posterior (dorsal) | Front / back | The sternum is anterior to the heart |
| Medial / lateral | Toward the midline / away from it | The nose is medial to the eyes |
| Proximal / distal | Closer to / farther from where a limb attaches | The elbow is proximal to the wrist |
| Superficial / deep | Toward the surface / away from it | Skin is superficial to muscle |
| Sagittal plane | Splits left from right | Midsagittal: two equal halves |
| Frontal (coronal) plane | Splits front from back | |
| Transverse plane | Splits top from bottom | A CT "slice" |
Levels of organization, smallest to largest: chemical, cell, tissue, organ, organ system, organism. The four tissue types are epithelial, connective, muscle and nervous. Homeostasis is keeping the inside steady; most of it runs on negative feedback (body temperature, blood glucose). Childbirth contractions and blood clotting are the usual examples of positive feedback.
The body systems on one table
| System | Main parts | Job | The fact questions use most |
|---|---|---|---|
| Cardiovascular | Heart, arteries, veins, capillaries, blood | Moves oxygen, nutrients and waste | Arteries carry blood away from the heart; veins carry it back |
| Respiratory | Nose, pharynx, larynx, trachea, bronchi, lungs, alveoli | Gas exchange | Oxygen and carbon dioxide swap across the alveoli by diffusion |
| Digestive | Mouth, esophagus, stomach, small and large intestine, liver, pancreas, gallbladder | Breaks food down and absorbs it | Most absorption happens in the small intestine |
| Nervous | Brain, spinal cord, nerves | Fast signals and control | Central (brain, cord) vs peripheral (nerves); sympathetic is "fight or flight" |
| Endocrine | Pituitary, thyroid, parathyroid, adrenals, pancreas, gonads | Slow signals by hormones | Hormones travel in the blood to target cells |
| Muscular | Skeletal, cardiac and smooth muscle | Movement, posture, heat | Only skeletal muscle is voluntary |
| Skeletal | 206 bones in an adult, cartilage, ligaments | Support, protection, blood cell production, mineral storage | Red marrow makes blood cells; ligaments join bone to bone, tendons join muscle to bone |
| Urinary | Kidneys, ureters, bladder, urethra | Filters blood, balances water and salts | The nephron is the filtering unit |
| Immune and lymphatic | White blood cells, lymph nodes, spleen, thymus | Defense; returns fluid to the blood | B cells make antibodies; T cells attack infected cells |
| Integumentary | Skin, hair, nails, sweat and oil glands | Barrier, temperature control, vitamin D | Layers: epidermis, dermis, hypodermis |
| Reproductive | Testes, ovaries, uterus, related ducts | Makes gametes and hormones | Fertilization usually happens in the fallopian tube |
The four flows to know in order
Ordered-response questions on the TEAS often ask you to put steps like these in order. Learn them as chains.
- Blood through the heart: body → superior and inferior vena cava → right atrium → tricuspid valve → right ventricle → pulmonary valve → pulmonary arteries → lungs → pulmonary veins → left atrium → mitral (bicuspid) valve → left ventricle → aortic valve → aorta → body.
- Air in: nose or mouth → pharynx → larynx → trachea → bronchi → bronchioles → alveoli. On inhaling the diaphragm contracts and moves down; on exhaling it relaxes and moves up.
- Food: mouth → pharynx → esophagus → stomach → small intestine (duodenum, jejunum, ileum) → large intestine → rectum → anus. Bile from the liver, stored in the gallbladder, breaks fat into small drops; the pancreas sends enzymes into the duodenum.
- Urine: blood in the glomerulus → Bowman's capsule → proximal tubule → loop of Henle → distal tubule → collecting duct → renal pelvis → ureter → bladder → urethra.
Two traps: the pulmonary arteries are the only arteries that carry low-oxygen blood, and the pulmonary veins are the only veins that carry oxygen-rich blood. The rule is direction (away from the heart or toward it), not oxygen.
Hormones: gland, hormone, effect
| Gland | Hormone | Effect |
|---|---|---|
| Pancreas | Insulin / glucagon | Lowers blood glucose / raises it |
| Thyroid | Thyroxine (T4) and T3 | Sets metabolic rate |
| Thyroid | Calcitonin | Lowers blood calcium |
| Parathyroids | Parathyroid hormone (PTH) | Raises blood calcium |
| Posterior pituitary | ADH (antidiuretic hormone) | Kidneys keep more water |
| Posterior pituitary | Oxytocin | Uterine contractions, milk let-down |
| Anterior pituitary | Growth hormone, TSH, ACTH, FSH, LH, prolactin | Growth; tell other glands what to do |
| Adrenal cortex | Cortisol / aldosterone | Stress response and blood glucose / kidneys keep sodium and water |
| Adrenal medulla | Epinephrine (adrenaline) | Fight or flight: heart rate and blood glucose up |
| Kidneys | Erythropoietin (EPO) | More red blood cells |
| Pineal | Melatonin | Sleep and wake cycle |
Numbers and pairs worth memorizing
- Normal blood pH: 7.35 to 7.45. Body temperature: about 37 °C (98.6 °F).
- Muscle types: skeletal (striated, voluntary), cardiac (striated, involuntary, intercalated discs), smooth (not striated, involuntary, in organ walls and vessels).
- Neuron signal path: dendrite → cell body → axon → axon terminal → synapse. Myelin speeds the signal.
- Immunity: innate (skin, mucus, fever, inflammation, phagocytes) vs adaptive (B and T cells, memory). Active immunity: your body makes the antibodies (infection, vaccine). Passive: you receive them (through the placenta, breast milk, an antibody injection).
- Red blood cells carry oxygen on hemoglobin; white blood cells fight infection; platelets clot.
The full system-by-system review, with 12 practice questions, is in TEAS anatomy and physiology: the 12 topics to know.
Biology cheat sheet
Cells and organelles
| Part | Job |
|---|---|
| Nucleus | Holds DNA; controls the cell |
| Mitochondrion | Cellular respiration: makes most of the ATP |
| Ribosome | Builds proteins |
| Rough ER / smooth ER | Folds and ships proteins (has ribosomes) / makes lipids, detoxifies |
| Golgi apparatus | Packages and sends proteins |
| Lysosome | Breaks down waste with enzymes |
| Cell membrane | Phospholipid bilayer; controls what enters and leaves |
| Cell wall, chloroplast, large central vacuole | Plant cells only (cell walls also in bacteria and fungi) |
Prokaryotes (bacteria) have no nucleus and no membrane-bound organelles; eukaryotes (animals, plants, fungi, protists) have both. Passive transport (diffusion, osmosis, facilitated diffusion) needs no ATP and moves from high to low concentration; active transport needs ATP and can move against it.
Mitosis vs meiosis
| Mitosis | Meiosis | |
|---|---|---|
| Purpose | Growth and repair | Makes eggs and sperm |
| Divisions | One | Two |
| Cells made | 2, identical | 4, all different |
| Chromosomes in a human daughter cell | 46 (diploid) | 23 (haploid) |
| Phases | Prophase, metaphase (line up in the middle), anaphase (pull apart), telophase; cytokinesis splits the cell | |
DNA, RNA and genetics
- DNA: double strand, deoxyribose sugar, bases A, T, C, G (A pairs with T, C with G). RNA: single strand, ribose, A, U, C, G (A pairs with U).
- Transcription (in the nucleus): DNA → mRNA. Translation (at the ribosome): mRNA → protein, three bases (a codon) per amino acid.
- Dominant allele: capital letter, shows whenever present. Recessive: shows only as two copies (aa). Genotype is the letters; phenotype is the trait you see.
- Aa × Aa: genotypes 1 AA : 2 Aa : 1 aa; phenotypes 3 dominant : 1 recessive. Aa × aa: 1 : 1. AA × aa: all Aa.
- Codominance shows both traits (AB blood); incomplete dominance blends them (red × white = pink).
Macromolecules and microbes
| Macromolecule | Built from | Job |
|---|---|---|
| Carbohydrates | Monosaccharides (glucose) | Quick energy; cellulose in plant walls |
| Lipids | Glycerol and fatty acids | Stored energy, membranes, some hormones |
| Proteins | Amino acids | Enzymes, structure, transport, antibodies |
| Nucleic acids | Nucleotides | DNA and RNA: genetic information |
Bacteria are treated with antibiotics; viruses are not cells and antibiotics don't work on them; fungi take antifungals; protozoa (malaria, giardia) take antiparasitic drugs. Every block above is taught in full, with worked Punnett squares, in TEAS biology: the 5 topics.
Before you go on: to see how science sits next to your other sections, take our free TEAS practice test, 15 questions across all four sections scored against your program's minimum.
Chemistry cheat sheet
Atoms and the periodic table
| Particle | Charge | Where | Mass |
|---|---|---|---|
| Proton | +1 | Nucleus | About 1 atomic mass unit |
| Neutron | 0 | Nucleus | About 1 atomic mass unit |
| Electron | −1 | Shells around the nucleus | About 1/1,836 of a proton |
- Atomic number = protons (it names the element). Mass number = protons + neutrons. Neutral atom: electrons = protons.
- Isotopes: same element, different numbers of neutrons (carbon-12, carbon-14). Ions: an atom that gained electrons (negative, anion) or lost them (positive, cation).
- Rows are periods; columns are groups. Elements in one group have the same number of valence electrons and behave alike. Metals on the left, nonmetals on the right, noble gases (group 18) barely react.
Bonds, states and reactions
| Bond | What happens | Example |
|---|---|---|
| Ionic | Electrons transferred, metal to nonmetal | NaCl (table salt) |
| Covalent | Electrons shared between nonmetals | H2O, CO2 |
| Hydrogen bond | Weak attraction between molecules | Between water molecules; holds the two DNA strands together |
- Changes of state: melting (solid to liquid), freezing, vaporization (liquid to gas), condensation (gas to liquid), sublimation (solid to gas), deposition (gas to solid).
- Reaction types: synthesis (A + B → AB), decomposition (AB → A + B), single replacement (A + BC → AC + B), double replacement (AB + CD → AD + CB), combustion (fuel + O2 → CO2 + H2O).
- Balancing: the same number of each atom on both sides. CH4 + 2O2 → CO2 + 2H2O has 1 C, 4 H and 4 O on each side. Change the big numbers in front, never the small ones inside a formula.
- A catalyst (an enzyme in the body) speeds a reaction by lowering its activation energy and is not used up. Heat, more concentration and more surface area also speed reactions.
- Solutions: the solute dissolves in the solvent (water is the body's solvent). Concentration is solute per amount of solution.
Acids, bases and pH
| pH | Means | Examples |
|---|---|---|
| 0 to below 7 | Acid: more H+ ions | Stomach acid (about 1.5 to 3.5), lemon juice, vinegar |
| 7 | Neutral | Pure water |
| Above 7 to 14 | Base: more OH− ions | Baking soda, bleach, ammonia |
Each step on the pH scale is ten times: pH 3 has 10 times the H+ of pH 4 and 100 times that of pH 5. An acid and a base together neutralize to a salt and water. A buffer resists a change in pH; the bicarbonate buffer keeps blood between 7.35 and 7.45. The worked examples and 10 practice questions are in TEAS chemistry.
Scientific reasoning cheat sheet
Experiments
| Term | Means | In "does caffeine change heart rate?" |
|---|---|---|
| Independent variable | What the researcher changes | The dose of caffeine |
| Dependent variable | What is measured | Heart rate |
| Controlled variables | Kept the same for every group | Time of day, age range, rest before the test |
| Control group | Gets no treatment, for comparison | A decaf drink with no caffeine |
| Hypothesis | A testable prediction | "More caffeine raises resting heart rate" |
- A theory explains a wide set of observations and has held up to many tests; a law describes what happens, often as a formula, without saying why.
- Correlation is not causation: two things that rise together may share a third cause.
- Bigger samples and repeated trials make a result more reliable. A result that others can repeat is reproducible.
- Graphs: line for change over time, bar for comparing groups, scatter for a relationship between two measures, pie for parts of a whole. The independent variable goes on the x-axis.
Metric units and tools
| Prefix | Symbol | Times the base unit |
|---|---|---|
| kilo | k | 1,000 |
| hecto | h | 100 |
| deka | da | 10 |
| (base: meter, liter, gram) | 1 | |
| deci | d | 0.1 |
| centi | c | 0.01 |
| milli | m | 0.001 |
| micro | µ (mc) | 0.000001 |
Moving down one row, multiply by 10; up one row, divide by 10. So 2.5 L = 2,500 mL and 450 mg = 0.45 g. Tools: a graduated cylinder for liquid volume (read the bottom of the meniscus at eye level), a balance for mass, a thermometer for temperature, a microscope for cells. More examples and 15 practice questions are in TEAS scientific reasoning.
12 quick checks from the sheet
Our own questions on the facts above. Cover the answers. If you miss one, reread its block today, not next week.
- Which chamber of the heart pumps blood into the aorta?
Answer: the left ventricle. - Which hormone raises blood calcium?
Answer: parathyroid hormone (PTH). - Put in order: bronchioles, trachea, alveoli, larynx.
Answer: larynx, trachea, bronchioles, alveoli. - The wrist is ___ to the elbow.
Answer: distal. - A vaccine gives which kind of immunity?
Answer: active (artificial) immunity. Your body makes the antibodies. - Which organelle packages proteins to leave the cell?
Answer: the Golgi apparatus. - Two Aa parents: what share of children show the recessive trait?
Answer: 25%. - An atom has 17 protons and 18 electrons. What is its charge?
Answer: −1. It is an anion (chloride). - Gas turning straight into a solid is called what?
Answer: deposition. - A solution at pH 4 has how many times the H+ of one at pH 6?
Answer: 100 times. - A study gives one group a new sleep routine and measures hours slept. What is the dependent variable?
Answer: hours slept. - Convert 0.75 kg to grams.
Answer: 750 g.
For timed questions in the exam's style across all four areas, take the TEAS science practice test: 20 free questions with answers.
A 7-day review plan with this cheat sheet
About 40 minutes a day: 25 on one block, 15 on questions. It assumes you have studied the topics once already; if a block is new to you, give it two days and use its full guide.
| Day | Review | Done when you can |
|---|---|---|
| 1 | Directions, planes, the systems table | Name each system's job and its most-tested fact from memory |
| 2 | The four flows | Write blood, air, food and urine paths in order without looking |
| 3 | Hormones and the numbers list | Say the gland and effect for every hormone in the table |
| 4 | Biology: cells, mitosis and meiosis, DNA, Punnett squares | Draw an Aa × Aa square and give both ratios in under a minute |
| 5 | Chemistry: atoms, bonds, reactions, pH | Balance a combustion equation; explain pH steps as powers of 10 |
| 6 | Scientific reasoning: variables, graphs, metric | Name the three variables in any described experiment |
| 7 | The 12 quick checks, then a timed science set | 11 of 12 right; reread the block for every miss |
Mistakes that cost points on TEAS science
- Studying chemistry as much as the body. Chemistry is 8 scored questions; anatomy and physiology is 18.
- Calling arteries "oxygen-rich vessels". Arteries go away from the heart. The pulmonary arteries carry low-oxygen blood.
- Mixing up ADH and aldosterone. ADH: keep water. Aldosterone: keep sodium (and water follows).
- Swapping calcitonin and PTH. Calcitonin "tones down" calcium; PTH pulls it up.
- Thinking each pH step is one unit of acid. Each step is ten times.
- Changing subscripts to balance an equation. That makes a different substance; change only the coefficients.
- Reading "controlled variable" as "control group". One is kept the same; the other gets no treatment.
TEAS science cheat sheet FAQ
Is there a TEAS science cheat sheet PDF?
This page is the sheet, and it prints: use your browser's print or save-as-PDF. Several prep sites offer PDF versions behind an email sign-up or for a few dollars; check any sheet against ATI's content outline before you rely on it.
Can you bring a cheat sheet to the TEAS?
No. Notes are not allowed in the exam, in person or remote, and the calculator is built in. Use the sheet in the weeks before; our TEAS exam day tips list what you can bring.
What is the most important science topic on the TEAS?
Human anatomy and physiology: 18 of the 44 scored science questions, more than biology and chemistry together.
Is TEAS science hard?
Many applicants find it the hardest section because it covers the most ground in 60 minutes. The questions are at the level of an introductory course, so steady review of the tables above, plus timed questions, is usually enough to move a score.
How many science questions are on the TEAS 7?
50 questions in 60 minutes; 44 are scored and 6 are unscored pretest questions you can't tell apart. For the whole exam, read what is on the TEAS test.
Sources
- ATI, ATI TEAS exam details: science questions, minutes and content areas. Read for our format guide, October 2026.
- ATI, ATI TEAS Version 7 content outline: the science objectives.
- OpenStax, Anatomy and Physiology 2e, Rice University: systems, flows, hormones, normal values.
- OpenStax, Biology 2e and Chemistry 2e, Rice University: cells, genetics, atoms, bonds, reactions, pH.
- NIST, Metric (SI) prefixes.
More science guides: TEAS anatomy and physiology, TEAS biology, TEAS chemistry, TEAS scientific reasoning, the TEAS science practice test, or all guides. To find out how far your science is from your program's minimum, take the free practice test: 15 questions, scored, with the reason for every answer.