Heart and vessels pump blood, delivering oxygen and nutrients

Lungs exchange oxygen and carbon dioxide

Brain, spinal cord, and nerves sense and control the body

Bones and muscles provide structure, protection, and movement

Breaks food into nutrients and absorbs them

Glands release hormones that regulate body processes

Kidneys filter blood and remove waste as urine

Skin protects, regulates temperature, and senses

Defends against infection and returns fluid to the blood

Produces gametes and, in females, supports pregnancy

How many questions are on the NLN PAX (NEX) and how long is it?

The NLN NEX administers 163 questions in total, of which 145 are scored and 18 are unscored pilot items. It has three sections — Verbal, Mathematics, and Science — each with its own 60-minute limit, for a total testing time of about 3 hours. An on-screen calculator is allowed on the Math and Science sections.

What is a passing score on the NLN PAX?

There is no fixed national passing score. The NEX reports a composite score from 0 to 300, formed by adding your percentile ranks on the three sections, plus a percentile rank for each section against the RN or LPN/VN norm group. Each nursing program sets its own minimum score for admission, so check your target program's requirement.

What does the NLN PAX cover?

Three sections. Verbal (50 scored items) tests word knowledge — prefixes, roots, suffixes, context clues, synonyms and antonyms — and reading comprehension (main idea, details, application, inference). Mathematics (40 items) covers numbers and operations, measurement and proportions, basic algebra, and data interpretation. Science (55 items) covers biology, human anatomy and physiology, chemistry, and health.

Does the NLN PAX have physics or geometry?

Not on the current exam. The 2024 NEX update removed physics, geometry, and earth science. The Science section now focuses on biology, human anatomy and physiology, chemistry, and health, and the Math section focuses on numbers, measurement and proportions, algebra, and data — so this guide does not teach physics or a separate geometry module.

How is the NLN PAX different from the TEAS and HESI A2?

They are three separate nursing-entrance exams. The NLN NEX (formerly PAX) has three sections and a 0–300 percentile-based composite, scored by the NLN. The ATI TEAS 7 has four sections (it adds English & Language Usage) and a 0–100% score. The HESI A2 is a modular battery of up to eight subtests chosen by each school and is scored per section. This guide teaches the PAX/NEX specifically.

Which section should I focus on for the NLN PAX?

Science is the largest section (about 38% of scored items) and historically the lowest-scoring, so it offers the most room to improve — prioritize biology and the body systems (anatomy and physiology). In Math, the Measurement area is the largest, so drill unit conversions and proportions. In Verbal, word parts and context clues give the fastest gains.

Is this NLN PAX study guide free?

Yes — the full guide, the glossary, the concept questions, the practice questions, and the flashcards are 100% free with no account required.

How do prefixes, roots, and suffixes help you figure out a word's meaning?

Most English words are built from word parts: a prefix at the front, a root in the middle, and a suffix at the end. Knowing common ones lets you decode an unfamiliar word — for example, "un-" means not, the root "-spect-" means to look, and "-able" means capable of, so something "inspectable" can be looked at closely. High-yield prefixes include un-/in- (not), re- (again), pre- (before), anti- (against), and hyper-/hypo- (over/under). Common roots include bio (life), cardio (heart), derm (skin), and -ology (the study of) — useful for the medically flavored vocabulary on the PAX.

How do you find the meaning of a word from context clues?

A context clue is information in the surrounding sentence that hints at an unfamiliar word's meaning. Look for definitions or restatements, synonyms, antonyms (signaled by "but," "however," "unlike"), and examples. Read the full sentence, predict a simple substitute word, then pick the answer choice closest to your prediction. Contrast words (however, although, whereas) often signal that the unknown word means the opposite of a nearby word. On a word-knowledge item with no sentence, fall back on word parts and on eliminating choices that are clearly the wrong part of speech.

What is the difference between the main idea and a supporting detail?

The main idea is the single most important point a passage makes — what it is mostly about — often stated in a topic sentence. A supporting detail is a fact, example, reason, or statistic that explains or backs up that main idea. The main idea is general; supporting details are specific. To find the main idea, ask "what one sentence would summarize this whole passage?" — not just one interesting fact from it. A common trap answer is a true detail from the passage that is too narrow to be the main idea.

What is an inference in reading comprehension?

An inference is a logical conclusion you draw from evidence in the text combined with reason — something the author implies but does not state directly. A valid inference stays one small step from the passage and can be supported by a specific line; if you cannot point to evidence for it, it is an over-inference and the wrong answer. Distinguish an inference (supported by the text) from an assumption (something you bring from outside the text). On the PAX, reject any "inference" choice that adds information the passage never gives, even if it sounds reasonable.

What is the difference between an author's purpose and tone?

An author's purpose is the reason they wrote a passage — usually to inform, persuade, entertain, or describe. Tone is the author's attitude toward the subject, conveyed through word choice (for example, hopeful, critical, neutral, or urgent). Purpose is the goal; tone is the feeling behind the words. Match the purpose to how the author actually writes, not how the topic feels — an informational passage on a sad topic is still informative, not persuasive. Identify tone from loaded versus neutral wording: emotional, opinion-laden words signal a persuasive or critical tone.

How do you convert between fractions, decimals, and percents?

To turn a fraction into a decimal, divide the numerator by the denominator (3/4 = 3 ÷ 4 = 0.75). To turn a decimal into a percent, multiply by 100 and add a percent sign (0.75 = 75%). To turn a percent into a decimal, drop the sign and divide by 100 (75% = 0.75). These three forms describe the same value. Memorize the common conversions cold — 1/2 = 0.5 = 50%, 1/4 = 0.25 = 25%, 1/5 = 0.2 = 20%, 1/3 ≈ 0.333 ≈ 33.3%. Converting fractions, decimals, and percents is among the most tested basic-math skills on nursing-entrance exams.

How do you solve a percent word problem?

Anchor every percent problem on one relationship: part = (percent ÷ 100) × whole. Identify the whole (the original or total) first, then plug in. To find a percent, use percent = (part ÷ whole) × 100. For an increase or decrease, use percent change = (new − old) ÷ old × 100. A $80 item marked up to $92 changed by (92 − 80) ÷ 80 × 100 = 15%. Most percent misses come from misreading what is asked — pin down the whole before you compute.

How do you solve a proportion using cross-multiplication?

A proportion sets two ratios equal, like a/b = c/d. Solve it by cross-multiplying: a × d = b × c, then isolate the unknown. For a dose of 5 mg per 10 kg given to a 70 kg patient, set 5/10 = x/70, cross-multiply to 10x = 350, and divide to get x = 35 mg. Keep matching units in matching positions. Proportions handle most dosage, unit-conversion, scaling, and recipe problems on the math section. Always check that your answer is reasonable in size — a setup error usually produces an answer that is wildly too big or small.

What is the order of operations (PEMDAS)?

PEMDAS is the agreed order for evaluating an expression: Parentheses first, then Exponents, then Multiplication and Division (left to right), then Addition and Subtraction (left to right). For 2 + 3 × (4 − 1)², do the parentheses (3), the exponent (9), the multiply (27), then the add (29). Multiplication and division share a rank — work them left to right, not all multiplication before all division. Following the order strictly prevents the most common arithmetic errors on the math section.

How do you convert between metric units like liters and milliliters?

The metric system uses powers of ten, so you move the decimal point. From a larger unit to a smaller one, multiply: 1 liter = 1,000 milliliters, so 2.5 L = 2,500 mL. From smaller to larger, divide: 1 kilogram = 1,000 grams, and 1 meter = 100 centimeters. The prefixes kilo-, centi-, and milli- mean 1,000, 1/100, and 1/1,000. Set conversions up as a proportion with the unit ratio (1 L / 1000 mL) so the units you do not want cancel. Metric conversions appear throughout the math section and are foundational for nursing dosage math later.

What is the function of the mitochondria in a cell?

The mitochondria are the cell's powerhouse: they produce most of the cell's usable energy (ATP) through aerobic cellular respiration. Using oxygen and glucose, they release energy the cell can spend on its activities, which is why highly active cells such as muscle and nerve cells contain many mitochondria. Ribosomes build proteins, the nucleus stores DNA and directs the cell, and the cell membrane controls what enters and leaves. Plant cells add chloroplasts (for photosynthesis), a cell wall, and a large central vacuole — structures animal cells lack.

What is the difference between mitosis and meiosis?

Mitosis is cell division that makes two genetically identical diploid daughter cells, used for growth and repair of body cells. Meiosis makes four genetically varied haploid cells (gametes — egg and sperm) for sexual reproduction, halving the chromosome number so that fertilization restores it. Mitosis copies; meiosis shuffles and halves. The phases of mitosis, in order, are prophase, metaphase, anaphase, and telophase (PMAT), followed by cytokinesis. In metaphase the chromosomes line up along the cell's equator — a frequently tested detail.

What does a Punnett square show in genetics?

A Punnett square predicts the possible genotypes of offspring from a cross. Crossing two heterozygous parents (Aa × Aa) fills the square with AA, Aa, Aa, and aa — a genotype ratio of 1:2:1 and a phenotype ratio of 3 dominant to 1 recessive (3:1). A dominant allele masks a recessive one when both are present. Genotype is the genetic makeup (Aa); phenotype is the observable trait the genotype produces. Only an organism with two recessive alleles (aa) shows the recessive trait.

What is the pH scale and what does it measure?

The pH scale runs from 0 to 14 and measures how acidic or basic a solution is. Below 7 is acidic, 7 is neutral (pure water), and above 7 is basic (alkaline). An acid donates hydrogen ions (H⁺) and a base accepts them or forms hydroxide (OH⁻). The scale is logarithmic, so each whole step is a tenfold change. Human blood is tightly held near pH 7.4 — slightly basic — a key homeostasis fact. Mixing an acid and a base neutralizes them, producing a salt and water.

What is the difference between osmosis and diffusion?

Diffusion is the movement of any particles from an area of higher concentration to lower concentration until they are evenly spread. Osmosis is the diffusion of water specifically, across a selectively permeable membrane, from where water is more concentrated (lower solute) to where it is less concentrated (higher solute). Both are passive — they need no energy. A hypertonic solution has more solute than the cell, so water leaves the cell and it shrinks; a hypotonic solution has less, so water enters and the cell swells. These transport processes underlie how nutrients, gases, and water move in and out of cells.

How does blood flow through the heart?

Oxygen-poor blood returns from the body to the right atrium, passes the tricuspid valve to the right ventricle, and is pumped to the lungs to pick up oxygen. Oxygen-rich blood returns to the left atrium, passes the mitral valve to the left ventricle, and is pumped through the aorta to the body. The left ventricle is the strongest chamber. Arteries carry blood away from the heart and veins carry it back — the pulmonary artery and vein are the famous exceptions. The path is: body → right heart → lungs → left heart → body, a high-yield anatomy and physiology topic.

What is the role of DNA and how does it relate to proteins?

DNA is the molecule that carries an organism's genetic instructions, stored as a sequence of four bases (A, T, C, G) wound in a double helix. A gene is a segment of DNA that codes for a protein. Through transcription DNA is copied into messenger RNA, and through translation ribosomes read that RNA to build proteins. In DNA, adenine pairs with thymine (A–T) and cytosine pairs with guanine (C–G). Proteins do most of the work in cells, so the flow DNA → RNA → protein is central to biology.

What is the difference between an ionic bond and a covalent bond?

An ionic bond forms when one atom transfers electrons to another, creating charged ions that attract — typically between a metal and a nonmetal, as in table salt (sodium chloride). A covalent bond forms when two atoms share electrons, typically between nonmetals, as in water. Ionic transfers; covalent shares. Ionic compounds tend to dissolve in water and conduct electricity when dissolved. The atomic number equals the number of protons and defines which element an atom is.

Pre-Admission Examination — the National League for Nursing's nursing-school entrance exam, now delivered as the NLN NEX (Nursing Entrance Exam).

Nursing Entrance Exam — the current name of the NLN's entrance test, which replaced the PAX in 2024 with the same three-section design.

National League for Nursing — the certifying body that creates and scores the PAX/NEX entrance exam used for nursing-program admission.

The reference population an applicant is compared against to get a percentile rank; the NEX reports separate RN and LPN/VN norm groups.

A score showing the percentage of test-takers in the norm group you scored higher than — a 70th percentile means you beat 70% of that group.

The NEX's overall 0–300 score, formed by summing the three section percentile ranks (Verbal + Math + Science).

Using a word's parts — prefix, root, and suffix — to determine its meaning; the largest Word Knowledge skill on the PAX.

A word part added to the front of a root that changes meaning, e.g. un- (not), re- (again), hyper- (over).

The core part of a word that carries its base meaning, e.g. cardi- (heart), derm- (skin), bio- (life).

A word part added to the end of a root, often changing its part of speech, e.g. -itis (inflammation), -ology (study of).

Information in the surrounding sentence — a definition, synonym, antonym, or example — that hints at an unfamiliar word's meaning.

A word with the same or nearly the same meaning as another (big / large).

A word with the opposite meaning of another (hot / cold).

A fact, example, reason, or statistic that explains or backs up the main idea.

FREE NLN PAX Study Guide 2026 + Quizzes & Readiness Score

This free NLN PAX study guide teaches the highest-yield content the tests for nursing-school admission, organized by its three sections — Verbal Ability, Mathematics, and Science.^[1]

Important: the PAX is now delivered as the . The NLN replaced the PAX with the NEX in 2024, keeping the same three-section design — so many programs still say “PAX” while administering the NEX. This guide teaches the current exam, which means it does not cover physics, geometry, or earth science (those were removed in the 2024 update).^[1]^[2]

It is interactive, not a wall of text: every section has worked examples, labeled diagrams, data tables that quiz you back, and built-in flashcards. Read it section by section, then round out your prep with our practice questions and flashcards. The PAX is one of three common nursing-entrance exams — alongside the ATI TEAS and the HESI A2 — but it is a separate test with its own sections and scoring, taught here specifically.

NLN PAX (NEX) Exam Snapshot

NLN PAX / NEX exam at a glance (2026)
Detail	NLN PAX (now the NEX)
Sections	3 — Verbal, Mathematics, Science
Questions	163 total; 145 scored + 18 unscored pilot
Format	Computer-based, 4-option multiple choice (linear, not adaptive)
Time limit	60 minutes per section — 180 minutes (3 hours) total
Calculator	On-screen calculator allowed on Math and Science
Scoring	Composite 0–300 (sum of the three section percentile ranks)
Norm groups	Separate RN and LPN/VN percentile norms
Passing score	No fixed national cutoff — each program sets its own
Cost	~$52–88 depending on school and proctoring (dated anchor — verify)
Retake	≥30 days between attempts; programs may add stricter limits
Certifying body	National League for Nursing (NLN)

Science is the largest section, at roughly 38% of scored items, followed by Verbal (~34%) and Mathematics (~28%).^[2] Because Science is also historically the lowest-scoring section, it usually offers the most room to raise your composite — so the biology and body-systems content deserves the most study time.

NLN PAX (NEX) weighting by section (share of scored items)

Science38% · 55 scored items — the largest section

Verbal Ability34% · 50 scored items (Word Knowledge + Reading)

Mathematics28% · 40 scored items

Percentages are each section’s share of the 145 scored items.^[2] This guide teaches all three sections as three study modules, so the structure matches the NLN NEX blueprint.

How the PAX (NEX) Is Built

The PAX/NEX follows the NLN’s official blueprint, which groups every scored item into three subject tests. The exam is linear (each test-taker gets a fixed-length form built to the blueprint) — not computer-adaptive. There is no guessing penalty, so an unanswered question counts as wrong; always answer every item.^[1]^[2]

Verbal Ability (~34%, 50 scored items) — (prefixes, roots, suffixes, context clues, synonyms and antonyms, confused words) and Reading Comprehension (main idea, supporting details, application, and inference).
Mathematics (~28%, 40 scored items) — Numbers & Operations, Measurement (the largest math area — conversions and proportions), Algebra, and Data & Information.
Science (~38%, 55 scored items) — Biology (the largest), Human Anatomy and Physiology (the body systems), Chemistry, and Health.

Each section is scored as a against a (RN or LPN/VN), and the three are summed into a 0–300 . Because there is no universal passing score, your goal is to beat your target program’s cutoff — so know what score your school requires before test day.^[2]

Verbal Ability

Verbal Ability is about 34% of the exam (50 scored items).^[2] It splits evenly into Word Knowledge (25 items) and Reading Comprehension (25 items). The vocabulary leans medical, so the word-attack skills below pay off twice — on the PAX and later in nursing school.

How the Verbal Section Is Built

Word Knowledge tests two skills: Word Analysis (using prefixes, roots, and suffixes — the largest single Verbal skill) and Vocabulary Development (context clues, synonyms, antonyms, and frequently-confused words). Reading Comprehension tests reading for information (main idea and details), application, and inference from short informational passages at roughly a 9th-grade-and-up reading level.^[1]

What the Verbal section tests
Skill	What it asks	How to attack it
Word Analysis	Meaning from prefix + root + suffix	Learn common affixes and medical roots
Vocabulary Development	Context clues, synonyms, antonyms, confused words	Predict a substitute word from the sentence
Reading for Information	Main idea and supporting details	Find the one summarizing sentence first
Application & Inference	Apply or extend the passage's ideas	Stay one step from the text; prove it from a line

Word Knowledge: Prefixes, Roots & Suffixes

Most English words are built from parts. A sits at the front and changes meaning; a carries the core meaning; a ends the word and often sets its part of speech. — decoding a word from its parts — is the largest single Word Knowledge skill, so this is the highest-leverage Verbal study you can do.^[1]

Decode a word from its parts — prefix + root + suffix

Prefix

un-

“not / reverse”

Root

-spect-

“to look”

Suffix

-able

“capable of”

un- + -spect- + -able → “unsuspectable” = not able to be looked at / noticed. Learn the common roots and you can decode words you have never seen.

Break an unfamiliar word into its prefix, root, and suffix to predict its meaning — the core Word Analysis skill on the PAX.

High-yield word parts (many are medical)
Word part	Meaning	Example
un- / in-	not	unbiased, inactive
hyper- / hypo-	over / under	hypertension, hypoglycemia
anti-	against	antibiotic, antiseptic
cardi-	heart	cardiology, cardiac
derm-	skin	dermatitis, dermatology
-itis	inflammation	arthritis, dermatitis
-ology	study of	biology, pathology
-ectomy	surgical removal	appendectomy

Context Clues & Confused Words

When a word sits in a sentence, use the around it. Look for a definition or restatement, a , an (often signaled by but, however, or unlike), or an example. Read the whole sentence, predict a simple substitute word, then choose the answer closest to your prediction.^[6]

Vocabulary Development also tests frequently-confused words — pairs that sound or look alike but differ in meaning. The most common are affect (usually a verb) vs effect (usually a noun), their / there / they’re, principal (main / a person) vs principle (a rule), and fewer (count) vs less (amount).^[6]

Reading: Main Idea & Details

The is the single most important point a passage makes — what it is mostly about — often stated in a topic sentence near the start or end. A is a fact, example, reason, or statistic that backs up that main idea. The main idea is general; details are specific.^[6]

Reading: Application & Inference

Application items ask you to take an idea from the passage and apply it to a new situation. Inference items ask for a conclusion the author implies but does not state outright. A valid stays one small step from the text and can be supported by a specific line — if you cannot point to the evidence, it is an over-inference and the wrong choice.^[6]

Checkpoint · Verbal Ability

Question 1 of 10

In the context of a medical research article, if a study is described as "double-blind," what does this imply?

Mathematics

Mathematics is about 28% of the exam (40 scored items).^[2] It runs from grade-8 arithmetic through Algebra I, and an on-screen calculator is allowed — so the challenge is setup and reading, not heavy computation. There is no geometry module on the current exam; the 2024 update removed it, so this guide folds only the most basic area ideas into measurement word problems.^[1]

How the Math Section Is Built

The math section has four content areas: Numbers & Operations (12 items — integers, decimals, fractions, percents), Measurement (14 items — the largest — unit conversions that keep a ratio or proportion, plus basic formulas), Algebra (7 items — solving equations and inequalities, order of operations), and Data & Information (7 items — descriptive statistics and reading graphs).^[1]^[2]

Mathematics content areas (share of the 40 scored math items)

Measurement35% · 14 items — conversions & proportions

Numbers & Operations30% · 12 items — fractions, decimals, percents

Algebra18% · 7 items

Data & Information18% · 7 items

Numbers: Fractions, Decimals & Percents

The most-tested and most-missed basic-math skill is moving among fractions, decimals, and percents. To turn a fraction into a decimal, divide the by the : $3/4 = 3 \div 4 = 0.75$ . To turn a decimal into a , multiply by 100: $0.75 = 75\%$ . Memorize the common conversions cold ( $1/2 = 0.5 = 50\%$ , $1/4 = 0.25 = 25\%$ , $1/5 = 0.2 = 20\%$ ).^[5]

Percent word problems all rest on one relationship: $\text{part} = (\text{percent} \div 100) \times \text{whole}$ . Identify the whole first, then rearrange to find what is asked. For an increase or decrease, use $\text{percent change} = \frac{\text{new} - \text{old}}{\text{old}} \times 100$ .^[5]

One relationship behind every percent problem

part = (percent ÷ 100) × whole

percent = (part ÷ whole) × 100

whole = part ÷ (percent ÷ 100)

percent change = (new − old) ÷ old × 100

Identify the WHOLE first (the original or total), then plug into the matching rearrangement. Most word-problem misses come from misreading what is asked.

Every percent problem comes from one relationship — find the WHOLE first, then rearrange for the part, the percent, or a percent change.

Measurement: Conversions & Proportions

Measurement is the largest math area, and it is essentially and work — the same skill behind nursing dosage math. The metric system uses powers of ten, so converting is just moving a decimal: $1 \text{ L} = 1000 \text{ mL}$ and $1 \text{ kg} = 1000 \text{ g}$ . Solve a proportion by : for $a/b = c/d$ , cross to $a \times d = b \times c$ , then isolate the unknown.^[5]

Solving a proportion word problem

1
Step 1
Set up two ratios with matching units in the same positions (e.g., mg/kg = mg/kg).
2
Step 2
Write them equal as a proportion: $a/b = c/x$ .
3
Step 3
Cross-multiply: $a \times x = b \times c$ .
4
Step 4
Divide to isolate $x$ .
5
Step 5
Check the units and that the answer is a reasonable size.

Algebra & Order of Operations

Algebra items are pre-algebra through Algebra I: solve a linear equation or inequality for a variable, and evaluate expressions using the (PEMDAS: Parentheses, Exponents, Multiplication/Division left-to-right, Addition/Subtraction left-to-right). To solve, undo operations in reverse and keep both sides balanced.^[5]

Data & Information: Statistics & Graphs

Data items test descriptive statistics and reading figures. The is the average; the is the middle of an ordered set; the is the most frequent value; and the is the largest minus the smallest. On graph and table items, read the axis labels and scale before choosing an answer.^[5]

A few items still fold in basic area or perimeter inside a word problem, so keep the simplest formulas handy: rectangle area $= L \times W$ , and for a right triangle the Pythagorean theorem $a^2 + b^2 = c^2$ . There is no standalone geometry section to study, however.

Pythagorean theorem — the 3-4-5 right triangle

a² + b² = c² → 3² + 4² = 9 + 16 = 25 → c = √25 = 5

The Pythagorean theorem for a right triangle — the 3-4-5 triangle is the classic example. Basic area shows up only inside measurement word problems, not a separate geometry section.

Checkpoint · Mathematics

Question 1 of 10

What is the next number in the sequence: 2, 6, 18, 54, ..

Science

Science is the largest section — about 38% of scored items (55 questions).^[2] It is also historically the lowest-scoring, so it is the best place to raise your composite.

It covers four areas: Biology (the largest), Human Anatomy and Physiology (the body systems — together about 40% of the section), Chemistry (small), and Health. The current exam has no physics and no earth science — the 2024 update removed them.^[1]

How the Science Section Is Built

The 55 scored Science items break down as Biology (20), Human Anatomy (11), Human Physiology (11), Chemistry (5), and Health (8). Biology plus Anatomy & Physiology together make up the great majority of the section, so weight your study heavily there.^[1]^[2]

Science content areas (share of the 55 scored Science items)

Biology36% · 20 items — the largest area

Anatomy & Physiology40% · 22 items combined — the body systems

Health15% · 8 items

Chemistry9% · 5 items — keep it lean

Biology: Cells, Mitosis & Genetics

Start with the and its organelles: the stores DNA and directs the cell, the make ATP energy, and the build proteins. Plant cells add a cell wall, chloroplasts, and a large vacuole that animal cells lack.^[4]

Animal cell organelles → what each one does

Nucleus

Control center — holds DNA and directs the cell

Mitochondria

Powerhouse — makes ATP through cellular respiration

Ribosomes

Build proteins by translating mRNA

Endoplasmic reticulum

Transport network; rough ER has ribosomes, smooth ER makes lipids

Golgi apparatus

Packages and ships proteins (the post office)

Cell membrane

Selectively controls what enters and leaves the cell

Cytoplasm

Gel-like fluid where organelles sit and reactions occur

Lysosome

Digestive sac — breaks down waste and worn-out parts

Plant cells add a cell wall, chloroplasts (photosynthesis), and a large central vacuole — animal cells have none of these.

The main animal-cell organelles and what each one does — the foundation of the Biology area.

divides a body cell into two genetically identical diploid daughter cells for growth and repair, through the phases prophase, metaphase, anaphase, and telophase (PMAT) plus cytokinesis. In metaphase the chromosomes line up along the cell’s middle. instead makes four genetically varied haploid gametes.^[4]

Mitosis — the phases in order (PMAT + cytokinesis)

1Prophase

Chromatin condenses into visible chromosomes; the nuclear envelope breaks down and spindle fibers form.

2Metaphase

Chromosomes line up single-file along the cell's middle (the metaphase / equatorial plate).

3Anaphase

Sister chromatids are pulled apart to opposite poles of the cell.

4Telophase

Two new nuclear envelopes form around each set of chromosomes; the cell nearly splits.

5Cytokinesis

The cytoplasm divides, producing two genetically identical diploid daughter cells.

Memory aid: “PMAT” — Prophase, Metaphase, Anaphase, Telophase. Mitosis makes 2 identical diploid cells; meiosis makes 4 genetically varied haploid gametes.

The phases of mitosis in order (PMAT + cytokinesis). Mitosis makes two identical cells; meiosis makes four varied gametes.

Genetics is light but tested. A (uppercase) masks a one (lowercase). A monohybrid cross $Aa \times Aa$ on a gives a 1:2:1 genotype ratio and a 3:1 phenotype ratio — only the offspring shows the recessive .^[4]

Punnett square: Aa × Aa → 3:1 phenotype ratio

Genotype ratio — 1 AA : 2 Aa : 1 aa (1:2:1)

Phenotype ratio — 3 dominant : 1 recessive (3:1)

A monohybrid Aa × Aa Punnett square: a 1:2:1 genotype ratio and a 3:1 phenotype ratio — only aa shows the recessive trait.

Round out biology with (the double-helix that stores genes; A pairs with T, C with G), the difference between (diffusion of water) and (any particles, high to low concentration), and the two energy reactions — photosynthesis (builds glucose in chloroplasts) and cellular respiration (releases ATP in mitochondria).^[4]

Anatomy & Physiology: The Body Systems

Anatomy (structure) and Physiology (function) together are the dominant Science content — the 11 body systems and how they work, all coordinated to maintain (a stable internal environment).^[4]

The body systems and their main jobs
System	Main function
Cardiovascular	Heart and vessels pump blood, delivering oxygen and nutrients
Respiratory	Lungs exchange oxygen and carbon dioxide
Nervous	Brain, spinal cord, and nerves sense and control the body
Musculoskeletal	Bones and muscles provide structure, protection, and movement
Digestive	Breaks food into nutrients and absorbs them
Endocrine	Glands release hormones that regulate body processes
Urinary	Kidneys filter blood and remove waste as urine
Integumentary	Skin protects, regulates temperature, and senses
Lymphatic / immune	Defends against infection and returns fluid to the blood
Reproductive	Produces gametes and, in females, supports pregnancy

The cardiovascular system is the most-tested. Oxygen-poor blood enters the right atrium and right ventricle and is pumped to the lungs; oxygen-rich blood returns to the left atrium and left ventricle and is pumped through the aorta to the body — so the path is body → right heart → lungs → left heart → body. Arteries carry blood away from the heart and veins return it; the pulmonary artery and vein are the famous exceptions.^[4]

Chemistry: Matter, Bonds & pH

Chemistry is a small area (about 5 items), so learn the essentials and move on. An atom’s (its proton count) defines the element.

An transfers electrons (metal + nonmetal, like table salt); a shares electrons (nonmetals, like water). A physical change keeps the substance (melting ice stays $\ce{H2O}$ ); a chemical change makes a new substance (rusting).^[4]

Master the (0–14): below 7 is acidic, 7 is neutral, above 7 is basic. It is logarithmic, so pH 3 is ten times more acidic than pH 4. An donates $\ce{H+}$ , a forms $\ce{OH-}$ , and neutralization yields a salt plus water. Human blood is held near pH 7.4.^[4]

The pH scale (0–14) — acids, neutral, bases

0–2

3–4

5–6

8–9

10–11

12–14

Strong acid

Stomach acid, lemon

Acidic

Soda, vinegar

Weak acid

Coffee, rain

Neutral

Pure water, blood ≈7.4

Weak base

Baking soda, sea water

Basic

Ammonia

Strong base

Bleach, lye

← more acidic (more H⁺)more basic (more OH⁻) →

The 0–14 pH scale: below 7 acidic, 7 neutral, above 7 basic. Each step is a tenfold change because the scale is logarithmic.

Health

The Health area (about 8 items) tests everyday personal-health knowledge: substance use and its effects, physical health and nutrition, human growth and development across the life span, mental and emotional health, and prevention and safety (including the physical environment). These are common-sense, health-literacy items — review the basics rather than memorizing details.^[4]

Checkpoint · Science

Question 1 of 10

What is the primary function of ribosomes in a eukaryotic cell?

How to Use This Study Guide

Work through the guide one section at a time. After each one, check it off in the contents to raise your exam-readiness score, then drill the same content in our free practice questions and flashcards — active recall and timed practice are what move knowledge into test-day performance.

A high-yield NLN PAX study sequence

1
Step 1
Start with Science — it is the largest section (~38%) and the most improvable. Lock in cells, mitosis, genetics, and the body systems.
2
Step 2
Finish Science with the lean Chemistry essentials (bonds, pH) and review the common-sense Health topics.
3
Step 3
Move to Mathematics: master fraction/decimal/percent conversions, then the largest area — measurement conversions and proportions.
4
Step 4
Cover the Math algebra and data items: solving equations, PEMDAS, and mean/median/mode/range. Skip geometry — it is no longer tested.
5
Step 5
Finish with Verbal: ~30 word parts and context-clue strategy, then reading for main idea, application, and inference. Then take full practice tests.

Weight your time by the sections. Science is the biggest and the most improvable — start there and give it the most time.
Make the conversions automatic. Fractions ↔ decimals ↔ percents, and metric unit conversions, are the densest, most-tested math.
Build a word-parts list. ~30 common affixes and medical roots unlock dozens of Verbal items.
Study the current exam. Don’t waste time on physics, geometry, or earth science — the 2024 NEX update removed them.
Then prove it. When a section feels easy, confirm it with our practice questions and flashcards — aim for 80%+ before test day.

Common questions PAX candidates search and get asked across all three sections — each answered briefly and backed by an official source (the NLN, NIH/MedlinePlus, NIST, or Purdue OWL). Tap any card to test yourself.

NLN PAX Concept Questions

NLN PAX Glossary

Key PAX terms in one place. Hover any dotted term throughout the guide for its definition; the full list is below.

PAX: Pre-Admission Examination — the National League for Nursing's nursing-school entrance exam, now delivered as the NLN NEX (Nursing Entrance Exam).
NEX: Nursing Entrance Exam — the current name of the NLN's entrance test, which replaced the PAX in 2024 with the same three-section design.
NLN: National League for Nursing — the certifying body that creates and scores the PAX/NEX entrance exam used for nursing-program admission.
norm group: The reference population an applicant is compared against to get a percentile rank; the NEX reports separate RN and LPN/VN norm groups.
percentile rank: A score showing the percentage of test-takers in the norm group you scored higher than — a 70th percentile means you beat 70% of that group.
composite score: The NEX's overall 0–300 score, formed by summing the three section percentile ranks (Verbal + Math + Science).
word analysis: Using a word's parts — prefix, root, and suffix — to determine its meaning; the largest Word Knowledge skill on the PAX.
prefix: A word part added to the front of a root that changes meaning, e.g. un- (not), re- (again), hyper- (over).
root: The core part of a word that carries its base meaning, e.g. cardi- (heart), derm- (skin), bio- (life).
suffix: A word part added to the end of a root, often changing its part of speech, e.g. -itis (inflammation), -ology (study of).
context clue: Information in the surrounding sentence — a definition, synonym, antonym, or example — that hints at an unfamiliar word's meaning.
synonym: A word with the same or nearly the same meaning as another (big / large).
antonym: A word with the opposite meaning of another (hot / cold).
main idea: The single most important point a passage makes — what it is mostly about.
supporting detail: A fact, example, reason, or statistic that explains or backs up the main idea.
inference: A logical conclusion drawn from textual evidence plus reasoning — what the author implies but does not state directly.
numerator: The top number of a fraction, showing how many parts are taken (the 3 in 3/4).
denominator: The bottom number of a fraction, showing how many equal parts the whole is divided into (the 4 in 3/4).
percent: A ratio out of 100; 75% means 75 per 100, or 0.75 as a decimal.
ratio: A comparison of two quantities, written 3:4 or 3/4.
proportion: An equation stating that two ratios are equal, solved by cross-multiplication.
cross-multiplication: Solving a proportion a/b = c/d by multiplying a × d = b × c, then isolating the unknown.
order of operations: The agreed sequence for evaluating an expression — PEMDAS: Parentheses, Exponents, Multiplication/Division, Addition/Subtraction.
mean: The arithmetic average — add the values and divide by how many there are.
median: The middle value of an ordered data set.
mode: The value that appears most often in a data set.
range: The difference between the largest and smallest values in a data set.
cell: The basic structural and functional unit of all living things.
mitochondria: The organelles that produce most of a cell's ATP energy through cellular respiration — the cell's powerhouse.
nucleus: The organelle that stores a cell's DNA and directs its activities.
ribosome: The cell structure that builds proteins by translating messenger RNA.
mitosis: Cell division producing two genetically identical diploid daughter cells, used for growth and repair.
meiosis: Cell division producing four genetically varied haploid gametes for sexual reproduction.
genotype: An organism's genetic makeup for a trait, e.g. Aa.
phenotype: The observable trait produced by a genotype, e.g. brown eyes.
dominant allele: An allele that masks a recessive one and is expressed whenever present (written uppercase, e.g. A).
recessive allele: An allele expressed only when two copies are present (written lowercase, e.g. a).
Punnett square: A grid used to predict the genotypes and phenotypes of offspring from a genetic cross.
DNA: Deoxyribonucleic acid — the double-helix molecule that stores genetic instructions in sequences of A, T, C, and G.
osmosis: The diffusion of water across a selectively permeable membrane from lower to higher solute concentration.
diffusion: The movement of particles from an area of higher concentration to lower concentration.
homeostasis: The body's maintenance of a stable internal environment despite external changes, via feedback loops.
ionic bond: A bond formed when one atom transfers electrons to another, creating attracting charged ions (metal + nonmetal).
covalent bond: A bond formed when two atoms share electrons (nonmetal + nonmetal).
atomic number: The number of protons in an atom, which defines the element.
pH: A 0–14 measure of how acidic or basic a solution is; below 7 is acidic, 7 neutral, above 7 basic.
acid: A substance that donates hydrogen ions (H⁺) in solution and has a pH below 7.
base: A substance that accepts hydrogen ions or forms hydroxide (OH⁻) and has a pH above 7.

NLN PAX Study Guide FAQ

Yes — the NEX (Nursing Entrance Exam) is the current version of the NLN PAX. The National League for Nursing replaced the PAX with the NEX in 2024, keeping the same three-section design (Verbal, Mathematics, Science). Many programs still call it the PAX, and some accept older PAX scores, so the names refer to the same nursing-entrance exam.

References

1.National League for Nursing (NLN). “NEX (Nursing Entrance Exam) — Assessment Page & Technical Brief (formerly the PAX; updated Jan 26, 2026).” NLN. ↑
2.National League for Nursing (NLN). “NEX Technical Manual — Blueprint, Scoring (Composite 0–300), and Norm Groups.” NLN. ↑
3.National League for Nursing (NLN). “Student Resources — Registration, Scores & Retake Policy.” NLN. ↑
4.National Institutes of Health / National Library of Medicine. “StatPearls & MedlinePlus (cell biology, genetics, body systems, acids & bases).” NIH/NLM. ↑
5.National Institute of Standards and Technology (NIST). “The International System of Units (SI) — Units, Conversions & Measurement.” NIST. ↑
6.Purdue Online Writing Lab (OWL). “General Writing — Vocabulary, Reading Comprehension & the Rhetorical Situation.” Purdue OWL. ↑
101.National Institutes of Health / National Library of Medicine. “MedlinePlus — Understanding Medical Words.” NIH/NLM, accessed 19 June 2026. ↑

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