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9th-grade-vocabulary-words

English Vocabulary · Grade 9 Live Review Preview

9th Grade Vocabulary Words

Ninth grade marks the transition to high-school reading and writing across literature, argument, research, biology, physical and Earth science, algebra, computing, world history, civics, and geography. This level develops precise academic and domain-specific vocabulary while strengthening context, nuance, source evaluation, figurative language, and evidence-based communication.

This independently authored 800-word beta curriculum is arranged in twenty-three pages of up to thirty-five words. Pages containing words 1–500 include five cloze questions drawn only from that enhanced range; words 501–800 remain fully visible and editable as list pages while the expanded practice layer is developed. Each row includes a subject-field label and an editable word-study note about a transparent affix, compound structure, capitalization, or dictionary base form. The cited Grade 9 resources calibrate difficulty and study skills only; all learner-facing definitions, examples, quizzes, and descriptions are original KSSR copy.

Please note: the vocabulary lists for grades 9~11 have been selected to ensure no overlap with the previous grade level. If the words are too specialized or difficult for you, please go back to grade levels 4~8 and review the words on those pages.

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800 words
Words 211–245 of 800
#WordDetailsMeaningSample sentence
211prokaryotenoun
Study

Field: Grade 9 life-science and ecology term

Word study: Base-form focus: prokaryote is the dictionary headword; compare its inflected or derived forms in context.

an organism whose cell lacks a nucleus and other membrane-bound organellesA bacterium is a prokaryote with DNA located in its cell interior.
212eukaryotenoun
Study

Field: Grade 9 life-science and ecology term

Word study: Base-form focus: eukaryote is the dictionary headword; compare its inflected or derived forms in context.

an organism whose cells contain a nucleus and membrane-bound organellesA mushroom is a eukaryote because its cells enclose DNA inside nuclei.
213facilitated diffusionnoun
Study

Field: Grade 9 life-science and ecology term

Word study: Term structure: facilitated + diffusion. Study the complete expression as one field-specific unit.

passive movement across a membrane through a transport proteinGlucose can enter some cells by facilitated diffusion.
214osmosisnoun
Study

Field: Grade 9 life-science and ecology term

Word study: Base-form focus: osmosis is the dictionary headword; compare its inflected or derived forms in context.

the movement of water across a selectively permeable membrane toward greater solute concentrationThrough osmosis, water entered the cell from the dilute solution.
215active transportnoun
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Field: Grade 9 life-science and ecology term

Word study: Term structure: active + transport. Study the complete expression as one field-specific unit.

movement across a cell membrane that requires energy, often against a concentration differenceThe sodium-potassium pump uses active transport.
216passive transportnoun
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Field: Grade 9 life-science and ecology term

Word study: Term structure: passive + transport. Study the complete expression as one field-specific unit.

movement across a cell membrane without the cell spending energySimple diffusion is a form of passive transport.
217concentration gradientnoun
Study

Field: Grade 9 life-science and ecology term

Word study: Term structure: concentration + gradient. Study the complete expression as one field-specific unit.

a difference in the amount of a substance across a distance or membraneOxygen moves down its concentration gradient into the cell.
218selectively permeableadjective
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Field: Grade 9 life-science and ecology term

Word study: Term structure: selectively + permeable. Study the complete expression as one field-specific unit.

allowing some substances to cross while blocking othersThe cell membrane is selectively permeable.
219enzyme specificitynoun
Study

Field: Grade 9 life-science and ecology term

Word study: Term structure: enzyme + specificity. Study the complete expression as one field-specific unit.

the tendency of an enzyme to act only on a particular substrate or small group of substratesEnzyme specificity allows lactase to act on lactose rather than every sugar.
220substratenoun
Study

Field: Grade 9 life-science and ecology term

Word study: Base-form focus: substrate is the dictionary headword; compare its inflected or derived forms in context.

the substance on which an enzyme actsThe substrate fits into the enzyme's active site.
221activation energynoun
Study

Field: Grade 9 life-science and ecology term

Word study: Term structure: activation + energy. Study the complete expression as one field-specific unit.

the minimum energy needed to begin a chemical reactionAn enzyme lowers the activation energy of a cellular reaction.
222cellular respirationnoun
Study

Field: Grade 9 life-science and ecology term

Word study: Term structure: cellular + respiration. Study the complete expression as one field-specific unit.

the process by which cells release usable energy from food moleculesDuring cellular respiration, cells transfer energy from glucose into ATP.
223light-dependent reactionnoun
Study

Field: Grade 9 life-science and ecology term

Word study: Term structure: light + dependent + reaction. Study the complete expression as one field-specific unit.

the stage of photosynthesis that captures light energy and splits waterThe light-dependent reaction occurs in the thylakoid membranes.
224glycolysisnoun
Study

Field: Grade 9 life-science and ecology term

Word study: Base-form focus: glycolysis is the dictionary headword; compare its inflected or derived forms in context.

the first stage of glucose breakdown, occurring in the cell's cytoplasmGlycolysis splits one glucose molecule into smaller molecules.
225fermentationnoun
Study

Field: Grade 9 life-science and ecology term

Word study: Suffix focus: -ation commonly forms a noun naming an action, process, or result.

an energy-releasing process that allows glycolysis to continue without oxygenYeast uses fermentation to produce carbon dioxide in bread dough.
226aerobicadjective
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Field: Grade 9 life-science and ecology term

Word study: Base-form focus: aerobic is the dictionary headword; compare its inflected or derived forms in context.

requiring or occurring in the presence of oxygenAerobic respiration releases more usable energy than fermentation.
227anaerobicadjective
Study

Field: Grade 9 life-science and ecology term

Word study: Base-form focus: anaerobic is the dictionary headword; compare its inflected or derived forms in context.

occurring without oxygenSome microorganisms carry out anaerobic metabolism in deep mud.
228ATPnoun
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Field: Grade 9 life-science and ecology term

Word study: Capitalization focus: ATP is an abbreviation or initialism; preserve its capital letters.

a molecule that transfers immediately usable energy within cellsMuscle contraction uses energy released when ATP loses a phosphate group.
229metabolic regulationnoun
Study

Field: Grade 9 life-science and ecology term

Word study: Term structure: metabolic + regulation. Study the complete expression as one field-specific unit.

control of the chemical pathways that sustain an organismMetabolic regulation slows a pathway when enough of its product has accumulated.
230metabolic pathwaynoun
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Field: Grade 9 life-science and ecology term

Word study: Term structure: metabolic + pathway. Study the complete expression as one field-specific unit.

a linked series of chemical reactions in a cellEach step of a metabolic pathway is usually controlled by a particular enzyme.
231amino acidnoun
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Field: Grade 9 life-science and ecology term

Word study: Term structure: amino + acid. Study the complete expression as one field-specific unit.

a small organic molecule that serves as a building block of proteinsThe order of each amino acid determines how a protein folds.
232nucleotidenoun
Study

Field: Grade 9 life-science and ecology term

Word study: Base-form focus: nucleotide is the dictionary headword; compare its inflected or derived forms in context.

the basic building block of DNA and RNA, containing a sugar, phosphate, and nitrogenous baseA nucleotide in DNA may contain the base adenine.
233nucleic acidnoun
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Field: Grade 9 life-science and ecology term

Word study: Term structure: nucleic + acid. Study the complete expression as one field-specific unit.

a DNA or RNA molecule that stores or helps express genetic informationDNA is a nucleic acid made of two nucleotide strands.
234carbohydratenoun
Study

Field: Grade 9 life-science and ecology term

Word study: Base-form focus: carbohydrate is the dictionary headword; compare its inflected or derived forms in context.

an organic molecule of sugars that can provide energy or structural materialA potato stores carbohydrate mainly as starch.
235lipidnoun
Study

Field: Grade 9 life-science and ecology term

Word study: Base-form focus: lipid is the dictionary headword; compare its inflected or derived forms in context.

a water-insoluble organic molecule such as a fat, oil, wax, or steroidA phospholipid is a lipid found in cell membranes.
236phospholipidnoun
Study

Field: Grade 9 life-science and ecology term

Word study: Base-form focus: phospholipid is the dictionary headword; compare its inflected or derived forms in context.

a lipid with a water-attracting head and water-repelling tailsPhospholipid molecules form a double layer around the cell.
237macromoleculenoun
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Field: Grade 9 life-science and ecology term

Word study: Prefix focus: macro- means large-scale.

a very large biological molecule built from smaller unitsA protein is a macromolecule made from amino acids.
238polymernoun
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Field: Grade 9 life-science and ecology term

Word study: Base-form focus: polymer is the dictionary headword; compare its inflected or derived forms in context.

a large molecule formed from many repeating or related smaller unitsStarch is a polymer composed of glucose units.
239monomernoun
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Field: Grade 9 life-science and ecology term

Word study: Base-form focus: monomer is the dictionary headword; compare its inflected or derived forms in context.

a small molecular unit that can join with others to form a polymerA nucleotide acts as a monomer in a nucleic acid.
240protein foldingnoun
Study

Field: Grade 9 life-science and ecology term

Word study: Term structure: protein + folding. Study the complete expression as one field-specific unit.

the process by which a protein chain takes on its functional three-dimensional shapeA temperature change can disrupt protein folding.
241chromosome duplicationnoun
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Field: Grade 9 life-science and ecology term

Word study: Term structure: chromosome + duplication. Study the complete expression as one field-specific unit.

the copying of a chromosome's DNA before cell divisionChromosome duplication produces two sister chromatids.
242chromatidnoun
Study

Field: Grade 9 life-science and ecology term

Word study: Base-form focus: chromatid is the dictionary headword; compare its inflected or derived forms in context.

one of two identical DNA copies joined after a chromosome is duplicatedEach chromatid separates during mitosis.
243centromerenoun
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Field: Grade 9 life-science and ecology term

Word study: Base-form focus: centromere is the dictionary headword; compare its inflected or derived forms in context.

the chromosome region that joins sister chromatids and attaches to division machinerySpindle fibers connect near the centromere.
244homologous pairnoun
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Field: Grade 9 life-science and ecology term

Word study: Term structure: homologous + pair. Study the complete expression as one field-specific unit.

two chromosomes carrying the same kinds of genes, one inherited from each parentA homologous pair may contain different alleles of a gene.
245gametenoun
Study

Field: Grade 9 life-science and ecology term

Word study: Base-form focus: gamete is the dictionary headword; compare its inflected or derived forms in context.

a reproductive cell containing one set of chromosomesA human gamete has twenty-three chromosomes.

Vocabulary reading and practice

Energy and Cell Division

Reading practice for pages 7–9. Five relevant words are highlighted.

English reading

Before a cell divides, chromosome duplication preserves genetic instructions for both new cells. ATP supplies energy for active transport, which moves substances against a concentration gradient. Passive transport requires no direct energy input. Meanwhile, correct protein folding allows many cell structures and enzymes to function as their shapes require.

Reading comprehension

1. Why does chromosome duplication occur?

It preserves genetic instructions for both new cells.

2. Which process uses ATP?

Active transport uses ATP.

3. Why is protein folding important?

A protein's shape enables its function.

Vocabulary quiz

Complete 5 review questions for this page.

1. A temperature change can disrupt ___.

Answer: protein folding

2. The sodium-potassium pump uses ___.

Answer: active transport

3. Muscle contraction uses energy released when ___ loses a phosphate group.

Answer: ATP

4. ___ produces two sister chromatids.

Answer: chromosome duplication

5. Simple diffusion is a form of ___.

Answer: passive transport

Sources and curriculum references

These references guide selection and calibration. Definitions, sample sentences, readings, questions, and teaching notes are independently written and reviewed.