Texas STAAR Biology EOC: complete guide to the redesigned end-of-course exam, the TEKS reporting categories, the new question types, and how to study each topic

The Texas STAAR Biology End-of-Course (EOC) exam is the high school biology assessment written by the Texas Education Agency (TEA) and aligned to the Texas Essential Knowledge and Skills (TEKS). It is a graduation-required exam. This page is the index: it explains the redesigned question types, the five reporting categories, the format and scoring, and how to study each content domain. The content is organized into six modules that mirror the five TEKS reporting categories, plus a module on the investigation and reasoning skills the exam embeds everywhere.

What STAAR Biology is

STAAR stands for the State of Texas Assessments of Academic Readiness. The high school program is made up of end-of-course (EOC) exams taken when a student finishes the matching course. Biology is one of five EOC exams required for a Texas high school diploma, alongside Algebra I, English I, English II, and U.S. History. Most students sit STAAR Biology in 9th or 10th grade, in the spring administration, with summer and fall retest windows for students who need to test again.

Every STAAR Biology question is aligned to the Biology TEKS, the state standards adopted by the State Board of Education. The revised science TEKS were implemented beginning in the 2024 to 2025 school year, organized around three strands: the biology content, the Scientific and Engineering Practices (SEPs), and the Recurring Themes and Concepts (RTCs).

The redesigned exam (STAAR 2.0)

Texas redesigned STAAR for the spring 2023 administration. The change that matters most for studying: under state law (House Bill 3906), no more than 75 percent of questions can be multiple choice, so at least a quarter of the exam now uses new, non-multiple-choice question types. You cannot prepare by only practicing four-option multiple choice.

The question types you will meet on STAAR Biology are:

• Multiple choice. Four options, one correct answer. Still the largest single type, capped at 75 percent of items.
• Multiselect. Like multiple choice, but more than one option is correct. The prompt tells you how many to choose (for example, "Select the two correct answers"). Usually scored all-or-nothing.
• Multipart. A question in two linked parts, Part A and Part B, scored separately. Often Part A asks for an answer and Part B asks for the evidence or reason behind it.
• Hot spot. You click one or more regions of a graphic, such as an organelle in a cell diagram or the part of a graph that shows a trend.
• Drag and drop. You move labels, words, numbers, or images into target locations, such as dragging organisms into the correct trophic level of a food web.
• Inline choice (drop-down). You pick the correct answer from a drop-down menu embedded inside a sentence.
• Text entry. You type a short answer, such as a number read from a graph or the name of a process.
• Short constructed response (SCR). You write a few sentences to explain or justify, scored on a 2-point rubric. Spelling and grammar are not scored; the science is.

Match-table grids (classifying statements into categories) and some inline-choice items are also field-tested in science. Because several of the new types are worth 2 points, the non-multiple-choice items count for more of the total score than their share of the question count.

Format and scoring

STAAR Biology is a single session with a 4-hour time limit (longer with approved accommodations).

• Questions. 45 questions per form. A typical form mixes about 37 one-point items with about 8 two-point items, so the raw-score total is larger than 45. Some questions on every form are unscored field-test items used to build future exams; you cannot tell which, so answer all of them.
• Reporting categories. The points are spread across five reporting categories, each contributing roughly 8 to 10 points (about a fifth of the test each).
• Scoring. Your raw score (total points earned) is converted to a scale score using a conversion table for that administration. The scale score sets your performance level.

Performance levels

STAAR reports four levels:

1. Did Not Meet Grade Level
2. Approaches Grade Level (the standard usually treated as passing for graduation)
3. Meets Grade Level
4. Masters Grade Level

The levels are defined by scale-score cut points (Approaches near 3500, Meets near 4000, and Masters near 4333 on the STAAR scale). The exact raw points needed shift a little between forms, so use the current TEA raw-to-scale conversion table rather than a fixed "X out of 45" rule.

The five reporting categories

The Biology TEKS group the content into five reporting categories. This library mirrors them as six modules (the fourth reporting category, Biological Processes and Systems, is broad, and the investigation skills are pulled into their own module because the exam embeds them everywhere).

Reporting Category 1: Cell Structure and Function

Cell theory, prokaryotic and eukaryotic cells, organelles, the cell membrane and transport, viruses, levels of cellular organization, and how the cell maintains homeostasis. This is Module 1.

Reporting Category 2: Mechanisms of Genetics

DNA structure and replication, protein synthesis, mutations, meiosis and chromosomes, Mendelian genetics and Punnett squares, and DNA technology. This is Module 2.

Reporting Category 3: Biological Evolution and Classification

Evidence for evolution, natural selection and adaptation, mechanisms of genetic change in populations, taxonomy, and reading cladograms. This is Module 3.

Reporting Category 4: Biological Processes and Systems

Photosynthesis, cellular respiration, enzymes and biological molecules, the human body systems, and feedback mechanisms that keep the body in balance. This is Module 4.

Reporting Category 5: Interdependence within Environmental Systems

Levels of ecological organization, energy flow and food webs, the cycling of matter, population dynamics and carrying capacity, and succession and human impact. This is Module 5.

The skills strand (scientific and engineering practices, plus the new question types) is Module 6.

The scientific and engineering practices

The Biology TEKS embed eight practices that the exam tests through the content:

1. Asking questions and defining problems
2. Developing and using models
3. Planning and carrying out investigations
4. Analyzing and interpreting data
5. Using mathematics and computational thinking
6. Constructing explanations and designing solutions
7. Engaging in argument from evidence
8. Obtaining, evaluating, and communicating information

The recurring themes and concepts

Six recurring themes run across the Biology TEKS and frame how questions are asked:

1. Patterns
2. Cause and effect
3. Systems and system models
4. Energy and matter
5. Structure and function
6. Stability and change

How to study STAAR Biology

1. Learn the content for all five reporting categories. No category is optional; each is about a fifth of your score.
2. Practice using the content, not just recalling it. Read data tables and graphs, interpret diagrams and models, complete Punnett squares, and explain results in your own words.
3. Master the short constructed response. Write a clear claim, cite specific evidence from the stimulus, and give reasoning that uses a biology idea. Partial answers earn partial points.
4. Get familiar with every question type. Practice multiselect, hot spot, drag and drop, inline choice, and text entry so the format never costs you a point you knew.
5. Use the recurring themes as a lens. When you study a process, ask how it shows structure and function, cause and effect, energy and matter, or stability and change. Those are the angles the questions take.

The modules, topic by topic

Each topic has a TEKS-level answer page with worked exam questions and cross-links, plus a deep-dive guide and a quiz. Browse the set at /tx-staar/biology/syllabus.

Module 1: Cell structure and function

cell structure and organelles, prokaryotic and eukaryotic cells, the cell membrane and transport, levels of cellular organization, viruses and cell theory, homeostasis and cellular regulation.

Module 2: Mechanisms of genetics

DNA structure and replication, protein synthesis: transcription and translation, gene mutations and their effects, meiosis and chromosomes, Mendelian genetics and Punnett squares, DNA technology and biotechnology.

Module 3: Biological evolution and classification

evidence for evolution, natural selection and adaptation, mechanisms of genetic change, taxonomy and classification, cladograms and phylogeny.

Module 4: Biological processes and systems

photosynthesis, cellular respiration, comparing photosynthesis and respiration, enzymes and biological molecules, human body systems, feedback mechanisms and homeostasis.

Module 5: Interdependence within environmental systems

levels of ecological organization, energy flow and food webs, the cycling of matter, population dynamics and carrying capacity, ecological succession and human impact.

Module 6: Scientific investigation and reasoning

experimental design and variables, analyzing and interpreting data, constructed response: claim, evidence, reasoning, STAAR item types and test strategy.

For the official guidance

TEA publishes the STAAR program page, released test questions and scoring guides, the assessed-curriculum blueprints, and the raw-to-scale conversion tables. Always study from the current TEA materials, because the redesigned question types and the embedded science practices are specific to this exam.