The Texas Biology Credit by Exam (CBE) — A Complete Guide to Testing Out of High School Biology (2026)
Biology is one of the most common subjects Texas students choose to test out of by Credit by Exam (CBE). The reason is straightforward: it is a required science credit, it is a STAAR end-of-course (EOC) subject, and a motivated student with a focused summer of self-study can earn the credit and walk into high school with one less course on the schedule. For many families, a strong middle-school science student tests out of Biology over the summer and starts 9th grade in a more advanced science course instead.
This guide explains how the Biology CBE works in Texas, what is actually tested under the state standards, where students tend to lose points, and how to prepare efficiently. It is general guidance only — always confirm current details with your campus counselor and the testing provider before you register.
What is the Biology CBE?
Credit by Exam lets a Texas school grant high-school credit when a student passes a standardized exam for a course they have not formally taken. For Biology, this most often means a student studies independently over the summer and then sits a proctored exam to earn the Biology credit. Because Biology is a STAAR EOC subject, the course content is anchored to the Texas Essential Knowledge and Skills (TEKS) for Biology, §112.34, so a CBE for Biology mirrors those same TEKS topics.
Exam format
The Biology CBE follows the general CBE format used across subjects:
| Feature | Detail |
|---|---|
| Format | Multiple-choice |
| Delivery | Online, proctored (Proctorio at home) |
| Time limit | 3 hours (180 minutes) |
| Length | Typically around 50 multiple-choice questions |
| Passing — acceleration (no prior instruction) | 80% |
| Passing — credit recovery (with prior instruction) | 70% |
Two important notes. First, the exact number of questions varies by exam — treat "around 50" as a planning figure, not an official count, and verify the current specification with UT High School (UTHS) or your campus. Second, there are two passing thresholds set by Texas law: 80% for credit by exam without prior instruction (acceleration, used when a student is testing out of a course they never took), and 70% for credit by exam with prior instruction (credit recovery). Most students testing out of Biology over the summer fall under the 80% acceleration threshold, so plan toward that higher bar.
A periodic table or other reference materials may be provided during the exam, but reference-material and calculator policies vary by subject and change over time — verify with UTHS exactly what you will and will not have on test day rather than assuming.
What is tested — the §112.34 TEKS by semester
The Biology TEKS (§112.34) organize the content into two semesters. A CBE that mirrors the TEKS will draw across these groupings:
| Semester A | Semester B |
|---|---|
|
|
If a single full-credit exam covers the whole course, expect questions spanning both semesters. Build your study plan around all eight groupings rather than only the topics you already find easy.
Topics students commonly underestimate
Biology rewards memorization in some areas and reasoning in others, and the reasoning-heavy topics are where well-prepared students still lose points. Based on the structure of the TEKS, these areas deserve extra attention:
- DNA, the genetic code, and protein synthesis. Replication, transcription, and translation are easy to "sort of" know and hard to answer precisely. Questions often ask you to trace a sequence change through to its effect, not just recite a definition.
- Genetics and inheritance. Punnett squares, dominant and recessive traits, and probability of outcomes look simple but trip students up under time pressure, especially dihybrid or multi-step problems.
- Ecology relationships. Food webs, energy flow, population dynamics, and symbiotic relationships require you to reason about cause and effect across a system rather than recall a single fact.
- Classification and taxonomy. The hierarchy of classification and the characteristics that distinguish groups are easy to underestimate and easy to confuse on test day.
None of these are unusually hard in isolation — the challenge is depth and precision across a broad standard while the clock is running.
A simple prep approach: diagnose -> focus -> confirm
- Diagnose. Start with a full-length practice run that mirrors the CBE format and the §112.34 topics. The goal is not a grade — it is a map of which of the eight TEKS groupings are strong and which are weak.
- Focus. Spend the bulk of your study time on the weak groupings. For most students that means the reasoning-heavy areas above — DNA and protein synthesis, genetics problems, and ecology systems — rather than re-reading topics they already know.
- Confirm. Re-test under realistic, timed, full-length conditions until your score is comfortably above the threshold that applies to you (80% for acceleration, 70% for recovery), with consistency across all topic areas — not one strong run.
How Texas CBE™ helps
Texas CBE™ is an independent practice platform built around exactly this diagnose -> focus -> confirm loop:
- TEKS-aligned Biology practice questions and full-length mock exams modeled after the official CBE format.
- Per-TEKS-category scoring so you can see precisely which §112.34 groupings need work.
- Step-by-step explanations for every question, plus smart question rotation so you keep seeing the items you miss.
- Free sample questions for Biology with no signup required, so you can try it before committing.
- A 5-language platform (English, Korean, Spanish, Vietnamese, Chinese) — useful when a student prefers to review explanations in another language.
Full-course Biology access is listed at $29.99 for 6 months, currently $23.99 with an automatic launch discount — typically less than a single CBE retake fee. (SAT Math practice is also available on the same platform.)
This post is general guidance based on publicly available information. Exam format, question counts, passing thresholds, fees, and scheduling are set by the testing provider (such as UT High School) and individual Texas school districts, and change over time. Texas CBE™ is an independent practice platform and is not affiliated with, endorsed by, or sponsored by the Texas Education Agency, UT High School, the College Board, or any school district. Always verify current requirements with your campus counselor and official sources before registering for any exam.