Biology CBE — Practice Tests & Mock Exams

Cells, genetics, ecology, evolution, and body systems. Covers TEKS §112.34.

Semester A

50 questions · 180 min · 80% to pass

Free Practice (10)
Semester B

50 questions · 180 min · 80% to pass

Free Practice (10)
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Learn the Concepts

Visual lessons that build Biology from first principles — diagrams, worked examples, embedded practice.

Concept Lesson · 9 min · TEKS 4A,4B,5D
Cell Structure & Organelles: A Tour Inside the Cell

Every Texas Biology CBE has at least one organelle-identification question. Master the eight structures every cell biology question is built around — what each one looks like, what it does, and how plant cells differ from animal cells.

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Concept Lesson · 8 min · TEKS 4B,5D
Cell Membrane & Transport: How Things Get In and Out

The cell membrane is the boundary that decides what enters and leaves. Master the phospholipid bilayer, transport proteins, osmosis, diffusion, and active transport in one focused lesson.

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Concept Lesson · 9 min · TEKS 5B,5C
Cell Cycle & Mitosis: How One Cell Becomes Two

The CBE tests both the cell cycle macro-phases (G1/S/G2/M) and the mitosis substages (Prophase, Metaphase, Anaphase, Telophase). Master both levels and how they connect.

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Concept Lesson · 8 min · TEKS 6A,6B
Mitosis vs Meiosis: Two Divisions, Two Outcomes

Mitosis and meiosis sound similar but serve completely different purposes. Master the four key differences (cell count, ploidy, purpose, genetic identity) and you'll never miss a comparison question.

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Concept Lesson · 9 min · TEKS 6B,6C,6D
DNA Structure & Replication: The Code of Life and How It Copies Itself

Three things every CBE asks: the four bases (A, T, G, C) and how they pair, the double helix structure, and semi-conservative replication. Plus the four enzymes that make replication work.

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Concept Lesson · 10 min · TEKS 6E,6F,6G
Genetics & Punnett Squares: Predicting Inheritance with a 2×2 Grid

The Punnett square is the single most-tested tool on the Biology CBE. Master monohybrid crosses, dihybrid crosses, and the four key terms — homozygous, heterozygous, dominant, recessive.

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What's on the Biology CBE

Every TEKS standard the official exam covers — and the exact topics our practice questions target.

SEMESTER A TEKS 1A–8C
  • 1A-3F Science Processes and Methods
  • 4A-5D Cells
  • 7A-7F Natural Selection
  • 8A-8C Taxonomy
SEMESTER B TEKS 6A–12F
  • 11A-12F Ecology
  • 6A-6H DNA and the Genetic Code
  • 9A-9D Biomolecules
  • 10A-10C Biological Systems

Biology CBE — Common Questions

What topics are on the Biology CBE?

The Biology CBE covers cell structure and function, mechanisms of genetics, biological evolution and classification, biological processes and systems, and interdependence within environmental systems. Each TEKS reporting category is sampled across Semester A and B mock exams.

How hard is the Biology CBE?

Expect a mix of factual recall (cell organelles, DNA replication steps, classification levels) and applied reasoning (interpreting graphs, predicting genetic outcomes, analyzing ecosystems). Lab-based experimental design questions are common. Students hitting 80%+ on our mocks typically pass first attempt.

How long is the Biology CBE?

The exam runs about 3 hours with roughly 55–60 questions. Our mock exams match this length and include the same diagram-heavy and graph-interpretation style so your pacing practice is accurate.

Do I need to memorize all the cell organelles?

Yes — and their functions. The CBE tests on cell structure recurrently. Our practice questions emphasize this: organelle identification from electron micrographs, function matching, and contrasting prokaryotic vs. eukaryotic features.

Is there a lab component to the Biology CBE?

No physical lab, but expect questions about experimental design — controls, variables, hypothesis testing, and interpreting lab data. About 15–20% of questions reward strong scientific method understanding.

What's the passing score for the Biology CBE?

70%. Aim for 85%+ on practice mocks because the genetics and ecology questions can spike in difficulty depending on which TEKS standards your specific exam draws from.