A Biology teacher is writing the safety rules for a field investigation at a creek. Which source do the Texas Biology standards name for the safety equipment and practices students are to use?19 TAC §112.42(c)(1)(C), Biology, Legal Information Institute copy. Written to TExES Life Science 7–12 (238) Domain I, competency 001
A class reads how nineteenth-century physicians tied one microbe to one disease. According to the first of Koch's postulates, where must the microorganism be found?Wikipedia, Koch's postulates, Postulates. Written to TExES Life Science 7–12 (238) Domain I, competency 003
A student says, "Evolution is only a theory, so it is a guess." Which statement about scientific theories comes from the Texas Biology standards?19 TAC §112.42(b)(3), Biology, Legal Information Institute copy. Written to TExES Life Science 7–12 (238) Domain I, competency 002
After a lab on DNA fingerprinting, students debate whether police should keep DNA from people who were never charged. Under "science and social ethics", what do the Texas Biology standards ask students to tell apart?19 TAC §112.42(b)(5), Biology, Legal Information Institute copy. Written to TExES Life Science 7–12 (238) Domain I, competency 003
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Scientific inquiry and processes, continued
During a unit on stem cell research a student asks, "Does science tell us whether this research is right or wrong?" Which answer matches what UC Berkeley's Understanding Science says about the limits of science?UC Museum of Paleontology, Understanding Science: Science has limits. Written to TExES Life Science 7–12 (238) Domain I, competency 002
Hershey and Chase labeled bacteriophages with radioactive phosphorus in one batch and radioactive sulfur in another. Only the phosphorus label entered the infected bacteria. What did this help confirm?Wikipedia, Hershey–Chase experiment, lead section. Written to TExES Life Science 7–12 (238) Domain I, competency 003
Students count the lichen species on trees at three sites and record what they see, without changing any variable or comparing treatments. In the Texas Biology standards, which type of investigation is this?19 TAC §112.42(b)(4), Biology, Legal Information Institute copy. Written to TExES Life Science 7–12 (238) Domain I, competency 002
The Texas Biology standards say science has recurring themes that connect its overarching concepts. Which three themes do they name?19 TAC §112.42(b)(6), Biology, Legal Information Institute copy. Written to TExES Life Science 7–12 (238) Domain I, competency 002
Cell structure and processes 10
A bacteriophage injects its DNA into a bacterium, and the DNA joins the host chromosome and is copied with it for many generations before any new viruses are made. Which viral cycle is this?Wikipedia, Lysogenic cycle, lead section. Written to TExES Life Science 7–12 (238) Domain II, competency 005
A diagram of the eukaryotic cell cycle marks three control points. Which one falls during M phase itself?Wikipedia, Cell cycle checkpoint, lead section. Written to TExES Life Science 7–12 (238) Domain II, competency 007
A fruit fly with a mutation in one gene grows legs where its antennae should be. Which family of genes sets out which body part forms where along the head-to-tail axis?Wikipedia, Hox gene, lead section. Written to TExES Life Science 7–12 (238) Domain II, competency 007
A student writes that the Calvin cycle "happens on the thylakoid membranes and makes ATP." Which correction is accurate?Wikipedia, Calvin cycle, lead section. Written to TExES Life Science 7–12 (238) Domain II, competency 006
An inhibitor shaped like the normal substrate slows an enzyme, but adding much more substrate restores the reaction rate. Where does this kind of inhibitor usually bind?Wikipedia, Enzyme inhibitor, reversible inhibition. Written to TExES Life Science 7–12 (238) Domain II, competency 004
Corn and sugarcane keep photosynthesis efficient in hot, bright fields. Where in a C4 leaf does the Calvin cycle run after carbon dioxide has first been fixed into a four-carbon molecule?Wikipedia, C4 carbon fixation, lead section. Written to TExES Life Science 7–12 (238) Domain II, competency 006
In a mitochondrion the electron transport chain pumps hydrogen ions across the inner membrane, and the ions flow back through ATP synthase. What is this coupling of an ion gradient to ATP production called?Wikipedia, Chemiosmosis, lead section. Written to TExES Life Science 7–12 (238) Domain II, competency 006
Plant cells are boxed in by cell walls, yet sugars and signals pass straight from one cell's cytoplasm to the next. Which structures make this possible?Wikipedia, Plasmodesma, lead section. Written to TExES Life Science 7–12 (238) Domain II, competency 005
What property defines a stem cell?National Institutes of Health, Stem Cell Basics: Introduction. Written to TExES Life Science 7–12 (238) Domain II, competency 007
Which observation is evidence that mitochondria and chloroplasts descend from free-living bacteria taken into another cell?Wikipedia, Symbiogenesis, lead section. Written to TExES Life Science 7–12 (238) Domain II, competency 005
Heredity and evolution of life 10
A peacock's tail makes him easier for predators to catch, yet males with larger tails father more chicks. Which process explains the spread of such a trait?UC Museum of Paleontology, Understanding Evolution: Sexual selection. Written to TExES Life Science 7–12 (238) Domain III, competency 010
A pedigree shows a disorder passing from an affected father to his son. Why does this rule out X-linked inheritance?MedlinePlus Genetics, What are the different ways a genetic condition can be inherited?. Written to TExES Life Science 7–12 (238) Domain III, competency 009
A single extra nucleotide is inserted early in a gene, and every amino acid after that point in the protein is wrong. Which kind of variant is this?MedlinePlus Genetics, What kinds of gene variants are possible?. Written to TExES Life Science 7–12 (238) Domain III, competency 009
After the dinosaurs died out, mammals diversified into runners, burrowers, fliers and swimmers. What is rapid diversification from one ancestral group into many new forms called?Wikipedia, Adaptive radiation, lead section. Written to TExES Life Science 7–12 (238) Domain III, competency 011
E. coli makes the enzymes for digesting lactose only when lactose is present. In the lac operon, what keeps the genes switched off when there is no lactose?Wikipedia, lac operon, lead section. Written to TExES Life Science 7–12 (238) Domain III, competency 008
Identical twins share one DNA sequence, yet a gene can be active in one twin and silent in the other. Which common epigenetic change attaches small chemical groups to DNA and typically turns a gene off?MedlinePlus Genetics, What is epigenetics?. Written to TExES Life Science 7–12 (238) Domain III, competency 008
In a family tree, every child of an affected mother has a muscle disorder, sons and daughters alike, but no child of an affected father has it. Which pattern of inheritance fits?MedlinePlus Genetics, What are the different ways a genetic condition can be inherited?. Written to TExES Life Science 7–12 (238) Domain III, competency 009
In Labrador retrievers one gene decides black or brown pigment, but a dog with two recessive alleles of a second gene is yellow whatever the first gene says. What is this interaction between genes called?Wikipedia, Labrador Retriever coat colour genetics, lead section and Eumelanin gene interactions; Epistasis, lead section. Written to TExES Life Science 7–12 (238) Domain III, competency 009
Pollen from a mainland population is blown to an island population of the same plant, where one flower-color variant had never existed. According to Understanding Evolution, what can gene flow be for the island population?UC Museum of Paleontology, Understanding Evolution: Gene flow. Written to TExES Life Science 7–12 (238) Domain III, competency 010
Two finch species have similar beaks where each lives alone, but on islands where they live together one has a clearly deeper beak and the other a shallower one. What is this pattern called?Wikipedia, Character displacement, lead section. Written to TExES Life Science 7–12 (238) Domain III, competency 010
Diversity of life 10
A dolphin and a shark both have a streamlined body and fins, though one is a mammal and the other a fish. Why are such traits poor evidence of close kinship?Wikipedia, Convergent evolution, lead section. Written to TExES Life Science 7–12 (238) Domain IV, competency 012
A female ground squirrel trills an alarm call when a coyote comes near. In her species only females with relatives nearby call at ground predators. Which idea explains how such behavior can evolve?Wikipedia, Belding's ground squirrel, Alarm calls; Kin selection, lead section. Written to TExES Life Science 7–12 (238) Domain IV, competency 015
A fern plant with roots and fronds releases spores, and each spore grows into a tiny heart-shaped plant that makes eggs and sperm. In this alternation of generations, which statement is correct?Wikipedia, Alternation of generations, lead section. Written to TExES Life Science 7–12 (238) Domain IV, competency 013
A goose sees an egg outside her nest and rolls it back with her bill. If the egg is taken away mid-roll, she finishes the whole movement anyway. What kind of behavior is this?Wikipedia, Fixed action pattern, lead section. Written to TExES Life Science 7–12 (238) Domain IV, competency 015
A grasshopper nymph looks like a small wingless adult. A butterfly passes through a caterpillar and a pupa that look nothing like the adult. Which term describes the butterfly's development?Wikipedia, Metamorphosis, lead section. Written to TExES Life Science 7–12 (238) Domain IV, competency 013
A lizard basks on a rock each morning before it hunts, while a mouse of the same mass stays active through a cold night. Which terms describe how each regulates body temperature?Wikipedia, Thermoregulation, lead section. Written to TExES Life Science 7–12 (238) Domain IV, competency 014
According to the sliding filament theory, what happens inside a sarcomere when a muscle fiber contracts?Wikipedia, Sliding filament theory, lead section. Written to TExES Life Science 7–12 (238) Domain IV, competency 013
Fungal threads wrap or enter the roots of most land plants. In this mycorrhizal partnership, what does each partner mainly supply?Wikipedia, Mycorrhiza, lead section. Written to TExES Life Science 7–12 (238) Domain IV, competency 013
In a flowering plant one sperm cell fertilizes the egg. What does the second sperm cell from the same pollen tube do?Wikipedia, Double fertilization, lead section. Written to TExES Life Science 7–12 (238) Domain IV, competency 013
Pond snails in a classroom tank pull into their shells when the glass is tapped. After twenty harmless taps they no longer react. Which kind of learning is this?Wikipedia, Habituation, lead section. Written to TExES Life Science 7–12 (238) Domain IV, competency 015
Interdependence of life and environmental systems 7
A farmer plants soybeans one year and corn the next because bacteria living with the soybean roots enrich the soil. What do nitrogen-fixing bacteria do?Wikipedia, Nitrogen fixation, lead section. Written to TExES Life Science 7–12 (238) Domain V, competency 016
A student's poster shows gases moving between air and living things for carbon, nitrogen and water. For which biogeochemical cycle should the atmosphere arrow be left out as insignificant?Wikipedia, Phosphorus cycle, lead section. Written to TExES Life Science 7–12 (238) Domain V, competency 016
An aquarium plant from another continent is dumped into a Texas lake. By the U.S. Geological Survey's definition, what makes an introduced, nonnative organism an invasive species?U.S. Geological Survey, What is an invasive species and why are they a problem?. Written to TExES Life Science 7–12 (238) Domain V, competency 017
Each summer survey ships map a large area of bottom water in the Gulf that holds too little oxygen for most marine life. What does NOAA call this condition?NOAA National Ocean Service, What is a dead zone?. Written to TExES Life Science 7–12 (238) Domain V, competency 016
Elephants bear one calf at a time after a long pregnancy and care for it for years. Where does such a species sit in r/K selection theory?Wikipedia, r/K selection theory, lead section. Written to TExES Life Science 7–12 (238) Domain V, competency 018
In a population of small lizards, about the same fraction dies each year whether the animals are young or old. Which survivorship curve fits?Wikipedia, Survivorship curve, lead section. Written to TExES Life Science 7–12 (238) Domain V, competency 018
In the open ocean a small standing crop of phytoplankton can support a larger mass of zooplankton, so one ecological pyramid is upside down. Which pyramid is normally upright in every ecosystem?Wikipedia, Ecological pyramid, lead section. Written to TExES Life Science 7–12 (238) Domain V, competency 016
Science learning, instruction and assessment 5
A student explains, "Bacteria became resistant because they tried hard to survive the antibiotic." Which correction does UC Berkeley's Understanding Evolution give for this misconception?UC Museum of Paleontology, Understanding Evolution: Misconceptions about evolution. Written to TExES Life Science 7–12 (238) Domain VI, competency 019
A student writes, "The giraffe stretched its neck during its life, so the giraffe evolved." Which correction from UC Berkeley's Understanding Evolution fits this misconception?UC Museum of Paleontology, Understanding Evolution: Misconceptions about evolution. Written to TExES Life Science 7–12 (238) Domain VI, competency 019
Before a genetics unit a teacher asks every student to sketch and explain why two brown-eyed parents can have a blue-eyed child, and reads the answers that night. What is the main purpose of this task?Carnegie Mellon University, Eberly Center, Assessing Prior Knowledge. Written to TExES Life Science 7–12 (238) Domain VI, competency 020
Before a unit on natural selection a teacher gives a short multiple-choice test that targets the fundamental concepts and is built to bring out systematic wrong ideas. What does Carnegie Mellon's Eberly Center call this kind of test?Carnegie Mellon University, Eberly Center, Assessing Prior Knowledge. Written to TExES Life Science 7–12 (238) Domain VI, competency 020
The Texas Biology standards organize the course around four main concepts. Which list is it?19 TAC §112.42(b)(1), Biology, Legal Information Institute copy. Written to TExES Life Science 7–12 (238) Domain VI, competency 019
How this list was compiled: Our own questions, written to the exam framework of TExES Life Science 7–12 (238) in Section 3 of the preparation manual on the Texas Educator Certification Examination Program website, https://www.tx.nesinc.com/Content/StudyGuide/TX_SG_obj_238.htm (copyright Texas Education Agency), read 2026-10-15: 100 selected-response questions in six domains, Scientific Inquiry and Processes about 15%, Cell Structure and Processes 20%, Heredity and Evolution of Life 20%, Diversity of Life 20%, Interdependence of Life and Environmental Systems 15%, Science Learning, Instruction and Assessment 10%. This bank holds 50 in those shares: 8, 10, 10, 10, 7 and 5. Every fact was read on the public page named under its question, each opened 2026-10-15: the Texas Essential Knowledge and Skills for Biology (19 TAC §112.42, read in the Legal Information Institute copy), UC Berkeley's Understanding Evolution and Understanding Science, MedlinePlus Genetics, the National Institutes of Health's Stem Cell Basics, NOAA's National Ocean Service, the U.S. Geological Survey, Carnegie Mellon University's Eberly Center and Wikipedia articles on cell biology, genetics, physiology, behavior and ecology. Licence: Questions, choices and explanations are original work of this site.
How it works
A free TExES 7-12 Life Science 238 practice test: 50 questions written for this site across the exam's six domains. Unofficial, and not affiliated with, endorsed by or sponsored by the Texas Education Agency or Pearson.
Read the full guide
Six domains
Cell Structure and Processes, Heredity and Evolution of Life, and Diversity of Life carry about 20% each. Scientific Inquiry and Processes and Interdependence of Life and Environmental Systems carry 15% each, and science teaching and assessment 10%. The bank: 10, 10, 10, 8, 7 and 5.
Length and timing
Life Science 7–12 has 100 selected-response questions and 4 hours 45 minutes of testing time in a 5-hour appointment. The timed round keeps that pace: 50 questions, 142 minutes.
Sources
Evolution answers were checked at UC Berkeley's Understanding Evolution, inheritance at MedlinePlus Genetics, and six inquiry and teaching answers in the Texas Biology standards, 19 TAC §112.42.
The Texas Biology standards sort investigations into descriptive, comparative and experimental; only the experimental kind names a control.
Behavior is its own competency: fixed action patterns, habituation and kin selection are in the bank.
Questions and answers
Is this a real TExES Life Science 7-12 practice test?
It is real practice but not the real exam. Every question is our own, written from a competency of the public framework and a public source. Nothing comes from the exam itself or from the sample questions in the preparation manual.
Where is the TExES Life Science 7-12 (238) study guide?
The Texas Educator Certification Examination Program publishes a free preparation manual for exam 238. Its Section 3 gives the six domains and all 20 competencies; the competency number is printed with each answer on this page.
Is Life Science 7-12 the TExES exam for high school life science?
It covers grades 7 to 12, so high school is included; the framework says its questions range across those grades. Science 7–12 (236) is the broader exam, which adds physics, chemistry and Earth and space science.
What is the passing score on TExES Life Science 238?
240 on a scaled score, by the exam's page. Because the exam may carry unscored questions and the scale is not a percent, this page gives no pass or fail.