Praxis Biology: Content Knowledge Online Center
This Praxis Biology: Content Knowledge Online Center brings together practice, lessons, worksheets, flashcards and review tools. Choose the resource that matches the skill you want to work on next.
Praxis Biology Practice Center
Take a full 150-minute form, then read the explanation under every question you missed. Over forty percent of the real test wraps content inside a science and engineering practice and about a quarter inside a task of teaching, so sort your misses by whether the biology was the problem or the reasoning about evidence was.
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Praxis Biology: Content Knowledge at a glance
This is the secondary biology content test. One hundred fifty questions in two and a half hours is a minute each, so it rewards recall that is genuinely automatic rather than reconstructible. The largest category is genetics and evolution at twenty-six percent, and the smallest is the nature of science at thirteen, but that smallest category is misleading: its practices are folded into questions across all the others.
| Test code | 5236 (Biology: Content Knowledge) |
|---|---|
| Status | Current. No retirement date or successor code is published. |
| Number of questions | 150 selected-response questions. There is no constructed response. |
| Time limit | 2 hours 30 minutes |
| Calculator | None is provided and ETS does not list this test as one where a calculator is permitted. |
| Format | Computer-delivered |
| Score scale | 100 to 200 |
| Passing score | ETS does not set one. Each state sets its own qualifying score. |
| How it is asked | More than 40 percent of questions integrate a science and engineering practice, and about 25 percent assess a task of teaching science. |
ETS publishes counts and percentages for all five categories: Nature and Impact of Science and Engineering 19 questions and 13 percent, Cell Biology 33 and 22 percent, Genetics and Evolution 39 and 26 percent, Diversity of Life and Organismal Biology 30 and 20 percent, and Ecology 29 and 19 percent. Genetics and evolution is the single largest block, and it is also the one where a candidate can lose points to a calculation error rather than a knowledge gap.
The five categories, in plain language
ETS lists each category and the topics under it. Here is what each one asks of you.
I. Nature and impact of science and engineering (13 percent, 19 questions)
How biology is done, and what it does in the world.
- Science and engineering practices
- Designing and critiquing an investigation
- Controls, variables, and experimental error
- Analyzing and interpreting data
- Laboratory safety
- Science, technology, and society
II. Cell biology (22 percent, 33 questions)
Structure, function, and the chemistry that runs them.
- Macromolecules and enzyme function
- Membrane structure and transport
- Organelles and their roles
- The cell cycle, mitosis, and meiosis
- Cellular respiration, step by step
- Photosynthesis, light reactions and Calvin cycle
- Cell signaling
III. Genetics and evolution (26 percent, 39 questions)
The largest category, and the most calculation-heavy.
- Mendelian and non-Mendelian inheritance
- Punnett squares, including dihybrid crosses
- Linkage, mapping, and pedigrees
- DNA replication, transcription, and translation
- Gene regulation and mutation
- Biotechnology: PCR, electrophoresis, CRISPR
- Hardy-Weinberg and population genetics
- Natural selection, speciation, and phylogeny
IV. Diversity of life and organismal biology (20 percent, 30 questions)
The range of living things and how their bodies work.
- Domains, kingdoms, and classification
- Viruses, bacteria, protists, and fungi
- Plant structure, transport, and reproduction
- Animal body systems and homeostasis
- Animal behavior
V. Ecology (19 percent, 29 questions)
Organisms in their environment.
- Population growth models
- Community interactions and succession
- Energy flow and trophic levels
- Biogeochemical cycles
- Biomes and biodiversity
- Human impact, including climate change
A study routine for a 150-question test
A minute a question means you cannot derive anything. The preparation that pays is the kind that turns recall into recognition, plus enough practice at the calculation types that they stop taking two minutes each.
Complete topic map
Every topic ETS lists under the five categories, weighted the way the test is weighted.
Nature and impact of science and engineering (13 percent, about 19 questions)
- 01Recognize that observations and experiments provide the evidence on which scientific knowledge rests
- 02Recognize that scientific understanding develops and changes over time in light of new evidence
- 03Recognize that science is interdisciplinary in nature, applying principles of chemistry, physics and earth science within biology
- 04Apply scientific methodologies and the process skills of observing, categorizing, comparing, generalizing, inferring and concluding
- 05Distinguish among scientific laws, scientific theories and hypotheses
- 06Explain how models are developed, revised and applied to explain natural phenomena
- 07Use standard units of measurement, dimensional analysis and unit conversion
- 08Use scientific notation and significant figures
- 09Design experiments, including developing a hypothesis, identifying variables and planning data collection
- 10Process, organize and report quantitative and qualitative data
- 11Perform error analysis, including identifying the sources and effects of error
- 12Interpret and extrapolate from data and draw valid conclusions
- 13Prepare materials for classroom or field use
- 14Use, store and dispose of chemicals and biological materials appropriately and safely
Cell biology: cell structure and function (22 percent, about 33 questions)
- 15Describe atomic and molecular structures and chemical bonding as they apply to biological molecules
- 16Distinguish organic from inorganic molecules
- 17Relate the properties of water to its structure and bonding characteristics
- 18Describe the major macromolecules, including nucleic acids, proteins, lipids and carbohydrates
- 19Analyze chemical and physical gradients and the factors that influence them
- 20Apply the laws of thermodynamics to biological processes
- 21Distinguish anabolic from catabolic reactions in metabolism
- 22Analyze reduction-oxidation reactions in metabolism
- 23Describe enzyme active site structure and substrate binding
- 24Compare the energy profile of a reaction in the presence and absence of an enzyme
- 25Analyze reaction kinetics, including the effects of temperature, pH, concentrations, and other molecules including inhibitors
- 26Explain enzyme regulation, including cooperative binding and feedback inhibition
- 27Identify the cellular locations of major biochemical pathways
- 28Describe the structure and function of ATP
Genetics and evolution (26 percent, about 39 questions)
- 29Describe the structure of nucleic acids, including the sugar-phosphate backbone and complementary base pairing, and distinguish DNA from RNA
- 30Describe chromosome structure, including nucleosomes and telomeres
- 31Explain the central dogma of molecular biology
- 32Explain the process of DNA replication
- 33Explain the process of RNA transcription and pre-mRNA processing in eukaryotes
- 34Explain translation, including the roles of mRNA, tRNA, rRNA and ribosomes
- 35Explain gene regulation, including promoters, enhancers, transcription factors and posttranslational regulation
- 36Use a genetic code chart
- 37Compare protein synthesis in eukaryotes and prokaryotes
- 38Identify causes of mutations, including recombination and mutagens
- 39Identify types of mutations, including substitution, deletion, insertion, inversion and translocation
- 40Relate disorders to point mutations, frameshift mutations, changes in chromosome structure and changes in chromosome number
- 41Explain the significance of somatic versus germ-line mutations
- 42Apply laboratory techniques including microscopy, gel electrophoresis, spectrophotometry, polymerase chain reaction, genome sequencing, gene therapy, protein sequence analysis, genetically engineered cells and transgenic organisms, and chromosome analysis
Diversity of life and organismal biology (20 percent, about 30 questions)
- 43Apply the taxonomic hierarchy, including domains and kingdoms, and use binomial nomenclature
- 44Identify the defining structural characteristics of viruses, eubacteria, archaea, protists, fungi, plants and animals
- 45Compare cellular organization, including unicellular versus multicellular
- 46Compare modes of nutrition, including autotrophic versus heterotrophic
- 47Compare modes of reproduction and replication across groups
- 48Apply the organizational hierarchy of cells, tissues, organs and organ systems
- 49Explain cell differentiation and specialization through differential gene expression
- 50Describe stem cells, including their characteristics and sources
- 51Identify major evolutionary trends in animals, including body plans, body cavities, cephalization and multicellularity
- 52Compare sexual and asexual reproduction in animals
- 53Compare endothermic and ectothermic temperature regulation
- 54Describe the structure and function of the major human organ systems: cardiovascular and respiratory, digestive and excretory, immune, musculoskeletal, nervous and endocrine, and reproductive
- 55Explain how homeostasis is maintained through organs and tissues such as the kidney, adrenals, hypothalamus and pituitary
- 56Explain the role of hormones such as insulin, antidiuretic hormone and sex hormones
Ecology: organisms and environment (19 percent, about 29 questions)
- 57Apply the hierarchical structure of the biosphere: biomes, ecosystems, communities, populations and organisms
- 58Analyze symbiotic relationships, including mutualism, parasitism and commensalism
- 59Analyze predator-prey relationships, including evolutionary adaptations
- 60Analyze competition and identify keystone species
- 61Relate reproductive strategies to demographics and population growth, comparing sexual and asexual reproduction and r-strategists and K-strategists
- 62Model exponential growth, logistic growth and carrying capacity, and interpret population demographics
- 63Analyze the influence of biotic and abiotic components on community structure, including limiting factors, habitat and niche, competition and predation
- 64Distinguish density-dependent from density-independent factors
- 65Evaluate human impacts through habitat destruction, including deforestation, fragmentation, urbanization and agriculture
- 66Evaluate pollution impacts, including plastics, acid precipitation and ozone layer destruction by CFCs
- 67Evaluate climate change impacts, including greenhouse gases and ocean acidification
- 68Evaluate the effects of introduced, reintroduced and invasive species and overconsumption of resources
- 69Evaluate remediation approaches such as reforestation, movement corridors, captive breeding programs and biotechnology
- 70Distinguish primary from secondary ecological succession
Before test day
Two habits carry this test. The first is precision about evolution: populations change in allele frequency, individuals do not adapt, and selection has no goal. Distractors are written for candidates who are loose about that. The second is arithmetic discipline in genetics, because a dihybrid cross done in a hurry produces a ratio that is on the answer list.
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