• The test contains about 200 five-choice questions, a number of which are grouped in sets toward the end of the test and are based on descriptions of laboratory and field situations, diagrams, or experimental results.

• The content of the test is organized into three major areas: cellular and molecular biology, organismal biology, and ecology and evolution. Approximately equal weight is given to each of these three areas. In addition to the total score, a subscore in each of these subfield areas is reported. Subject area subdivisions indicated by Arabic numerals may not contain equal numbers of questions.

The approximate distribution of questions by content category is shown below.

• Fundamentals of cellular biology, genetics, and molecular biology are addressed.
• Major topics in cellular structure and function include metabolic pathways and their regulation, membrane dynamics, cell surfaces, organelles, cytoskeleton, and cell cycle.
• Major areas in genetics and molecular biology include chromatin and chromosomal structure, genomic organization and maintenance, and the regulation of gene expression.
• The cellular basis of immunity, the mechanisms of antigen-antibody interactions, and cell-pathogen interactions are included.
• Distinctions between prokaryotic and eukaryotic cells are considered where appropriate.
• Attention is also given to experimental methodology.

• Macromolecular structure and bonding
• Abiotic origin of biological molecules

• Respiration, fermentation, and photosynthesis
• Synthesis and degradation of macromolecules
• Hormonal control and intracellular messengers

• Transport, endocytosis, and exocytosis
• Electrical potentials and neurotransmitters
• Mechanisms of cell recognition, cell junctions, and plasmodesmata
• Cell wall and extracellular matrix

• Actin-based systems
• Microtubule-based systems
• Intermediate filaments
• Bacterial flagella and movement

• Mendelian inheritance; Pedigree analysis
• Prokaryotic genetics (transformation, transduction, and conjugation)
• Genetic mapping

• Nucleosomes
• Karyotypes
• Chromosomal aberrations
• Polytene chromosomes

• Introns and exons; Single-copy and repetitive DNA
• Transposable elements

• DNA replication; DNA mutation and repair

• The operon; Promoters and enhancers; Transcription factors; RNA and protein synthesis; Processing and modifications of both RNA and protein

• Control of normal development; Cancer and oncogenes
• Signaling mechanisms in cells

• Cellular basis of immunity; Antibody diversity and synthesis
• Antigen-antibody interactions

• Viral genomes, replication, and assembly
• Virus-host cell interactions

• Restriction endonucleases; Blotting and hybridization
• Restriction fragment length polymorphisms;
• DNA cloning, sequencing, and analysis;
• Polymerase chain reaction

• The structure, physiology, behavior, and development of plants and animals are addressed.
• Topics covered include nutrient procurement and processing, gas exchange, internal transport, regulation of fluids, control mechanisms and effectors, and reproduction in autotrophic and heterotrophic organisms.
• Examples of developmental phenomena range from fertilization through differentiation and morphogenesis.
• Perceptions and responses to environmental stimuli are examined as they pertain to both plants and animals.
• Major distinguishing characteristics and phylogenetic relationships of selected groups from the various kingdoms are also covered.

• Nutrient, salt, and water exchange
• Gas exchange; Energy

• Circulatory, gastrovascular, and digestive systems

• Support systems (external, internal, and hydrostatic)
• Movement systems (flagellar, ciliary, and muscular)

• Nervous and endocrine systems

B. Animal Reproduction and Development — 5-6%
1. Reproductive structures
2. Meiosis, gametogenesis, and fertilization
3. Early development (e.g., polarity, cleavage, and gastrulation)
4. Developmental processes (e.g., induction, determination, differentiation, morphogenesis, and metamorphosis)
5. External control mechanisms (e.g., photoperiod)
C. Plant Structure, Function, and Organization, with Emphasis on Flowering Plants — 6-7%
1. Tissues, tissue systems, and organs
2. Water transport, including absorption and transpiration
3. Phloem transport and storage
4. Mineral nutrition
5. Plant energetics (e.g., respiration and photosynthesis)
D. Plant Reproduction, Growth, and Development, with Emphasis on Flowering Plants — 4-5%
1. Reproductive structures
2. Meiosis and sporogenesis
3. Gametogenesis and fertilization
4. Embryogeny and seed development
5. Meristems, growth, morphogenesis, and differentiation
6. Control mechanisms (e.g., hormones, photoperiod, and tropisms)
E. Diversity of Life — 6-7%
1. Archaebacteria Morphology, physiology, and identification
2. Eubacteria (including cyanobacteria)

• Morphology, physiology, pathology, and identification

• Protozoa, other heterotrophic Protista (slime molds and Oomycota), and autotrophic Protista


Major distinguishing characteristics
Phylogenetic relationships
Importance (e.g., eutrophication, disease)

• Distinctive features of major phyla (vegetative, asexual, and sexual reproduction)
• Generalized life cycles
• Importance (e.g., decomposition, biodegradation, antibiotics, and pathogenicity)
• Lichens

• Major distinguishing characteristics
• Phylogenetic relationships

• Alternation of generations
• Major distinguishing characteristics
• Phylogenetic relationships

• Interactions of organisms and their environment, emphasizing biological principles at levels above the individual.
• Ecological and evolutionary topics are given equal weight.
• Ecological questions range from physiological adaptations to the functioning of ecosystems.
• Although principles are emphasized, some questions may consider applications to current environmental problems.
• Questions in evolution range from its genetic foundations through evolutionary processes to their consequences.
• Evolution is considered at the molecular, individual, population, and higher levels.
• Principles of ecology, genetics, and evolution are interrelated in many questions.
• Some questions may require quantitative skills, including the interpretation of simple mathematical models.

• Biogeographic patterns; Adaptations to environment; Temporal patterns

• Habitat selection; Mating systems; Social systems; Resource acquisition

• Population dynamics/regulation; Demography and life history strategies

• Interspecific relationships; Community structure and diversity; Change and succession

• Productivity and energy flow; Chemical cycling

• Origins (mutations, linkage, recombination, and chromosomal alterations)
• Levels (e.g., polymorphism and heritability)
• Spatial patterns (e.g., clines and ecotypes)
• Hardy-Weinberg equilibrium

• Gene flow and genetic drift; Natural selection; Levels of selection (e.g., individual and group)

• Fitness and adaptation; Speciation; Systematics and phylogeny; Convergence, divergence, and extinction

• Origin of prokaryotic and eukaryotic cells
• Fossil record