GRE Biology Syllabus

• The test consists of approximately 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 sub score 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.

I. Cellular And Molecular Biology - 33-34%

A. Cellular Structure and Function - 16-17%

Enzyme activity, receptor binding, and regulation
Major metabolic pathways and regulation
Respiration, fermentation, and photosynthesis
Synthesis and degradation of macromolecules
Hormonal control and intracellular messengers

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

Organelles: structure, function, and targeting

Cytoskeleton, motility, and shape
Actin-based systems
Microtubule-based systems
Intermediate filaments
Bacterial flagella and movement

Cell cycle, growth, division, and regulation

B. Genetics and Molecular Biology - 16-17%

Chromatin and chromosomes
Nucleosomes
Karyotypes
Chromosomal aberrations
Polytene chromosomes

Genome sequence organization
Introns and exons; Single-copy and repetitive DNA
Transposable elements Genome maintenance
DNA replication; DNA mutation and repair

Gene expression and regulation in prokaryotes and eukaryotes: mechanisms
The operon; Promoters and enhancers; Transcription factors; RNA and protein synthesis; Processing and modifications of both RNA and protein

Gene expression and regulation: effects
Control of normal development; Cancer and oncogenes
Signaling mechanisms in cells

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

Bacteriophages, animal viruses, and plant viruses
Viral genomes, replication, and assembly
Virus-host cell interactions

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

II. Organismal Biology - 33-34%

A. Animal Structure, Function, and Organization - 9-10%

Internal transport and exchange
Circulatory, gastrovascular, and digestive systems

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

Integration and control mechanisms
Nervous and endocrine systems

Behavior (communication, orientation, learning, and instinct)

Metabolic rates (temperature, body size, and activity)

B. Animal Reproduction and Development - 5-6%

Meiosis, gametogenesis, and fertilization

Early development (e.g., polarity, cleavage, and gastrulation)

Developmental processes (e.g., induction, determination, differentiation, morphogenesis, and metamorphosis)

External control mechanisms (e.g., photoperiod)

C. Plant Structure, Function, and Organization, with Emphasis on Flowering Plants - 6-7%

Water transport, including absorption and transpiration

Phloem transport and storage

Mineral nutrition

Plant energetics (e.g., respiration and photosynthesis)

D. Plant Reproduction, Growth, and Development, with Emphasis on Flowering Plants - 4-5%

Reproductive structures

Meiosis and sporogenesis

Gametogenesis and fertilization

Embryogeny and seed development

Meristems, growth, morphogenesis, and differentiation

Control mechanisms (e.g., hormones, photoperiod, and tropisms)

E. Diversity of Life - 6-7%

Archaebacteria Morphology, physiology, and identification

Eubacteria (including cyanobacteria)
Morphology, physiology, pathology, and identification

Protista
Protozoa, other heterotrophic Protista (slime molds and Oomycota), and autotrophic Protista
Major distinguishing characteristics
Phylogenetic relationships
Importance (e.g., eutrophication, disease)

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

Animalia with emphasis on major phyla
Major distinguishing characteristics
Phylogenetic relationships

Plantae with emphasis on major phyla
Alternation of generations
Major distinguishing characteristics
Phylogenetic relationships

III. Ecology and Evolution - 33-34%

• 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

A. Ecology - 16-17%

Behavioral Ecology
Habitat selection; Mating systems; Social systems; Resource acquisition

Population structure and function
Population dynamics/regulation; Demography and life history strategies

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

Ecosystems
Productivity and energy flow; Chemical cycling

B. Evolution - 16-17%

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

3. Evolutionary consequences
Fitness and adaptation; Speciation; Systematics and phylogeny; Convergence, divergence, and extinction

4. History of life
Origin of prokaryotic and eukaryotic cells
Fossil record
Paleontology and paleoecology