GRE Biology

GRE will comprises of around 200 five-choice questions, a number of which are clubbed in sets toward the end of the test and on the basis of descriptions of laboratory and field situations, diagrams or experimental results.

The content of the test is organized into three core areas: Cellular and molecular biology, organismal biology, and ecology and evolution. Approximately equal weight is given to each of these three areas. Along with the total score, a sub score in every subfield areas is reported. Subject area subdivisions indicated by Arabic numerals may not contain equal numbers of questions.

The distribution of questions is mention below:

Cellular And Molecular Biology

Around 33 − 34% questions are asked.

  • Basics of cellular biology, genetics and molecular biology are addressed.
  • Major topics in cellular structure and function consist metabolic pathways and their regulation, membrane dynamics, cell surfaces, organelles, cytoskeleton and cell cycle.
  • Major areas in genetics and molecular biology consist 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 covered.
  • Distinctions between prokaryotic and eukaryotic cells are considered wherever required.
  • Emphasis is also on experimental methodology.

Cellular Structure and Function-16 − 17%

  • Biological compounds
  • Macromolecular structure and bonding
  • Abiotic origin of biological molecules
  • 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

Genetics and Molecular Biology-16 − 17%

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

Organismal Biology

Around 33 − 34% questions are asked.

The structure, physiology, behavior and development of plants and animals are consistd.

The topics that are covered will comprise of 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 evaluated as they pertain to both plants and animals.

Major features and phylogenetic relationships of selected groups from the various kingdoms are also consistd.

Animal Structure, Function and Organization-9 − 10%

  • Exchange with environment
  • Nutrient, salt, and water exchange
  • Gas exchange; Energy
  • 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)

Animal Reproduction and Development-5 − 6%

  • Reproductive structures
  • Meiosis, gametogenesis and fertilization
  • Early development (like, polarity, cleavage and gastrulation)
  • Developmental processes (like induction, determination, differentiation, morphogenesis and metamorphosis)
  • External control mechanisms (like photoperiod)

Plant Structure, Function and Organization with more Emphasis on Flowering Plants-6 − 7%

  • Tissues, tissue systems and organs
  • Water transport including absorption and transpiration
  • Phloem transport and storage
  • Mineral nutrition
  • Plant energetics (like respiration and photosynthesis)

Plant Reproduction, Growth and Development with more 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 (like hormones, photoperiod and tropisms)

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 (like eutrophication, disease)
  • Fungi
  • Major characteristics of phyla (vegetative, asexual and sexual reproduction)
  • Generalized life cycles
  • Importance (like 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

Ecology and Evolution

Around 33 − 34% questions are asked.

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.

Few questions may need quantitative skills consisting the interpretation of simple mathematical models.

Ecology-16 − 17%

  • Environment/organism interaction
  • Biogeographic patterns; Adaptations to environment; Temporal patterns
  • 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

Evolution-16 − 17%

  • Genetic variability: Origins (mutations, linkage, recombination, and chromosomal alterations) Levels (like polymorphism and heritability) Spatial patterns (like clines and ecotypes) Hardy-Weinberg equilibrium
  • Evolutionary processes: Gene flow and genetic drift; Natural selection; Levels of selection (like individual and group)
  • Evolutionary consequences: Fitness and adaptation; Speciation; Systematics and phylogeny; Convergence, divergence, and extinction
  • History of life: Origin of prokaryotic and eukaryotic cells, Fossil record, Paleontology and paleoecology