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A-B-C-D-E-F-G-H-I-J-K-L-M-N-O-P-Q-R-S-T-U-V-W-X-Y-Z
- Races (subspecies)
- [Discussion]
- Rad
- Radiation
- [ionizing] [and cancer] [spectrum of electromagnetic radiation]
- Radicle
- Root portion of the embryo of seed plants. [View]
- RAG-1 and RAG-2
- Recombination Activating Genes
- Random assortment
- [of chromosomes in meiosis]
- Rapamycin
- [as immunosuppressant] [as regulator of transgene expression]
- RB
- Retinoblastoma gene
- Reactant
- Substance that enters into a chemical reaction.
- Recapitulation
- Occurrence, in embryonic development, of stages thought to have occurred in the embryonic development of its ancestors. [Discussion]
- Recognition helix
- Recombinant DNA
- Discussion
- Recombination
- in meiosis
- Recombination Signal Sequence (RSS)
- Recommended dietary allowances (RDAs) (table)
- Red blood cells
- Redox potential
- Redox reaction
- A chemical reaction in which electrons are transferred from one atom (which is thereby oxidized) to another (which is thereby reduced).
- Reduction
- Process of adding electrons to a substance.
- Reductionism
- Reflex
- [stretch reflex] [withdrawal reflex]
- Refractory period
- Brief interval following the propagation of an action potential in a neuron or muscle fiber during which it is incapable of propagating a second action potential. [in neurons] [in muscle fibers]
- Regulator gene
- A gene that encodes a transcription factor and thus controls the expression of other genes.
- Relaxin
- Releaser
- REM (Roentgen equivalent man)
- Renin
- Repetitive DNA
- Replication origin
- Reporter genes
- Repressor
- A protein that blocks gene transcription by combining with its operator. [lac repressor] [tryptophan repressor]
- Reptiles
- Resistin
- Respiratory chain
- [in mitochondria]
- Respiratory Syncytial Virus (RSV)
- Response element (RE)
- A particular DNA sequence which, when bound by a protein specific for it, turns its associated gene(s) on (or off). Many response elements bind to a complex of a hormone with its protein receptor. [steroid response elements] [response element of a protein hormone]
- Resting potential
- Restriction endonuclease
- An enzyme that cuts DNA molecules at, or close to, a certain sequence of nucleotides.[Discussion]
- Restriction fragment length polymorphism (RFLP)]
- Reticular formation
- Retina
- of human eye
- Retinoblastoma
- Retinal
- Retinol
- vitamin A
- Retrotransposons
- Retrovirus
- A virus whose genome consists of RNA which, after infection, is copied by reverse transcriptase into DNA. The human immunodeficiency viruses (HIV) are retroviruses. [life cycle] [as vector in gene therapy]
- Reverse transcriptase
- An enzyme that catalyzes the synthesis of DNA that is complementary to an RNA template; that is, an RNA-dependent DNA polymerase. [More] [inhibitors]
- Rh disease
- Hemolytic disease of the newborn
- Rheumatoid arthritis
- as autoimmune disease
- Rhizobia
- Rhizoid
- Hairlike structure that serves as a root for bryophytes, fern prothallia, and certain fungi and lichens.
- Rhizome
- Underground stem.
- Riboflavin
- vitamin B12
- Ribonuclease P
- Ribonucleic acid (see RNA)
- Ribonucleoprotein
- A complex of RNA and protein.
- Ribose
- Ribosome
- [structure] [in protein synthesis]
- Ribozyme
- [general discussion] [synthetic]
- Ribulose bisphosphate carboxylase oxygenase (RUBISCO)
- [in photosynthesis] [genes] [and photorespiration]
- Rickets
- Rickettsias
- Rifampin
- Risk, relative
- Ritalin
- Rituximab
- RNA
- Ribonucleic acid. A polymer of
ribonucleotides.
[types] [processing] [small nuclear (snRNA)] [guide RNA (gRNA)] [antisense RNA] [small temporal RNA (stRNA)]
- RNA editing
- RNA interference (RNAi)
- RNA polymerase
- [types in eukaryotes]
- RNA World
- Robertsonian fusions
- Rods
- of human retina
- Roots
- Root pressure
- Rough endoplasmic reticulum (RER)
- RUBISCO
- see Ribulose bisphosphate carboxylase oxygenase
- RU-486
- A progesterone antagonist used to prevent or terminate pregnancy. Also called mifepristone. [More] [still more]