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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

O

Obestatin
Oceanic zone
Okazaki fragment
OKT3
[More]
Olfaction, the sense of smell
Oligonucleotide
A short polymer of, for example, 20 or so deoxyribonucleotides or ribonucleotides; thus a fragment of DNA or RNA.
Ommatidia
Oncogenes
Oncogenic
Cancer causing.
One Gene - One enzyme Theory
Oogenesis
Ooplasmic transfer
Open Reading Frame (ORF)
DNA sequence beginning with ATG and read in triplets until it ends with a STOP codon. An ORF is potentially able to encode a polypeptide.
Operator
The DNA sequence in prokaryotes to which a repressor or activator protein binds, turning on (or off) transcription of the associated structural genes of the operon.
Operon
A set of adjacent structural genes and the operator that controls them. [lac operon]
Opiates
[and pain relief]
Opsin
Opsonin
Organ
Group of tissues that performs a specific function for an animal or plant (e.g., stomach, leaf).
Organelle
Specialized part of a cell (e.g., mitochondrion) analogous to an organ.
Organic
Term describing all compounds whose molecules contain carbon, with a few exceptions such as carbon dioxide and carbonates. [types and functional groups]
Organism
Individual living being.
Organizer (in frog embryology)
Organ of Corti
Organophosphates
Origin of Life
Origin Recognition Complex (ORC)
Ornithine
Orthologous genes
Homologous genes in different species; thus genes that have descended from a gene in the common ancestor of those species. Compare paralogous genes.
Osmosis
Osmotic pressure
[in guard cells of leaf]
Ossicles
Osteichthyes (bony fishes)
Osteoclasts and osteoblasts
Osteogenesis imperfecta
Osteomalacia
Osteoporosis and calcium
Otoliths
Ovary
Ovulation
[role of hormones in]
Ovule
Oxidation
Process of removing electrons from a substance. [in mitochondria]
Oxygen
transport by blood
Oxytocin
Ozone
Highly active form of oxygen (O3 instead of O2). [ozone hole] [and photochemical smog]
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