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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

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
Ontogeny
The development of an individual organism from fertilization to maturity.
Oogenesis
Oomycetes
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
A DNA sequence in bacteria to which a repressor or activator protein binds, turning off (or on) transcription of the associated genes of the operon.
Operon
A set of adjacent 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] [in phloem] [in capillaries] [in kidney function] [and root pressure]
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] [in cellular respiration] [in photosynthesis (More)] [in breathing] [Bond energies (More)] [Electronegativity] [Redox potential]
Oxytocin
Ozone
Highly active form of oxygen (O3 instead of O2). [ozone hole] [and photochemical smog]
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