J acid
| cholesterol ester transport proteins | A protein that transports cholesterol esters from HDL to VLDL and LDL; a deficiency of this protein is associated with elevated HDL cholesterol. (05 Mar 2000) |
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| monosaccharide transport proteins | Membrane transport proteins which bind glucose and sodium ions and enter the cell together. The sodium ions are then pumped out of the cell by a sodium potassium atpase. The rate and extent of the sugar transport depends on the sodium ion concentration. Inhibitors of the monosaccharide transport system are phlorizin, cytochalasin b, and inhibitors of the sodium potassium atpase system. Insulin increases the rate of monosaccharide transport across the membrane into the cell. (12 Dec 1998) |
| cotranslational transport | <cell biology> Process whereby a protein is moved across a membrane as it is being synthesised. This process occurs during the translation of the message at membrane associated ribosomes in rough endoplasmic reticulum during the synthesis of secreted proteins in eukaryotic cells. (18 Nov 1997) |
| coupled transport | The linked, simultaneous transport of two substances across a cell membrane (or another intracellular membrane). If the two substances are moving in the same direction (both into the cell or both out of the cell) it is called symport. If the two substances are moving in opposite directions (one moves into the cell while the other moves out) it is called antiport. (09 Oct 1997) |
| hydrogen transport | The transfer of hydrogen from one metabolite (hydrogen donor) to another (hydrogen acceptor) through the action of an enzyme system; the donor is thus oxidised and the acceptor reduced. (05 Mar 2000) |
| sperm transport | Passive transport or active migration of spermatozoa from the testes through the male genital system as well as within the female genital system. (12 Dec 1998) |
| nuclear transport | <cell biology> Passage of molecules in and out of the nucleus, presumably via nuclear pores. Passage of proteins into the nucleus may depend on possession of a nuclear location sequence containing five consecutive positively charged residues PKKKRKV). (18 Nov 1997) |
| nucleocytoplasmic transport | <cell biology, molecular biology> Transport of molecules from the nucleus to the cytoplasm. (18 Nov 1997) |
| iodide transport defect | See: familial goiter. (05 Mar 2000) |
| ion transport | The movement of ions across energy-transducing cell membranes. Transport can be active or passive. Passive ion transport (facilitated diffusion) derives its energy from the concentration gradient of the ion itself and allows the transport of a single solute in one direction (uniport). Active ion transport is usually coupled to an energy-yielding chemical or photochemical reaction such as ATP hydrolysis. This form of primary active transport is called an ion pump. Secondary active transport utilises the voltage and ion gradients produced by the primary transport to drive the cotransport of other ions or molecules. These may be transported in the same (symport) or opposite (antiport) direction. (12 Dec 1998) |
| orthograde transport | Axonal transport from the cell body of the neuron towards the synaptic terminal. Opposite of retrograde transport and probably dependent on a different mechanochemical protein (almost definitely kinesin) interacting with microtubules. (18 Nov 1997) |
| ovum transport | Transport of the ovum or zygote from the site of ovulation to the site of implantation. (12 Dec 1998) |
| electron transport | The transport of electrons through a number of electron carriers in a set sequence. (09 Oct 1997) |
| electron transport chain | <biochemistry, chemistry> A series of compounds that transfer electrons to an eventual donor with concomitant energy conversion. One of the best studied is in the mitochondrial inner membrane, that takes NADH (from the tricarboxylic acid cycle) or FADH and transfers electrons via ubiquinone, cytochromes and various other compounds, to oxygen. Other electron transport chains are involved in photosynthesis. (18 Nov 1997) |
| electron transport particles | <cell biology> Fragments of mitochondria still capable of transporting electrons. One of the units occurring on the matrical surface of mitochondrial cristae; the head of the particle which measures about 9 nm, attaches to the membrane of the crista by a stalk 5 nm in length; the particle may be concerned with the electron transport system. Synonym: submitochondrial particles. (05 Mar 2000) |