Lysosome

An organelle (a little organ) within a cell containing enzymes that degrade macromolecules (large molecules) and other materials (such as bacteria) taken up by a cell during the process of endocytosis. In endocytosis, macromolecules and particles outside the cell are taken up by the cell via a progressive invagination (inpouching) and eventual pinching off of a region of the cell membrane, forming a membrane-bound vesicle (bubble) within the cytoplasm of the cell. The vesicle then fuses with the lysosome and the lysosomal enzymes carry out their appointed task of destruction (by hydrolysis). Quite amazingly, the lysosomal enzymes do not normally damage the cell itself.
* * *
A cytoplasmic membrane-bound vesicle measuring 5-8 nm (primary l.) and containing a wide variety of glycoprotein hydrolytic enzymes active at an acid pH; serves to digest exogenous material, such as bacteria, as well as effete organelles of the cells. [lyso- + G. soma, body]
- definitive lysosomes SYN: secondary lysosomes.
- primary lysosomes lysosomes produced at the Golgi apparatus where hydrolytic enzymes are incorporated; they fuse with phagosomes or pinosomes to become secondary lysosomes.
- secondary lysosomes lysosomes in which lysis takes place, owing to the activity of hydrolytic enzymes; they are believed to eventually become residual bodies. SYN: definitive lysosomes, digestive vacuole.

* * *

ly·so·some 'lī-sə-.sōm n a saclike cellular organelle that contains various hydrolytic enzymes
ly·so·som·al .lī-sə-'sō-məl adj
ly·so·som·al·ly -mə-lē adv

* * *

n.
a particle in the cytoplasm of cells that contains enzymes responsible for breaking down substances in the cell and is bounded by a single membrane. Lysosomes are especially abundant in liver and kidney cells. Foreign particles (e.g. bacteria) taken into the cell are broken down by the enzymes of the lysosomes. When the cell dies, these enzymes are released to break down the cell's components.

* * *

ly·so·some (liґso-sōm) [lyso- + -some] a membrane-bound cytoplasmic organelle, generally 250–750 nm in diameter, containing hydrolytic enzymes in an acidic environment and involved in intracellular digestion. Lysosomal enzyme defects result in the progressive accumulation of undigested products within the cell, which leads to lysosomal storage disease (q.v.). See Plate 11. lysosomal adj

Medical dictionary. 2011.

Look at other dictionaries:

  • lysosome — [ lizozom ] n. m. • 1968; du gr. lusis (cf. lyse) et sôma « corps » ♦ Biol. Vésicule cytoplasmique des eucaryotes contenant un grand nombre d enzymes qui dégradent la plupart des macromolécules biologiques. Adj. LYSOSOMIAL, IALE, IAUX . ●… …   Encyclopédie Universelle

  • lysosome — lysosome. См. лизосома. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.

  • lysosome — 1955, from LYSO (Cf. lyso ) + some, from Gk. soma body …   Etymology dictionary

  • lysosome — [lī′sə sōm΄] n. [lyso , pertaining to dissolving < Gr lysis (see LYSIS) + SOME3] a particle in the cytoplasm of cells containing a number of digestive enzymes capable of breaking down most of the constituents of living matter: see CELL… …   English World dictionary

  • Lysosome — Les principaux organites d une cellule. Les lysosomes sont légendés en haut à gauche …   Wikipédia en Français

  • Lysosome — s: (1) nucleolus (2) nucleus (3) ribosomes (little dots) (4) vesicle (5) rough endoplasmic reticulum (ER) (6) Golgi apparatus (7) Cytoskeleton (8) smooth endoplasmic reticulum (9) mitochondria (10) vacuole (11) cytoplasm (12) lysosome (13)… …   Wikipedia

  • lysosome — lysosomal, adj. /luy seuh sohm /, n. Cell Biol. a cell organelle containing enzymes that digest particles and that disintegrate the cell after its death. See diag. under cell. [1950 55; LYSO + SOME3] * * * Membrane enclosed organelle found in all …   Universalium

  • lysosome — noun Etymology: International Scientific Vocabulary lys + 3 some Date: 1955 a saclike cellular organelle that contains various hydrolytic enzymes see cell illustration • lysosomal adjective …   New Collegiate Dictionary

  • lysosome — (li so sōm) A spherical membranous eucaryotic organelle that contains hydrolytic enzymes and is responsible for the intracellular digestion of substances …   Dictionary of microbiology

  • lysosome — Membrane bounded cytoplasmic organelle containing a variety of hydrolytic enzymes that can be released into a phagosome or to the exterior. Release of lysosomal enzymes in a dead cell leads to autolysis (and is the reason for hanging game, to… …   Dictionary of molecular biology

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.