To show that lines are parallel, we draw small arrow marks on them. In the figure above, note the arrows on the lines PQ and RS. When we write about parallel lines there is a shorthand we can use. We can write which is read as the line segment PQ is parallel to the segment RS.
Lysosome[edit] Lysosomes are spherical bodies, or vacuoles that are enclosed by a single membrane. The membrane serves as a protectorate to the cell, since lysosomes contain harsh digestive enzymes, which would cause significant damage if exposed to cell content.
A lysosome contains hydrolase enzymes capable of breaking down wastes and old cells. They are found in animal cells. Lysosomes sometimes get the nickname suicide sac as their enzymes digest worn out cells and organelles and can also digest food that is in a food vacuole. The enzymes in a lysosome are acidic. Lysosomes were discovered by Christian de Duve in the 1960's--a...