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.
Lysosomes can be said to be a cell's digestive system.    â¦    Lysosomes are organelles that contain digestive enzymes They digest excess or worn out organelles, food particles, and engulfed viruses or bacteria. The membrane surrounding a lysosome prevents the digestive enzymes inside from destroying the cell. Lysosomes fuse with vacuoles and dispense their enzymes into the vacuoles, digesting their contents. They are built in the Golgi apparatus.