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.
The membrane-bound structure that contains digestive enzymes is the lysosome. Lysosomes contain enzymes that break down organic macromolecules such as carbohydrates, fats and proteins. All animal cells contain lysosomes, but they are most present in the cells of the immune system, such as white blood cells. Keep Learning.