Biology
Cell: The Unit of Life
6. What are NAM and NAG individually, and what do they do collectively?
a) Each is a monosaccharide, together they make up peptidoglycan in bacterial cell walls. b) Each is a
monosaccharide, together they polymerize into cellulose cell walls. c) Each is a monosaccharide,
together they make up chitin in bacterial cell walls. d) Each is a glycolipid, together they anchor cell
walls into plasma membranes. e) Each is a tetrapeptide, together they hold cell walls together.
7. Lemon juice has a pH of ~2 and coffee has a pH of ~5, so lemon juice must be
a) 1000x more acidic b) 3x more basic c) 100x more acidic d) 3x more acidic
than coffee.
e) 2x more acidic
8. What is an axial filament?
a) a bundle of endoflagella b) the primary structure of a polypeptide c) a lipoprotein that anchors
peptidoglycan to the cell membrane d) a part of an electron microscope e) None of these is correct.
9. What type of bond holds polymers of nucleotides together?
a) peptide bond b) disulfide bridge c) hydrophobic interactions
e) glycosidic linkages
d) phosphodiester bond
10. What is the difference between pili and fimbriae?
a) Pili are present only in Eukaryotes, but fimbriae are present only in Prokaryotes. b) Pili are long and
spiral-shaped, but fimbriae are short and straight. c) Pili are short and straight, but fimbriae are long
and spiral-shaped. d) Pili are internal, but fimbriae are external. e) Pili and fimbriae are considered
by many to be two different names for the same structures.
