Bio 251 Chapter 1 &4 Test
(2026-2027 Edition)
Questions with 100% Correct
Answers and Rationales | Latest
Update | Grade A+
, What are the basic shapes of bacteria? Bacillus (rod-shaped), Coccus (spherical), Spiral.
What is a glycocalyx? It is an external structure to the cell wall, viscous and gelatinous, made of
polysaccharides and/or polypeptides.
What are the two types of glycocalyx? Capsule (organized and firmly attached) and slime layer (unorganized and
loose).
What is the function of flagella? They are filamentous appendages that propel bacteria.
What are the three parts of a flagellum? Filament, hook, and basal body.
What is the function of fimbriae? They are hairlike appendages that allow for attachment.
What is the role of pili in bacteria? They facilitate the transfer of DNA from one cell to another.
What is the primary function of the cell wall? To prevent osmotic lysis and protect the cell membrane.
What distinguishes Gram-positive cell walls? They have thick peptidoglycan and teichoic acids.
What are the characteristics of Gram-negative cell They have thin peptidoglycan, an outer membrane, and a periplasmic space.
walls?
What is the Gram stain mechanism for Gram-positive Alcohol dehydrated the peptidoglycan, preventing CV-I crystals from leaving.
bacteria?
(2026-2027 Edition)
Questions with 100% Correct
Answers and Rationales | Latest
Update | Grade A+
, What are the basic shapes of bacteria? Bacillus (rod-shaped), Coccus (spherical), Spiral.
What is a glycocalyx? It is an external structure to the cell wall, viscous and gelatinous, made of
polysaccharides and/or polypeptides.
What are the two types of glycocalyx? Capsule (organized and firmly attached) and slime layer (unorganized and
loose).
What is the function of flagella? They are filamentous appendages that propel bacteria.
What are the three parts of a flagellum? Filament, hook, and basal body.
What is the function of fimbriae? They are hairlike appendages that allow for attachment.
What is the role of pili in bacteria? They facilitate the transfer of DNA from one cell to another.
What is the primary function of the cell wall? To prevent osmotic lysis and protect the cell membrane.
What distinguishes Gram-positive cell walls? They have thick peptidoglycan and teichoic acids.
What are the characteristics of Gram-negative cell They have thin peptidoglycan, an outer membrane, and a periplasmic space.
walls?
What is the Gram stain mechanism for Gram-positive Alcohol dehydrated the peptidoglycan, preventing CV-I crystals from leaving.
bacteria?
