Microbiology: Cell Structure and Function Flashcards
7 cards from real AP practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Microbiology: Cell Structure and Function flashcards as text
Which structural feature allows gram-negative bacteria to be inherently resistant to many antibiotics like penicillin?
Answer: Outer membrane containing LPS
The outer membrane of gram-negative bacteria acts as a permeability barrier that excludes many antibiotics, including penicillin, from reaching the peptidoglycan layer.
Bacterial flagella rotate to produce movement. Which component anchors the flagellum to the cell membrane and generates torque?
Answer: Basal body
The basal body is embedded in the cell membrane and wall, functioning as a motor that uses proton motive force to rotate the flagellum.
A microbiologist observes a bacterium with fimbriae. What is the PRIMARY function of these structures?
Answer: Attachment to host cell surfaces
Fimbriae (also called pili) are short, hair-like appendages that mediate adhesion of bacteria to host tissues and surfaces.
What is the function of porins found in the outer membrane of gram-negative bacteria?
Answer: Form channels that allow passive diffusion of small molecules
Porins are transmembrane proteins that form water-filled channels permitting passive diffusion of small hydrophilic molecules across the outer membrane.
Which of the following correctly describes the nucleoid region of a prokaryotic cell?
Answer: A region containing circular DNA not enclosed by a membrane
The nucleoid is an irregularly shaped region in prokaryotes where the circular chromosomal DNA is compacted, but it lacks a surrounding membrane.
Magnetotactic bacteria contain magnetosomes. What are magnetosomes and what is their cellular classification?
Answer: Membrane-enclosed crystals of iron minerals; considered organelles
Magnetosomes are membrane-bound organelles containing magnetite or greigite crystals that allow bacteria to orient along geomagnetic fields.
A student claims that all prokaryotes lack a cytoskeleton. Why is this claim incorrect?
Answer: Prokaryotes have homologs such as MreB and FtsZ that function similarly to eukaryotic cytoskeletal proteins
Prokaryotes possess cytoskeletal homologs like MreB (actin homolog) that maintains cell shape and FtsZ (tubulin homolog) that forms the division ring during binary fission.