AP-Micro Microbiology: Cell Structure and Function 2

Question 1

Which structural feature allows gram-negative bacteria to be inherently resistant to many antibiotics like penicillin?

Accepted Answer

Outer membrane containing LPS

Answer

Thicker peptidoglycan layer

Answer

Absence of a cell wall

Answer

Presence of efflux pumps only

Question 2

Bacterial flagella rotate to produce movement. Which component anchors the flagellum to the cell membrane and generates torque?

Accepted Answer

Basal body

Answer

Hook

Answer

Filament

Answer

Cap protein

Question 3

A microbiologist observes a bacterium with fimbriae. What is the PRIMARY function of these structures?

Accepted Answer

Attachment to host cell surfaces

Answer

Locomotion through liquid media

Answer

DNA transfer between cells

Answer

Protection against phagocytosis

Question 4

What is the function of porins found in the outer membrane of gram-negative bacteria?

Accepted Answer

Form channels that allow passive diffusion of small molecules

Answer

Actively pump ions using ATP

Answer

Synthesize lipopolysaccharide

Answer

Anchor flagella to the membrane

Question 5

Which of the following correctly describes the nucleoid region of a prokaryotic cell?

Accepted Answer

A region containing circular DNA not enclosed by a membrane

Answer

A membrane-bound organelle containing linear chromosomes

Answer

A structure equivalent to the eukaryotic nucleus with a double membrane

Answer

A specialized compartment for ribosome synthesis

Question 6

Magnetotactic bacteria contain magnetosomes. What are magnetosomes and what is their cellular classification?

Accepted Answer

Membrane-enclosed crystals of iron minerals; considered organelles

Answer

Protein complexes on the cell surface; considered part of the glycocalyx

Answer

Lipid storage droplets; considered inclusion bodies

Answer

RNA-protein complexes; considered ribosomes

Question 7

A student claims that all prokaryotes lack a cytoskeleton. Why is this claim incorrect?

Accepted Answer

Prokaryotes have homologs such as MreB and FtsZ that function similarly to eukaryotic cytoskeletal proteins

Answer

Prokaryotes have actin and tubulin identical to eukaryotes

Answer

Prokaryotes use flagella as a cytoskeletal framework

Answer

Prokaryotes have intermediate filaments but not microfilaments