Domanda del libro di testo
Gram-positive bacteria __________.
a. have a thick cell wall, which retains crystal violet dye
b. contain teichoic acids in their cell walls
c. appear purple after Gram staining
d. all of the above
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7. Prokaryotic Cell Structures & Functions
Gram-Positive Cell Walls
Scelta multipla
Each of the following statements concerning the gram-positive cell wall is true EXCEPT:
A
It stains purple in the Gram stain procedure.
B
It has an outer membrane similar to that of gram-negative bacteria.
C
Teichoic acids are commonly found in its structure.
D
It contains a thick layer of peptidoglycan.
Guida verificata passo dopo passo1
Step 1: Understand the structure of the gram-positive bacterial cell wall. Gram-positive bacteria have a thick peptidoglycan layer and lack an outer membrane, which is a key difference from gram-negative bacteria.
Step 2: Recall the Gram stain procedure. Gram-positive bacteria retain the crystal violet stain and appear purple under the microscope due to their thick peptidoglycan layer.
Step 3: Identify the presence of teichoic acids. These are commonly found in the gram-positive cell wall and contribute to its structure and function.
Step 4: Recognize that gram-negative bacteria have an outer membrane, but gram-positive bacteria do not. Therefore, any statement claiming gram-positive bacteria have an outer membrane similar to gram-negative bacteria is false.
Step 5: Conclude that the false statement (EXCEPT) is the one about the outer membrane, as it contradicts the known structural characteristics of gram-positive bacteria.
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