Textbook Question
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
7. Prokaryotic Cell Structures & Functions
Gram-Positive Cell Walls
Multiple Choice
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.
Verified step by step guidance1
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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