Question

What is the difference between Gram-positive and Gram-negative bacteria? A) Gram-positive bacteria are surrounded by a single membrane, whereas Gram-negative bacteria are surrounded by a double membrane, with an outer membrane that is porous to ions and small molecules. B) Gram-positive bacteria are motile and Gram-negative bacteria are not. C) Gram-positive bacteria make gramicidin A and Gram-negative bacteria do not. D) Gram-positive bacteria are surrounded by a single membrane, while Gram-negative bacteria have a dual-membrane system with an inner membrane that is porous to small molecules and ions.

Answer 1

Gram-positive bacteria are surrounded by a single membrane, whereas Gram-negative bacteria are surrounded by a double membrane, with an outer membrane that is porous to ions and small molecules.

Step-by-step explanation:

Cell wall structure differs in Gram-positive and Gram-negative bacteria. The Gram-positive bacterial cell wall is made up of a single homogenous layer in peptidoglycan. It is 20-80 nm thick and is present outside of the plasma membrane.

The cell wall in Gram-negative bacteria consists of a 2-7 nm thick peptidoglycan layer covered by 7-8 nm thick outer membrane. The porin proteins of the outer membrane for channels across it to allow the small molecules to enter the periplasm.