Regrding prokaryotic organisms, all of the following are correct EXCEPT?
A Their DNA is not enclosed within a membrane.
B They lack membrane-enclosed organelles.
C They typically have a circular chromosome.
D They lack a plasma membrane.
E They reproduce by binary fission.
The correct answer and explanation is:
The correct answer is D: They lack a plasma membrane.
Prokaryotic organisms, which include bacteria and archaea, have a variety of characteristic features, but they do not lack a plasma membrane. All prokaryotes have a plasma membrane that serves as a barrier to control the movement of substances into and out of the cell. The plasma membrane also plays an essential role in maintaining the cell’s internal environment, energy production (through processes like cellular respiration or photosynthesis in some cases), and communication with the external environment.
Let’s break down the other options:
- A. Their DNA is not enclosed within a membrane: This is true. In prokaryotes, the DNA is located in the nucleoid region, which is not enclosed by a membrane. This is one of the key differences between prokaryotes and eukaryotes, where the DNA is contained in a membrane-bound nucleus.
- B. They lack membrane-enclosed organelles: This is also correct. Prokaryotes do not have organelles such as a nucleus, mitochondria, or endoplasmic reticulum. Instead, their cellular functions are carried out in the cytoplasm or across the plasma membrane.
- C. They typically have a circular chromosome: This is true as well. Most prokaryotes have a single, circular chromosome that contains their genetic material. This is in contrast to the linear chromosomes found in eukaryotes.
- E. They reproduce by binary fission: This is correct. Prokaryotes reproduce asexually through a process known as binary fission, where the cell divides into two genetically identical daughter cells. This is different from the more complex process of mitosis seen in eukaryotes.
Thus, the only incorrect statement here is D, because prokaryotes do have a plasma membrane, which is crucial for their survival and function.