Which of the following statements is INCORRECT regarding prokaryotic cells?
A They typically have a circular chromosome. They lack a plasma membrane.
B They reproduce by binary fission.
C They lack membrane-enclosed organelles.
D Their DNA is not enclosed within a membrane. None
The Correct Answer and Explanation is :
The incorrect statement regarding prokaryotic cells is:
A. They typically have a circular chromosome. They lack a plasma membrane.
Explanation:
- Circular Chromosome: Prokaryotic cells do indeed typically have a circular chromosome. This chromosome is located in a region called the nucleoid, not enclosed within a membrane-bound nucleus, as in eukaryotic cells.
- Lack of Plasma Membrane: This part of the statement is incorrect. Prokaryotic cells do have a plasma membrane. The plasma membrane is a crucial structure that surrounds the cell and regulates the movement of substances in and out of the cell. It plays a similar role in prokaryotic cells as it does in eukaryotic cells. In fact, all cells, whether prokaryotic or eukaryotic, have a plasma membrane. So, the claim that prokaryotes “lack a plasma membrane” is factually wrong.
Now, let’s look at the other options:
- B. They reproduce by binary fission: This is correct. Prokaryotic cells reproduce asexually by binary fission, where the cell divides into two identical daughter cells. This process involves the duplication of the chromosome and the division of the cytoplasm.
- C. They lack membrane-enclosed organelles: This is correct. Prokaryotic cells do not have membrane-bound organelles such as mitochondria, endoplasmic reticulum, or the Golgi apparatus. They do, however, have ribosomes, which are not membrane-enclosed.
- D. Their DNA is not enclosed within a membrane: This is correct. In prokaryotic cells, the DNA is typically found in the nucleoid, which is an area of the cell where the genetic material is concentrated but not enclosed by a membrane. This contrasts with eukaryotic cells, where DNA is enclosed within a membrane-bound nucleus.
Thus, A is the only incorrect statement because it misrepresents the presence of the plasma membrane in prokaryotic cells.