To determine which statements concerning prokaryotes are true, let's analyze each statement step by step.
### Step 1: Analyze the first statement
**Statement:** Prokaryotes do not contain organelles, so they cannot photosynthesize or carry out cellular respiration.
**Analysis:** This statement is false. While prokaryotes lack membrane-bound organelles, they do have structures that allow them to carry out essential functions. For example, some prokaryotes, such as cyanobacteria, can photosynthesize using thylakoid membranes, which are not organelles in the traditional sense but serve a similar function. Additionally, prokaryotes can perform cellular respiration using their cell membrane.
**Conclusion:** This statement is incorrect.
### Step 2: Analyze the second statement
**Statement:** Prokaryotes have no chromosomes and therefore lack DNA.
**Analysis:** This statement is also false. Prokaryotes do have genetic material, which is typically in the form of a single circular chromosome. They also possess plasmids, which are small, circular pieces of DNA that can carry additional genes. Therefore, prokaryotes do contain DNA.
**Conclusion:** This statement is incorrect.
### Step 3: Analyze the third statement
**Statement:** Prokaryotic flagella is similar in structure to the eukaryotic flagella.
**Analysis:** This statement is false. Prokaryotic flagella and eukaryotic flagella differ significantly in structure. Prokaryotic flagella are composed of a protein called flagellin and consist of three main parts: the hook, filament, and basal body. In contrast, eukaryotic flagella are more complex, made up of microtubules arranged in a "9+2" structure.
**Conclusion:** This statement is incorrect.
### Step 4: Analyze the fourth statement
**Statement:** None of the above.
**Analysis:** Since all previous statements have been found to be incorrect, this statement is true.
**Conclusion:** The correct answer is option 4, "none of the above," as none of the statements about prokaryotes are true.
### Final Answer:
The correct answer is option 4: None of the above.
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