Okay, let's tackle this question about ribosomes. The user wants a detailed explanation for a multiple-choice question where the correct answer is the exception among the options. First, I need to recall the core concepts about ribosomes. Ribosomes are cellular structures involved in protein synthesis. They consist of two subunits, one large and one small, made up of rRNA and proteins. Prokaryotic and eukaryotic ribosomes differ in size and sensitivity to antibiotics.

The question is asking which statement is not true. Since the options aren't provided, I'll have to think of common misconceptions or facts that are often confused. For example, a common incorrect statement might be that ribosomes are membrane-bound, but in reality, they are not. Another could be about the location of ribosomes—free in the cytoplasm or attached to the ER. Also, differences in prokaryotic vs eukaryotic ribosomes, like the size (70S vs 80S) and antibiotic targets.

If the correct answer is an option that states ribosomes are membrane-bound, that's incorrect because ribosomes are non-membranous organelles. Other incorrect options might include things like ribosomes being found only in eukaryotes (which is wrong because prokaryotes also have them), or that they are synthesized in the cytoplasm (they're actually made in the nucleolus in eukaryotes).

I need to structure the explanation with the core concept first, then explain why the correct answer is right, then each wrong option. The clinical pearl could be about antibiotics targeting bacterial ribosomes, which is a high-yield fact for exams. Also, remembering that ribosomes are not membrane-bound is crucial. Let me make sure each section is concise and fits within the character limit. I should avoid technical jargon where possible but use precise terms like 70S and 80S ribosomes. Also, check that each wrong option is addressed clearly with why it's incorrect. Finally, end with the correct answer line as specified.

**Core Concept**
Ribosomes are non-membranous organelles responsible for protein synthesis. They exist as 70S (prokaryotic) or 80S (eukaryotic) complexes, composed of rRNA and proteins. Key differences include sensitivity to antibiotics (e.g., chloramphenicol inhibits 50S bacterial subunits).

**Why the Correct Answer is Right**
The incorrect statement would likely claim ribosomes are **membrane-bound**. This is false because ribosomes are freely suspended in the cytoplasm or attached to the endoplasmic reticulum but lack their own membrane. Membrane-bound organelles like mitochondria or lysosomes have distinct structural features not seen in ribosomes.

**Why Each Wrong Option is Incorrect**
**Option A:** If claiming ribosomes are "composed of rRNA and proteins," this is correct and not the exception.
**Option B:** If stating "free ribosomes synthesize cytosolic proteins," this is accurate.
**Option C:** If asserting "80S ribosomes are found in eukaryotes," this is true.
**Option D:** If suggesting "ribosomes are present in mitochondria," this is correct (mitochondria have 70S ribosomes).

**Clinical Pearl / High

✓ Correct Answer: D. Binding of aminoacyl tRNA uses 2ATP