Protein synthesis occurs in?

ISRO- 2016

Biochemistry & Nutrition

Easy

Appeared in: ISRO- 2016

Explanation

Ribosomes are the cellular machinery responsible for protein synthesis, a process called translation.
They read the sequence of messenger RNA (mRNA) and, using transfer RNA (tRNA), link amino acids together to form a polypeptide chain.
This fundamental process occurs on both free ribosomes in the cytoplasm and ribosomes bound to the rough endoplasmic reticulum.
The provided diagram visually confirms the presence of ribosomes as distinct organelles within the cell, both free and attached to the ER.

Option B: Lysosomes are membrane-bound organelles containing hydrolytic enzymes. Their function is to break down waste materials, cellular debris, and foreign invaders like bacteria, not to synthesize proteins.
Option C: Endosomes are membrane-bound compartments involved in the endocytic pathway. Their primary role is to sort and transport material that has been brought into the cell before it is sent to the lysosome for degradation.
Option D: The Golgi apparatus functions as a 'post office' for the cell. It receives proteins and lipids from the endoplasmic reticulum, modifies them, sorts them, and packages them into vesicles for delivery to other destinations. It processes proteins but does not synthesize them.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain The function of cellular organelles, specifically the site of protein synthesis as background academic context rather than a clinical decision trigger.
Understanding the function of ribosomes is crucial for pharmacology, as many antibiotics (e.g., aminoglycosides, tetracyclines, macrolides) specifically target bacterial ribosomes to inhibit protein synthesis, thereby killing the bacteria while sparing human cells.
Errors in protein synthesis or folding can lead to numerous diseases, including cystic fibrosis and certain neurodegenerative disorders. Nurses may care for patients whose conditions stem from these fundamental cellular-level problems.
What if a genetic mutation affected the structure of ribosomal RNA (rRNA)? This could impair the ribosome's ability to synthesize proteins correctly, potentially leading to a wide range of severe developmental disorders or cellular dysfunction, as the production of all proteins would be compromised.

How to Approach the Question

First, identify the key process in the question stem, which is 'protein synthesis'.
This is a factual recall question. Access your knowledge of basic cell biology and the functions of different organelles.
Consider each option: A) Ribosome, B) Lysosome, C) Endosome, D) Golgi apparatus.
Recall the primary function of each organelle. Ribosomes are known as the 'protein factories' of the cell.
Lysosomes are for 'digestion/waste disposal'. Endosomes are for 'sorting'. The Golgi apparatus is for 'processing and packaging'.
Match the function 'protein synthesis' with the correct organelle. The clear match is the ribosome.

Concept Tested & Keywords

Concept Tested: The function of cellular organelles, specifically the site of protein synthesis.
Stem keywords: Protein synthesis, cell, organelle
Lead-in keywords: occurs in

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