Which of the following components of the ring structure of chlorophyll helps in maintaining the ribosome stru… - UP CHO - 10 September 2021

UP CHO - 10 September 2021

Biochemistry & Nutrition

Medium

Appeared in: UP CHO - 10 September 2021

Explanation

Magnesium (Mg²⁺) is the central metal ion chelated in the porphyrin ring structure of chlorophyll, which is essential for photosynthesis.
Magnesium ions are also critical for maintaining the structure of ribosomes.
They act as counter-ions to neutralize the negatively charged phosphate backbone of ribosomal RNA (rRNA).
This neutralization allows the large and small ribosomal subunits to associate, forming a functional ribosome capable of protein synthesis.

Option B: Iron is the central atom in the heme group of hemoglobin and myoglobin, not chlorophyll. While essential for many cellular processes like electron transport (in cytochromes), it is not the primary ion for maintaining ribosome structure.
Option C: Sulphur is a key component of certain amino acids (methionine, cysteine) and vitamins (thiamine, biotin), and is important for protein structure through disulfide bonds. It is not a component of the chlorophyll ring.
Option D: Potassium is the major intracellular cation, vital for maintaining membrane potential, nerve impulse transmission, and osmotic balance. It is not part of the chlorophyll molecule.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Biochemical roles of minerals, specifically Magnesium in chlorophyll and ribosome structure as background academic context rather than a clinical decision trigger.
Magnesium's role in ribosome stability means it is fundamental for protein synthesis in all cells, including human cells. Many enzymes require magnesium as a cofactor.
Clinically, hypomagnesemia (low magnesium levels) can impair enzyme function and protein synthesis, contributing to a wide range of symptoms.
What if? If a patient has severe hypomagnesemia, they can present with neuromuscular hyperexcitability (e.g., tremors, tetany, seizures) and cardiac arrhythmias. This is because magnesium is also crucial for the function of ion channels, like the Na⁺/K⁺-ATPase pump.

How to Approach the Question

First, identify the key concepts in the question: 'chlorophyll ring structure' and 'ribosome structure'.
The question asks for a single component common to or involved in both.
Recall or deduce the composition of chlorophyll. The most defining feature of its porphyrin ring is the central metal ion.
Consider the options provided. Evaluate each mineral's known biological roles.
Recall that Magnesium is the central atom in chlorophyll, analogous to Iron in heme.
Recall or deduce the role of ions in stabilizing large biological molecules like ribosomes, which are made of negatively charged RNA and proteins. Divalent cations like Mg²⁺ are known to be crucial for this stabilization.

Concept Tested & Keywords

Concept Tested: Biochemical roles of minerals, specifically Magnesium in chlorophyll and ribosome structure.
Stem keywords: chlorophyll, ring structure, ribosome structure
Lead-in keywords: Which
Negative lead-in flag: false

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