Question

Ions of an element X is required for interneuronal transmission. Ions of an element Y helps in the transport of sugars into cells. X and Y are respectively

• A. Mg, K
• B. Ca, Na
• C. Ca, K
• D. Mg, Na

Hint:

{Biological roles:} - $Ca^{2+}$: Blood clotting, Muscle contraction, Nerve signal release. - $Na^+$: Nerve impulse conduction (Action potential), Fluid balance, Glucose transport.

Answer 1

The Correct Option is B

Step 1: Identify X (Interneuronal Transmission):
The transmission of nerve impulses across a synapse (interneuronal transmission) relies heavily on the influx of Calcium ions ($Ca^{2+}$) into the presynaptic neuron. This triggers the release of neurotransmitters (like acetylcholine) from synaptic vesicles into the synaptic cleft. Thus, X is Calcium.
Step 2: Identify Y (Sugar Transport):
The transport of sugars (like glucose) and amino acids into cells (e.g., intestinal epithelial cells) occurs via secondary active transport. This process is driven by the concentration gradient of Sodium ions ($Na^+$). The transporter protein (SGLT) co-transports sodium and glucose into the cell. Thus, Y is Sodium.
Step 3: Conclusion:
X is Calcium ($Ca$) and Y is Sodium ($Na$). This matches Option (B).