Problem 9 - 43 Years JEE ADVANCED (1978-2020) + JEE MAIN Chapterwise & Topicwise Solved Papers Chemistry

Question

The correct statement(s) among I to III with respect to potassium ions that are abundant within the cell fluidsis/are: [Main Jan. 12, 2019 (II)] I. They activate many enzymes II. They participate in the oxidation of glucose to produce ATP III. Along with sodium ions, they are responsible for the transmission of nerve signals (a) I and II only (b) I and III only (c) I, II and III (d) III only

Step-by-Step Solution

Answer

(b) I and III only

Step 1: Analyze Statement I

Statement I says that potassium ions activate many enzymes. Potassium ions are indeed essential for the activation of various enzymes involved in protein and carbohydrate metabolism. Hence, Statement I is correct.

Step 2: Analyze Statement II

Statement II states that potassium ions participate in the oxidation of glucose to produce ATP. The oxidation of glucose mainly involves processes like glycolysis and the citric acid cycle, which do not specifically require potassium ions. Thus, Statement II is incorrect.

Step 3: Analyze Statement III

Statement III says that potassium ions, along with sodium ions, are responsible for the transmission of nerve signals. Potassium and sodium ions play key roles in creating action potentials for nerve signal transmission. Therefore, Statement III is correct.

Step 4: Determine the Correct Option

Based on the analysis: Statement I is correct, Statement II is incorrect, and Statement III is correct. Thus, the correct statements are I and III.

Key Concepts

Enzyme Activation

Potassium ions play a crucial role in enzyme activation, especially within a cell's metabolic processes. Enzymes are proteins that speed up chemical reactions in the body. But not all enzymes can work effectively on their own. Here is where potassium ions come in handy. They can change the shape of enzymes or help them hold onto substrates - the molecules enzymes act on. This makes the reactions happen quicker and more efficiently.
For example, many enzymes involved in protein and carbohydrate metabolism need potassium to function properly. They act like a helper that turns the "on" switch for enzymes, allowing vital processes such as energy production and the breakdown of nutrients to occur at the right speed.

• Potassium ions adjust the physical structure of enzymes to aid in their function.
• This makes metabolic processes, like breaking down food for energy, happen faster.

Without enough potassium, our enzymes wouldn't work as well, which would slow down essential cellular functions.

Nerve Signal Transmission

Both potassium and sodium ions are fundamental to the transmission of nerve signals. Our nerves communicate with each other by sending electrical signals. This process is much like flipping a switch. It relies on the careful movement of ions, mainly potassium and sodium, across nerve cell membranes.
The movement creates an electrical pulse called an action potential. Here's a simplified sequence of events:

• In the "resting" state, sodium ions are outside the nerve cell, while potassium ions are inside. This setup maintains a difference in electrical charge across the membrane.
• To send a signal, sodium ions rush into the neuron, changing the charge inside the cell (making it more positive).
• Afterwards, potassium ions flow out to reset the charge balance to its resting state. By doing so, the nerve is ready to send another signal.

Potassium ions help reset the nerve's "switch," allowing the electrical signals to be sent quickly and accurately across vast neuron networks.

Cellular Functions

Potassium ions are not only crucial for specific processes like enzyme activation and nerve signaling but are also indispensable for general cellular functions. Every cell in the body relies on this essential ion to maintain its health and perform tasks efficiently.
Potassium's primary role in cellular functions includes:

• Maintaining cellular fluid balance: Potassium helps control what enters and exits the cell, ensuring stability and proper function.
• Regulating electrolyte and acid-base balance: Potassium keeps the pH levels of cells within a healthy range.
• Supporting muscle function: Sufficient potassium levels allow muscles to contract and relax properly.

In essence, potassium ions contribute to almost every cellular operation, making them vital for life. Without them, cells couldn't function, leading to a cascade of physiological problems.