**Core Concept**
Glutathione is a tripeptide composed of cysteine, glycine, and glutamic acid, playing a crucial role in cellular antioxidant defense and redox regulation. It is a key player in maintaining cellular homeostasis by scavenging reactive oxygen species (ROS) and participating in various cellular processes.

**Why the Correct Answer is Right**
Glutathione (GSH) helps in membrane transport by facilitating the transport of amino acids, including cysteine, across cell membranes. This process is essential for maintaining cellular glutathione levels, which are critical for antioxidant defenses. GSH also participates in the gamma-glutamyl cycle, which enables the transport of amino acids into cells. The gamma-glutamyl cycle involves the enzyme gamma-glutamyl transpeptidase, which catalyzes the transfer of the gamma-glutamyl moiety from glutathione to an amino acid, resulting in the formation of gamma-glutamyl-amino acid and cysteineglycine.

**Why Each Wrong Option is Incorrect**
**Option A:** Glutathione is not directly involved in the absorption of amino acids. While it does participate in the gamma-glutamyl cycle, which enables the transport of amino acids into cells, its primary role is not in absorption.
**Option B:** Glutathione does not inactivate enzymes. Instead, it donates its reducing equivalents to oxidized proteins and enzymes, helping to maintain their function.
**Option D:** Not all the given statements are true, making this option incorrect.

**Clinical Pearl / High-Yield Fact**
Glutathione plays a crucial role in maintaining cellular antioxidant defenses and is often depleted in oxidative stress conditions, such as in critically ill patients or those with chronic diseases. Its levels can be replenished through dietary supplementation or intravenous administration.

**✓ Correct Answer: C. It helps in membrane transpo**