Question

The degradation of stored glycogen in liver and muscles is known as:

• A. Glycogenolysis
• B. Glycolysis
• C. Gluconeogenesis
• D. Glycogenesis

Hint:

Break down the word root:
Glycogen + lysis (breakdown) = Glycogenolysis.
Glyco + genesis (creation) = Glycogenesis.

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
The question asks for the specific biochemical pathway me corresponding to the breakdown of stored glycogen into glucose units in animal tissues.

Step 2: Key Formula or Approach:
Reviewing metabolic terminology for carbohydrate pathways:
• Glycogen breakdown $\to$ Glycogenolysis

• Glycogen synthesis $\to$ Glycogenesis

• Glucose oxidation to pyruvate $\to$ Glycolysis

• Synthesis of glucose from non-carbohydrate precursors $\to$ Gluconeogenesis

Step 3: Detailed Explation:

• Mechanism of Glycogenolysis: Glycogenolysis is the metabolic breakdown of intracellular glycogen reserves into glucose-1-phosphate (G1P) and free glucose.

• Key Enzymes Involved:
• Glycogen Phosphorylase: Cleaves $\alpha(1 \to 4)$ glycosidic linkage from non-reducing ends via phosphorolysis to produce glucose-1-phosphate.

• Debranching Enzyme: Handles $\alpha(1 \to 6)$ glycosidic branch points.

• Tissue Differences:
• Liver: Expresses glucose-6-phosphatase, allowing converted glucose-6-phosphate to yield free glucose released into the bloodstream to maintain glycemia.

• Skeletal Muscle: Lacks glucose-6-phosphatase; glucose-6-phosphate enters glycolysis directly to generate ATP for muscle contraction.

Step 4: Fil Answer:
The degradation of stored glycogen is termed glycogenolysis.