Question

fill in the blank question

muscle cells contain blank, a starch-like carbohydrate that provides energy during intense exercise.

Explanation:

Identify the key clues in the statement

The question asks for a "starch-like carbohydrate" found in muscle cells that "provides energy during intense exercise."

Analyze the biological components of muscle cells

Using the Sarcoplasm Components knowledge point, we recall that the cytoplasm of a muscle fiber (sarcoplasm) contains substantial amounts of stored carbohydrates and oxygen-binding proteins.

Determine the specific carbohydrate

The primary stored carbohydrate in animal tissues, particularly in skeletal muscle and liver cells, is glycogen. Glycogen is a highly branched polymer of glucose, which makes its structure chemically similar to amylopectin (a component of plant starch). Thus, it is frequently described as a "starch-like carbohydrate" or "animal starch."

Verify the physiological function

During intense exercise, muscle cells rapidly break down glycogen into glucose-1-phosphate (via glycogenolysis) to fuel glycolysis and generate ATP, providing the necessary energy for muscle contraction. Therefore, the correct term to fill in the blank is "glycogen".

Answer:

Muscle cells contain <blank>glycogen</blank>, a starch-like carbohydrate that provides energy during intense exercise.