Problem 7 - Campbell Biology

Question

If you were to jog \(1 \mathrm{~km}\) a few hours after lunch, which stored fuel would you probably tap? (A) muscle proteins (B) muscle and liver glycogen (C) fat in the liver (D) fat in adipose tissue

Step-by-Step Solution

Answer

B) muscle and liver glycogen

Step 1: Understand the question

Determine which stored fuel the body would use for a short, moderate exercise such as jogging 1 km.

Step 2: Review stored fuels

Differentiate between muscle proteins, muscle and liver glycogen, fat in the liver, and fat in adipose tissue. Understand that muscle proteins are generally not used for short-term energy, fats in the liver and adipose tissue are used for longer-term energy, and glycogen is used for immediate energy.

Step 3: Identify the likely energy source

For short-term exercise, the body relies on stored glycogen in muscles and the liver because it is readily available.

Step 4: Conclusion

The most likely sources of energy for jogging 1 km are muscle and liver glycogen.

Key Concepts

Glycogen Utilization

When you engage in physical activities like jogging 1 km, your body needs a quick energy source. Glycogen serves as this immediate fuel. Glycogen is stored in your muscles and liver. It’s a form of glucose that can be readily broken down into energy. When you start exercising, your body taps into these glycogen stores. This happens because glycogen can be rapidly converted back into glucose to fuel your muscles. Consequently, muscle and liver glycogen are the go-to sources for activities requiring short, intense bursts of energy. Think of glycogen as your body's quick-reaction energy reserve.

Short-term Energy

Short-term energy sources are crucial for quick, immediate physical activities. These include exercises like sprinting, lifting weights, or jogging short distances. When your body requires instant energy, it primarily relies on glycogen stored in the muscles and liver. Glycogen is easily accessible and can be converted to glucose without any delay. Unlike fat, which takes longer to break down, glycogen offers a swift energy supply. Muscle proteins are usually preserved and not used for short-term energy needs because breaking down proteins is not a quick process.
Hence, for short-distance jogging, you can count on glycogen to power you up with the energy you need.

Exercise Physiology

Exercise physiology helps us understand how our bodies respond to physical activity. When you jog, your muscles need energy immediately. The stored glycogen in muscles and liver plays a key role here. The process of breaking down glycogen into glucose is quick, ensuring your muscles get the energy they need right away. Glycogen also helps maintain blood glucose levels during exercise.
Rather than using fats from adipose tissue, which takes longer to convert to energy, your body prefers glycogen for short-term activities. Knowing how your body fuels itself during different types of exercise can help you plan your workouts better and optimize your performance.