Question

biomolecules on the menu
part 3: extension
some athletes do \carb - loading\ several days before a major endurance event, such as running a marathon. this involves eating a lot of complex carbohydrates, such as starch, which is found in pasta, bread, and rice. carb - loading also involves decreasing physical activity.

1. explain how carb - loading might allow cells to produce more atp during a marathon.
2. some marathon runners eat energy gels (food label shown in figure 3) during a marathon.

energy gel packs
serving size: about 1 pack (40g)
servings per box: 12
amount per serving calories: 100
total fat 0g
saturated fat 0g
trans fat 0g
cholesterol 0mg
sodium 2mg
total carbohydrate 25g
dietary fiber 0g
sugars* 25g
added sugars* 25g
protein 0g
figure 3. the food labels for energy gels. *another word for \sugars\ is monosaccharides.
a. based on the food label, what is the main energy source in energy gels?
b. what advantage might runners who eat energy gels have over runners who do not?

1. during the race, the runners breathing and heart rates will increase. why is that?

Explanation:

1. Carb - loading involves eating complex carbohydrates. These are broken down into glucose. During a marathon, more glucose means more substrate for cellular respiration (glycolysis, Krebs cycle, and oxidative phosphorylation), allowing for more ATP production.

25a. The food label shows 25g of total carbohydrates and 25g of sugars (monosaccharides). Carbohydrates, especially sugars, are the main energy source as they are quickly metabolized to release energy.
25b. Runners who eat energy gels have a readily - available source of glucose. This can provide a quick energy boost during the marathon, helping to maintain energy levels and performance compared to those who do not consume them.

1. During a race, the body's energy demand increases. To meet this demand, more oxygen is needed for cellular respiration to produce ATP. The increased breathing rate brings in more oxygen, and the increased heart rate pumps more oxygen - rich blood to the working muscles.

Answer:

1. Eating complex carbohydrates during carb - loading provides more glucose for cellular respiration, resulting in more ATP production during a marathon.

25a. Carbohydrates (specifically sugars/monosaccharides) are the main energy source in energy gels.
25b. They have a quick source of energy to maintain performance.

1. To supply more oxygen for increased energy - producing cellular respiration.