Given the data presented in the table about the energy storage in humans, let's analyze each statement to determine the best conclusion.
1. Blood is a primary location for energy storage.
- According to the table, glucose in the blood provides only 40 kcal of energy, which supports life for just a few minutes. Therefore, blood is not a primary storage site for energy.
2. Fat molecules contain more energy-containing bonds than simple sugars.
- The table shows that lipids (fats) provide 9 kcal of energy per gram, whereas free glucose in the blood and glycogen both provide 4 kcal per gram. This indicates that fat molecules indeed contain more energy per gram compared to simple sugars and glycogen. This statement is correct.
3. A gram of glycogen has twice as much energy as a gram of fat.
- From the table, a gram of glycogen provides 4 kcal, whereas a gram of fat provides 9 kcal. This means that a gram of fat has more than twice the energy of a gram of glycogen. This statement is incorrect.
4. The human body stores approximately 1,000 kcal of glucose.
- The table indicates that the energy stored as free glucose in the blood is 40 kcal, and glycogen stores range between 600 and 1600 kcal. Therefore, the total energy from glucose sources (both free glucose and glycogen) is in the range of 640 to 1640 kcal, which means that stating 'approximately 1,000 kcal' could be a rough approximation. However, this does not specifically refer only to free glucose.
The best conclusion based on the data provided is:
- Fat molecules contain more energy-containing bonds than simple sugars.
