49) Why are carbohydrates and fats frequently considered high-energy foods? 10
A) They contain many oxygen atoms.
B) They contain no nitrogen atoms.
C) They contain many electrons associated with hydrogen atoms.
D) They are strong oxidizing molecules.
50) A cell has enough available ATP to meet its needs for about 30 seconds. What is likely to happen when an athlete exhausts his or her ATP supply?
A) He or she has to sit down and rest.
B) Catabolic processes are activated that generate more ATP.
C) ATP is transported into the cell from the circulatory system.
D) Other cells take over, and the muscle cells that have used up their ATP cease to function.
51) In liver cells, the inner mitochondrial membranes are about five times the area of the outer mitochondrial membranes. What purpose must this serve?
A) It allows for an increased rate of glycolysis.
B) It allows for an increased rate of the citric acid cycle.
C) It increases the surface for oxidative phosphorylation.
D) It increases the surface for substrate-level phosphorylation.
52) A person on a strict diet and exercise regimen lost 7 kg (about 15 pounds) of body fat in just two weeks. What is the most likely way that the lost fat left the body?
A) It was released as CO2 and H2O.
B) It was converted to heat and then released.
C) It was converted to ATP, which weighs much less than fat.
D) It was eliminated from the body as feces.
The Correct Answer and Explanation is :
Here are the answers with explanations for the questions you provided:
49) Why are carbohydrates and fats frequently considered high-energy foods?
- Correct Answer: C) They contain many electrons associated with hydrogen atoms. Explanation: Carbohydrates and fats are considered high-energy foods because they contain many electrons associated with hydrogen atoms. These electrons are involved in the process of cellular respiration, where they are transferred through electron transport chains in mitochondria, leading to the production of ATP, the energy currency of the cell. The more hydrogen atoms in a molecule, the more potential energy it holds when those electrons are transferred and used to produce ATP.
50) A cell has enough available ATP to meet its needs for about 30 seconds. What is likely to happen when an athlete exhausts his or her ATP supply?
- Correct Answer: B) Catabolic processes are activated that generate more ATP. Explanation: When an athlete exhausts their ATP supply, the body activates catabolic processes such as glycolysis and fatty acid oxidation to produce more ATP. These processes break down molecules like glucose and fatty acids to regenerate ATP, ensuring that the body can continue functioning during periods of high energy demand, like intense exercise.
51) In liver cells, the inner mitochondrial membranes are about five times the area of the outer mitochondrial membranes. What purpose must this serve?
- Correct Answer: C) It increases the surface for oxidative phosphorylation. Explanation: The inner mitochondrial membrane is much larger than the outer membrane to provide a larger surface area for oxidative phosphorylation, a critical step in ATP production. The increased surface allows for more ATP synthase complexes and electron transport chain proteins, which are essential for efficiently converting energy from nutrients into ATP in the presence of oxygen.
52) A person on a strict diet and exercise regimen lost 7 kg (about 15 pounds) of body fat in just two weeks. What is the most likely way that the lost fat left the body?
- Correct Answer: A) It was released as CO2 and H2O. Explanation: When fat is broken down in the body, it is converted to carbon dioxide (CO2) and water (H2O). The majority of the fat is exhaled as CO2 through the lungs, and the rest is excreted as water. This process occurs through metabolic pathways like beta-oxidation and the citric acid cycle, where the fat molecules are oxidized to release energy, and the by-products are primarily CO2 and H2O.
I have also generated a scientific illustration of the mitochondria to help visualize oxidative phosphorylation in liver cells.