Question 1

For aerobic glucose breakdown to take place,two- and three-carbon fragments must enter which cell organelle to be metabolized into carbon dioxide and water?

Accepted Answer

The mitochondrion is the organelle responsible for aerobic glucose breakdown. Glucose is first broken down into two three-carbon molecules called pyruvate in the cytoplasm through glycolysis. Pyruvate then enters the mitochondria, where it is metabolized into carbon dioxide and water through the citric acid cycle and oxidative phosphorylation. The nucleus is not involved in energy metabolism, and the Golgi body and smooth endoplasmic reticulum are involved in cellular transport and lipid metabolism, respectively, but not in glucose breakdown.

Question 2

For which of the following activities would carbohydrate loading be useful?

Accepted Answer

Carbohydrate loading is most beneficial for endurance events lasting longer than 90 minutes, such as a marathon, to maximize glycogen stores.

Question 3

Protein supplies approximately _______ % of a human's typical energy needs.

Accepted Answer

B

Question 4

Zelda is a marathon runner.She completes the marathon in 2 hours and 30 minutes.Which of the following is true regarding her fuel use during the marathon?

Accepted Answer

Amino acids may supply up to 15% of energy needs. This is because during prolonged exercise, the body may break down muscle protein for energy if adequate carbohydrate stores are not available. However, it is unlikely that Zelda would completely deplete her glycogen stores during a 2-hour and 30-minute marathon, so option A is false. Option B is also false because during a marathon, the majority of ATP production comes from aerobic metabolism, not anaerobic glucose breakdown. Option C is also false because the intensity of a marathon is not considered "intense muscular activity."

Question 5

The training effect,in which individuals experience improvements in physical fitness as they continue a regular exercise regimen,is a product of

Accepted Answer

The training effect is a result of all three factors listed in the answer choices: an increase in the number of mitochondria in muscle cells, an increase in the number of capillaries in muscles, and an increase in the number of aerobic enzymes. As fitness improves, the body becomes more efficient at delivering oxygen and nutrients to the muscles, which enhances their capacity for work. This, in turn, leads to further increases in mitochondrial density, capillary volume, and aerobic enzyme activity.

Question 6

Anaerobic glucose breakdown provides most of the energy for sports activities lasting

Accepted Answer

Anaerobic glucose breakdown, also known as anaerobic glycolysis, is the primary source of energy for high-intensity activities lasting from 30 seconds to 2 minutes. This process quickly generates energy without the need for oxygen, making it ideal for short, intense bursts of activity.

Question 7

Which of the following is true about fatty acid usage for energy?

Accepted Answer

Gram for gram, fatty acids provide more than twice as much energy as glucose. This is because fatty acids contain more carbons and hydrogens, which can be oxidized to produce ATP. However, fatty acid metabolism requires oxygen and is slower than glucose metabolism, so it is not as useful for intense exercise. Energy is not released from fatty acids anaerobically, and lipogenesis is the process of synthesizing fatty acids, not breaking them down for energy.

Question 8

The conversion of glucose to lactic acid is called

Accepted Answer

The conversion of glucose to lactic acid is a type of anaerobic glucose breakdown, as it occurs in the absence of oxygen. Aerobic glucose breakdown and aerobic glycogen breakdown both require oxygen, while anaerobic glycogen breakdown is not a commonly used term.

Question 9

To help maintain adequate glycogen stores,an endurance athlete should eat

Accepted Answer

Bagels are a good source of carbohydrates which are necessary for the maintenance of glycogen stores. Endurance athletes need to consume enough carbohydrates to fuel their activities and also replenish their glycogen stores after exercise. Broccoli and cheese soup, peanut butter, and tuna are not good sources of carbohydrates, and therefore not the best choice to maintain glycogen stores.

Question 10

Carbohydrate loading

Accepted Answer

Carbohydrate loading is a strategy used by endurance athletes to maximize the storage of glycogen (or energy) in the muscles and liver. It involves a period of tapering exercise intensity while increasing carbohydrate intake in the days leading up to an event. This method is scientifically proven to increase glycogen stores significantly, allowing for improved endurance performance.

Question 11

Which of the following is a benefit of physical fitness?

Accepted Answer

Physical fitness has been shown to improve sleep quality and quantity, leading to better overall health and well-being. Options B, C, and D are all negative outcomes of poor physical fitness.

Question 12

A meal representative of what an endurance athlete should eat before an event is

Accepted Answer

The spaghetti provides carbohydrates for energy, the sauce provides some protein, and the green beans add some fiber and vitamins. Low-fat milk provides additional protein and calcium.

Question 13

Which of the following is true about protein as an energy source?

Accepted Answer

Protein is primarily used for growth, repair, and maintenance of body tissues, not as a primary energy source. However, during prolonged endurance activities, when carbohydrate stores are depleted, the body may increase its use of protein for energy. This is why the use of protein as an energy source is greater for endurance athletes than for those who focus on bodybuilding or weight lifting, who primarily rely on anaerobic energy systems that do not typically use protein for energy.

Question 14

What is the name of the high-energy compound that cells use directly to fuel other chemical reactions?

Accepted Answer

The high-energy compound that cells use directly to fuel other chemical reactions is adenosine triphosphate (ATP). Glucose, amino acids, and fatty acids are all sources of energy for the cell, but they must first be processed and converted into ATP before they can be used to fuel other reactions.

Question 15

The difference between aerobic and anaerobic glucose breakdown is

Accepted Answer

The end products of aerobic glucose breakdown are carbon dioxide and water, while the end product of anaerobic glucose breakdown is lactic acid. The other choices are incorrect.

Question 16

Aerobic glucose breakdown provides most of the energy for sports activities lasting

Accepted Answer

Aerobic glucose breakdown relies on oxygen for energy production and is a slower process than anaerobic glucose breakdown. Therefore, it provides energy for activities lasting longer than 2 minutes up to 4 hours, such as endurance activities like distance running and cycling. Activities lasting up to 30 seconds rely more on the immediate energy provided by ATP and creatine phosphate, while activities lasting 30 seconds to 1 minute rely more on anaerobic glycolysis. Activities lasting 1 to 2 minutes also rely primarily on anaerobic glycolysis, although aerobic metabolism may start to contribute.

Question 17

A 120-pound woman is training for a bodybuilding competition and needs to build muscle mass.What is the maximum recommended daily protein intake for this woman?

Accepted Answer

For individuals engaging in high-intensity training such as bodybuilding, the recommended protein intake can range from 1.6 to 2.2 grams per kilogram of body weight per day. For a 120-pound woman, which is approximately 54.5 kilograms, the maximum recommended intake would be around 2.2 grams per kilogram, totaling about 120 grams per day. The closest option to this calculation is 110 grams per day.

Question 18

Which of the following supplies energy for quick bursts of intense activity lasting up to one minute?

Accepted Answer

Phosphocreatine is a molecule that can quickly donate a phosphate group to ADP, producing ATP. This process is anaerobic and can last for up to one minute, providing energy for quick bursts of intense activity such as sprints, weightlifting, or jumping. Aerobic glucose breakdown and lactic acid production are more suited for longer-lasting activities, whereas caffeine does not directly supply energy but can improve focus and reduce perceived effort during exercise.

Question 19

If an athlete's body fat level is too high,what is the best weight-loss approach?

Accepted Answer

Eating about 200 to 500 kilocalories less than one's EER (estimated energy requirement) per day is a safe and effective way to lose weight. This approach creates a calorie deficit without drastically reducing energy intake, which can negatively impact athletic performance. It is important for athletes to maintain adequate nutrient intake to support optimal performance and recovery. The other options (A, B, and D) are not recommended for safe or sustainable weight loss for athletes.

Question 20

Athletes who consume adequate carbohydrates experience

Accepted Answer

Adequate carbohydrate intake is necessary for optimal liver and muscle glycogen stores, which are critical for energy during physical activity. This can help optimize athletic performance and prevent fatigue during exercise. Carbohydrate intake does not directly lead to increased lean body mass, nor does it necessarily increase the risk of chronic disease (assuming the carbohydrates consumed are from whole, nutrient-dense sources). Chronic fatigue may occur in athletes who consume inadequate carbohydrates, but not those who consume adequate amounts.

Quiz 14: Nutrition: Fitness and Sports