Question 1

The branched chain amino acids can be relatively easily metabolized by skeletal muscle but they are considered the least preferred fuel source when compared to carbohydrates and fats.

Accepted Answer

The branched chain amino acids (BCAAs) can be oxidized and used by skeletal muscle for energy, but they are generally considered a less preferred fuel source than carbohydrates and fats. This is because BCAAs are primarily used for building and repairing muscle tissue rather than as an immediate energy source. During prolonged exercise or periods of fasting, BCAAs may become a more significant source of energy for muscle cells.

Question 2

The net ATP for the aerobic metabolism of glucose in muscle is 38, slightly more than the 36 ATP produced in other tissues.

Accepted Answer

The net ATP yield from aerobic metabolism of glucose is generally considered to be 36-38 ATP per glucose molecule, depending on the efficiency of the electron transport chain and the shuttle systems used, but it is not specifically higher in muscle tissue compared to other tissues.

Question 3

The energy system that has the fastest rate of ATP replenishment is anaerobic glycolysis.

Accepted Answer

The phosphagen system (also known as the ATP-PC system) has the fastest rate of ATP replenishment, not anaerobic glycolysis.

Question 4

The major function of the Krebs cycle portion of oxidative phosphorylation is to produce moderate to large amounts of ATP.

Accepted Answer

The major function of the Krebs cycle (also known as the citric acid cycle or TCA cycle) is to generate high-energy electron carriers (NADH and FADH2) and a small amount of ATP, which are then used in the electron transport chain to produce a larger amount of ATP through oxidative phosphorylation.

Question 5

The relationship between oxygen consumption and exercise intensity is linear until maximum oxygen consumption is reached.

Accepted Answer

The relationship between oxygen consumption and exercise intensity is linear up to an individual's maximum oxygen consumption (VO2 max), beyond which oxygen consumption plateaus even if exercise intensity increases.

Question 6

Those who eat meat or fish consume about 5 g of creatine daily.

Accepted Answer

The average daily intake of creatine from meat and fish is typically around 1-2 grams, not 5 grams.

Question 7

The terms Krebs cycle and the tricarboxylic acid (TCA) cycle are interchangeable.

Accepted Answer

The terms Krebs cycle and TCA cycle are commonly used interchangeably to refer to the same metabolic pathway. The cycle was first discovered and described by Sir Hans Adolf Krebs and hence the name Krebs cycle was given. However, because the cycle begins with the condensation of a 3-carbon compound (oxaloacetate) with a 2-carbon acetyl-CoA molecule to form a 6-carbon citrate molecule that undergoes a series of enzymatic reactions to ultimately regenerate the 4-carbon oxaloacetate molecule while producing CO2 and energy in the form of ATP, the cycle is also referred to as the tricarboxylic acid (TCA) cycle.

Question 8

Lactate Threshold and Anaerobic Threshold are interchangeable terms.

Accepted Answer

Lactate threshold refers to the point during exercise where lactate production exceeds clearance, while anaerobic threshold refers to the point where the body relies on anaerobic metabolism to produce energy. While the two are related, they are not interchangeable terms.

Question 9

The purpose of the three energy systems is to use chemical energy to re-form ATP.

Accepted Answer

The three energy systems (phosphagen, glycolytic, and oxidative) are used by the body to create ATP (adenosine triphosphate) using chemical energy from different sources. ATP is the primary source of energy used by the body for muscle contractions and other cellular functions.

Question 10

An all-out sprint lasting 15 seconds would depend primarily on anaerobic glycolysis as a source of ATP.

Accepted Answer

An all-out sprint lasting 15 seconds primarily relies on the phosphagen system (ATP-PCr system) for immediate energy, not anaerobic glycolysis.

Question 11

Most research has shown that short-term creatine "loading" results in an immediate increase in absolute, maximal power.

Accepted Answer

The answer of Most research has shown that short-term creatine...

Question 12

Anaerobic glycolysis is a process that begins with glucose and ends with lactate.

Accepted Answer

Anaerobic glycolysis is also known as fermentation, and it involves the breakdown of glucose in the absence of oxygen to produce energy in the form of ATP and lactate as a byproduct.

Question 13

Creatine supplements are effective for both strength and endurance athletes.

Accepted Answer

The answer of Creatine supplements are effective for both strength...

Question 14

Once pyruvate is converted to lactate in the muscle it cannot be converted back.

Accepted Answer

Pyruvate can be converted back to lactate through the process of lactate dehydrogenase in the Cori cycle, which occurs in the liver.

Question 15

Highly aerobic muscle fibers and other tissues can use lactate as an energy source.

Accepted Answer

Highly aerobic muscle fibers, such as those used during endurance exercise, can use lactate as a fuel source during prolonged exercise. Other tissues, such as the heart and brain, can also use lactate as an energy source. This process is known as the lactate shuttle.

Question 16

Most research has shown that creatine supplementation results in the maintenance of exercise power output rather than an immediate increase in absolute, maximal power.

Accepted Answer

Most studies have shown that creatine supplementation helps maintain exercise power output during high-intensity exercise, but does not necessarily increase maximal power output immediately.

Question 17

Beta-oxidation is a process associated with the breakdown of amino acids for energy.

Accepted Answer

Beta-oxidation is actually a process associated with the breakdown of fatty acids for energy, not amino acids.

Question 18

The major disadvantage of using anaerobic glycolysis is the decrease in pH that occurs.

Accepted Answer

Anaerobic glycolysis produces lactic acid as a byproduct, which leads to a decrease in pH and can inhibit further glycolysis. This can lead to fatigue and decreased performance in athletes.

Question 19

ATP and CrP are both high-energy phosphate compounds.

Accepted Answer

Both ATP and CrP have high-energy bonds that can be broken to release energy for cellular processes.

Question 20

Exercising muscle prefers to use glycogen rather than glucose because the net yield of ATP is greater.

Accepted Answer

When exercising, muscle cells prefer to use glycogen (stored glucose) as their energy source because the breakdown of glycogen yields more ATP molecules than the breakdown of glucose. Additionally, glycogen is stored in the muscle cells themselves, making it a more rapidly available source of energy than glucose from the bloodstream.

Quiz 3: Energy Systems and Exercise