CSSD Exercise Physiology & Energy Metabolism

Question 1

Which energy system provides the most immediate source of ATP?

Accepted Answer

Phosphagen system

Answer

The phosphagen system, also known as the ATP-PCr system, provides the most immediate source of ATP for muscle contraction. It utilizes stored creatine phosphate to rapidly regenerate ATP from ADP, making it crucial for very high-intensity, short-duration activities. This system operates anaerobically and is the primary energy pathway for activities lasting up to about 10-15 seconds.

Question 2

Which of the following is a byproduct of anaerobic glycolysis?

Accepted Answer

Lactate

Answer

Anaerobic glycolysis is a metabolic pathway that breaks down glucose without oxygen to produce ATP. During high-intensity exercise, when oxygen supply is limited, pyruvate (a product of glycolysis) is converted to lactate. Lactate is a key byproduct of this process, and its accumulation can contribute to muscle fatigue, though it can also be used as a fuel source by other tissues.

Question 3

What is the primary fuel source during high-intensity exercise?

Accepted Answer

Carbohydrate

Answer

Carbohydrates are the primary fuel source during high-intensity exercise because they can be metabolized both aerobically and anaerobically to produce ATP quickly. Glucose, derived from carbohydrates, is readily available in the bloodstream and muscle glycogen stores, allowing for rapid energy production needed for intense efforts. While fats provide more energy per gram, their breakdown is slower and requires oxygen, making them less suitable for immediate high-intensity demands.

Question 4

Which hormone increases during exercise to promote lipolysis?

Accepted Answer

Epinephrine

Answer

Epinephrine, also known as adrenaline, is a hormone released during exercise that plays a crucial role in mobilizing energy stores. It stimulates lipolysis, the breakdown of triglycerides into free fatty acids, making them available as fuel for working muscles. This helps to spare glycogen stores and provide sustained energy during prolonged activity, especially as exercise intensity increases.

Question 5

Where does aerobic metabolism primarily occur in the cell?

Accepted Answer

Mitochondria

Answer

Aerobic metabolism, which includes the Krebs cycle (citric acid cycle) and oxidative phosphorylation, primarily occurs within the mitochondria of cells. These organelles are often referred to as the 'powerhouses' of the cell because they are responsible for generating the vast majority of ATP through oxygen-dependent pathways. Glycolysis, the initial step of glucose breakdown, occurs in the cytosol.

(CSSD) Board Certified Specialist in Sports Dietetics Practice Test

(CSSD) Board Certified Specialist in Sports Dietetics Practice Test

CSSD Exercise Physiology & Energy Metabolism