Module 1: Bioenergetics - Chapter 2 (KIN 476)

Flashcards covering metabolism, ATP structure and function, enzymes and pH effects, lactate and Cori cycle, training effects, and the three energy systems from Module 1: Bioenergetics.

What is metabolism?

The total sum of all chemical reactions that occur in the body.

Name the two main types of metabolism and their definitions.

Anabolic (anabolism): synthesis/building of molecules. Catabolic (catabolism): breakdown of molecules.

What is bioenergetics?

The process of converting food (fats, carbohydrates, proteins) into a usable form of energy.

What does ATP stand for?

Adenosine Triphosphate.

How many phosphate groups does ATP have?

Three (triphosphate).

What is the resting intramuscular concentration of ATP?

About 5 mmol/kg.

Resting ATP accounts for what percent of total ATP?

About 90% (not an energy store).

How much can muscle contraction increase cellular ATP demand?

500-1000 times.

How long could a sprint be powered by resting ATP concentrations?

Approximately 1.4 seconds.

How long could moderate cycling be powered by resting ATP concentrations?

Approximately 12.5 seconds.

Calorie densities of macronutrients?

Proteins 4 kcal/g; Carbohydrates 4 kcal/g; Fats 9 kcal/g.

What do enzymes do?

Speed up reactions by lowering activation energy; they do not cause reactions.

What factors influence enzyme activity?

pH; each enzyme has an optimum pH.

Optimum pH for Pepsin?

Approximately pH 2.

Optimum pH for Urease?

Approximately pH 7.

Optimum pH for Trypsin?

Approximately pH 8.

What is the typical optimal muscle pH?

Approximately neutral, around pH 7.

What happens to muscle pH during intense exercise?

H+ ions accumulate, lowering pH; lactate is produced via fermentation.

What is the fate of pyruvate under anaerobic conditions?

Converted to lactate (lactic acid fermentation).

What is the Cori Cycle?

Lactate produced in muscle is transported to the liver and converted to glucose.

Training effect on lactate buffering?

Training increases ability to buffer lactate; higher blood lactate threshold in trained individuals.

What are the three energy systems?

Phosphagen, Glycolysis, Oxidative phosphorylation.

Phosphagen energy system uses what substrate?

Phosphocreatine (PCr) and creatine phosphate to rapidly regenerate ATP.

Why is the phosphagen system the fastest energy source?

It provides immediate ATP regeneration from PCr for short durations (roughly 3-15 seconds).

Glycolysis without oxygen yields what?

Lactate production; anaerobic glycolysis with rapid ATP production.

Glycolysis with oxygen yields what?

Pyruvate enters mitochondria to form acetyl-CoA; NADH produced; continues to Krebs cycle and ETC.

Where does oxidative phosphorylation occur?

In mitochondria, across the inner membrane (ETC and ATP synthase).

What are the key products of the ETC?

NADH, FADH2 donate electrons; O2 is the final electron acceptor; proton gradient drives ATP synthase to produce ATP.

What is the role of ATP synthase?

Enzyme that uses the proton gradient to convert ADP + Pi into ATP.

What occurs in the Krebs cycle?

Acetyl-CoA enters the cycle, producing NADH, FADH2, CO2 and a small amount of ATP/GTP.

What are the Big 3 energy systems?

Phosphagen, Glycolysis, Oxidative phosphorylation (aerobic).

Which energy systems require O2?

Oxidative phosphorylation (aerobic).

Which energy systems are anaerobic?

Phosphagen system and glycolysis (fast glycolysis).

What does the table relating intensity and duration indicate?

Which primary energy system is used for a given event based on duration and intensity.

Phosphagen duration window?

Approximately 3-15 seconds; immediate ATP regeneration.

Glycolysis duration window without O2?

Approximately 15-120 seconds; anaerobic glycolysis predominates.

Oxidative phosphorylation duration window?

Greater than 120 seconds; oxidative system dominates.

What is the Cori Cycle in brief?

Lactate produced in muscle is transported to liver and converted to glucose.

What does aerobic mean?

Relating to the presence of oxygen; oxidative metabolism.

What does anaerobic mean?

No oxygen required for the energy-producing process (phosphagen and fast glycolysis).