KINE 433: Topic 2 Study Guide

What is the difference between glycogen and glucose?

Glucose (six-carbon) is stored as glycogen

Where does storage and release of glycogen and glucose occur primarily?

Glycogen is stored primarily in the liver (~110g) and muscles (~500g) and is supplied to the bloodstream.

Define glycogenesis

Converting glucose to glycogen

Define glycogenolysis

Breaking down glycogen to glucose

Define gluconeogenesis

Converting non-carb sources to glucose

In what condition(s) is protein used as an energy resource?

Can be used as energy source during prolonged exercise or extreme conditions such as illness or starvation

How does protein deamination occur and where?

Amino acids are deaminated mainly in the liver by removing Nitrogen

According to Jager et al. (2017), athletes require how many g/kg of protein per day?

Athletes require anywhere between 1.4- 2.0 g of protein per kg of body weight per day

According to Witard and colleagues (2019), how many g/kg of protein intake per meal should be sufficient?

0.3 - 0.4g/kg of isolated protein intake per meal may be adequate

What are the 3 BCAA’s?

1. Isoleucine

2. Leucine

3. Valine

Define enzyme

Energy catalyst; helps to accelerate chemical reactions

• Lowers activation energy

Define rate-limiting enzyme

Limits the rate at which conversion will happen

Define negative feedback

A negative feedback system responds to changes in its output by counteracting them, reducing fluctuations and helping maintain stability or homeostasis.

Ex. thermostat

What is the Law of Mass Action

Also called Mass Action Effect, the rate of product formation is greatly influenced by the concentrations of the reactants

Identify the 3 primary energy systems

1. ATP-PCr (phosphogen system)

2. Glycolysis

3. Oxidative

Where does each energy system occur?

• ATP-PCr and glycolysis

  • both occur in the cytoplasm of cell

• Oxidation

  • occurs in mitochondria

What is the rate and capacity (high/low) of ATP synthesis for each energy system? (Be very specific in terminology)

• ATP-PCr

  • highest rate, lowest capacity; burns fast but does not result in a lot of ATP

• Aerobic Glycolysis

  • moderate rate, moderate capacity

• Oxidative

  • slowest rate, highest capacity; most bang for your buck

Identify the amount of time each system is the primary contributor to ATP resynthesis (also see the Helpful Notes document from Chapter 2).

• ATP-PCr

  • ~3-15 seconds of high-intensity activity

• Fast glycolysis

  • 30 seconds to 2 minutes

• Slow glycolysis

  • 2 to 3 minutes

• Oxidative

  • 3+ minutes

What three factors will glycolysis be dependent on?

Please identify the fate of pyruvate with or without oxygen present.

• If O2 is not present, pyruvate is converted to lactate and recycled for energy (fast glycolysis). No O2 present indicates higher intensity and a need for faster energy production.

  • Pyruvate becomes lactate (anaerobic)

• If O2 is present, pyruvate is shuttled to mitochondria and converted to acetyl-CoA for oxidation (slow glycolysis). With O2 present, this indicates lower intensity. ATP is generated at a slower rate, but must be sustained for longer term.

  • Begins the Krebs Cycle

Identify the primary VO2max percentage ranges where we see the crossover concept occur for primary carbohydrate utilization and primary fat utilization, according to Ball (2015), Purdom et al. (2018), and Kenney et al. (2025). Know specific percentages for each.

Ball (2015):

• < or equal to 30% of VO2max → fats are primary energy source

• 40-65% of VO2 max → 50/50 of fats and carbs

• > or equal to 70% of VO2 max → carbs are primary source

Purdom et al. (2018):

• Maximal fat utilization occurs between 45-75% of VO2 max

• > or equal to 75% of VO2 max → carbs are the primary source

Kenney et al. (2025):

• Fats are primary substrate <60% maximal VO2: CHO is dominant >75%

What is the Cori Cycle?

A metabolic pathway in which lactate, produced by anaerobic glycolysis in muscles, is transported to the liver and converted to glucose, which then returns to the muscles and is cyclically metabolized back to lactate.