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Physiology of Exercise Which scantron? (green scantron 882)
Exam I Review
NOTE:
Calculators allowed, but
NOT
Smartphones, Tablets or Laptops Energy Metabolism
Identify caloric yield from the three macronutrients.
○ Carbs: 4 kcal/g, Fats: 9 kcal/g, Proteins: 4 kcal/g
Identify caloric content released when splitting one molecule of ATP.
○ 7.3 kcal of energy
Explain which programming variable (i.e., volume or intensity) influences fuel utilization most significantly.
○ intensity
■ Intensity requires a more efficient fuel source. When you increase intensity, you need carbs. Compared to fat utilization at lower intensities
Explain the basic role and timing of use of each energy system.

System

ATP
Production

Substrate

System
Capacity

Activities

Limitation

Phosphagen

Very Rapid

Creatine
Phosphate,
ATP

Very Limited

Highest­intensity, very short­duration

Limited energy Fast
Glycolytic

Rapid

Blood/muscle glucose, glycogen

Limited

High­intensity, short­duration Lactate

Aerobic

Slow

Glucose, glycogen, FFA, proteins

Unlimited

Lower­intensity, longer­duration Slow ATP
Production

Duration of event

Intensity

Energy system

o
0 – 6 seconds

o
Extremely High

o
Phosphagen

o
6 – 30 seconds

o
Very High

o
Phosphagen and Fast
Glycolytic

o
30 – 120 seconds

o
High

o
Fast Glycolytic

o
2 – 3 minutes

o
Moderate

o
Fast Glycolytic and
Oxidative

o
> 3 minutes

o
Lower

o
Oxidative

● Identify carbohydrate storage locations and quantities.
○ Blood glucose: 5­15 g (in small quantities because blood stream is a delivery system that allows us to deliver glucose to vital organs like the brain and CNS)
○ Liver: 90­110g (replenished as we eat daily, our reserve for when blood sugar drops) ○ Muscle tissue: 250­600g
○ Total= 2000 kcal
● Define basic energy pathway terminology (e.g., lipolysis, gluconeogenesis).
○ Lipolysis
: Fat oxidation requires mobilization of stored triglycerides ­ process of breaking down stored fats in fat cells to FA + glycerol
○ Gluconeogenesis
: Transformation of glycogen to glucose or pyruvate ­ occurs in the liver ­a metabolic pathway that results in generation of glucose from non­carbohydrate sources (pyruvate)
○ Ketogenesis
: Accumulation of excess Acetyl­CoA (from FFA breakdown or not enough oxaloacetate) results in build up of ketone bodies (KB)
○ Amino acid de­amination:
■ Remove amino groups for glucogenic or ketogenic amino acids:
■ Glucogenic ­ have ability to be converted to glucose thru pyruvate
(manufacture of glucose from non­carbohydrate source =
Gluconeogenesis).
■ Ketogenic ­ can only be converted to intermediate products that feed into metabolic pathways to make energy or FFAs.
Converted to acetyl­CoA
(energy).

● Explain the meaning behind the terms ‘caloric quantity’ and ‘caloric quality’.
○ quantity = how many calories you burn­ total overall despite their source
○ quality = where the kcals are coming from (fat/carb/amino acids)
● Discuss the role of lactate production. •
Pyruvate suffers 2 fates:
○ Most is shuttled to the mitochondria to continue oxidative metabolism
(aerobic
pathway).
Amount determined by O availability.
2
○ Excess (beyond aerobic pathway capacity/ when low O is present) is converted to
2
lactate
(anaerobic) ­ called
Glycolytic Flux
.
­Hydrogen ions from step 6 (slide 39 Module 1ppt) binds with pyruvate to form lactate.

+
• Glycolysis depends upon H ions being picked up by NAD (step6).
+

+
○ Inability to remove accumulating H ions forces lactate formation to remove H
.
○ The formation of lactate from pyruvate is catalyzed by lactate dehydrogenase by adding 2 hydrogen ions:
+
NADH + Pyruvate←(LDH enzyme)→ NAD + Lactate
2
○ Converted back to pyruvate and used for ATP or glucose
■ Lactate