Energetics Flashcards
Explain why core temperature increases during exercise
ATP breakdown occurs at only 40% efficiency
– Remaining 60% is released as heat within the body
Explain the difference between lactic acid and lactate
Lactic Acid (C3H6O3) vs Lactate (C3H5O3) – Lactic acid dissociates, a H+ is then
removed via a number of pathways
Lactic Acid dissociates into: – Lactate and H+ ions
* What happens to the Lactate?
a) Cori Cycle converts much of it
b) Substrate for energy in cardiac tissue
* What happens to the H+?
a) O2 binds to some
b) NAD/FAD accepts some
c) Remaining H+ ions are “Buffered” by electrolytes (NaHCO3)
* Cool down benefits both of these processes
How does the body get rid of lactic acid
Monocarboxylate Transporters (MCT’s)
Why is the use of protein as an energy source a “last resort”
more complex molecules, harder to break down
have other jobs(catalyst for chemical reactions)
gluconeogenesis is limited by the availability of the enzymes needed to break down proteins
Explain the Anaerobic Alactic Energy System
ATP Cycle
– When used it is broken down into
ADP
* Energy & heat is released
– Creatine Phosphate (CP) is also stored in our cells
* Creatine Kinase removes a phosphate from the Creatine Phosphate and adds it to the ADP by ATP Synthase
– Phosphorylation – ADP + Phosphate = ATP
ATP Cycle
– When used it is broken down into
ADP
* Energy & heat is released
– Creatine Phosphate (CP) is also stored in our cells
* Creatine Kinase removes a phosphate from the Creatine Phosphate and adds it to the ADP by ATP Synthase
– Phosphorylation – ADP + Phosphate = ATP
Explain the Anaerobic Lactic Energy System
Glycogenolysis
– Breaking apart glycogen to produce ATP
* Initiated by glycogen phosphorylase
* Glycolysis
– Breaking apart glucose to produce ATP
* Initiated by Hexokinase
* More energy from the breakdown of glycogen (3 ATP) then from glucose (2 ATP)
– Why more energy from glycogen??
There is enough stored glycogen in a muscle for approximately 2-3 minutes of maximal activity
* End Product of Glycolysis is: – Pyruvate (C3H3O3)
* plus LDH and 3 H+’s and you get…
What happens if there is excessive H+ ions or lactate in the muscle?
– Alters muscle pH (‘burning muscles’)
a) Impedes ATP production b) Prevents calcium binding c) Inhibitory sensory feedback d) Effects muscle repair
Explain the Aerobic Energy System
Requires oxygen (Aerobic)
* Slow process but has very large energy stores
* Oxidation of all the following can occur to produce energy: a) Carbs
b) Fats
c) Proteins
Oxidation of Carbohydrates
– 3 Steps (in order) to maximize as much ATP production as
possible
* Aerobic glycolysis
* Krebs Cycle
* Electron Transport Chain (ETC)
Oxidation of Fat (FFA’s that have been mobilized from adipocytes)
– 3 stages to maximize ATP production * Beta-oxidation
* Kreb’s Cycle
* Electron Transport Chain
Fatty Acids MUST be delivered to the muscle
* How:
1. Cyclic AMP (cAMP)
* Located on adipocyte membrane, detects hormones in blood (example)
2. Hormone Sensitive Lipase (HSL)
* Cyclic AMP then enters the adipocyte and
activates HSL which removes a fatty acid
3. Plasma Albumins
* Free fatty acids (FFA’s) enter blood and
attach to plasma albumins
4. FABP’s (Fatty Acid Binding Proteins)
* Albumins (with the FFA’s) arrive at the muscle and attach to FABP’s
FABP’s allow FFA’s to enter the muscle cell
* Beta-oxidation
– In the mitochondria, FFA’s are split into multiple molecules of Acetyl- CoA
– What then happens to this Acetyl- CoA?
* Kreb’s Cycle
– Same as oxidative glycolysis
* Electron Transport Chain
– Same as oxidative glycolysis
Aerobic Breakdown (Oxidation) of
Protein
– Some amino acids are converted into glucose in the liver (gluconeogenesis)
– Some amino acids can be converted into Acetyl CoA directly
– Branch chain amino acids (ie. Leucine, isoleucine)
– Least efficient as some of the energy produced goes to removing nitrogen
