Chapter 2- Energy Metabolism Flashcards
What is metabolism?
the use of energy for bodily processes, including all chemical changes
What are the two categories of metabolic processes?
anabolism and catabolism
What is anabolism?
“growth”, uses energy to produce new molecules
Anabolism is sparked by what?
food intake
What is catabolism?
breaking down molecules to generate usable energy
What are the three stages energy is extracted from food?
- digestion, absorption, and transportation of energy-yielding nutrients
2.production of metabolites - body’s cells can use energy-producing metabolites to completely break down these compounds to a converted form of energy the body can use
Most of the food consumed is…
lost as heat
What does the TCA Cycle do?
within the mitchochondria, the TCA cycle can accept metabolites from the cytosol as pyruvate, fatty acids, and amino acids following oxidation from acetyl-CoA
What does the Electron Transport Chain do?
harnesses energy to fuel the final step in ATP formation, known as oxidative phosphorylation
Key to the ETC?
presence of oxygen
What is ATP (adenosine triphosphate)?
the molecular unit of currency and primary energy molecule powering cellular functions
What is the result of the breakdown of ATP?
ADP and inorganic phosphate
Explain the ATP-PCr (phosphates energy system)
uses phosphocreatine exclusively to regenerate ATP in muscle tissue (3-15 seconds), creatine kinase breaks down Per to get an inorganic phosphate to attach to ADP and resynthesizes ATP
Glycolytic (anaerobic energy system)
glycolysis (12-steps), rapid rate of ATP production without the need for oxygen
Aerobic (oxidative system)
Can produce ATP from any macronutrient and can take minutes to produce enough ATP to fuel a physical workload, but endless if fuel is provided
What system do we use at rest?
Aerobic ATP because it is unlimited when adequate oxygen is available
What is aerobic capacity?
the maximal amount of oxygen a person can use in 1 minute per kg BW
What is beta-oxidation?
the process of turning fatty acids into acetyl-CoA for entry into the TCA cycle
Before a fatty acid can cross into the mitochondrion…
it must be linked to coenzyme A
Energy derived from protein
compared to carbs and fats, proteins yield very little energy
Amino acids stripped of their nitrogen component costs ATP and produces wastes
Energy from alcohol
Since alcohol detoxification is the body’s priority, accumulating acetyl-CoAs are rerouted to fatty acid synthesis rather than used for energy
What are the effects of alcohol in the body?
fat accumulation in the liver can be seen after a single bout of heavy drinking, alcohol consumption post exercise can slow rates of rehydration via is suppressive effect on antidiuretic hormone, alcohol consumption post exercise impairs the muscle protein synthesis response desired for muscle adaptation and repair, and mild disturbances in acid-base balance, inflammatory pathways, ability to metabolize glucose, and cardiovascular function
What is the Crossover Concept?
The point at which the body “crosses over” and starts using more carbohydrates as an energy source, preserves and protects limited carb stores until high-intensity effort
The longer you can hold off on using the carbohydrates…
the longer you will be able to exercise and do what you want
What is biosynthesis?
production of complex molecules within living organisms or cells
What is gluconeogensis?
creates glucose for the body from noncarbohydrate precursors (happens 90% of the time in the liver)
What is glycogenesis?
assembles glucose molecules into branded chains from storage as glycogen
What is lipogenesis?
making fats, it is accelerated during times of excess calorie consumption; often leads to the gain of fat tissue
What are factors that can increase energy intake needs (metabolic rate)?
exposure to heat or cold, fear, stress, high altitude, physical injuries (wound healing), stimulant drugs, increases in fat-free mass (more muscle)
Men have higher fat-free mass =
higher metabolic rate
what are the 3 primary reasons the body burns calories?
- maintain basic physiological function, ex: pumping blood + breathing
- process the food we eat
- power muscles for all movements (thermic effect of activity)
What is calorimetry?
General measurement of energy expenditure (heat production)
What is direct calorimetry?
Directly measure the heat you give off and is indicative of the amount of calories you’re burning
What is indirect calorimetry?
determines energy expenditure without directly measuring the production of heat, estimated based on the amount of oxygen you use
Why is calorimetry important?
helps understand the effects of age, gender, and exercise on energy expenditure
