Energy Pathways (6) Flashcards
How does the body use macromolecules for energy?
Any macromolecule can be used by the body for energy, but it must be catabolized into a molecule that can be used in the cellular respiration pathway at some point.
How are proteins used in cellular respiration?
Proteins are catabolized into amino acids, which enter cellular respiration at different points depending on the amino acid. Ammonia is a waste product.
How do monosaccharides enter cellular respiration?
Monosaccharides are modified to enter cellular respiration at glycolysis.
How are fats used in cellular respiration?
When fat is broken down into glycerol and fatty acids, glycerol is used to make G3P in glycolysis, and fatty acids are used to make Acetyl-CoA.
How is cellular respiration regulated?
Cellular respiration is controlled by both positive and negative feedback loops. Excess ATP and citrate inhibit glycolysis, while excess AMP or ADP stimulate glycolysis.
What are energy pathways, and why do cells adjust ATP production?
Energy pathways are the four main ways humans supply their cells with ATP. Depending on the intensity and duration of exertion, the cells adjust how much ATP is being produced.
What happens to ATP stores when a muscle is engaged, and how is energy supplied afterward?
Once a muscle is engaged, its ATP stores run out in about 2 seconds. The ATP/PC system is then engaged to supply cells with enough energy to keep going for about 10 seconds.
Why can’t ATP be stored in large amounts?
ATP is a high-energy molecule that is not stable enough to be stored in large amounts.
What is the ATP/PC system, and how is excess energy stored?
In the ATP/PC system, excess energy in cells is stored as the slightly more stable phosphocreatine (PC) through a reversible reaction.:
What role does creatine play in the ATP/PC system?
Creatine is a phosphate carrier that extends anaerobic exertion time to 10 seconds. When given a chance to rest, it takes a cell about 30-60 seconds to resynthesize its ATP and PC supply.
Where is creatine made naturally, and who commonly uses it as a supplement?
The liver, kidneys, and pancreas make natural creatine. It is also a common supplement sold to athletes, especially weightlifters.
What happens after 10 seconds of exertion in the human body?
After 10 seconds of exertion, human body cells perform fermentation to create 2 ATP from each glucose available, resulting in a build-up of lactic acid (lactate).
Why does the body rely on fermentation after 10 seconds of exertion?
Fermentation is the only option at this point since O2 in the cell is still low, and NADH must be oxidized to continue ATP synthesis in glycolysis.
when is lactic acid fermentation performed by body cells, and what happens to lactate afterward?
Lactic acid fermentation is performed by body cells when the energy demand is high, but there is insufficient O2. The body will metabolize the lactate when it is at rest.
What is the connection between lactate build-up and DOMS?
Lactate build-up is often blamed for delayed onset muscle soreness (DOMS), though recent research claims otherwise.
