Energy Metabolism Flashcards
What are the various metabolic pathways used by the body to make ATP?
Glycolysis
Citric Acid Cycle (Krebs)
Electron Transport Chain
-Glucose splitting - one six-carbon glucose molecule into 2 three-carbon pyruvate molecules
-does not require oxygen
-occurs in the cytoplasm
-Using several reactions and transfers high-energy electrons to NAD+ shuttle molecules
Glycolysis
When oxygen is in short supply, what does pyruvate turn into as an alternative fuel that muscle cells can use or that liver cells can convert to glucose?
lactate
-Acetyl CoA combines with oxaloacetate to form citrate and release Coenzyme A.
-the two-carbon atoms from acetyl CoA combine with oxygen to form Carbon Dioxide.
-one glucose molecule produces two acetyl CoA molecules, the citric acid cycle will occur twice.
-reactions produce: 1 GTP, transfer pairs of high-energy electrons to 3 molecules of NAD+ and one molecule of FAD, and Oxaloacetate.
Citric Acid Cycle
-NADH and FADH2, deliver their cargo of high-energy electrons
-as the electrons travel, they give up energy to power the production of ATP (ADP + Pi).
-electrons move from high> low energy and pumps H+ ions into the intermembrane space, establishing an electrochemical gradient; thus powering ATP synthase
-at the end, an oxygen “basket” accepts the energy-depleted electrons and combines with H to form H2O.
Electron Transport Chain
How does the body make ATP from carbohydrates?
Glycolysis
Pyruvate to Acetyl CoA
Citric Acid Cycle
Electron Transport Chain
How does the body make ATP from fats?
-Lipids digest into glycerol and Free Fatty Acids
-Breakdown of fatty acids take place inside mitochondria
-Acetyl CoA enters Krebs (TCA) cycle to generate NADH and FADH2 for transferring pairs of high-electrons to ETC to fuel ATP synthesis.
-Carnitine transports Fatty Acids across mitochondrial membrane.
How does the body make ATP from proteins?
-during starvation the body breaks down protein and extracts energy from the amino acids
-deamination strips down the amino acid to a “carbon skeleton” and urea
-carbons skeleton structure determines catabolic path and ATPs produced
What is the connection between metabolism and respiration?
The Respiratory Quotient (RQ) is an index of which nutrient is being used by the body to generate ATP.
RQ=volume of carbon dioxide exhaled/volume of oxygen used.
What fuels does the body use for different types of physical activities?
Why does RQ values indicate the type of activity and the substrate used to make ATP?
Why does RQ value indicate the type of activity and the substrate used to make ATP?
-Anaerobic metabolism can only use glucose and glycogen.
-Areobic metabolism can also break down fats and protien
-fats and amino acids (<1.0) require more O2 to produce CO2 and water.
