NUTR 202 Chapter 6b Flashcards

Study Notes

Energy Metabolism Overview

Aerobic metabolism occurs inside the mitochondria; anaerobic metabolism occurs in the cytoplasm.

Glycolysis and Carbohydrate Metabolism

Glycolysis is the initial step in carbohydrate metabolism, converting glucose to pyruvate; it operates anaerobically in the cytoplasm.
If oxygen is present, pyruvate enters the mitochondria for aerobic metabolism, producing acetyl CoA, which feeds into the TCA cycle (Kreb's cycle) for significant ATP production.
In the absence of oxygen, pyruvate is converted to lactate, yielding a small amount of ATP.

Fat Metabolism

Fats are stored as triglycerides; during energy use, they are broken down into fatty acids and glycerol.
Glycerol can transform into glucose or pyruvate, while fatty acids undergo beta-oxidation to yield acetyl CoA.
Acetyl CoA combines with oxaloacetate to enter the Kreb's cycle. Low carbohydrate intake can cause ketone build-up, risking ketosis and ketoacidosis.

Amino Acid Metabolism

Proteins can serve as an energy source during starvation or limited carbohydrates.
Deamination removes the nitrogen group from amino acids, converting it to urea for excretion.
The remaining carbon skeletons can enter the Kreb's cycle as pyruvate or acetyl CoA.

Final Steps in Energy Production

Electrons from the Kreb's cycle are shuttled by NAD and FAD to the Electron Transport Chain (ETC), producing ATP.
Oxygen is crucial in aerobic metabolism, acting as the final electron acceptor, while water and CO2 are byproducts.

Glycogen Storage and Energy Use

Excess glucose is stored as glycogen; liver glycogen maintains blood glucose levels, while muscle glycogen provides energy for muscular activity.
Glycogen stores are limited and deplete quickly; any surplus glucose is converted to fat.

Macronutrient Metabolism and Storage

Fats, carbohydrates, alcohol, and amino acids can be converted and stored as fat when energy needs are satisfied.

Metabolic Processes

Catabolism defines the breakdown of molecules for energy production.
Anabolism describes the process of building larger molecules from smaller units.

Metabolic Definitions

Anaerobic metabolism operates without oxygen and produces lesser ATP.
Aerobic metabolism requires oxygen and generates substantial ATP.
Urea is a key nitrogenous waste product formed from protein metabolism, excreted in urine.
Lipogenesis is the process by which substances converting into acetyl CoA can be synthesized into fat.

Description

Test your knowledge with these flashcards focused on Chapter 6b of NUTR 202. This quiz covers key concepts related to aerobic and anaerobic metabolism, including the locations and processes involved. Challenge yourself and reinforce your understanding of energy metabolism!