Metabolism and Metabolic Pathways Quiz

Metabolism Overview

• Metabolism is the sum of all chemical reactions that occur in an organism.

Catabolism and Anabolism

• Catabolism: breakdown of large molecules into smaller ones, releasing energy.
• Anabolism: synthesis of large molecules from smaller ones, absorbing energy.

Metabolic Pathways

• Metabolic pathways are series of consecutive reactions, either linear or cyclic.
• Linear pathway: generates a final product different from any of the reactants.
• Cyclic pathway: regenerates the first reaction.

Catabolism of Food

• Begins with digestion, catalyzed by enzymes in saliva, stomach, and small intestines.
• Carbohydrates:
  • Hydrolyzed into monosaccharides by amylase enzymes in saliva and small intestine.
• Protein:
  • Digestion begins with stomach acid denaturing protein, followed by pepsin cleaving protein backbone into peptides.
  • In small intestine, trypsin and chymotrypsin cleave peptides into amino acids.
• Triacylglycerols:
  • Emulsified by bile secreted by liver, then hydrolyzed by lipases in small intestine into 3 fatty acids and a glycerol backbone.

Cellular Respiration

• Monosaccharides, amino acids, and fatty acids are degraded into acetyl groups.
• Acetyl groups bond to coenzyme A, forming acetyl-CoA.
• Acetyl-CoA is oxidized to CO2 in the mitochondria through the citric acid cycle.