CHE 211 Study Guide - Final Guide: Bile Acid, Glycerol, Mayonnaise
Organic Chemistry 2: Carbohydrate Metabolism
Overview of Catabolic Processes
All catabolic processes must begin with a supply of nutrients; when we eat, we are
eating quantities of carbohydrates, fats and proteins
At this point, the catabolic processes can be broken down into a series of stages:
Stage 1: This is the hydrolysis of dietary macromolecules into smaller subunits
Stage 2: Conversion of monomers into a form that can be completely oxidized (usually
to acetyl-CoA)
Stage 3: Complete oxidation of nutrients and the production of ATP
Carbohydrates, fats, and proteins can be degraded to release energy
Carbohydrates are the most readily used energy source
Stage I: Hydrolysis of Dietary Macromolecules into Small Subunits
The purpose of Stage I in catabolism is to degrade large food molecules into component
subunits:
Polysaccharides degraded into monosaccharides
• Begins in the mouth with amylase action on starch
• Continues in small intestine with pancreatic amylase to form
monosaccharides
Proteins digested to amino acids
• Begins in the stomach with acid hydrolysis and broken down to the amino
acid level
• Serine proteases act in the small intestine and broken down to the amino acid
level
Fats broken into fatty acids and glycerol
• Begins in small intestine with fat globules
• Disperse with bile salts
• Degrade with pancreatic lipase
These subunits such as sugars, amino acid, fatty acid and glycerol are taken into the
cells of the body for use as an energy source; once these subunits are in the cells,
that is when Stage 2 begins
Stage2: The digestion products that are now in the cell are broken into 2 or 3 carbon
compounds called pyruvate and acetyl-CoA
Stage 3: this stage begins with the oxidation of the 2-carbon Acetyl-CoA in the citric
acid cycle, which we will discuss in the next chapter
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Document Summary
All catabolic processes must begin with a supply of nutrients; when we eat, we are eating quantities of carbohydrates, fats and proteins. At this point, the catabolic processes can be broken down into a series of stages: Stage 1: this is the hydrolysis of dietary macromolecules into smaller subunits. Stage 2: conversion of monomers into a form that can be completely oxidized (usually to acetyl-coa) Stage 3: complete oxidation of nutrients and the production of atp. Carbohydrates, fats, and proteins can be degraded to release energy. Carbohydrates are the most readily used energy source. Stage i: hydrolysis of dietary macromolecules into small subunits. The purpose of stage i in catabolism is to degrade large food molecules into component subunits: Polysaccharides degraded into monosaccharides: begins in the mouth with amylase action on starch, continues in small intestine with pancreatic amylase to form monosaccharides.
