Carbohydrate Metabolism Overview

Study Notes

Carbohydrate metabolism is the process by which cells convert carbohydrates into energy or other molecules
It involves the breakdown (catabolism) and synthesis (anabolism) of carbohydrates, such as glucose, glycogen, and starch

Glycolysis: breakdown of glucose into pyruvate, producing ATP and NADH
- Takes place in the cytosol
- Net gain of 2 ATP and 2 NADH
Pyruvate Oxidation: conversion of pyruvate into acetyl-CoA, which enters the citric acid cycle
- Takes place in the mitochondria
- Produces NADH and FADH2
Citric Acid Cycle (Krebs Cycle): breakdown of acetyl-CoA into carbon dioxide, producing ATP, NADH, and FADH2
- Takes place in the mitochondria
- Net gain of 2 ATP, 6 NADH, and 2 FADH2
Electron Transport Chain: transfer of electrons from NADH and FADH2 to oxygen, producing ATP
- Takes place in the mitochondrial inner membrane
- Net gain of 32-34 ATP

Glycogen Synthesis: conversion of glucose into glycogen, a stored form of energy
- Takes place in the liver and muscles
- Regulated by insulin and glucagon
Gluconeogenesis: synthesis of glucose from non-carbohydrate sources, such as amino acids and lactate
- Takes place in the liver and kidneys
- Regulated by insulin, glucagon, and cortisol

Insulin: promotes glucose uptake, glycogen synthesis, and glycolysis
Glucagon: promotes glycogen breakdown, gluconeogenesis, and glucose release
Hormonal Regulation: other hormones, such as cortisol and epinephrine, also play a role in regulating carbohydrate metabolism
Feedback Mechanisms: regulation of carbohydrate metabolism through feedback loops, involving ATP, NADH, and other molecules

Carbohydrate metabolism is the process of converting carbohydrates into energy or other molecules
It involves the breakdown (catabolism) and synthesis (anabolism) of carbohydrates, such as glucose, glycogen, and starch

Glycolysis is the breakdown of glucose into pyruvate, producing 2 ATP and 2 NADH, and takes place in the cytosol
Pyruvate oxidation is the conversion of pyruvate into acetyl-CoA, producing NADH and FADH2, and takes place in the mitochondria
The citric acid cycle (Krebs cycle) is the breakdown of acetyl-CoA into carbon dioxide, producing 2 ATP, 6 NADH, and 2 FADH2, and takes place in the mitochondria
The electron transport chain is the transfer of electrons from NADH and FADH2 to oxygen, producing 32-34 ATP, and takes place in the mitochondrial inner membrane

Glycogen synthesis is the conversion of glucose into glycogen, a stored form of energy, and takes place in the liver and muscles
Glycogen synthesis is regulated by insulin and glucagon
Gluconeogenesis is the synthesis of glucose from non-carbohydrate sources, such as amino acids and lactate, and takes place in the liver and kidneys
Gluconeogenesis is regulated by insulin, glucagon, and cortisol

Insulin promotes glucose uptake, glycogen synthesis, and glycolysis
Glucagon promotes glycogen breakdown, gluconeogenesis, and glucose release
Cortisol and epinephrine also play a role in regulating carbohydrate metabolism
Feedback mechanisms regulate carbohydrate metabolism through feedback loops involving ATP, NADH, and other molecules