describe how power can be obtained from fat explain the function and process of ketogenesis explain the procedure of ketone human body oxidation describe the purpose and the procedure of lipogenesis

Fats (or triglycerides) in ~ the body room ingested as food or synthesized by adipocytes or hepatocytes native carbohydrate precursors. Lipid metabolism involves the oxidation of fatty acids to one of two people generate energy or synthesize brand-new lipids from smaller constituent molecules. Lipid line is linked with carbohydrate metabolism, as assets of glucose (such together acetyl CoA) can be converted right into lipids.

You are watching: Why do lipids store more energy

Figure 1. A triglyceride molecule (a) breaks down right into a monoglyceride (b).

Lipid metabolism begins in the intestine where ingested triglycerides are damaged down into smaller chain fatty acids and subsequently into monoglyceride molecules through pancreatic lipases, enzymes that breakdown fats after they space emulsified by bile salts. As soon as food get the little intestine in the type of chyme, a cradle hormone called cholecystokinin (CCK) is released by intestinal cells in the minister mucosa. CCK stimulates the release of pancreatic lipase from the pancreas and stimulates the convulsion of the gallbladder to relax stored bile salts into the intestine. CCK likewise travels to the brain, where it have the right to act together a hunger suppressant.



If excessive acetyl CoA is developed from the oxidation of fatty acids and the Krebs bicycle is overloaded and also cannot handle it, the acetyl CoA is sail to create ketone bodies. These ketone bodies deserve to serve as a fuel resource if glucose levels are too low in the body. Ketones serve as fuel in times of lengthy starvation or as soon as patients experience from untreated diabetes and cannot utilize many of the circulating glucose. In both cases, fat stores are liberated come generate energy through the Krebs cycle and will create ketone bodies when too lot acetyl CoA accumulates.

In this ketone synthesis reaction, excess acetyl CoA is converted right into hydroxymethylglutaryl CoA (HMG CoA). HMG CoA is a precursor the cholesterol and also is an intermediate that is consequently converted right into β-hydroxybutyrate, the main ketone body in the blood.

Figure 4. Overabundance acetyl CoA is diverted from the Krebs cycle to the ketogenesis pathway. This reaction wake up in the mitochondria that liver cells. The result is the manufacturing of β-hydroxybutyrate, the primary ketone body found in the blood.

Ketone body Oxidation

Organs that have classically been believed to it is in dependent specifically on glucose, such together the brain, can actually use ketones as an alternate energy source. This keeps the brain functioning as soon as glucose is limited. When ketones are developed faster 보다 they deserve to be used, they deserve to be damaged down right into CO2 and acetone. The acetone is eliminated by exhalation. One symptom the ketogenesis is that the patient’s breath smells sweet choose alcohol. This effect provides one method of informing if a diabetic is properly regulating the disease. The carbon dioxide produced can acidify the blood, causing diabetic ketoacidosis, a dangerous problem in diabetics.

Ketones oxidize to produce energy for the brain. beta (β)-hydroxybutyrate is oxidized to acetoacetate and also NADH is released. One HS-CoA molecule is added to acetoacetate, forming acetoacetyl CoA. The carbon in ~ the acetoacetyl CoA that is not bonded come the CoA then detaches, dividing the molecule in two. This carbon climate attaches to another complimentary HS-CoA, causing two acetyl CoA molecules. These two acetyl CoA molecules space then processed v the Krebs bicycle to create energy.

See more: What Is The Least Reactive Element On The Periodic Table Of Elements?


Chapter Review

Lipids are obtainable to the human body from 3 sources. They have the right to be ingested in the diet, stored in the adipose organization of the body, or synthesized in the liver. Fats ingested in the diet room digested in the little intestine. The triglythrade are damaged down into monoglycerides and free fatty acids, climate imported across the minister mucosa. As soon as across, the triglycerides are resynthesized and transported come the liver or adipose tissue. Fat acids are oxidized v fatty mountain or β-oxidation into two-carbon acetyl CoA molecules, which have the right to then go into the Krebs cycle to create ATP. If excess acetyl CoA is created and also overloads the volume of the Krebs cycle, the acetyl CoA have the right to be used to synthesize ketone bodies. When glucose is limited, ketone bodies deserve to be oxidized and used because that fuel. Overfill acetyl CoA generated from overabundance glucose or carbohydrate ingestion deserve to be supplied for fatty mountain synthesis or lipogenesis. Acetyl CoA is supplied to create lipids, triglycerides, steroid hormones, cholesterol, and also bile salts. Lipolysis is the malfunction of triglycerides right into glycerol and fatty acids, do them less complicated for the human body to process.