Question

Whạt ạre the processes for the ạbsorption of dietạry fạt ạnd the mobilizạtion of stored fạt within the body?

ạnd

Whạt is the role of ạcetyl-CoẠ cạrboxylạse ạnd Ạkt in the synthesis of lipids?

Answer 1

Dietary fat is helpful of brain development, control inflammation etc. Digestion of fat takes much more time than other components of foods. Saturated fat, trans fat, mono unsaturated fatty acid, poly unsaturated fatty acids are types of fat. Fat digestion depends on types of fat.

Digestion of fat:-

Digestion of fat begins in mouth. Teeth helps to breakdown into smaller component. Saliva helps to mix with food and easy movement through esophagus and stomach.also lipase present in saliva breaks the lipid in food.lipid then goes to stomach and chemical digestion by gastric lipase takes place . Peristalsis also helps in mechanical grinding. Main digestion and absorption takes place in small intestine. Pancreatic lipase and bile salt helps breakdown of lipid into sampler units fatty acids . These fatty acid unit can be absorbed by epithelial cells of small intestine. Pancreatic lipase perform breakdown of triglyceride into fatty acid and glycerol in small intestine.

Lipid absorption:-

In stomach small chain fatty acids can be absorbed . Major absorption of fat takes place in small intestine. After breakdown of triglyceride in small intestine it become fatty acid and glycerol. These fatty acid and glycerol form a structure known as micelle. Later fatty acid and glycerol loose this structure and diffuse into intestinal epithelial cells. Fatty acids and glycerol recombined to form triglyceride inside the cytosol of epithelial cell. These triglycerides and cholestrol are packed into chylomicrons ( amphipathic structure). These chylomicrons transport the digested lipids. Chylomicrons travels through blood stream inorder to diffuse into adipose tissue other tissues of body.

Transportation of lipid.:-

Lipoproteins are protein helps for transportation of lipid. Amphipathic nature of lipoprotein helps to transfer of triglycerides and cholestrol. Chylomicron is a lipoprotein which carry triglycerides from small intestine into rest of the body. Different lipoproteins are present based on density. Very low density lipoprotein (VLDL) , Low density lipoprotein (LDL) . VLDL transport synthesised triglycerides in body.. LDL transport cholesterol to pheripheral tissues.

Acetyl coA carboxylase is an important enzyme for biosynthesis of fatty acids. It is a biotin dependent enzyme. This enzyme catalysis irreversible carboxylation of acteyl coA. This result in production of malonyl coA. Malonyl coA is a substrate for fatty acid biosynthesis.