The document discusses lipid transport and the major classes of lipoproteins in the bloodstream:
1. Chylomicrons transport dietary lipids from the intestine.
2. Very low-density lipoproteins (VLDL) transport lipids from the liver.
3. Low-density lipoproteins (LDL) are formed from VLDL and transport cholesterol to tissues.
4. High-density lipoproteins (HDL) transport cholesterol from tissues back to the liver.
This document summarizes lipid transport and storage. It discusses the structure of the small intestine and how triglycerides are packed and transported via chylomicrons through the lymphatic system and blood circulation to tissues like liver, muscle and adipose tissue. It also outlines the roles of various apolipoproteins involved in lipid transport, including ApoA, ApoB, ApoC, ApoD and ApoE. Finally, it briefly mentions disorders related to lipid transport and recommended textbooks for further reading on the topic.
The document outlines lipoprotein structure and function, including:
- Lipoproteins are protein-lipid complexes that transport lipids between tissues. They have a hydrophobic core of triglycerides and cholesterol esters surrounded by a hydrophilic surface.
- The main classes of lipoproteins are chylomicrons, VLDL, IDL, LDL, and HDL. They differ in size, density, and protein/lipid content.
- Apolipoproteins associated with each lipoprotein help with structure and regulate metabolism. Chylomicrons contain apoB-48 and transport dietary lipids. VLDL contains apoB-100 and transports endogenous lipids.
This document discusses lipoprotein metabolism and summarizes the key points. It notes that plasma consists of triglycerides, phospholipids, cholesterol, and other components. There are four major classes of lipoproteins that transport lipids in plasma: chylomicrons, VLDL, LDL, and HDL. The document outlines the formation and catabolism of chylomicrons and VLDL, which involves lipoprotein lipase, and the metabolism of LDL and HDL. Abnormalities in lipoprotein metabolism can lead to hypo- or hyperlipoproteinemia and diseases like atherosclerosis.
The bile salts such as cholic acid contain a hydrophobic side and a hydrophilic side, thus allowing bile salts to dissolve at an oil-water interface, with the hydrophobic surface in contact with the non-polar phase and the hydrophilic surface in the aqueous medium. This detergent action emulsifies fats and yields mixed micelles, which allow attack by water-soluble digestive enzymes and facilitate the absorption of lipids through the intestinal mucosa. Mixed Micelles also serve as transport vehicles for those lipids that are less water-soluble than fatty acids, such as cholesterol or the fat-soluble vitamins A, D, E, and K. Thus, efficient absorption of lipids depends on the presence of sufficient bile acids to solubilize the ingested lipids.
What are lipoproteins?
Structure of lipoprotein complex.
Classification of lipoproteins.
Important enzyme and protein involved in lipoprotein metabolism.
Apolipoprotein.
Lipoprotein metabolism.
Clinical disorders
Importance of lipoprotein.
Conclusion
Reference.
1. Introduction to biochemistry: Cell and its biochemical organization, transport process across the cell membranes. Energy rich compounds: ATP, Cyclic AMP and their biological significance.
2. Biological oxidation: Coenzyme system involved in Biological oxidation. Electron transport chain (its mechanism in energy capture: regulation and inhibition): Uncouplers of ETC: Oxidative phosphorylation.
3. Enzymes: Definition: Nomenclature, IUB classification, Factor affecting enzyme activity, Enzyme action, enzyme inhibition. Isoenzymes and their therapeutic and diagnostic applications, Coenzymes and their biochemical role and deficiency diseases.
4. Carbohydrate metabolism: Glycolysis, Citric acid cycle (TCA cycle), HMP shunt, Glycogenolysis, gluconeogenesis, glycogenesis. Metabolic disorders of carbohydrate metabolism (diabetes mellitus and glycogen storage diseases): Glucose, Galactose tolerance test and their significance, hormonal regulation of carbohydrate metabolism.
5. Lipid metabolism: Oxidation of saturated (-oxidation): Ketogenesis and ketolysis, biosynthesis of fatty acids, lipids, metabolism of cholesterol, Hormonal regulation of lipid metabolism. Defective metabolism of lipids (Atherosclerosis, fatty liver, hypercholesterolemia).
6. Protein and amino acid metabolism: protein turn over, nitrogen balance, Catabolism of Amino acids (Transamination, deamination & decarboxylation).Urea cycle and its metabolic disorders, production of bile pigments, hyperbilirubinemia, porphoria, jaundice. Metabolic disorder of Amino acids.
7. Nucleic acid metabolism: Metabolism of purine and pyrimidine nucleotides, Protein synthesis, inhibition of protein synthesis
8. Introduction to clinical chemistry:
a) Urine analysis (macroscopic and physical examination, quantitative and
semi quantitative tests).
b) Test for NPN constituents. (Creatinine /urea clearance, determination of
blood and urine creatinine, urea and uric acid).
c) Test for hepatic dysfunction-Bile pigments metabolism.
d) Test for hepatic function: test- Serum bilirubin, urine bilirubin and urine
urobilinogen.
e) Lipid profile tests: Lipoproteins, composition, functions. Determination of
serum lipids, total cholesterol, HDL cholesterol, LDL cholesterol and
triglycerides.
This document summarizes lipid transport and storage. It discusses the structure of the small intestine and how triglycerides are packed and transported via chylomicrons through the lymphatic system and blood circulation to tissues like liver, muscle and adipose tissue. It also outlines the roles of various apolipoproteins involved in lipid transport, including ApoA, ApoB, ApoC, ApoD and ApoE. Finally, it briefly mentions disorders related to lipid transport and recommended textbooks for further reading on the topic.
The document outlines lipoprotein structure and function, including:
- Lipoproteins are protein-lipid complexes that transport lipids between tissues. They have a hydrophobic core of triglycerides and cholesterol esters surrounded by a hydrophilic surface.
- The main classes of lipoproteins are chylomicrons, VLDL, IDL, LDL, and HDL. They differ in size, density, and protein/lipid content.
- Apolipoproteins associated with each lipoprotein help with structure and regulate metabolism. Chylomicrons contain apoB-48 and transport dietary lipids. VLDL contains apoB-100 and transports endogenous lipids.
This document discusses lipoprotein metabolism and summarizes the key points. It notes that plasma consists of triglycerides, phospholipids, cholesterol, and other components. There are four major classes of lipoproteins that transport lipids in plasma: chylomicrons, VLDL, LDL, and HDL. The document outlines the formation and catabolism of chylomicrons and VLDL, which involves lipoprotein lipase, and the metabolism of LDL and HDL. Abnormalities in lipoprotein metabolism can lead to hypo- or hyperlipoproteinemia and diseases like atherosclerosis.
The bile salts such as cholic acid contain a hydrophobic side and a hydrophilic side, thus allowing bile salts to dissolve at an oil-water interface, with the hydrophobic surface in contact with the non-polar phase and the hydrophilic surface in the aqueous medium. This detergent action emulsifies fats and yields mixed micelles, which allow attack by water-soluble digestive enzymes and facilitate the absorption of lipids through the intestinal mucosa. Mixed Micelles also serve as transport vehicles for those lipids that are less water-soluble than fatty acids, such as cholesterol or the fat-soluble vitamins A, D, E, and K. Thus, efficient absorption of lipids depends on the presence of sufficient bile acids to solubilize the ingested lipids.
What are lipoproteins?
Structure of lipoprotein complex.
Classification of lipoproteins.
Important enzyme and protein involved in lipoprotein metabolism.
Apolipoprotein.
Lipoprotein metabolism.
Clinical disorders
Importance of lipoprotein.
Conclusion
Reference.
1. Introduction to biochemistry: Cell and its biochemical organization, transport process across the cell membranes. Energy rich compounds: ATP, Cyclic AMP and their biological significance.
2. Biological oxidation: Coenzyme system involved in Biological oxidation. Electron transport chain (its mechanism in energy capture: regulation and inhibition): Uncouplers of ETC: Oxidative phosphorylation.
3. Enzymes: Definition: Nomenclature, IUB classification, Factor affecting enzyme activity, Enzyme action, enzyme inhibition. Isoenzymes and their therapeutic and diagnostic applications, Coenzymes and their biochemical role and deficiency diseases.
4. Carbohydrate metabolism: Glycolysis, Citric acid cycle (TCA cycle), HMP shunt, Glycogenolysis, gluconeogenesis, glycogenesis. Metabolic disorders of carbohydrate metabolism (diabetes mellitus and glycogen storage diseases): Glucose, Galactose tolerance test and their significance, hormonal regulation of carbohydrate metabolism.
5. Lipid metabolism: Oxidation of saturated (-oxidation): Ketogenesis and ketolysis, biosynthesis of fatty acids, lipids, metabolism of cholesterol, Hormonal regulation of lipid metabolism. Defective metabolism of lipids (Atherosclerosis, fatty liver, hypercholesterolemia).
6. Protein and amino acid metabolism: protein turn over, nitrogen balance, Catabolism of Amino acids (Transamination, deamination & decarboxylation).Urea cycle and its metabolic disorders, production of bile pigments, hyperbilirubinemia, porphoria, jaundice. Metabolic disorder of Amino acids.
7. Nucleic acid metabolism: Metabolism of purine and pyrimidine nucleotides, Protein synthesis, inhibition of protein synthesis
8. Introduction to clinical chemistry:
a) Urine analysis (macroscopic and physical examination, quantitative and
semi quantitative tests).
b) Test for NPN constituents. (Creatinine /urea clearance, determination of
blood and urine creatinine, urea and uric acid).
c) Test for hepatic dysfunction-Bile pigments metabolism.
d) Test for hepatic function: test- Serum bilirubin, urine bilirubin and urine
urobilinogen.
e) Lipid profile tests: Lipoproteins, composition, functions. Determination of
serum lipids, total cholesterol, HDL cholesterol, LDL cholesterol and
triglycerides.
This document summarizes lipid digestion and metabolism. It discusses how lipids are not digested in the mouth or stomach but are broken down by enzymes in the small intestine. Bile salts produced by the liver emulsify lipids and activate pancreatic lipase. Lipids are hydrolyzed into fatty acids and monoglycerides which are absorbed via micelles into intestinal cells. There they are re-esterified and packaged into chylomicrons which enter the lymphatic system and blood. Chylomicrons deliver lipids to tissues while liver produces VLDL to export endogenous lipids. VLDL and chylomicrons exchange triglycerides for cholesterol to become LDL and HDL which circulate lipids through the body
Lipoproteins are protein-lipid complexes that transport lipids between tissues. They have an outer surface containing proteins and phospholipids and an inner hydrophobic core containing triglycerides and cholesterol esters. The main classes of lipoproteins are chylomicrons, VLDL, IDL, LDL, and HDL. Chylomicrons transport dietary lipids from the intestine to tissues. VLDL is produced in the liver and transports triglycerides. Through the action of lipoprotein lipase, VLDL loses triglycerides to become IDL and LDL, which transports cholesterol. HDL transports cholesterol from tissues back to the liver in the reverse cholesterol transport pathway. Cholesterol homeostasis is maintained through hepatic
1. Lipoproteins are spherical aggregates that transport lipids like triglycerides and cholesterol in the bloodstream. They are composed of a hydrophobic core of lipids surrounded by a hydrophilic surface containing proteins and lipids.
2. There are several classes of lipoproteins defined by their density: chylomicrons, VLDL, IDL, LDL, and HDL. Chylomicrons transport dietary lipids from the intestine. VLDL transports triglycerides made in the liver. LDL transports cholesterol to tissues. HDL transports excess cholesterol from tissues back to the liver.
3. Apolipoproteins bind to lipids and target different lipoproteins to tissues. Lipoprotein lipase breaks
Lipoproteins are biochemical assemblies containing both proteins and lipids that transport fats like triglycerides through the water-based plasma. They consist of a nonpolar lipid core surrounded by a layer of amphipathic lipids and proteins. Lipoproteins can be classified based on density, electrophoretic mobility, and apolipoprotein content. They transport lipids between tissues and are involved in lipid metabolism through interactions with enzymes like lipoprotein lipase. Defects in lipoprotein metabolism can cause diseases like atherosclerosis and coronary artery disease.
25.1Digestion and Absorption of Lipids
25.2Triacylglycerol Storage and Mobilization
25.3 Glycerol Metabolism
25.4 Oxidation of Fatty Acids
25.5 ATP Production from Fatty Acid Oxidation
25.6 Ketone Bodies
25.7 Biosynthesis of Fatty Acids: Lipogenesis
25.8 Relationship Between Lipogenesis and Citric Acid Cycle Intermediates
25.9 Fate of Fatty-Acid Generated Acetyl CoA
25.10 Relationships Between Lipid and Carbohydrate Metabolism
25.11B Vitamins and Lipid Metabolism
This document summarizes lipoproteins and their classification and functions. Lipoproteins are complexes of lipids and proteins that transport lipids in the bloodstream. They are classified into five main types based on density: chylomicrons, very low density lipoproteins (VLDL), intermediate density lipoproteins (IDL), low density lipoproteins (LDL), and high density lipoproteins (HDL). Chylomicrons transport dietary triglycerides from the intestine to tissues, VLDL transports endogenous triglycerides from the liver, and HDL transports cholesterol from tissues back to the liver in reverse cholesterol transport. Apolipoproteins associated with each lipoprotein particle facilitate their metabolism and functions.
This document discusses lipoproteins and cholesterol. It describes the structure of lipoproteins which contain a core of cholesterol esters, triglycerides, and phospholipids surrounded by apolipoproteins. The main lipoproteins are chylomicrons, VLDL, LDL, and HDL which transport lipids between tissues and the liver. High levels of certain lipoproteins can lead to hyperlipidemias and cardiovascular disease, while low levels cause hypolipoproteinemias. Cholesterol is an important component of cell membranes and a precursor for steroid hormones, and plays roles in bile acid synthesis and vitamin D production.
This document discusses lipoproteins, which are complexes that transport lipids through the bloodstream. It describes their structure, classification based on density and size or electrophoretic pattern, and major apolipoproteins. Key aspects of lipoprotein metabolism are explained, including the assembly of chylomicrons and VLDL, the role of HDL in reverse cholesterol transport, and the antioxidant activities of HDL components. Clinical significance is discussed regarding fatty liver disease that can arise from impaired lipoprotein formation or secretion.
1. Lipids play major roles in cell structure and energy storage. Triacylglycerols are the main form of stored energy in mammals while phospholipids and cholesterol are components of cell membranes.
2. There are two main types of lipids - simple lipids like fats and oils which are esters of fatty acids and alcohols, and compound lipids which also contain phosphate, nitrogenous bases or other groups.
3. Triglycerides from the diet and from adipose tissue are broken down into fatty acids and glycerol. Fatty acids are transported to tissues via the bloodstream bound to albumin or within lipoproteins, then undergo beta-oxidation in the mitochondria to
The document discusses lipid metabolism and β-oxidation of fatty acids. It notes that triacylglycerols are broken down into free fatty acids and glycerol in the gut. Fatty acids are transported via lipoproteins or albumin and undergo β-oxidation in the mitochondria to generate acetyl-CoA. β-Oxidation involves four steps per fatty acid: dehydrogenation, hydration, second dehydrogenation, and thiolysis. This shortens the fatty acid by two carbons, producing acetyl-CoA and reducing equivalents.
This document discusses lipoprotein metabolism and structure. It describes the different lipoproteins including chylomicrons, VLDL, IDL, LDL, and HDL. It outlines the roles of apoproteins and how lipoproteins transport triglycerides and cholesterol through the body. The pathways of exogenous and endogenous cholesterol are summarized along with lipoprotein processing and targets for treating dyslipidemia.
This document discusses lipoproteins, which are complexes of protein and lipids that transport lipids in the bloodstream. It defines the major classes of lipoproteins - chylomicrons, very low density lipoprotein (VLDL), low density lipoprotein (LDL), and high density lipoprotein (HDL) - based on their density. It also describes the apolipoproteins that are components of the different lipoproteins and their various structural and functional roles. The metabolism and transport of lipids by each class of lipoprotein is then outlined.
Apolipoprotein and their function, chromium as muscle building tissue and rel...preeti bartwal
Apolipoproteins are proteins that bind lipids like cholesterol to form lipoproteins, which transport lipids through the body. There are two major types - apolipoproteins B form LDL particles while others form HDL particles. Apolipoproteins serve critical functions like acting as enzymes, transporting lipids between tissues, and regulating lipid metabolism. Chromium supports muscle building by helping insulin transport protein into cells for new muscle tissue growth. Maintaining proper chromium levels can lower blood sugar, triglycerides and cholesterol to reduce heart disease and diabetes risk.
This document discusses the structure and function of various apolipoproteins. It describes the major apolipoproteins, including apoA-I, apoA-II, apoA-IV, apoB, apoC-I, apoC-II, apoC-III, and apoE. For each one, it provides information on genetics, protein structure, function in lipid transport and metabolism, role in health conditions, and clinical significance. The document serves as an overview of the key apolipoproteins, their roles in lipoprotein formation and regulation, and their involvement in cardiovascular and other genetic diseases.
1) The document discusses lipid metabolism, including the classification, digestion, and metabolism of various lipids like triglycerides, cholesterol, and phospholipids.
2) It provides details on the classification of fatty acids, the digestion of triglycerols in the small intestine, and the catabolism of triglycerols through beta-oxidation in the mitochondria to produce acetyl-CoA.
3) The synthesis of triglycerides is also summarized, including the monoacylglycerol and diacylglycerol pathways. Lipogenesis, the synthesis of fatty acids from acetyl-CoA, and the metabolism of cholesterol are also covered.
Lipoproteins are spherical complexes formed by lipids and proteins that transport insoluble lipids through the blood. There are four main classes of lipoproteins: chylomicrons, very low density lipoproteins (VLDL), low density lipoproteins (LDL), and high density lipoproteins (HDL). Chylomicrons and VLDL are involved in transporting triglycerides, LDL transports cholesterol, and HDL transports excess cholesterol from tissues back to the liver.
Disorders Associated with Fatty Acid Catabolismcoco_dawn_96
Disorders associated with fatty acid catabolism are caused by deficiencies in enzymes needed to break down fatty acids. This results in the buildup of fatty acid breakdown products and prevents the body from efficiently producing and using energy from fats. Specific disorders include medium-chain acyl-CoA dehydrogenase deficiency and carnitine uptake defect. Symptoms can include hypoglycemia, seizures, and delayed development. Treatment focuses on providing alternative energy sources and supplements.
Chylomicrons are large lipoprotein particles that are formed in the intestines and transport triglycerides and other lipids from the diet from the intestines to other tissues. They originate in the small intestine as triglyceride-rich particles called nascent chylomicrons that mature through the addition of apolipoproteins as they circulate. Chylomicrons deliver triglycerides to tissues like liver and adipose tissue through interaction with enzymes and receptors. Their life cycle involves transitioning from nascent to mature to remnant particles as triglycerides are removed. Chylomicron retention disease is a rare inherited condition where chylomicrons cannot be transported properly, preventing
This document defines and classifies different types of lipoproteins. It discusses lipoproteins' roles in transporting lipids like triglycerides and cholesterol through the bloodstream. The main lipoproteins described are chylomicrons, VLDL, IDL, LDL, and HDL. Chylomicrons and VLDL transport lipids from the intestine and liver to tissues. Their triglycerides are broken down by lipoprotein lipase, forming chylomicron/VLDL remnants taken up by the liver. LDL transports cholesterol to tissues, while HDL transports excess cholesterol from tissues back to the liver in reverse transport.
This document discusses abetalipoproteinemia, a rare genetic disorder characterized by the lack of apolipoprotein B, which is necessary for the formation of chylomicrons, VLDLs, and LDLs. This leads to an inability to absorb and transport dietary fats and fat-soluble vitamins. Patients with abetalipoproteinemia experience fat accumulation in intestinal and liver cells, malabsorption of fat and fat-soluble vitamins like vitamin E, and associated neurological and vision complications. The underlying genetic defect is mutations in the microsomal triglyceride transfer protein gene, which is essential for producing beta-lipoproteins needed for fat absorption and transport.
This document summarizes lipid digestion and metabolism. It discusses how lipids are not digested in the mouth or stomach but are broken down by enzymes in the small intestine. Bile salts produced by the liver emulsify lipids and activate pancreatic lipase. Lipids are hydrolyzed into fatty acids and monoglycerides which are absorbed via micelles into intestinal cells. There they are re-esterified and packaged into chylomicrons which enter the lymphatic system and blood. Chylomicrons deliver lipids to tissues while liver produces VLDL to export endogenous lipids. VLDL and chylomicrons exchange triglycerides for cholesterol to become LDL and HDL which circulate lipids through the body
Lipoproteins are protein-lipid complexes that transport lipids between tissues. They have an outer surface containing proteins and phospholipids and an inner hydrophobic core containing triglycerides and cholesterol esters. The main classes of lipoproteins are chylomicrons, VLDL, IDL, LDL, and HDL. Chylomicrons transport dietary lipids from the intestine to tissues. VLDL is produced in the liver and transports triglycerides. Through the action of lipoprotein lipase, VLDL loses triglycerides to become IDL and LDL, which transports cholesterol. HDL transports cholesterol from tissues back to the liver in the reverse cholesterol transport pathway. Cholesterol homeostasis is maintained through hepatic
1. Lipoproteins are spherical aggregates that transport lipids like triglycerides and cholesterol in the bloodstream. They are composed of a hydrophobic core of lipids surrounded by a hydrophilic surface containing proteins and lipids.
2. There are several classes of lipoproteins defined by their density: chylomicrons, VLDL, IDL, LDL, and HDL. Chylomicrons transport dietary lipids from the intestine. VLDL transports triglycerides made in the liver. LDL transports cholesterol to tissues. HDL transports excess cholesterol from tissues back to the liver.
3. Apolipoproteins bind to lipids and target different lipoproteins to tissues. Lipoprotein lipase breaks
Lipoproteins are biochemical assemblies containing both proteins and lipids that transport fats like triglycerides through the water-based plasma. They consist of a nonpolar lipid core surrounded by a layer of amphipathic lipids and proteins. Lipoproteins can be classified based on density, electrophoretic mobility, and apolipoprotein content. They transport lipids between tissues and are involved in lipid metabolism through interactions with enzymes like lipoprotein lipase. Defects in lipoprotein metabolism can cause diseases like atherosclerosis and coronary artery disease.
25.1Digestion and Absorption of Lipids
25.2Triacylglycerol Storage and Mobilization
25.3 Glycerol Metabolism
25.4 Oxidation of Fatty Acids
25.5 ATP Production from Fatty Acid Oxidation
25.6 Ketone Bodies
25.7 Biosynthesis of Fatty Acids: Lipogenesis
25.8 Relationship Between Lipogenesis and Citric Acid Cycle Intermediates
25.9 Fate of Fatty-Acid Generated Acetyl CoA
25.10 Relationships Between Lipid and Carbohydrate Metabolism
25.11B Vitamins and Lipid Metabolism
This document summarizes lipoproteins and their classification and functions. Lipoproteins are complexes of lipids and proteins that transport lipids in the bloodstream. They are classified into five main types based on density: chylomicrons, very low density lipoproteins (VLDL), intermediate density lipoproteins (IDL), low density lipoproteins (LDL), and high density lipoproteins (HDL). Chylomicrons transport dietary triglycerides from the intestine to tissues, VLDL transports endogenous triglycerides from the liver, and HDL transports cholesterol from tissues back to the liver in reverse cholesterol transport. Apolipoproteins associated with each lipoprotein particle facilitate their metabolism and functions.
This document discusses lipoproteins and cholesterol. It describes the structure of lipoproteins which contain a core of cholesterol esters, triglycerides, and phospholipids surrounded by apolipoproteins. The main lipoproteins are chylomicrons, VLDL, LDL, and HDL which transport lipids between tissues and the liver. High levels of certain lipoproteins can lead to hyperlipidemias and cardiovascular disease, while low levels cause hypolipoproteinemias. Cholesterol is an important component of cell membranes and a precursor for steroid hormones, and plays roles in bile acid synthesis and vitamin D production.
This document discusses lipoproteins, which are complexes that transport lipids through the bloodstream. It describes their structure, classification based on density and size or electrophoretic pattern, and major apolipoproteins. Key aspects of lipoprotein metabolism are explained, including the assembly of chylomicrons and VLDL, the role of HDL in reverse cholesterol transport, and the antioxidant activities of HDL components. Clinical significance is discussed regarding fatty liver disease that can arise from impaired lipoprotein formation or secretion.
1. Lipids play major roles in cell structure and energy storage. Triacylglycerols are the main form of stored energy in mammals while phospholipids and cholesterol are components of cell membranes.
2. There are two main types of lipids - simple lipids like fats and oils which are esters of fatty acids and alcohols, and compound lipids which also contain phosphate, nitrogenous bases or other groups.
3. Triglycerides from the diet and from adipose tissue are broken down into fatty acids and glycerol. Fatty acids are transported to tissues via the bloodstream bound to albumin or within lipoproteins, then undergo beta-oxidation in the mitochondria to
The document discusses lipid metabolism and β-oxidation of fatty acids. It notes that triacylglycerols are broken down into free fatty acids and glycerol in the gut. Fatty acids are transported via lipoproteins or albumin and undergo β-oxidation in the mitochondria to generate acetyl-CoA. β-Oxidation involves four steps per fatty acid: dehydrogenation, hydration, second dehydrogenation, and thiolysis. This shortens the fatty acid by two carbons, producing acetyl-CoA and reducing equivalents.
This document discusses lipoprotein metabolism and structure. It describes the different lipoproteins including chylomicrons, VLDL, IDL, LDL, and HDL. It outlines the roles of apoproteins and how lipoproteins transport triglycerides and cholesterol through the body. The pathways of exogenous and endogenous cholesterol are summarized along with lipoprotein processing and targets for treating dyslipidemia.
This document discusses lipoproteins, which are complexes of protein and lipids that transport lipids in the bloodstream. It defines the major classes of lipoproteins - chylomicrons, very low density lipoprotein (VLDL), low density lipoprotein (LDL), and high density lipoprotein (HDL) - based on their density. It also describes the apolipoproteins that are components of the different lipoproteins and their various structural and functional roles. The metabolism and transport of lipids by each class of lipoprotein is then outlined.
Apolipoprotein and their function, chromium as muscle building tissue and rel...preeti bartwal
Apolipoproteins are proteins that bind lipids like cholesterol to form lipoproteins, which transport lipids through the body. There are two major types - apolipoproteins B form LDL particles while others form HDL particles. Apolipoproteins serve critical functions like acting as enzymes, transporting lipids between tissues, and regulating lipid metabolism. Chromium supports muscle building by helping insulin transport protein into cells for new muscle tissue growth. Maintaining proper chromium levels can lower blood sugar, triglycerides and cholesterol to reduce heart disease and diabetes risk.
This document discusses the structure and function of various apolipoproteins. It describes the major apolipoproteins, including apoA-I, apoA-II, apoA-IV, apoB, apoC-I, apoC-II, apoC-III, and apoE. For each one, it provides information on genetics, protein structure, function in lipid transport and metabolism, role in health conditions, and clinical significance. The document serves as an overview of the key apolipoproteins, their roles in lipoprotein formation and regulation, and their involvement in cardiovascular and other genetic diseases.
1) The document discusses lipid metabolism, including the classification, digestion, and metabolism of various lipids like triglycerides, cholesterol, and phospholipids.
2) It provides details on the classification of fatty acids, the digestion of triglycerols in the small intestine, and the catabolism of triglycerols through beta-oxidation in the mitochondria to produce acetyl-CoA.
3) The synthesis of triglycerides is also summarized, including the monoacylglycerol and diacylglycerol pathways. Lipogenesis, the synthesis of fatty acids from acetyl-CoA, and the metabolism of cholesterol are also covered.
Lipoproteins are spherical complexes formed by lipids and proteins that transport insoluble lipids through the blood. There are four main classes of lipoproteins: chylomicrons, very low density lipoproteins (VLDL), low density lipoproteins (LDL), and high density lipoproteins (HDL). Chylomicrons and VLDL are involved in transporting triglycerides, LDL transports cholesterol, and HDL transports excess cholesterol from tissues back to the liver.
Disorders Associated with Fatty Acid Catabolismcoco_dawn_96
Disorders associated with fatty acid catabolism are caused by deficiencies in enzymes needed to break down fatty acids. This results in the buildup of fatty acid breakdown products and prevents the body from efficiently producing and using energy from fats. Specific disorders include medium-chain acyl-CoA dehydrogenase deficiency and carnitine uptake defect. Symptoms can include hypoglycemia, seizures, and delayed development. Treatment focuses on providing alternative energy sources and supplements.
Chylomicrons are large lipoprotein particles that are formed in the intestines and transport triglycerides and other lipids from the diet from the intestines to other tissues. They originate in the small intestine as triglyceride-rich particles called nascent chylomicrons that mature through the addition of apolipoproteins as they circulate. Chylomicrons deliver triglycerides to tissues like liver and adipose tissue through interaction with enzymes and receptors. Their life cycle involves transitioning from nascent to mature to remnant particles as triglycerides are removed. Chylomicron retention disease is a rare inherited condition where chylomicrons cannot be transported properly, preventing
This document defines and classifies different types of lipoproteins. It discusses lipoproteins' roles in transporting lipids like triglycerides and cholesterol through the bloodstream. The main lipoproteins described are chylomicrons, VLDL, IDL, LDL, and HDL. Chylomicrons and VLDL transport lipids from the intestine and liver to tissues. Their triglycerides are broken down by lipoprotein lipase, forming chylomicron/VLDL remnants taken up by the liver. LDL transports cholesterol to tissues, while HDL transports excess cholesterol from tissues back to the liver in reverse transport.
This document discusses abetalipoproteinemia, a rare genetic disorder characterized by the lack of apolipoprotein B, which is necessary for the formation of chylomicrons, VLDLs, and LDLs. This leads to an inability to absorb and transport dietary fats and fat-soluble vitamins. Patients with abetalipoproteinemia experience fat accumulation in intestinal and liver cells, malabsorption of fat and fat-soluble vitamins like vitamin E, and associated neurological and vision complications. The underlying genetic defect is mutations in the microsomal triglyceride transfer protein gene, which is essential for producing beta-lipoproteins needed for fat absorption and transport.
Lipoproteins are complexes of lipids and proteins that transport lipids in blood plasma. There are five major classes of lipoproteins - chylomicrons, very low density lipoproteins (VLDL), low density lipoproteins (LDL), high density lipoproteins (HDL), and free fatty acid-albumin. They differ in their lipid and protein composition and function to transport lipids between tissues and the liver. Genetic defects in lipoprotein metabolism can result in various hyperlipoproteinemias or hypolipoproteinemias.
Lipoproteins are complexes of lipids and proteins that transport lipids in the bloodstream. There are five major classes of lipoproteins - chylomicrons, very low density lipoproteins (VLDL), low density lipoproteins (LDL), high density lipoproteins (HDL), and free fatty acid-albumin. Each class transports different lipids and has distinct roles, sizes, and protein components. Disorders can arise from defects in lipoprotein metabolism, leading to abnormal lipid levels and increased disease risk.
Lipoproteins are complexes of lipids and proteins that transport lipids through the bloodstream. There are four main types of plasma lipoproteins - chylomicrons, VLDL, LDL, and HDL - which differ in size, density, and lipid/protein composition. Chylomicrons carry dietary lipids from the intestine to other tissues, VLDL transports endogenous lipids from the liver, LDL carries cholesterol, and HDL transports cholesterol from tissues to the liver for processing or excretion. The metabolism and interactions between these lipoproteins, such as the transfer of lipids between them, are tightly regulated and essential for maintaining lipid homeostasis.
1) Chylomicrons are assembled in the intestines and carry dietary lipids through the lymphatic system and bloodstream to tissues. They are formed when apo B-48 is loaded with lipids by MTP in the ER and Golgi.
2) Nascent chylomicrons acquire apo C and E from HDL in the bloodstream. Lipoprotein lipase on capillary walls hydrolyzes chylomicron triglycerides, providing fatty acids to tissues.
3) Remnant chylomicrons are taken up by the liver via apo E binding to hepatic receptors, where lipids are metabolized and reused or stored.
1. Lipids are transported through the body bound to proteins in structures called lipoproteins. Lipoproteins are classified based on their density, with chylomicrons being the lowest density and HDL being the highest.
2. Chylomicrons transport dietary lipids from the intestine to tissues, VLDL transports lipids made in the liver, LDL transports cholesterol, and HDL transports cholesterol from tissues back to the liver.
3. The major lipoproteins each contain different apolipoproteins that determine their structure and function. For example, ApoB48 is major protein of chylomicrons while ApoA1 is the major protein of HDL.
Lipoprotein metabolism and disorders
The document discusses lipoprotein metabolism and related disorders. It describes how lipoproteins transport lipids in the bloodstream, including their classification based on density and composition. The metabolism of chylomicrons and very low density lipoproteins is summarized, including the roles of apolipoproteins and lipoprotein lipase. Disorders involving abnormal high or low levels of lipoproteins are described, such as familial hypercholesterolemia and Tangier disease. Fatty liver and impaired lipoprotein synthesis can also disrupt lipid transport.
HDL is the smallest and densest lipoprotein particle, composed of proteins, phospholipids, free cholesterol, cholesterol esters, and triglycerides. HDL particles transport cholesterol from tissues like macrophages to the liver for processing or excretion. The liver synthesizes nascent HDL particles that acquire cholesterol through interactions with the ATP-binding cassette transporter A1 and other receptors on cells. Enzymes further process and enlarge HDL as it circulates, eventually returning mature HDL to the liver to offload cholesterol through the scavenger receptor class B type 1. This reverse cholesterol transport pathway is important for reducing atherosclerosis and is part of HDL's anti-inflammatory and antioxidant functions that provide protection against cardiovascular disease.
Lipoproteins: Structure, classification, metabolism and significanceenamifat
This document discusses lipoproteins and their role in transporting lipids like triglycerides and cholesterol in the body. It describes the different types of lipoproteins, including chylomicrons, VLDL, LDL, and HDL. Chylomicrons transport dietary lipids from the intestine to tissues, while VLDL transports endogenous lipids from the liver. VLDL is converted to LDL as it delivers lipids to tissues. HDL transports cholesterol from tissues back to the liver in a process called reverse cholesterol transport. The document provides details on the composition and metabolism of each lipoprotein class and their role in lipid transport.
lipoproteins transfer lipids such as triacylglycerol, cholestryl ester, fat soluble vitamins in the body. there are 5 categories of lipoproteins which includes chylomicrone, VLDL, IDL, LDL and HDL. LDL-cholesterol is called bad cholestrol while HDL-cholesterol is called good cholesterol.
Lipoprotein introduction, their general characteristics, exogenous and endogenous metabolism focusing on chylomicron and vldl metabolism, ldl metabolism and HDL metabolism , reverse cholesterol transport.
This document summarizes the metabolism of lipoproteins in the human body. It discusses how lipids are transported in the blood using lipoproteins, which are classified based on their density. The main lipoproteins are chylomicrons, VLDL, LDL, and HDL. Each carries out specific functions to transport lipids between the intestines, liver, and peripheral tissues. The document outlines the synthesis and catabolism of each lipoprotein class and their roles in cholesterol transport. It also discusses inherited disorders that can disrupt lipoprotein metabolism.
Cholesterol is converted to bile acids in the liver which aid in digestion. Bile acids are synthesized from cholesterol through a reaction that adds hydroxyl groups. They help emulsify lipids and aid in their absorption. Most bile acids are reabsorbed and recycled in a process called enterohepatic circulation. A small amount of bile acids are lost in feces, which is the main route for eliminating cholesterol from the body. When bile acid or cholesterol levels are too high, gallstones can form. Cholesterol is also a precursor for steroid hormones and vitamin D. High levels of cholesterol in the blood can increase risk of heart disease.
Lipoproteins are biochemical assemblies that transport hydrophobic lipid molecules in water and blood. They consist of a phospholipid and cholesterol outer shell with apolipoproteins embedded that stabilize the complex and determine its function. The main types of lipoproteins are chylomicrons, VLDL, IDL, LDL, and HDL, which differ in size, density, and lipid and protein composition. They enable the transport and metabolism of triglycerides, cholesterol, and other lipids throughout the body.
The high risks of lipids and its relevance towards the development of different cardiovascular diseases has been known to all where this present slide focuses on that only along with the different treatment procedures,.
Lipids are insoluble in water, the problem of transportation in the aqueous plasma is solved by associating nonpolar lipids (triacylglycerols and cholesteryl esters) with amphipathic lipids (phospholipids and cholesterol) and proteins to make water-miscible lipoproteins.
This document provides an overview of lipid metabolism and hypolipidemic drugs. It discusses lipids, lipoproteins, lipoprotein classification, lipid metabolism pathways including exogenous and endogenous pathways, atherogenesis, and drug therapy. The endogenous pathway can be separated into the atherogenic apo-B100 lipoprotein system and the antiatherogenic apo-A1 lipoprotein system. The document provides details on the structure and function of lipoproteins, their classification based on density and electrophoretic mobility, and the roles of apolipoproteins.
- Video recording of this lecture in English language: https://youtu.be/Pt1nA32sdHQ
- Video recording of this lecture in Arabic language: https://youtu.be/uFdc9F0rlP0
- Link to download the book free: https://nephrotube.blogspot.com/p/nephrotube-nephrology-books.html
- Link to NephroTube website: www.NephroTube.com
- Link to NephroTube social media accounts: https://nephrotube.blogspot.com/p/join-nephrotube-on-social-media.html
STUDIES IN SUPPORT OF SPECIAL POPULATIONS: GERIATRICS E7shruti jagirdar
Unit 4: MRA 103T Regulatory affairs
This guideline is directed principally toward new Molecular Entities that are
likely to have significant use in the elderly, either because the disease intended
to be treated is characteristically a disease of aging ( e.g., Alzheimer's disease) or
because the population to be treated is known to include substantial numbers of
geriatric patients (e.g., hypertension).
The biomechanics of running involves the study of the mechanical principles underlying running movements. It includes the analysis of the running gait cycle, which consists of the stance phase (foot contact to push-off) and the swing phase (foot lift-off to next contact). Key aspects include kinematics (joint angles and movements, stride length and frequency) and kinetics (forces involved in running, including ground reaction and muscle forces). Understanding these factors helps in improving running performance, optimizing technique, and preventing injuries.
“Psychiatry and the Humanities”: An Innovative Course at the University of Mo...Université de Montréal
“Psychiatry and the Humanities”: An Innovative Course at the University of Montreal Expanding the medical model to embrace the humanities. Link: https://www.psychiatrictimes.com/view/-psychiatry-and-the-humanities-an-innovative-course-at-the-university-of-montreal
These lecture slides, by Dr Sidra Arshad, offer a simplified look into the mechanisms involved in the regulation of respiration:
Learning objectives:
1. Describe the organisation of respiratory center
2. Describe the nervous control of inspiration and respiratory rhythm
3. Describe the functions of the dorsal and respiratory groups of neurons
4. Describe the influences of the Pneumotaxic and Apneustic centers
5. Explain the role of Hering-Breur inflation reflex in regulation of inspiration
6. Explain the role of central chemoreceptors in regulation of respiration
7. Explain the role of peripheral chemoreceptors in regulation of respiration
8. Explain the regulation of respiration during exercise
9. Integrate the respiratory regulatory mechanisms
10. Describe the Cheyne-Stokes breathing
Study Resources:
1. Chapter 42, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 36, Ganong’s Review of Medical Physiology, 26th edition
3. Chapter 13, Human Physiology by Lauralee Sherwood, 9th edition
Osvaldo Bernardo Muchanga-GASTROINTESTINAL INFECTIONS AND GASTRITIS-2024.pdfOsvaldo Bernardo Muchanga
GASTROINTESTINAL INFECTIONS AND GASTRITIS
Osvaldo Bernardo Muchanga
Gastrointestinal Infections
GASTROINTESTINAL INFECTIONS result from the ingestion of pathogens that cause infections at the level of this tract, generally being transmitted by food, water and hands contaminated by microorganisms such as E. coli, Salmonella, Shigella, Vibrio cholerae, Campylobacter, Staphylococcus, Rotavirus among others that are generally contained in feces, thus configuring a FECAL-ORAL type of transmission.
Among the factors that lead to the occurrence of gastrointestinal infections are the hygienic and sanitary deficiencies that characterize our markets and other places where raw or cooked food is sold, poor environmental sanitation in communities, deficiencies in water treatment (or in the process of its plumbing), risky hygienic-sanitary habits (not washing hands after major and/or minor needs), among others.
These are generally consequences (signs and symptoms) resulting from gastrointestinal infections: diarrhea, vomiting, fever and malaise, among others.
The treatment consists of replacing lost liquids and electrolytes (drinking drinking water and other recommended liquids, including consumption of juicy fruits such as papayas, apples, pears, among others that contain water in their composition).
To prevent this, it is necessary to promote health education, improve the hygienic-sanitary conditions of markets and communities in general as a way of promoting, preserving and prolonging PUBLIC HEALTH.
Gastritis and Gastric Health
Gastric Health is one of the most relevant concerns in human health, with gastrointestinal infections being among the main illnesses that affect humans.
Among gastric problems, we have GASTRITIS AND GASTRIC ULCERS as the main public health problems. Gastritis and gastric ulcers normally result from inflammation and corrosion of the walls of the stomach (gastric mucosa) and are generally associated (caused) by the bacterium Helicobacter pylor, which, according to the literature, this bacterium settles on these walls (of the stomach) and starts to release urease that ends up altering the normal pH of the stomach (acid), which leads to inflammation and corrosion of the mucous membranes and consequent gastritis or ulcers, respectively.
In addition to bacterial infections, gastritis and gastric ulcers are associated with several factors, with emphasis on prolonged fasting, chemical substances including drugs, alcohol, foods with strong seasonings including chilli, which ends up causing inflammation of the stomach walls and/or corrosion. of the same, resulting in the appearance of wounds and consequent gastritis or ulcers, respectively.
Among patients with gastritis and/or ulcers, one of the dilemmas is associated with the foods to consume in order to minimize the sensation of pain and discomfort.
NAVIGATING THE HORIZONS OF TIME LAPSE EMBRYO MONITORING.pdfRahul Sen
Time-lapse embryo monitoring is an advanced imaging technique used in IVF to continuously observe embryo development. It captures high-resolution images at regular intervals, allowing embryologists to select the most viable embryos for transfer based on detailed growth patterns. This technology enhances embryo selection, potentially increasing pregnancy success rates.
Discover the benefits of homeopathic medicine for irregular periods with our guide on 5 common remedies. Learn how these natural treatments can help regulate menstrual cycles and improve overall menstrual health.
Visit Us: https://drdeepikashomeopathy.com/service/irregular-periods-treatment/
3. Fat from the diet and lipids synthesized by the
liver and adipose tissue must be transported
between the various tissues and organs for
utilization and storage.
Lipids are insoluble in water
3Joseph Dut Buol
4. The Plasma Lipoproteins
Lipids Are Transported in the Plasma as
Lipoproteins.
Lipoproteins are spherical macromolecular
complexes of lipids and specific proteins
(apolipoproteins or apoproteins)
4Joseph Dut Buol
5. Surface: polar
Core (centre): non polar
Non-polar lipid core consists of TAG and
cholesteryl ester.
Surface: of amphipathic phospholipid and free
cholesterol & proteins.
The protein part is known as an
apolipoprotein or apoprotein
5Joseph Dut Buol
7. Major Groups of Plasma Lipoproteins
The density of a lipoprotein decreases as the proportion of lipid to protein
increases.
Four major groups of lipoproteins have been identified that are important
physiologically and in clinical diagnosis.
These are:
1. Chylomicrons, derived from intestinal absorption of TAG and other lipids
2. Very low density lipoproteins (VLDL) derived from the liver for the
export of TAG
3. Low-density lipoproteins (LDL) representing a final stage in the
catabolism of VLDL
4. High-density lipoproteins (HDL) involved in cholesterol transport and
also in VLDL and chylomicron metabolism.
TAG is the predominant lipid in chylomicrons and VLDL, whereas
cholesterol is predominant in LDL and phospholipid are the predominant
lipids in HDL.
7Joseph Dut Buol
8. The main apolipoprotein of HDL (α-
lipoprotein) designated A
The main apolipoprotein of LDL (β-
lipoprotein) is apolipoprotein B (B-100) and is
found also in VLDL.
Chylomicrons apoB (B-48)
B-48: synthesis(intestine)
B-100 synthesis(liver)
Apolipoproteins
8Joseph Dut Buol
9. Apo C-I, C-II, and C-III are smaller polypeptides
Freely transferable between different
lipoproteins.
Apo E is found in VLDL, HDL, chylomicrons,
and chylomicron remnants;
9Joseph Dut Buol
10. Funtions of Apolipoproteins:
1. form part of the structure of the lipoprotein
2. enzyme cofactors, eg, C-II for lipoprotein
lipase
3. ligands for interaction with lipoprotein
receptors in tissues, eg, apo B-100 and apo E
for the LDL receptor.
10Joseph Dut Buol
11. Four Major Lipid Classes Are Present in
Lipoproteins
Plasma lipids consist of
1. Triacylglycerols (16%)
2. Phospholipids (30%)
3. Cholesterol (14%)
4. Cholesteryl esters (36%) and
5. Free fatty acids (FFA) (4%)
11Joseph Dut Buol
12. Major Groups of Plasma Lipoproteins
The density of a lipoprotein decreases as the proportion of lipid to protein
increases.
Four major groups of lipoproteins have been identified that are important
physiologically and in clinical diagnosis.
These are:
1. Chylomicrons, derived from intestinal absorption of TAG and other lipids
2. Very low density lipoproteins (VLDL) derived from the liver for the
export of TAG
3. Low-density lipoproteins (LDL) representing a final stage in the
catabolism of VLDL
4. High-density lipoproteins (HDL) involved in cholesterol transport and
also in VLDL and chylomicron metabolism.
TAG is the predominant lipid in chylomicrons and VLDL, whereas
cholesterol is predominant in LDL and phospholipid are the predominant
lipids in HDL.
12Joseph Dut Buol
13. The major components of lipoproteins are triacylglycerols,
cholesterol, cholesterol esters, phospholipids, and proteins. The
protein components (called apoproteins) are designated A, B, C,
and E.
1. Chylomicrons are the least dense of the blood lipoproteins
because they have the most TAG and the least protein.
2. Very-low-density lipoprotein (VLDL) is more dense than
chylomicrons but still has a high content of TAG.
3. Intermediate-density lipoprotein (IDL), which is derived from
VLDL, is denser than VLDL and has less than half the amount of
TAG of VLDL.
4. Low density lipoprotein (LDL) has less TAG than IDL and more
protein and, therefore, is denser than the IDL from which it is
derived. LDL has the highest content of cholesterol and its esters.
5. High-density lipoprotein (HDL) is the densest lipoprotein. It has
the lowest TAG content and the highest protein content of all the
lipoprotein particles.
13Joseph Dut Buol
15. Metabolism of Chylomicrons
Chylomicrons are synthesized in intestinal epithelial cells. Their
TAGs are derived from dietary lipid, and their major apoprotein
(apo) is apo B-48.
Chylomicrons travel through the lymph into the blood. (Step 1) Apo
C-II, the activator of lipoprotein lipase, and apo E are transferred to
nascent chylomicrons from HDL, and mature chylomicrons are
formed. (Step 2)
In peripheral tissues, particularly adipose and muscle, the TAGs are
digested by lipoprotein lipase. As the chylomicron loses TAG, a
chylomicron remnant is formed.
The chylomicron remnants interact with receptors on liver cells and
are taken up by endocytosis.
The contents are degraded by lysosomal enzymes, and the
products (amino acids, fatty acids, glycerol, cholesterol, and
phosphate) are released into the cytosol and reused.
15Joseph Dut Buol
16. Metabolism of VLDL
VLDL is synthesized in the liver, particularly after a
high-carbohydrate meal. It is formed from TAGs that
are packaged with cholesterol, apoproteins
(particularly apo B-100), and phospholipids, and it is
released into the blood.(Step 3)
In peripheral tissues, particularly adipose and muscle,
VLDL TAGs are digested by lipoprotein lipase, and VLDL
is converted to IDL.
IDL returns to the liver, is taken up by endocytosis, and
is degraded by lysosomal enzymes. (Step 4)
IDL can also be further degraded, forming LDL. (Step 5)
16Joseph Dut Buol
17. LDL
LDL reacts with receptors on various cells, is taken up by
endocytosis, and is digested by lysosomal enzymes. (Step 6)
Cholesterol, released from cholesterol esters by a lysosomal
esterase, can be used for the synthesis of cell membranes or for
the synthesis of bile salts in the liver or steroid hormones in
endocrine tissue.
Cholesterol inhibits HMG-CoA reductase (a key enzyme in
cholesterol biosynthesis) and, thus, decreases the rate of
cholesterol synthesis by the cell.
Cholesterol inhibits synthesis of LDL receptors (downregulation)
and, thus, reduces the amount of cholesterol taken up by cells.
Cholesterol activates acyl:cholesterol acyltransferase (ACAT), which
converts cholesterol to cholesterol esters for storage in cells.
17Joseph Dut Buol
20. Metabolism of HDL
HDL is synthesized by the liver and released into
the blood as small, disk-shaped particles.
The major protein of HDL is apo A
Apo C-II, which is transferred by HDL to
chylomicrons and VLDL, serves as an activator of
lipoprotein lipase.
Apo E is also transferred and serves as a
recognition factor for cell surface receptors.
Apo C-II and apo E are transferred back to HDL
after digestion of TAGs of chylomicrons and VLDL.
20Joseph Dut Buol
21. Tangier disease is a disease of cholesterol transport. The first case was
identified in a patient who lived on the island of Tangier and who had
characteristic orange-colored tonsils, a very low HDL level, and an
enlarged liver and spleen. Because of a mutation in a transport protein,
cholesterol cannot properly exit the cell to bind to apo A (forming HDL).
This results in a very low HDL level.
21Joseph Dut Buol
22. Cholesterol, obtained by HDL from cell membranes or
from other lipoproteins, is converted to cholesterol
esters within the HDL particle by the
lecithin:cholesterol acyltransferase (LCAT)[known as
phosphatidylcholine:cholesterol acyltransferase (PCAT)]
reaction, which is activated by apo A-I.
a. A fatty acid from position 2 of lecithin
(phosphatidylcholine), a component of HDL, forms an
ester with the 3-hydroxyl group of cholesterol,
producing lysolecithin and a cholesterol ester.
b. As cholesterol esters accumulate in the core of the
lipoprotein, HDL particles become spheroids.
22Joseph Dut Buol
23. HDL transfers cholesterol esters to other lipoproteins
in exchange for various lipids. Cholesterol ester
transfer protein (CETP) mediates this exchange. VLDL
and other lipoproteins carry the cholesterol esters back
to the liver.
HDL particles and other lipoproteins are taken up by
the liver by endocytosis and hydrolyzed by lysosomal
enzymes.
Cholesterol, released from cholesterol esters, can be
packaged by the liver in VLDL and released into the
blood or converted to bile salts and secreted into the
bile.
23Joseph Dut Buol
24. LCAT deficiency results in an inability to convert cholesterol associated with
HDL to cholesterol esters. Ordinarily, these cholesterol esters would be transferred
to other lipoproteins, which would then be taken up by receptors in the liver.
Therefore, by inducing esterification of cholesterol, LCAT is important for the
continued removal of cholesterol from the periphery. Clinical manifestations
include defects in the kidneys, red blood cells, and the cornea of the eyes.
24Joseph Dut Buol
26. Hyperlipidemias
Disease Description Etiology of Lipid
Disorder
Biochemical Finding
Type I Hyperlipoproteinemia (rare
genetic disorders)
Lipoprotein lipase
deficiency or apo C-II
deficiency
Chylomicrons high
Type IIa Familial hypercholesterolemia
(common autosomal dominant
inheritance)
LDL receptor deficiency Elevated LDL only
Type IIb Familial combined
hyperlipoproteinemia (common
autosomal dominant inheritance
Decreased LDL receptor
and increased Apo B
LDL and VLDL high and
triglycerides < 1000
mg/dL
Type III Familial dysbetalipoproteinemia
(rare)
Apo E defect Increased IDL (a VLDL
remnant)
Type IV Familial hyperlipemia (common) VLDL overproduction along
with decreased clearance
Increased VLDLs
Type V Hypertriglyceridemia with
Chylomicronemia (uncommon)
Increased VLDL production
and decreased lipoprotein
lipase production
Chylomicrons and VLDL
elevated
26Joseph Dut Buol
28. ONE
Which of the following apoproteins is an
activator of lipoprotein lipase?
(A) Apo A
(B) Apo B
(C) Apo C-II
(D) Apo D
(E) Apo E
28Joseph Dut Buol
29. TWO
The major carriers of triacylglycerols are
which of the following?
(A) Chylomicrons and VLDL
(B) IDL and LDL
(C) VLDL and LDL
(D) HDL and LDL
(E) Chylomicrons and LDL
29Joseph Dut Buol
30. THREE
An 8-year-old boy presents with orange-colored tonsils,
a very low HDL level, and an enlarged liver and spleen
and is diagnosed with Tangier disease. Which of the
following statements best describes HDL?
(A) It is produced in skeletal muscle.
(B) It scavenges cholesterol from cell membranes.
(C) Its major protein is apo E.
(D) It is formed when VLDL is digested by lipoprotein
lipase.
(E) It activates ACAT.
30Joseph Dut Buol
31. FOUR
A 25-year-old woman presents with a low red blood
cell count, corneal opacities, and kidney insufficiency.
She is diagnosed with LCAT deficiency. LCAT is involved
in which of the following processes?
(A) Converting cholesterol to cholesterol esters
(B) The transfer of cholesterol esters from HDL to other
lipoproteins
(C) Endocytosis of HDL particles into hepatocytes
(D) Hydrolysis of HDL
(E) Decreased uptake of cholesterol by hepatocytes
31Joseph Dut Buol
32. FIVE
A 55-year-old woman presents with crushing substernal
chest pain and shortness of breath. A coronary artery is
occluded owing to an atherosclerotic plaque, and a high
myocardial infarct is diagnosed. High serum HDL levels are
protective against the development of atherosclerosis
because HDL does which of the following?
(A) Inhibits cholesterol production by the liver
(B) Inhibits HMG-CoA reductase
(C) Increases VLDL production
(D) Increases LDL production
(E) Brings cholesterol esters back to the liver
32Joseph Dut Buol
33. SIX
A 30-year-old man presents with weakness in his right upper and
lower extremities. He is diagnosed with an acute middle cerebral
artery stroke secondary to atherosclerosis. Genetic studies show
that he has familial hypercholesterolemia, type II, a disorder caused
by a deficiency of LDL receptors. Which of the following statements
best describes patients with type II familial hypercholesterolemia?
(A) After LDL binds to the LDL receptor, the LDL is degraded
extracellularly.
(B) The number of LDL receptors on the surface of hepatocytes
increases.
(C) Cholesterol synthesis by hepatocytes increases.
(D) Excessive cholesterol is released by LDL.
(E) The cholesterol level in the serum decreases.
33Joseph Dut Buol
34. SEVEN
A young girl with a history of severe
abdominal pain was taken to her local hospital
at 5 a.m. in severe distress. Blood was drawn,
and the plasma appeared milky, with the
triacylglycerol level in excess of 2,000 mg/dl
(normal = 4–150 mg/dl). The patient was
placed on a diet severely limited in fat, but
supplemented with medium-chain fatty acids.
34Joseph Dut Buol
35. A
Which of the following lipoprotein particles are
most likely responsible for the appearance of the
patient’s plasma?
A. Chylomicrons.
B. Very-low-density lipoproteins.
C. Intermediate-density lipoproteins.
D. Low-density-lipoproteins.
E. High-density-lipoproteins.
35Joseph Dut Buol
36. B
Medium-chain fatty acids are given because they:
A. Are more calorically dense than long-chain fatty acids.
B. Enter directly into the portal blood, and can be
metabolized by the liver.
C. Are activators of lipoprotein lipase.
D. Are more efficiently packed into serum lipoproteins.
E. Can be converted into a variety of gluconeogenic
precursors.
F. Stimulates VLDL production by the liver.
36Joseph Dut Buol