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Questions and Answers
Questions and Answers
What is the primary function of lipids in living cells?
What is the primary function of lipids in living cells?
- Structural component of cell membranes
- Cell signaling
- Energy storage for excess calories (correct)
- Protein synthesis
What is the characteristic of fatty acids in plasma?
What is the characteristic of fatty acids in plasma?
- Non-covalently bound to albumin (correct)
- Covalently bound to albumin
- Bound to other proteins
- Free fatty acids
What is a precursor to steroid hormones?
What is a precursor to steroid hormones?
- Carbohydrates
- Proteins
- Lipids (correct)
- Nucleic acids
What is the characteristic of the bonds in lipids?
What is the characteristic of the bonds in lipids?
What are some of the biomolecules that lipids can be converted to?
What are some of the biomolecules that lipids can be converted to?
What is the typical carbon atom count of short-chain fatty acids?
What is the typical carbon atom count of short-chain fatty acids?
What type of fatty acid has a carbon atom count of more than 12?
What type of fatty acid has a carbon atom count of more than 12?
Which type of fatty acid is bound to albumin?
Which type of fatty acid is bound to albumin?
What is a characteristic of esterified fatty acids?
What is a characteristic of esterified fatty acids?
What is the main difference between medium-chain and long-chain fatty acids?
What is the main difference between medium-chain and long-chain fatty acids?
What type of fatty acid has no double bonds?
What type of fatty acid has no double bonds?
How many fatty acids are attached to a molecule of glycerol in a triglyceride?
How many fatty acids are attached to a molecule of glycerol in a triglyceride?
What is the characteristic of triglycerides in terms of their charge?
What is the characteristic of triglycerides in terms of their charge?
What type of bond holds the fatty acids to the glycerol molecule in a triglyceride?
What type of bond holds the fatty acids to the glycerol molecule in a triglyceride?
What is the characteristic of triglycerides in terms of their solubility in water?
What is the characteristic of triglycerides in terms of their solubility in water?
What is the number of fatty acids attached to a molecule of glycerol in a phospholipid?
What is the number of fatty acids attached to a molecule of glycerol in a phospholipid?
What is the characteristic of the head and tails of phospholipids?
What is the characteristic of the head and tails of phospholipids?
What is the structure of cholesterol?
What is the structure of cholesterol?
What is the characteristic of phospholipids and cholesterol?
What is the characteristic of phospholipids and cholesterol?
What is the location of the phospholipid head group?
What is the location of the phospholipid head group?
Synthesized from acetyl co-A
Synthesized from acetyl co-A
What is the range of size of lipoproteins?
What is the range of size of lipoproteins?
What is the composition of lipoproteins?
What is the composition of lipoproteins?
What is the term for unesterified cholesterol?
What is the term for unesterified cholesterol?
What is the term for esterified cholesterol?
What is the term for esterified cholesterol?
What shape are lipoproteins typically?
What shape are lipoproteins typically?
What is the main apoprotein found on the surface of chylomicrons?
What is the main apoprotein found on the surface of chylomicrons?
What percentage of chylomicrons are composed of triglycerides?
What percentage of chylomicrons are composed of triglycerides?
What is the characteristic of chylomicrons when plasma is stored overnight?
What is the characteristic of chylomicrons when plasma is stored overnight?
What is the percentage of phospholipid in chylomicrons?
What is the percentage of phospholipid in chylomicrons?
What is the function of chylomicrons in the body?
What is the function of chylomicrons in the body?
What percentage of triglycerides are present in VLDL molecules?
What percentage of triglycerides are present in VLDL molecules?
Which apolipoprotein is mainly present on the surface of VLDL molecules?
Which apolipoprotein is mainly present on the surface of VLDL molecules?
Where are VLDL molecules secreted into the blood from?
Where are VLDL molecules secreted into the blood from?
What percentage of phospholipid is present in VLDL molecules?
What percentage of phospholipid is present in VLDL molecules?
What is the purpose of VLDL molecules in normal lipid metabolism?
What is the purpose of VLDL molecules in normal lipid metabolism?
What percentage of triglycerides are present in IDL molecules?
What percentage of triglycerides are present in IDL molecules?
What is the main apolipoprotein present on the surface of IDL molecules?
What is the main apolipoprotein present on the surface of IDL molecules?
What is the percentage of cholesterol in IDL molecules?
What is the percentage of cholesterol in IDL molecules?
What is the percentage of phospholipid in IDL molecules?
What is the percentage of phospholipid in IDL molecules?
What is formed from IDL molecules after modification in the liver?
What is formed from IDL molecules after modification in the liver?
What percentage of LDL is composed of cholesterol?
What percentage of LDL is composed of cholesterol?
What is the main function of LDL in the body?
What is the main function of LDL in the body?
What is the composition of LDL?
What is the composition of LDL?
What is present on the surface of LDL molecules?
What is present on the surface of LDL molecules?
What is the consequence of elevated levels of LDL in the body?
What is the consequence of elevated levels of LDL in the body?
What is the primary site of HDL synthesis?
What is the primary site of HDL synthesis?
What is the main apoprotein present on the surface of HDL molecules?
What is the main apoprotein present on the surface of HDL molecules?
What is the percentage of cholesterol in HDL molecules?
What is the percentage of cholesterol in HDL molecules?
What is HDL composed of?
What is HDL composed of?
What are HDL molecules formed from?
What are HDL molecules formed from?
What is Lp(a) primarily composed of?
What is Lp(a) primarily composed of?
What is associated with elevated levels of Lp(a)?
What is associated with elevated levels of Lp(a)?
What is the significance of Lp(a) in the body?
What is the significance of Lp(a) in the body?
What apolipoprotein is present in Lp(a)?
What apolipoprotein is present in Lp(a)?
What is the composition of Lp(a) lipoprotein?
What is the composition of Lp(a) lipoprotein?
What are the two main pathways involved in lipoprotein physiology and metabolism?
What are the two main pathways involved in lipoprotein physiology and metabolism?
What is the role of lipase, lipoprotein lipase, epinephrine, and cortisol in lipid metabolism?
What is the role of lipase, lipoprotein lipase, epinephrine, and cortisol in lipid metabolism?
What is the consequence of abnormal lipid metabolism?
What is the consequence of abnormal lipid metabolism?
What is the purpose of the ATP III Classification?
What is the purpose of the ATP III Classification?
What is the result of recycling glycerol in lipid metabolism?
What is the result of recycling glycerol in lipid metabolism?
What is the relationship between lipid metabolism and coronary heart disease?
What is the relationship between lipid metabolism and coronary heart disease?
What is hypercholesterolemia characterized by?
What is hypercholesterolemia characterized by?
What is combined hyperlipidemia characterized by?
What is combined hyperlipidemia characterized by?
What is hypertriglyceridemia characterized by?
What is hypertriglyceridemia characterized by?
What is hypoproteinemia characterized by?
What is hypoproteinemia characterized by?
Which condition is characterized by high levels of lipoproteins in the blood?
Which condition is characterized by high levels of lipoproteins in the blood?
What is the term for abnormally high levels of lipids in the blood?
What is the term for abnormally high levels of lipids in the blood?
What is the term for the narrowing, blockage, or spasms in a blood vessel?
What is the term for the narrowing, blockage, or spasms in a blood vessel?
What is the deposition of esterified cholesterol in the artery wall known as?
What is the deposition of esterified cholesterol in the artery wall known as?
What is the term for the class of diseases that involve the heart or blood vessels?
What is the term for the class of diseases that involve the heart or blood vessels?
What is the term for a common heart condition where the coronary arteries struggle to send enough blood, oxygen, and nutrients to the heart muscle?
What is the term for a common heart condition where the coronary arteries struggle to send enough blood, oxygen, and nutrients to the heart muscle?
What is the primary cause of elevated cholesterol in Familial Hypercholesterolemia?
What is the primary cause of elevated cholesterol in Familial Hypercholesterolemia?
What is the characteristic of intracellular cholesterol in Familial Hypercholesterolemia?
What is the characteristic of intracellular cholesterol in Familial Hypercholesterolemia?
What is Hypertriglyceridemia a result of?
What is Hypertriglyceridemia a result of?
What is the consequence of elevated levels of LDL in the body?
What is the consequence of elevated levels of LDL in the body?
What is the primary difference between Familial Hypercholesterolemia and Hypertriglyceridemia?
What is the primary difference between Familial Hypercholesterolemia and Hypertriglyceridemia?
What is responsible for the excessive hepatic synthesis of apo B, leading to increased VLDL secretion and LDL production?
What is responsible for the excessive hepatic synthesis of apo B, leading to increased VLDL secretion and LDL production?
What is the result of excessive hepatic synthesis of apo B in Combined Hyperlipoproteinemia?
What is the result of excessive hepatic synthesis of apo B in Combined Hyperlipoproteinemia?
What is the characteristic of Familial dysbetalipoproteinemia?
What is the characteristic of Familial dysbetalipoproteinemia?
What is the result of the accumulation of cholesterol-rich VLDL and chylomicrons remnants in Familial dysbetalipoproteinemia?
What is the result of the accumulation of cholesterol-rich VLDL and chylomicrons remnants in Familial dysbetalipoproteinemia?
What is the underlying cause of Combined Hyperlipoproteinemia?
What is the underlying cause of Combined Hyperlipoproteinemia?
What is characteristic of Lp(a)?
What is characteristic of Lp(a)?
What does apolipoprotein (a) in Lp(a) compete with for binding sites?
What does apolipoprotein (a) in Lp(a) compete with for binding sites?
What is the effect of Lp(a) on plaque formation?
What is the effect of Lp(a) on plaque formation?
What is the consequence of elevated levels of Lp(a)?
What is the consequence of elevated levels of Lp(a)?
What is the role of apolipoprotein (a) in Lp(a)?
What is the role of apolipoprotein (a) in Lp(a)?
What is hypoalphalipoproteinemia characterized by?
What is hypoalphalipoproteinemia characterized by?
What mutations are associated with hypoalphalipoproteinemia?
What mutations are associated with hypoalphalipoproteinemia?
What is Tangier's disease?
What is Tangier's disease?
What is the typical circulating HDL level in hypoalphalipoproteinemia?
What is the typical circulating HDL level in hypoalphalipoproteinemia?
What is the underlying genetic defect in hypoalphalipoproteinemia?
What is the underlying genetic defect in hypoalphalipoproteinemia?
What is the normal reference range for triglycerides in the blood?
What is the normal reference range for triglycerides in the blood?
What is the borderline high for triglyceride reference range?
What is the borderline high for triglyceride reference range?
What is high for triglyceride reference range?
What is high for triglyceride reference range?
What is the very high reference range for triglyceride levels?
What is the very high reference range for triglyceride levels?
What is the optimal reference range for LDL Cholesterol?
What is the optimal reference range for LDL Cholesterol?
What is the near optimal reference range for LDL cholesterol?
What is the near optimal reference range for LDL cholesterol?
What is the borderline high reference range for LDL cholesterol?
What is the borderline high reference range for LDL cholesterol?
What is the high reference range for LDL cholesterol?
What is the high reference range for LDL cholesterol?
What is the very high reference range for LDL cholesterol?
What is the very high reference range for LDL cholesterol?
What is the near protective against heart disease range for HDL cholesterol reference range?
What is the near protective against heart disease range for HDL cholesterol reference range?
What is the higher the better range for HDL cholesterol reference range?
What is the higher the better range for HDL cholesterol reference range?
What is the major risk factor for heart disease range for HDL cholesterol reference range?
What is the major risk factor for heart disease range for HDL cholesterol reference range?
What is the desirable range for total cholesterol reference range?
What is the desirable range for total cholesterol reference range?
What is the borderline high range for total cholesterol in the reference range?
What is the borderline high range for total cholesterol in the reference range?
What is the high range for total cholesterol reference range?
What is the high range for total cholesterol reference range?
Questions and Answers
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Flashcards
Flashcards
Lipids
Lipids
Lipids are organic molecules composed primarily of carbon-hydrogen bonds, serving as energy storage and precursors to various biomolecules like hormones.
Fatty Acids
Fatty Acids
Fatty acids are chains of carbon and hydrogen atoms ending in a carboxyl group (-COOH). In blood, they're often loosely attached to albumin.
Short-Chain Fatty Acids
Short-Chain Fatty Acids
Fatty acids with 4-6 carbon atoms.
Medium-Chain Fatty Acids
Medium-Chain Fatty Acids
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Long-Chain Fatty Acids
Long-Chain Fatty Acids
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Saturated Fatty Acids
Saturated Fatty Acids
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Monounsaturated Fatty Acids
Monounsaturated Fatty Acids
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Polyunsaturated Fatty Acids
Polyunsaturated Fatty Acids
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Triglycerides
Triglycerides
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Phospholipids
Phospholipids
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Cholesterol
Cholesterol
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Chylomicrons
Chylomicrons
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VLDL (Very-Low-Density Lipoprotein)
VLDL (Very-Low-Density Lipoprotein)
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LDL (Low-Density Lipoprotein)
LDL (Low-Density Lipoprotein)
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HDL (High-Density Lipoprotein)
HDL (High-Density Lipoprotein)
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Study Notes
Study Notes
Lipids
- Composed mostly of carbon-hydrogen (C-H) bonds
- Serve as energy storage for excess calories
- Function as precursors for various biomolecules:
- Steroid hormones
- Prostaglandins
- Leukotrienes
- Lipoxins
Fatty Acids
- Chains of carbon-hydrogen bonds terminating with a carboxyl (-COOH) group
- In plasma, mostly non-covalently bound to albumin
Classification of Fatty Acids by Length
- Fatty acids with 4 to 6 carbon atoms are classified as short-chain fatty acids
- Medium-chain fatty acids have 8 to 12 carbon atoms
- Long-chain fatty acids have more than 12 carbon atoms
Classification of Fatty Acids by Bonding
- Unesterified fatty acids are bound to albumin
- Esterified fatty acids are constituents of triglycerides or phospholipids
Classification of Fatty Acids
- Classified according to the number of C=C double bonds present
- Three categories: Saturated, Monounsaturated, and Polyunsaturated
Saturated Fatty Acids
- Have no double bonds
Monounsaturated Fatty Acids
- Contain one double bond
Polyunsaturated Fatty Acids
- Contain 2 or more double bonds
Triglycerides
- Composed of 3 fatty acids attached to 1 molecule of glycerol
- Held together by ester bonds
- No charged groups, making them water insoluble
- Classified as neutral lipids
Phospholipids
- Consist of 2 fatty acids attached to 1 molecule of glycerol
- 3rd position contains phospholipid head groups
- Amphipathic, meaning they have:
- Hydrophobic (water-repelling) tails
- Hydrophilic (water-attracting) heads
Cholesterol
- Unsaturated steroid alcohol
- Composed of 4 rings
- Has a single C-H side chain tail
- Also an amphipathic lipid
Classification of Cholesterol
- Cholesterol exists in two forms: unesterified (free cholesterol) and esterified (cholesteryl ester)
- Cholesteryl ester is a neutral lipid
Lipoprotein Characteristics
- Lipoproteins are typically spherical in shape
- Lipoproteins range in size from 10-1200 nm
- Lipoproteins are composed of two main components: lipids and proteins
Lipoproteins: Chylomicrons
- Chylomicrons are the largest lipoproteins and have the lowest density.
- They are formed in the intestines and transport triglycerides after a meal, giving serum a turbid appearance.
- Due to their low density, chylomicrons will float to the top and form a creamy layer when plasma is stored overnight.
- Composition of chylomicrons:
- 86% triglyceride
- 5% cholesterol
- 7% phospholipid
- 2% apolipoprotein
- Apoproteins present on the surface of chylomicrons:
- Mainly apoprotein B-48
- Lesser amounts of apoproteins A-I, C-I, C-II, and C-III
VLDL Composition and Function
- VLDL (Very Low-Density Lipoprotein) carries endogenous triglycerides synthesized in the liver.
- VLDL molecules consist of:
- 55% triglycerides
- 19% cholesterol
- 18% phospholipid
- 8% apolipoprotein
- VLDLs have the following apolipoproteins on their surface:
- Apolipoprotein B-100 (mainly)
- Apolipoprotein C-I
- Apolipoprotein C-II
- Apolipoprotein C-III
- Apolipoprotein E
- Normal lipid metabolism: VLDLs are secreted into the blood by the liver for metabolism in peripheral tissues.
IDL (Intermediate-Density Lipoprotein)
- A transitional form of lipoprotein formed from VLDL (Very-Low-Density Lipoprotein)
- Modified in the liver to form LDL (Low-Density Lipoprotein)
- Carries endogenous triglycerides and cholesterol esters
- Composed of:
- 23% triglycerides
- 38% cholesterol
- 19% phospholipid
- 19% apolipoprotein
- Surface apolipoproteins include:
- Mainly B-100
- Some E
Low-Density Lipoprotein (LDL)
- LDL is the body's major cholesterol carrier, transporting a large amount of endogenous cholesterol.
- LDL is commonly known as "bad cholesterol" due to its association with increased risk for atherosclerosis when levels are elevated.
- LDLs are composed of:
- 50% cholesterol
- 22% phospholipids
- 6% triglycerides
- 22% protein
- LDLs have apoprotein B-100 on their surface.
High-Density Lipoprotein (HDL)
- Also known as "good cholesterol"
- Synthesized in the intestine and liver cells
- HDL molecules are recycled from chylomicron and VLDL molecules
- Composed of 50% protein, 28% phospholipids, 19% cholesterol, and 3% triglycerides
- Has apoproteins A-I, mainly, and A-II on its surface
Lipoprotein (a) [Lp(a)]
- Primarily composed of cholesterol esters, phospholipids, and apolipoprotein (a) and B-100
- Elevated levels of Lp(a) are associated with increased risk for: • Coronary heart disease • Myocardial infarction • Cerebrovascular disease
Lipoprotein Physiology & Metabolism
- Lipoprotein metabolism involves the transport of lipids in the bloodstream, playing a crucial role in maintaining cellular lipid homeostasis.
Lipid Absorption
- Lipid absorption occurs in the small intestine, where dietary fats are broken down into fatty acids and cholesterol.
- Fatty acids are taken up by enterocytes, re-esterified into triglycerides, and packaged into chylomicrons.
- Chylomicrons are then transported to the lymphatic system, ultimately entering the bloodstream.
Endogenous Pathway
- The endogenous pathway involves the synthesis of lipids in the liver, which are then transported to peripheral tissues.
- The liver produces very-low-density lipoproteins (VLDLs), which are rich in triglycerides.
- VLDLs are converted into low-density lipoproteins (LDLs) in the bloodstream, which are then taken up by peripheral tissues.
Exogenous Pathway
- The exogenous pathway involves the uptake of dietary lipids from the small intestine, which are then transported to the liver.
- Chylomicrons are converted into chylomicron remnants in the bloodstream, which are then taken up by the liver.
Reverse Cholesterol Transport
- Reverse cholesterol transport is a process by which excess cholesterol from peripheral tissues is transported back to the liver for excretion.
- High-density lipoproteins (HDLs) play a crucial role in this process, taking up excess cholesterol from peripheral tissues and transporting it to the liver.
- The liver then excretes the cholesterol into the bile, which is eventually eliminated from the body.
Lipid Metabolism
- Lipid metabolism involves releasing fatty acids to cells for energy, then recycling glycerol into triglycerides.
- Enzymes involved in breaking down triglycerides include lipase, lipoprotein lipase, epinephrine, and cortisol.
Clinical Significance of Lipids
- Abnormal lipid metabolism can be due to genetic defects or can be acquired.
- Abnormal lipid metabolism is associated with an increased risk of coronary heart disease and other disorders.
ATP III Classification
- The National Cholesterol Education Program (NCEP) established the Adult Treatment Panel III Classification (ATP III).
- ATP III sets cutoff values for cholesterol and triglyceride levels based on a 9- to 12-hour fast.
Blood Disorders
- Hypoproteinemia: a condition characterized by very low protein levels in the blood
- Hyperlipoproteinemia: high levels of lipoproteins in the blood
Cholesterol-related Disorders
- Hypercholesterolemia: high cholesterol, characterized by increased levels of cholesterol in the blood
- Hypertriglyceridemia: high amounts of triglycerides in the blood
Combined Lipid Disorder
- Combined hyperlipidemia: elevated levels of fats in the blood, including low-density lipoprotein (LDL) cholesterol ("bad" cholesterol) and triglycerides
Dyslipidemia
- Abnormally high levels of lipids (fats) in the blood
- Typically asymptomatic, but can lead to cardiovascular diseases
- Can cause coronary artery disease, a common heart condition
Coronary Artery Disease
- Occurs when major blood vessels (coronary arteries) struggle to supply enough blood, oxygen, and nutrients to the heart muscle
- A common heart condition that can lead to cardiovascular disease
Peripheral Vascular Disease (PVD)
- A slow and progressive disorder of the blood vessels
- Caused by narrowing, blockage, or spasms in a blood vessel
- A type of cardiovascular disease
Cardiovascular Disease
- A class of diseases involving the heart or blood vessels
- May include conditions such as coronary artery disease, peripheral vascular disease, and arteriosclerosis
Arteriosclerosis
- Characterized by deposition of esterified cholesterol in the artery wall
- A type of cardiovascular disease that can lead to narrowing or blockage of blood vessels
Hypercholesterolemia and Familial Hypercholesterolemia
- Elevated cholesterol levels are associated with increased LDL (Low-Density Lipoprotein) due to genetic abnormalities.
- Despite normal intracellular cholesterol levels, individuals with Familial Hypercholesterolemia have a deficiency in active LDL receptors.
Hypertriglyceridemia
- Characterized by an imbalance between the synthesis and clearance of VLDL (Very-Low-Density Lipoprotein) in the circulation.
- Can be caused by familial or hormonal abnormalities.
Combined Hyperlipoproteinemia
- Characterized by elevated levels of serum total cholesterol and triglycerides
- Caused in part by excessive hepatic synthesis of apo B
- Leads to increased VLDL secretion
- Results in increased LDL production from VLDL
- Can be associated with Familial Dysbetalipoproteinemia
Familial Dysbetalipoproteinemia
- Caused by accumulation of cholesterol-rich VLDL and chylomicrons remnants
Lp(a) and its Impact on Plaque Formation
- Lp(a) is a variant of LDL (low-density lipoprotein) with an additional apolipoprotein (a)
- Apolipoprotein (a) has a high degree of homology with plasminogen, a coagulation factor
- Due to this homology, apo(a) competes with plasminogen for binding sites on fibrin
- This competition leads to increased plaque formation
Hypoalphalipoproteinemia
- Characterized by an isolated decrease in circulating high-density lipoprotein (HDL) cholesterol
- Defined as HDL levels less than 40 mg/dL or 1.0 mmol/L
- Not associated with hypertriglyceridemia
- Can result from mutations in genes involved in HDL metabolism
- Specifically, mutations in LCAT, apo A-I, and ABCA1 transporter genes can cause hypoalphalipoproteinemia
Tangier's Disease
- An extreme form of hypoalphalipoproteinemia
- Caused by mutations in the ABCA1 transporter gene
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