Cholesterol and Lipoproteins Functions
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Questions and Answers

What is the role of triglycerides in the body?

  • To build cells of the nervous system
  • To provide energy to the body when needed (correct)
  • To flush out cholesterol from the body
  • To produce vitamin D and hormones
  • What is the function of High-Density Lipoprotein (HDL)?

  • To carry cholesterol back to the liver to be flushed out of the body (correct)
  • To increase the risk of cardiovascular disease
  • To build plaque buildup in blood vessels
  • To carry cholesterol that accumulates as plaque inside blood vessels
  • What is the result of plaque buildup in blood vessels?

  • Cardiovascular disease
  • Atherosclerosis (correct)
  • Heart attacks and stroke
  • All of the above
  • What is the role of Apolipoprotein A in LDL particles?

    <p>It makes LDL particles stickier</p> Signup and view all the answers

    What determines the levels of Lipoprotein A?

    <p>Genes</p> Signup and view all the answers

    What is the function of Very Low-Density Lipoproteins (VLDLs)?

    <p>To carry triglycerides and cholesterol to the tissues</p> Signup and view all the answers

    What is the result of high levels of HDL in the blood?

    <p>Reduced risk of cardiovascular disease</p> Signup and view all the answers

    What is the function of Intermediate-Density Lipoproteins (IDLs)?

    <p>To be removed by the liver or converted into LDL</p> Signup and view all the answers

    What is the primary function of essential fatty acids in the membrane structure?

    <p>To maintain fluidity and flexibility</p> Signup and view all the answers

    Which of the following is NOT a function of essential fatty acids?

    <p>Regulation of blood sugar levels</p> Signup and view all the answers

    What is the term used to describe the deterioration of fats and oils resulting in an unpleasant taste?

    <p>Rancidity</p> Signup and view all the answers

    Which of the following fatty acids is an omega-3 fatty acid?

    <p>α-linolenic acid</p> Signup and view all the answers

    What is the primary cause of oxidative rancidity?

    <p>Oxidation of unsaturated fatty acids</p> Signup and view all the answers

    Which of the following is a consequence of rancidity?

    <p>Formation of unpleasant products such as dicarboxylic acids, aldehydes, ketones</p> Signup and view all the answers

    What is the term used to describe the process of partial hydrolysis of triacylglycerols by bacterial enzymes?

    <p>Hydrolytic rancidity</p> Signup and view all the answers

    Which of the following is a common source of linoleic acid?

    <p>Sesame seeds</p> Signup and view all the answers

    What is the purpose of determining the acid number of an oil or fat?

    <p>To check for the presence of free fatty acids and ensure safety for human consumption</p> Signup and view all the answers

    What is the significance of a high saponification number?

    <p>It indicates the presence of short chain fatty acids</p> Signup and view all the answers

    What is the unit of measurement for iodine number?

    <p>g of iodine absorbed by 100 g of fat or oil</p> Signup and view all the answers

    What is the purpose of determining the Reichert-Meissl (RM) number?

    <p>To detect the presence of soluble volatile fatty acids</p> Signup and view all the answers

    What happens to the acid number of an oil or fat when it is contaminated or decomposed?

    <p>It increases</p> Signup and view all the answers

    What is the relationship between iodine number and the degree of unsaturation?

    <p>Directly proportional</p> Signup and view all the answers

    What is the significance of a low iodine number?

    <p>It indicates a low degree of unsaturation</p> Signup and view all the answers

    What is the purpose of determining the saponification number of an oil or fat?

    <p>To determine the average molecular size of the fatty acids</p> Signup and view all the answers

    What is the primary reason why the RM number is useful in testing the purity of butter?

    <p>Because it contains a high concentration of volatile fatty acids</p> Signup and view all the answers

    What is the product of the reaction between fatty acids and alcohols?

    <p>Esters and water</p> Signup and view all the answers

    What is the result of acid hydrolysis of esters?

    <p>Production of fatty acids and water</p> Signup and view all the answers

    What is the characteristic of the hydrocarbon tail of a soap molecule?

    <p>It is long and uncharged</p> Signup and view all the answers

    What is the function of the micelles formed by soap molecules?

    <p>To dissolve oil and dirt particles</p> Signup and view all the answers

    What is the purpose of the RM number in butter?

    <p>To detect adulteration of butter</p> Signup and view all the answers

    What is a common consequence for individuals who inherit gene changes that make them more prone to high levels of lipoprotein A?

    <p>They have a higher risk of heart disease at a younger age.</p> Signup and view all the answers

    What type of lipids undergo hydrolysis to produce derived lipids?

    <p>Group 1 and group 2 lipids</p> Signup and view all the answers

    Which of the following is NOT a function of lipids?

    <p>Help in the absorption of proteins</p> Signup and view all the answers

    Which vitamin is an example of a derived lipid?

    <p>Vitamin D</p> Signup and view all the answers

    What is the main function of lipids in cell membranes?

    <p>They are a structural component</p> Signup and view all the answers

    Which of the following is a function of lipids in the improvement of taste and palatability?

    <p>They reduce surface tension</p> Signup and view all the answers

    What is the main function of lipoproteins in the body?

    <p>They transport lipids</p> Signup and view all the answers

    Which of the following is NOT a precursor of steroid hormones?

    <p>Triglycerides</p> Signup and view all the answers

    Study Notes

    Cholesterol and Lipids

    • Cholesterol helps the body produce vitamin D and hormones, including estrogen, testosterone, and cortisol.
    • It also helps build cells of the nervous system.
    • Triglycerides are produced by the liver and intestines and are stored in fat cells, released into the bloodstream when the body needs energy.

    Types of Lipoproteins and Functions

    • High-density lipoprotein (HDL) is the "good" cholesterol, carrying cholesterol back to the liver to be flushed out of the body.
    • High levels of HDL reduce the risk of cardiovascular disease.
    • Low-density lipoprotein (LDL) is the "bad" cholesterol, increasing the risk of coronary artery disease, heart attacks, and stroke.
    • LDL carries cholesterol that accumulates as plaque inside blood vessels, leading to atherosclerosis.
    • Very low-density lipoproteins (VLDL) are also bad cholesterol, carrying triglycerides and cholesterol to tissues.
    • Intermediate-density lipoproteins (IDL) are produced when VLDLs give up their fatty acids, then either removed by the liver or converted into LDL.
    • Chylomicrons are large particles that transport triglycerides.
    • Apolipoprotein A (Apo(a)) is a type of LDL that makes particles stickier, increasing the risk of cardiovascular problems.

    Derived Lipids

    • Derived lipids are obtained through the hydrolysis of group 1 and 2 lipids, possessing characteristics of lipids.
    • Examples include vitamin A, fatty acids, and steroids.

    Functions of Lipids

    • Lipids serve as a storage form of energy.
    • They help in the absorption of fat-soluble vitamins.
    • Lipids are a structural component of cell membranes.
    • They act as thermal insulators, protecting internal organs.
    • Lipids also act as electric insulators in neurons.

    Essential Fatty Acids (EFAs)

    • EFAs are required for membrane structure and function.
    • They are necessary for the transport of cholesterol.
    • EFAs are involved in the formation of lipoproteins.
    • They prevent fatty liver disease.
    • EFAs are also needed for the synthesis of eicosanoids.

    Rancidity

    • Rancidity is the deterioration of fats and oils, resulting in an unpleasant taste.
    • Fats containing unsaturated fatty acids are more susceptible to rancidity.
    • Rancidity occurs when fats and oils are exposed to air, moisture, light, and bacteria.
    • Hydrolytic rancidity occurs due to partial hydrolysis of triacylglycerols by bacterial enzymes.
    • Oxidative rancidity is due to oxidation of unsaturated fatty acids.

    Test for Purity of Fats and Oils

    • Acid number is the number of milligrams of potassium hydroxide required to completely neutralize the free fatty acids present in 1 g of the oil or fat.
    • Saponification number is the number of milligrams of potassium hydroxide required to hydrolyze one gram of fat or oil.
    • Iodine number is the number of grams of iodine absorbed by 100 g of fat or oil, indicating the degree of unsaturation.
    • Reichert-Meissl (RM) number is the number of ml of 0.1 N potassium hydroxide required to completely neutralize the soluble volatile fatty acids distilled from 5 g of fat.

    Chemical Reactions of Fatty Acids

    • Esterification: reacts fatty acids with alcohols to form esters and water.
    • Fatty Acid Hydrolysis: reverses esterification, producing fatty acids from esters.
    • Saponification: base-catalyzed hydrolysis of an ester, producing an alcohol and a soap.

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    Description

    Learn about the role of cholesterol in producing vitamin D and hormones, and the different types of lipoproteins and their functions in the body.

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