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?

It makes LDL particles stickier Signup and view all the answers

What determines the levels of Lipoprotein A?

Genes Signup and view all the answers

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

To carry triglycerides and cholesterol to the tissues Signup and view all the answers

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

Reduced risk of cardiovascular disease Signup and view all the answers

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

To be removed by the liver or converted into LDL Signup and view all the answers

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

To maintain fluidity and flexibility Signup and view all the answers

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

Regulation of blood sugar levels Signup and view all the answers

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

Rancidity Signup and view all the answers

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

α-linolenic acid Signup and view all the answers

What is the primary cause of oxidative rancidity?

Oxidation of unsaturated fatty acids Signup and view all the answers

Which of the following is a consequence of rancidity?

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

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

Hydrolytic rancidity Signup and view all the answers

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

Sesame seeds Signup and view all the answers

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

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

What is the significance of a high saponification number?

It indicates the presence of short chain fatty acids Signup and view all the answers

What is the unit of measurement for iodine number?

g of iodine absorbed by 100 g of fat or oil Signup and view all the answers

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

To detect the presence of soluble volatile fatty acids Signup and view all the answers

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

It increases Signup and view all the answers

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

Directly proportional Signup and view all the answers

What is the significance of a low iodine number?

It indicates a low degree of unsaturation Signup and view all the answers

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

To determine the average molecular size of the fatty acids Signup and view all the answers

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

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

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

Esters and water Signup and view all the answers

What is the result of acid hydrolysis of esters?

Production of fatty acids and water Signup and view all the answers

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

It is long and uncharged Signup and view all the answers

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

To dissolve oil and dirt particles Signup and view all the answers

What is the purpose of the RM number in butter?

To detect adulteration of butter 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?

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

What type of lipids undergo hydrolysis to produce derived lipids?

Group 1 and group 2 lipids Signup and view all the answers

Which of the following is NOT a function of lipids?

Help in the absorption of proteins Signup and view all the answers

Which vitamin is an example of a derived lipid?

Vitamin D Signup and view all the answers

What is the main function of lipids in cell membranes?

They are a structural component Signup and view all the answers

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

They reduce surface tension Signup and view all the answers

What is the main function of lipoproteins in the body?

They transport lipids Signup and view all the answers

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

Triglycerides 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.