Lipid Chemistry

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Questions and Answers

What is the primary difference between lipids and carbohydrates?

The presence of nitrogen

The presence of oxygen

The level of hydrogen (correct)

The presence of carbon

What percentage of the body's energy requirement is met by lipids?

30% (correct)

40%

50%

20%

What is the function of essential fatty acids in the body?

To build biologically active materials

To protect the body from excessive heat or cold

To provide energy to the body

To reduce inflammation and regulate blood pressure (correct)

What is the role of lipids in the absorption of vitamins?

Lipids are necessary for the absorption of fat-soluble vitamins Signup and view all the answers

Where are lipids primarily stored in animals?

In the subcutaneous tissue Signup and view all the answers

What are the building blocks of lipids?

Fatty acids Signup and view all the answers

What is a fatty acid?

A carboxylic acid with a long aliphatic chain Signup and view all the answers

What is the characteristic of saturated fatty acids?

They are solid at room temperature Signup and view all the answers

What is the characteristic of monounsaturated fatty acids?

They have one carbon-to-carbon double bond Signup and view all the answers

What is the characteristic of polyunsaturated fatty acids?

They have more than one carbon-to-carbon double bond Signup and view all the answers

What is an essential fatty acid?

A fatty acid not manufactured by the body Signup and view all the answers

What is a result of a deficiency of essential fatty acids?

Sterility in adults Signup and view all the answers

What is a source of saturated fatty acids?

Whole milk, cheese, egg yolks, chicken skin, red meat Signup and view all the answers

Which type of lipids is better for human health?

Unsaturated lipids Signup and view all the answers

What is atherosclerosis associated with?

Lipids Signup and view all the answers

What type of lipid is lecithin classified as?

Complex lipid Signup and view all the answers

What is the main storage form of fatty acids and chemical energy?

Triacylglycerol (TAG) Signup and view all the answers

What is the product of hydrolysis of triacylglycerol?

Glycerol and 3 free fatty acids Signup and view all the answers

What is the physical property of triacylglycerol in terms of its solubility in water?

Insoluble in water Signup and view all the answers

What is the characteristic of fats at room temperature?

Solid due to high content of long chain saturated fatty acids Signup and view all the answers

What is the characteristic of oils at room temperature?

Liquid due to high content of unsaturated fatty acids Signup and view all the answers

What is the characteristic of waxes?

Esters of fatty acids and long chain alcohols Signup and view all the answers

What is the main role of phospholipids in biological systems?

To construct biological membranes Signup and view all the answers

What is the function of lung surfactant, which is mainly composed of phospholipids?

To prevent alveolar collapse Signup and view all the answers

What is the structure of sphingomyelins?

Sphingosine + Fatty acid + Phosphate + Choline Signup and view all the answers

Where are glycolipids primarily found?

Cell membrane of RBCs and myelin sheath Signup and view all the answers

What is the composition of lipoproteins?

Central hydrophobic lipid core surrounded by hydrophilic membrane Signup and view all the answers

What is the function of lipoproteins?

To facilitate the transport of dietary lipids Signup and view all the answers

What is the main characteristic of cholesterol?

It is a white waxy compound Signup and view all the answers

What is the main biological function of cholesterol?

To construct biological membranes Signup and view all the answers

What is the main function of dietary fats as a source of energy?

9 Kcal/g Signup and view all the answers

Which of the following fatty acids are found in Mackerel, salmon, and tuna?

Omega-3 fatty acids Signup and view all the answers

What is the process of bad odor and taste development in fats and oils?

Rancidity Signup and view all the answers

What is the main source of phospholipids?

Sunflower Signup and view all the answers

Which of the following is a health benefit of ω3 fatty acids?

Reduce blood triglyceride levels Signup and view all the answers

What is the function of dietary fats in carrying vitamins?

Fat-soluble vitamins A, D, E, and K Signup and view all the answers

Which of the following is a type of complex lipid?

Phospholipids Signup and view all the answers

What is the structure of phospholipids similar to?

Triacylglycerols Signup and view all the answers

Study Notes

Introduction to Lipids

Lipids are a heterogeneous group of organic compounds containing carbon, hydrogen, and oxygen.
They have a higher level of hydrogen than carbohydrates, making them a more energy-rich source for the body.
Lipids are insoluble in water but soluble in organic solvents like ether, chloroform, benzene, and acetone.
The human body requires 30% of its energy from lipids.
Lipids are widely distributed in plants and animals, with sources including nuts, seeds, milk, egg, meat, liver, fish, and nuts.

Biological Significance of Lipids

Lipids serve as fuel in the body and provide energy.
Essential fatty acids (unsaturated) reduce inflammation, help regulate blood pressure, and cannot be manufactured by the body.
Lipids protect the body from excessive heat or cold.
Breakdown products of fats can be used for building biologically active materials like cholesterol.
Lipids are necessary for absorbing fat-soluble vitamins A, D, E, and K.
Lipids act to produce hormones.

Diseases Associated with Lipids

Atherosclerosis
Obesity

Classification of Lipids

Simple Lipids: esters of fatty acids with alcohol
- Triacylglycerol (TAG): a simple lipid consisting of glycerol and three fatty acids, serving as the main storage form of fatty acids and chemical energy.
- Waxes: simple lipids consisting of fatty acid esters of long chain mono-hydroxy alcohols.
Complex Lipids: phospholipids, glycolipids, and derived lipids
- Phospholipids: contain phosphate group
- Glycolipids: contain fatty acid, sphingosine, and carbohydrate
- Derived Lipids: steroids, fatty acids, and fat-soluble vitamins

Fatty Acids

Fatty acids are the major unit of lipids and are carboxylic acids with a long aliphatic chain.
Fatty acids are insoluble in water but soluble in fat solvents like ether, chloroform, benzene, and acetone.
The human body can synthesize saturated fatty acids from carbohydrates.
Classification of fatty acids:
- Saturated fatty acids: usually from animal origin, solid at room temperature, and have no carbon-to-carbon double bonds.
- Unsaturated fatty acids (essential fatty acids): usually from plant origin, liquid at room temperature, and have one or more carbon-to-carbon double bonds.
Nutritional classification of fatty acids:
- Essential fatty acids: not manufactured by the body and must be taken in diet, e.g., linoleic acid and α-linolenic acid.
- Non-essential fatty acids: can be formed in the body in good amounts, mainly from carbohydrates.

Sources of Fatty Acids

Saturated fatty acids: whole milk, cheese, egg yolks, chicken skin, red meat, ice cream, butter, chocolate, coconuts, coconut milk, and coconut oil.
Monounsaturated fatty acids: olives, olive oil, sesame oil, canola oil, peanut oil, cashews, almonds, and avocados.
Polyunsaturated fatty acids: sunflower oil, cotton seed oil, corn, soybean, fish, omega-3 fatty acids (found in Mackerel, salmon, tuna, and cod), and omega-6 fatty acids (found in palm oil, soybean, and sunflower oil).

Functions of Dietary Fats

Concentrated sources of energy
Carriers of fat-soluble vitamins A, D, E, and K
Sources of essential fatty acids
Satiety value
Impart taste and flavor to foods

Chemical Reactions of Fatty Acids

Ester formation
Salt formation
Reduction
Rancidity: development of bad odor and taste due to exposure to high temperature, oxygen, moisture, light, and metals.

Phospholipids

Similar in structure to triacylglycerols, but with a phosphate group instead of a fatty acid.
Sources: sunflower, chicken, eggs, bovine milk.
Examples: lecithin, cephalin, and sphingomyelin.
Importance:
- Required for construction of biological membranes.
- Important constituent of plasma lipoproteins, acting as carriers of triglycerides and cholesterol.
- Form lung surfactant, which prevents alveolar collapse.

Glycolipids

Found mainly in the myelin sheath and cell membrane of RBCs.
Act as cell membrane receptors for hormones and external stimuli, providing recognition properties.

Cholesterol

A white, waxy compound and the most important animal sterol.
Present either free or esterified with fatty acid to form cholesteryl ester.
Widely distributed in all tissues, but with higher concentrations in brain, nerves, liver, skin, and adipose tissue.
Important biological functions:
- One of the important members of membrane lipids.
- Building block for bile salts and steroid hormones.
- Precursor for vitamin D.

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Description

This quiz covers the basics of lipid chemistry, including their biological significance, classification, and diseases associated with them. It also explores specific types of lipids, such as fatty acids, cholesterol, and glycolipids.