Biochemistry

There are several definitions of biochemistry in this first paragraph:

The study of the chemistry of living systems.

The study of the structure, organization, and interaction of the substances within living matter.

The study of the chemical processes in health and disease.

The study of all the chemical processes that occur in living organisms.

Biochemistry

Biochemistry can also be known as:

Biological chemistry.

Physiological chemistry.

Carbohydrates

The carbohydrates are defined as derivatives of polyhydric alcohols containing an aldehyde or a ketone group.

They can also be defined as the result of the oxidation of polyhydroxy alcohols.

Carbohydrates

As a class of compounds we often identify the carbohydrates with sugars, starches, cellulose, and glycogen.

Carbohydrates

Carbohydrates are often named using the suffix “-OSE”.

Those carbohydrates containing an aldehyde functional group are called aldoses. Those with a ketone group are called ketoses.

Carbohydrates

Carbohydrates are composed of only 3 elements:

Carbon.

Hydrogen.

Oxygen.

Monosaccharides

Carbohydrates can range from relatively simple compounds to those which are quite complex.

Monosaccharides

The simplest of the carbohydrates of the simple sugars we call monosaccharides.

Monosaccharides

The simple sugars may have from 3 to 7 carbons in their structure. Because the number of carbons is important they may be grouped according to this number.

3 carbons – triose.

4 carbons – tetrose.

5 carbons – pentose.

6 carbons – hexose.

Monosaccharides

The monosaccharides of greatest significant to the body are the hexose monosaccharides. They have the molecular formula C6H12O6.

Monosaccharides

Hexose monosaccharides are an excellent source of energy for the body providing about 4 calories per gram.

Glucose, fructose, and galactose are the ones we will discuss.

Glucose

Glucose is an aldose which has several alternate names:

Dextrose.

Grape sugar.

Blood sugar.

Glucose

Its importance to the body is its presence in the blood.

Fructose

Fructose is a ketose. It is the sweetest of the sugars, almost twice as sweet as table sugar.

Fructose is also known as:

Levulose.

Fruit sugar.

Fructose

Honey is about 80% fructose and glucose and the remainder is water and a few other ingredients. This gives you an idea of why honey is as sweet as it is.

Galactose

Galactose is another aldose important to the body because it is found in the makeup of the brain and nerve tissue.

It is derived from lactose (milk sugar).

Disaccharides

Disaccharides are carbohydrates containing two saccharide groups.

Disaccharides derived from the hexose monosaccharides will all have the molecular formula C12H22O11.

This is basically the equivalent of dehydrating between two monosaccharides.

Disaccharides

You can derive the molecular formula by adding the formulas for two monosaccharides and then subtracting the formula for a water molecule.

Disaccharides

The disaccharides which contain the hexose monosaccharides discussed above are sucrose, maltose, and lactose.

Sucrose

Sucrose is table sugar (cane sugar).

It is formed from the dehydration between a molecule of glucose and a molecule of fructose.

Sucrose may be hydrolyzed to yield glucose and fructose.

Maltose

Maltose is malt sugar.

It is formed by dehydrating between two glucose molecules.

Maltose may be hydrolyzed to yield two molecules of glucose.

Lactose

Lactose is milk sugar.

It is formed by dehydrating between a molecule of glucose and a molecule of galactose.

Lactose may be hydrolyzed to yield glucose and galactose.

Polysaccharides

Polysaccharides are complex sugars which will have many saccharide groups.

Polysaccharides

The polysaccharides include starches, cellulose, and glycogen.

They may be hydrolyzed repeatedly to eventually yield monosaccharides.

A monosaccharide not be further hydrolyzed.

Starches

Starches occur in plants such as tubers and grains.

Starches are the most important polysaccharides to humans.

Complete hydrolysis of a starch yields monosaccharides.

Glycogen

Glycogen occurs as a stored polysaccharide in the liver of humans and other animals.

The buildup of glycogen is important because this is how our bodies store sugar for later use.

Cellulose

Cellulose occurs in the makeup of many plants.

It is not digestible by the human digestive tract so it serves only as a bulking agent in our diets.

If you are not getting enough fiber, you are not getting enough cellulose.

Reactions of Carbohydrates

The hydrolytic products of carbohydrates are ultimately the monosaccharides.

Hydrolysis refers to the splitting apart by the addition of water.

Reactions of Carbohydrates

One should note that merely adding water would not hydrolyze most sugars, each reaction requires the addition of the appropriate enzyme.

Hydrolysis of Carbohydrates

The oxidation of carbohydrates would ultimately yield carbon dioxide and water.

Oxidation of carbohydrates is also referred to as animal metabolism of carbohydrates.

Hydrolysis of Carbohydrates

This process is the body’s chief source of energy. It is the opposite of the photosynthesis reaction that occurs in plants.

Photosynthesis

Photosynthesis is the process by which plants convert carbon dioxide, water, and solar energy into carbohydrates and oxygen while in the presence of the catalyst, chlorophyll.

Obviously it is the exact opposite of oxidation of simple sugars.

Fermentation of Carbohydrates

Fermentation has several definitions:

The anaerobic breakdown of organic compounds (carbohydrates) by microorganisms into simpler products, releasing carbon dioxide.

The oxidative decomposition of complex substances (carbohydrates) through the action of enzymes, produced by microorganisms.

In the embalming textbook, this definition is simplified down to the breakdown of carbohydrates by anaerobic bacteria.

Fermentation of Carbohydrates

This is the reaction often associated with the fermentation of glucose in the presence of the enzyme mixture, zymase, which is found in yeast to produce ethanol.

Fermentation is the foundation of all bad decisions and the phrase "hold my beer.”

Lipids

Lipids are substances able to yield fatty acids when hydrolyzed.

They are made with alcohol combined with a fatty acid.

Lipids

Technically, lipids are types of esters.

The name “lipid” comes from a Greek word which means “fat”.

The word “fat” refers to only a certain class of lipid rather than all of them.

Lipids

All lipids must have the same elements present as in a carbohydrate but also have other elements which may be present such as nitrogen and phosphorus.

Lipids

As a group, the lipids are very different. One of the few similarities the lipids have in common is that they are generally insoluble in water but they are soluble in organic solvents such as:

Some alcohols.

Some ethers.

Acetone.

Benzene.

Chloroform.

Carbon tetrachloride.

Lipids

A simple lipid is an ester of fatty acids.

Fats and oils are simple lipids which once hydrolyzed will yield fatty acid(s) and glycerol.

Fats and Oils

Fats and oils can be described as glyceryl esters of fatty acids or esters of glycerol and fatty acids, sometimes just called glycerides.

Fats and Oils

Recall that an ester is derived from an alcohol and organic acid. Each molecule of a fat or an oil may be hydrolyzed to yield a single glycerin and up to 3 fatty acids.

There are 2 major categories: simple glycerides and mixed glycerides.

Types of Glycerides

Glycerides in which all the fatty acids are the same are called simple glycerides.

Those glycerides containing more than one type of fatty acid are called mixed glycerides.

Types of Glycerides

Those glycerides containing only one molecule of fatty acid are called monoglycerides (monoacylglycerols).

2 molecules equals diglycerides, 3 molecules; triglycerides.

Fats and Oils

The distinction between a fat or an oil is determined by the characteristics of the fatty acid(s) they contain.

Fats and Oils

If the fatty acids are saturated than the glyceride is a fat.

Fats generally tend to be solid at room temperatures.

Fats and Oils

If the fatty acids are unsaturated, then the glyceride is an oil.

Oils tend to be liquids at room temperatures.

Fats and Oils

Tristearin (stearin) is an example of a fat:

It contains the fatty acid stearic acid which has a relatively high molecular weight and is saturated.

Both stearic acid and palmitic acid are saturated acids.

Fats and Oils

Oils containing the unsaturated fatty acids, oleic acid or linoleic acid, would be liquid at room temperatures.

Fats and Oils

The more unsaturated the fatty acid, the lower the molecules melting point which causes many to be liquids at room temperature.

Fatty acids go by the general formula RX-COOH.

If the RX is saturated than the lipid is a fat and will be a solid.

If the RX is unsaturated than the lipid is an oil and will be a liquid.

Fats and Oils

Fats are very important to the human body. They are superior to carbohydrates as a source of energy in that they yield 9 calories per gram of fat as compared to 4 calories per gram of carbohydrate.

Fats and Oils

The body is able to store fats in unlimited quantities. Fats serve to prevent dehydration of body cells as well as to insulate the body in terms of heat retention and even serve to cushion certain body organs.

Fats and Oils

The oxidation of a fat or an oil results in the end products carbon dioxide, water, and a release of energy.

When hydrolyzed, a fat or an oil results in the end products glycerol and fatty acids.

Saponification

Saponification is defined as the alkaline hydrolysis of a fat or an oil to produce a soap and a glycerol (glycerine).

The alkaline substance used may be a base such as lye (NaOH).

When sodium hydroxide is used the end products are glycerine and lye soap.

Saponification

Grave wax, also known as adipocere, is a result of the saponification of fatty acids and the dead human body by alkaline substances in the water or the earth surrounding the grave.

Saponification

Grave wax is usually associated with the body that has been immersed in water for period of time or is buried in a damp grave. The appearance of grave wax is not very frequent due to the use of protective caskets and vaults.

Saponification

A soap is defined as the substance besides glycerol produced when saponification of a fat or oil occurs.

The anion of the base has become a part of what would have been the fatty acid to form the soap. Soaps are very important because they are used to make emulsions.

Saponification

An emulsion is a mixture of two liquids which do not ordinarily mix such as water and oil to which you add a soap which causes them to mix.

This is the reason why we wash with soaps because the soap isolates the individual particles of oil on the surface of the skin containing dirt and allows these particles to be removed by mechanically washing the surface of the skin.

Saponification

Emulsification refers to the process of creating an emulsion by adding a soap. In the digestive tract of the human body bile serves as an emulsifier to allow absorption of the fats in our diet.

Waxes

Waxes are lipids that are esters of fatty acids and high molecular weight alcohols, other than glycerol.

Waxes

The more common waxes are:

Beeswax.

Lanolin.

Spermaceti.

Carnauba wax.

Waxes

Lanolin and spermaceti are significant to cosmetologists because they are used in creams, lotions, and cosmetics.

Do not confuse paraffin with true waxes; paraffin does not contain an ester.

Mixed or Compound Lipids

A mixed or compound lipid is one which when hydrolyzed will yield fatty acids, and alcohol, and some other compound.

Phospholipids and glycolipids, two important compounds found in the tissues of the brain, are in this category.

References:

The following Textbook References were used to create this presentation:

Funeral Service Chemistry by Professional Trade Schools

Embalming: Theory, History, and Practice by Robert G. Mayer (5th Edition).

Charts were taken from the textbook unless otherwise indicated

Pictures and art used in this presentation have the reference and location stored in the graphic. Please hover the mouse over the image to find where it was obtained.