BIOCHEMISTRY (2)

Question 1

OXIDATION

Answer 1

Oxidation of a fat or oil results in the end products carbon dioxide, water and energy.
This reaction takes place readily in the human body and is accompanied by the liberation of considerable energy.
When one gram of fat is oxidized it yields nine (9) Calories of energy, roughly 3500 calories per pound.
On the flip side of this, you need to burn roughly 3500 calories to lose one pound of fat.
Fats yield almost twice as much energy by their oxidation than carbohydrates do.

Question 2

EMULSIFICATION

Answer 2

The mixing two insoluble (immiscible) liquids.
We utilize this process every time we wash greasy dirty hands.
Emulsification is a physical property because the chemical composition of the fat or oil was not changed, only the size of the particles.

Question 3

EMULSIFYING AGENT

Answer 3

a third substance was required in order to create the emulsions of oil and water or digestive fats.
Soap is an emulsifying agent, and in our body it is bile that serves as the emulsifier.

Question 4

HYDROLYSIS

Answer 4

Hydrolysis of either a fat or oil (triglyceride) will yield glycerol and fatty acids

Question 5

SAPONIFICATION

Answer 5

The process of boiling fats or oils with an aqueous alkali resulting in the products glycerol and metallic (alkali) salts of fatty acids.
Lipid + alkali →
soap + Glycerol

Question 6

Grave Wax / Adipocere

Answer 6

A white waxy material produced by the saponification of body fat (fatty acids) by alkaline substances in the water or earth surrounding the grave

Question 7

COMPOUND LIPIDS

Answer 7

Compound lipids are esters of fatty acids containing some characteristic group in addition to the alcohol and the fatty acid.

Question 8

DERIVED LIPIDS

Answer 8

Derived lipids are compounds derived from simple and compound lipids on hydrolysis, such as fatty acids, glycerol, other alcohols, terpenes and steroids.

Question 9

TERPENES

Answer 9

another subcategory of lipids.
Many terpenes are hydrocarbons, but oxygen-containing compounds such as alcohols, (e.g., menthol from peppermint oil), aldehydes (e.g., citronella), or ketones (terpenoids) can also be found.
Terpenes are a large group of compounds made up of repeating isoprene (C5H8) units. Terpenes represent the oldest group of small molecular products.
Next to methane it is the most common volatile organic compound,
Terpenes represent the oldest group of small molecular products synthesized by plants and are probably the most widespread group of natural products.

Question 10

STEROIDS

Answer 10

Steroids are one type of lipid that you have probably heard of.   
As an important class of lipids, the steroids are actually metabolic derivatives of terpenes, but they are customarily treated as a separate group.      
Steroids are built of simple three carbon terpene units called isoprene units.    
Steroids are widely distributed in animals, where they are associated with a number of physiological processes

Question 11

Cholesterol

Answer 11

Cholesterol is the best known and most abundant of the steroids in the body.
Cholesterol is formed in brain tissue, nerve tissue, the liver and the blood stream.
Cholesterol serves some important positive functions in the body.
It is associated with cell membranes and their proper functioning.
It serves as a precursor to other steroids and Vitamin D
It is the major compound found in gallstones and the bile salts that are used in digesting fat.

Question 12

Hormones

Answer 12

Steroids are probably most familiar from their role as the male and female sex hormones.
The primary male hormone, testosterone is synthesized from cholesterol in the testes.
Two female sex hormones, estrogen (synthesized from testosterone), along with progesterone regulate the menstrual cycle therefore they are used in birth control pills.

Question 13

Cortisol

Answer 13

another hormone, has the function of increasing glucose and glycogen concentrations in the body.
The reactions occur in the liver by taking fatty acids from lipid storage cells and amino acids from body proteins to make glucose and glycogen.
In addition, cortisol and its ketone derivative, cortisone, have an anti-inflammatory effect.

Question 14

PROTEINS

Answer 14

Proteins are the most important biochemical compounds
Proteins are composed of the elements Carbon, Hydrogen, Oxygen, and Nitrogen. All four elements must be present to form a protein.
An amino acid is the structural unit or building block of a protein which contains one Amine Group (NH2) and one Carboxyl Group (COOH).

Question 15

GLYCINE

Answer 15

The smallest identifiable protein molecule is a single amino acid molecule called Glycine which consists of a molecule of methyl amine chemically joined to a carboxylic acid molecule.

Question 16

AMPHOTERIC

Answer 16

Property type of an Amino Acid - An amphoteric compound is one that can act as both an acid and a base in solution.
An amino acid is amphoteric because of its structure. Look at the structure of Glycine below and see that it has a base (amine) side and an acid (carboxyl) side.

Question 17

BUFFERS

Answer 17

Because amino acids are amphoteric they act as buffers in solution.
Buffers are substances that when placed in solution are capable of neutralizing, within limits, both acids and bases. Neutralizing helps solutions maintain their original or constant pH.
Buffers protect a solution against changes in pH.
Since proteins are polymers of amino acids, proteins are also buffers.

Question 18

PEPTIDE BOND

Answer 18

The peptide bond occurs between the carboxyl atom of one amino acid and the amine nitrogen of another.

Question 19

PEPTIDE LINKAGE

Answer 19

Peptide Linkage occurs between the amine group (NH2) of one amino acid and the carboxyl group (COOH) of another. Water is formed for each linkage that takes place.

Question 20

IMBIBITION

Answer 20

Imbibition is the swelling and softening of tissues as a result of absorbing moisture (a identifying property of protein).
Through the process of imbibition the body is able to prevent dehydration of the tissues even when excessive heat is present such as with high fevers or hot weather.

Question 21

COAGULATION

Answer 21

Coagulation is the process of converting soluble protein to insoluble protein by heating or by contact with a chemical. Examples of chemicals that would convert soluble proteins into insoluble protein are alcohols or aldehydes.

Question 22

HYDROLYSIS (property of Protein)

Answer 22

Hydrolysis is the reverse reaction of forming a protein. You are adding water that was removed in peptide linkage back into the protein molecule breaking the peptide bond and resulting in two amino acids.
The final products of the hydrolysis of proteins are amino acids.

Question 23

DEAMINATION

Answer 23

Deamination is the removal of the amine group (NH2) from a compound (protein or amino acid) with the resulting products being ammonia and an organic acid.
Amino acid → ammonia + carboxylic acid
If extensive putrefaction has occurred before embalming, there will be a higher than normal formaldehyde demand due to the production of ammonia because ammonia neutralizes formaldehyde and produces urotropin which will make preserving the body more difficult.

Question 24

DECARBOXYLATION

Answer 24

Decarboxylation is the removal of the carboxyl group (COOH) from the amino acid or protein resulting in the products carbon dioxide, water and an amine.
Which amine results depends on the original protein or amino acid. The amines may then be further broken down into ammonia and various hydrocarbons.
The formula for decarboxylation is shown below:
Amino acid → carbon dioxide + water + amine + hydrocarbons

Question 25

ENZYMES

Answer 25

Enzymes are proteins that function as organic catalysts. A catalyst decreases the activation or threshold energy of a chemical reaction. The threshold or activation energy is the minimum energy that is necessary for a specific reaction to occur. A major role of proteins is their activity as enzymes in the cell. Enzymes are produced by all living organisms. The activity of enzymes occurs chiefly in living organisms but is not limited to living organisms.
Enzyme activity is responsible for decomposition through autolysis.

Question 26

Protein constitution of Enzymes

Answer 26

Enzymes possess physical and chemical properties similar to proteins. Enzymes are protein catalysts. One significant difference, however, is that proteins are crystalloidal in nature and therefore are capable of passing through a semi-permeable membrane, whereas enzymes are colloidal and therefore cannot pass through semi-permeable membranes.

Question 27

Explain Enzyme Specificity

Answer 27

Enzymes are specific in their action.
In reactions involving enzymes, the molecules at the beginning of the process are called substrates, and the enzyme converts these into different molecules, the products. Therefore, the substance upon which an enzyme acts is called a substrate.
Each enzyme acts on a single SUBSTRATE and the shape of the enzyme must be complementary to that of its substrate so they may interact. An enzymes can only take part in reactions in which the substrate it works with is present.

Question 28

Inhibitors

Answer 28

Enzyme activity can be affected by other molecules. Inhibitors are molecules that decrease enzyme activity; Many drugs and poisons are enzyme inhibitors.

Question 29

Activators

Answer 29

Enzyme activity can be affected by other molecules activators are molecules that increase activity.

Question 30

Thermally labile

Answer 30

Enzymes are labile. A substance that is labile readily undergoes change or breakdown and changes quickly.
Enzymes require favorable temperatures for their activity. They have an optimum temperature of 38°C, which is pretty close to normal body temperature of 37°C.
Above 50°C their activity diminishes rapidly.
Between 60 - 70°C enzymes will stop working and begin to coagulate.
A temperature between 70 - 80°C will irreversibly destroy the enzymes because heat denatures proteins.
…a cold environment does not destroy enzymes, it only retards their activity.

Question 31

Chemically labile

Answer 31

The optimum pH for most enzymes is 7.2 – 7.4. This is very close to physiological pH which is 7.35 – 7.45.
Because of this labile property, enzymes do not cease their action upon the death of the organism which created them.
If there is no more substrate to act upon the enzyme will act upon the tissue which created it. This is called autolysis.

It is essential that the exoenzymes of the digestive system and the endoenzymes of the body cells be neutralized after death to minimize the damage caused by autolysis. The cavities of the torso and the arterial system must be injected with a formaldehyde based fluid to neutralize these enzymes because the formaldehyde fluid has an affinity for nitrogen containing protein and protein derivatives like enzymes.

Question 32

NAMING AN ENZYME

Answer 32

There are two ways to name an enzyme.

1. By the Substrate: names of many enzymes end in the suffix – ase. Change the suffix of the name of the substrate to “ASE” to get the name of the enzyme. Therefore the enzyme that digests lactose is lactase.
2. By their Reaction: Using this method of naming is almost the same as above however instead of the using the substrate’s name you use the type of reaction in which the enzyme participates to get the enzyme’s name.
   If an enzyme hydrolyzes something it is named Hydrolase.
   If an enzyme takes part in oxidation it is named Oxidase.