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Concepts in Biochemistry
Chapter 2
Wendy Herndon, BIS, RDH, CDA
Introduction
Dental professionals need to have a basic understanding of biochemistry
It is the foundation for understanding and applying the concepts of nutrition
What is Biochemistry?
It is the study of life at the molecular level
A molecule is:
The smallest particle of a substance that retains all the properties of the substance
A biomolecule is
Any molecule that is produced by a living cell or organism
https://www.youtube.com/watch?v=YO244P1e9QM
Metabolism involves
Production and use of energy which can come from dietary carbs, proteins, and lipids
Bioinformation involves
The transfer of biological information from DNA to RNA to protein which carries out all of the processes of life
DNA is deoxyribonucleic acid
RNA is Ribonucleic acid
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Fundamentals
Atoms are:
Made of three tiny particles called:
Protons
Neutrons
Electrons
An atom itself is made up of three tiny kinds of particles called subatomic particles: protons, neutrons, and electrons. The protons and the neutrons make up the center of the atom called the nucleus and the electrons fly around above the nucleus in a small cloud. All matter is made up of atoms.
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Fundamentals
Molecules are:
A group of atoms bonded together
An example is when two atoms of hydrogen bond with one atom of oxygen, it forms a water molecule
A molecule is a group of atoms bonded together
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Fundamentals
The mass of the human body is made of atoms which form molecules (groups of atoms)
Molecules form cells (made up of billions of molecules)
Cells form tissues
Tissues form organs
Organs work together to form systems
Systems form organisms such as a human
Atomic Bonds Ionic
Ionic bonds form between a positively charged metal and a negatively charged non-metal
An example of an ionic bond is the hydroxyapatite in enamel which is composed of ionic bonds between calcium and phosphate
Atomic Bonds Covalent
-A covalent bond occurs when two non-metal atoms equally share electrons
-An example of this would be when nitrogen and oxygen bond together to form nitrous oxide
-Laughing gas
Carbon Element
Carbon is the fourth most abundant element in the universe and is the building block of life on earth
Cells are made of many complex molecules called macromolecules
These include proteins, nucleic acids (RNA and DNA), carbohydrates, and lipids
The carbon atom has unique properties that allow it to form covalent bonds to as many as four different atoms, making this versatile element ideal to serve as the basic structural component, or “backbone,” of the macromolecules (many complex molecules)
Main Biomolecules in Nutrition (any molecule formed by a living cell or organism)
The four major biomolecules are:
Carbohydrates
Lipids
Proteins
Nucleic acids
These biomolecules are characterized by the type of polymer or monomer they contain and by their function
A polymer is a large molecule containing repeating units known as monomers
A monomer is the smallest repeating unit in the polymer
Carbohydrate Structure and Function
Carbs Provide Your Body With Energy. One of the primary functions of carbohydrates is to provide your body with energy. Most of the carbohydrates in the foods you eat are digested and broken down into glucose before entering the bloodstream
Glucose is a simple sugar which is an important energy source in living organisms and is a component of many carbohydrates
Glucose is a monosaccharide
Monosaccharides, also called simple sugar, are the simplest form of sugar and the most basic units of carbohydrates
Carbohydrates Classified
Monosaccharides
Simplest sugar that cannot be hydrolyzed (broken down) to give a simpler sugar
Disaccharide
Any of a class of sugars whose molecules contain two monosaccharides that are joined together
Polysaccharide
Consist of a number of sugar molecules (monosaccharides) bonded together.
Glycogen
A polysaccharide which forms glucose on hydrolysis
Hydrolysis is the chemical breakdown of a compound
It is important for the storage of energy in animals
Glycogen is mainly stored in the liver and the muscles and provides the body with a readily available source of energy if blood glucose levels decrease
Proteins
Proteins are essential for almost every physiologic (normal) function
They are composed of amino acids
Amino acids are organic compounds that combine to form proteins
Amino acids and proteins are the building blocks of life
Proteins
When proteins are digested or broken down, amino acids are left. The human body uses amino acids to make proteins to help the body:
Break down food
Grow
Repair body tissue
Perform many other body functions
Proteins Polypeptides
Polypeptides are chains of amino acids
Amino acids are linked covalently (non-metal to non-metal atoms bond sharing electrons) by peptide bonds
Remember; proteins are composed of amino acids
Enzymes
Enzymes begin the process of digesting a substance and are produced by a living organism which acts as a catalyst:
Proteases break down proteins
Amylases break down carbohydrates
Lipases break down lipids
Co-Enzymes
Many enzymes need help completing their biochemical reaction
They are non-protein substances that assist enzymes
Many vitamins are converted into these important coenzymes
Vitamins
Vitamins are compounds that are required in the diet, either because the organism cannot synthesize them, or because the rate of usage by the organism typically exceeds the rate of synthesis by the body
Vitamins are generally classed as either water soluble or fat soluble
The water soluble vitamins generally act as precursors (a substance from which another is formed) to coenzymes (B complex, Folic acid, vitamin C)
The fat soluble vitamins have a variety of roles; Vitamin K is the only one that acts as a classical coenzyme
Nucleic Acids
Nucleic acids store and transfer genetic information
DNA (deoxyribonucleic acid)
The hereditary material in humans and almost all other organisms
RNA
Present in all living cells
Act as a messenger carrying instructions from DNA for controlling the synthesis of proteins
The genome contains all the information needed for complete development of a an organism
The genome of an organism is the whole of its hereditary information encoded in its DNA
The genome is the complete set of genes or genetic material present in a cell or organism.
Nutrigenomics
Nutrigenomics is the scientific study of the interaction of nutrition and genes
Eventually this may lead to diets that are personalized based on genetic makeup
This may help to prevent or treat disease
Lipids
A lipid is a type of organic (derived from living matter)molecule found in living things
It is oily or waxy
Fats are made from lipid molecules
Lipids act as hormones that regulate body systems
They do not readily combine with water (hydrophobic)
Fatty Acids
Fatty acids are the building blocks of the fat in our bodies and in the food we eat
During digestion, the body breaks down fats into fatty acids, which can then be absorbed into the blood
Fatty acid molecules are usually joined together in groups of three, forming a molecule called a triglyceride
Fats are made of long chains of carbon atoms
Fatty Acids (FA'S)
Fatty acids can be classified:
Saturated (animal fat products)
Long chains of single carbon atoms
Most harmful
Unsaturated (avocado, nuts, and soybean, canola, and olive oils)
At least one double bond between the carbon atoms
Monosaturated (plant based oils)
One double bond and the rest are single bonds of carbon atoms
These are the best
Polyunsaturated (nuts, seeds, fish, seed oils, and oysters)
Two or more double bonds
Triglycerides
Triglycerides are the storage forms of Fatty Acids
Triglycerides are the main constituents of natural fats and oils, and high concentrations in the blood indicate an elevated risk of stroke
Triglycerides are stored in adipose tissue or fat
Fat cushions or insulates the body
Hydrogenation
Hydrogenation is a process of adding an additional hydrogen molecules to form a saturated fat (FA)
Creates solid unhealthy fats
Partial hydrogenation can be used to create a liquid or semi-soft fat product such as:
Spreadable margarine
Solid shortening
Steroids
Steroids are lipids
Cholesterol is the most abundant steroid and is important for stabilizing biological membranes
It is found in most body tissues
It is synthesized in the body
It is also the precursor for the hormones:
Progesterone
Estradiol
Testosterone
Bile acids
Lipid soluble vitamin D
To Summarize
Metabolism is how cells acquire, transform, and store energy
This includes the coordination, regulation, and energy requirements needed for metabolism
Protein is broken down into amino acids
Carbohydrates are broken down into monosaccharides
Lipids are broken down into glycerol and fatty acids
Carbohydrate Metabolism
Digestion begins in the mouth
Amylase enzymes hydrolyze polysaccharides into monosaccharides
Monosaccharides enter into the bloodstream and are transported to the tissues that need energy
Excessive amounts of glucose is store as glycogen in the liver and muscles
When blood glucose (sugar) levels decrease and the body needs energy; glycogen is converted to glucose
Carbohydrate Metabolism
Three hormones regulate carbohydrate metabolism:
Insulin
Secreted when blood glucose is high; lowers blood glucose levels
Glucagon
Signal of the starved state
Secreted when blood sugar levels are low
Epinephrine
Fight or flight
Secreted for immediate energy needs
Protein Metabolism
It is an energy source of last resort
The use of amino acids for energy
Ketogenic amino acids
Converted to ketone bodies to be used for fuel
Glucogenic amino acids
Can be converted to glucose to fuel the body
Essential amino acids must be obtained in the diet because humans cannot synthesize all 20 essential amino acids
Lipid Metabolism
Can be oxidized to produce more energy than carbohydrates or proteins
Lipids can be stored in fat in unlimited amounts
When blood glucose is low and glycogen storage in the liver and muscle is depleted, the use of triglycerides stored in the fat tissue is activated which yields free fatty acids and glycerol for energy