Body Chemistry

Elements in the body:

Each electron shell accommodates a certain number of electrons the number of electrons in the outer shell determines the property of each element

Molecular Bonds

Molecules are combinations of two or more atoms

·        Covalent bonds connect atoms thru sharing of electrons

o        Non-polar bonds – electrons are shared equally

o        Polar bonds – electrons are not shared equally

o        Carbon is a critical component of biomolecules and is capable of forming four covalent bonds

·        Hydrogen bonds connect atoms thru attraction between a hydrogen ion and a negatively charged site

·        Ionic bonds connect atoms thru electrical attraction after one atom loses one or more electrons

 

Water

·        The solvent property of water is due to the presence of polar molecules that lead to hydrogen bonds and that disrupt ionic bonds of solutes

 

• Substances that dissolve in water are Hydroplilic
• Substances that do not dissolve in water are Hydrophobic

 

·        The fluidity of water is due to the hydrogen bonds that hold water together

Acids, Bases and Salts

• Acid - a solute that dissociates and releases H⁺
• Base - a solute that dissociates and releases OH^-
• Salt - compound created by reaction of an acid and a base

Electrolytes in the body:

Common Ions:

 

BioMolecules

contain carbon, hydrogen and usually oxygen

Carbohydrates

• usually contain the ratio of 1C:2H:1O
• generally are polar, hydrophilic and dissolve in water

Lipids

• usually contain the ratio of ~1C:~2H:<1O
• generally are non-polar, hydrophobic, and do not dissolve in water
• some lipids contain O₂ and/or HPO₄ that create polar regions; both hydrophobic and hydrophilic (amphipathic)

Proteins

• chains of amino acids each containing H, and amino group (NH2), a carboxyl group (COOH), and a variable group (R)
• may be polar or non-polar
• peptides, polypeptides, proteins - two to a hundred or more amino acids bonded together

nucleosides

• composed of two subunits, ribose or deoxyribose attached to a nitrogenous base.

 

Carbohydrates

usually contain the ratio of 1C:2H:1O

·        Monosaccharides - simple sugars with 3 to 7 carbon atoms

• Glucose, Fructose, Galactose; Ribose, Deoxyribose

• Disaccharides - two simple sugars covalently bonded

• Sucrose, Maltose, Lactose

• Polysaccharides - more than two simple sugars covalently bonded

• Starch, Glycogen, Cellulose

• linked by dehydration synthesis (removal of water)
• broken down by hydrolysis (addition of water)

Lipids

usually contain the ratio of ~1C:~2H:<1O

·        Fatty Acids - long chain of carbons with hydrogen attached and a carboxyl group (-COOH)

·        Glycerol - a chain of three carbons that can attach to fatty acids

·        Glycerides

• Monoglyceride, Diglycerides and Triglycerides - Glycerol with one, two or three fatty acids

• Phospholipids

• Phosphatidyl Inositol. Phosphatidylcholine

• Eicosanoids - two fatty acids connected by a carbon ring

• Prostaglandins, Thromboxanes, Prostacylins, Leukotrienes

• Steroids and Cholesterol - based on 4 rings of carbons

• Glucocorticoids, Mineralocorticoids, Androgens, Estrogens

 

Proteins

Contain amino groups (NH₂)

• chains of amino acids each containing H, and amino group (NH₂), a carboxyl group (COOH), and a variable group (R)
• peptides, polypeptides, proteins - two to a hundred or more amino acids bonded together

Nucleosides and Nucleotides

nucleoside - composed of two subunits, ribose or deoxyribose attached to a nitrogenous base.

nucleotide - comprised of 3 subunits, ribose or deoxyribose attached to both a nitrogenous base and a mono-, di-, or triphosphate group

Nitrogenous Bases

• Pyrimidines

o       Cytosine, Thymine, Uracil

• Purines

o       Adenine, Guanine

RNA Nucleoside Triphosphates

·        nitrogenous base attached to Ribose and three phosphate groups

o       RNA Adenine Nucleoside Triphosphate

(also referred to as Adenosine Triphosphate, ATP)

o       RNA Guanine Nucleoside Triphosphate

(also referred to as Guanosine Triphosphate, GTP)

o       RNA Cytosine Nucleoside Triphosphate

(also referred to as Cytidine Triphosphate, CTP)

o       RNA Uracil Nucleoside Triphosphate

(also referred to as Uridine Triphosphate, UTP)

• High Energy Compounds - nitrogenous base attached to Ribose and one to three phosphate groups

o       ATP, ADP, AMP - Adenine + ribose + 1, 2, or 3 phosphate groups

o       GTP, GDP, GMP - Guanine + ribose + 1, 2, or 3 phosphate groups

 

DNA Nucleoside Triphosphates

·        nitrogenous base attached to Deoxyibose and three phosphate groups

o       DNA Adenine Nucleoside Triphosphate

o       DNA Guanine Nucleoside Triphosphate

o       DNA Cytosine Nucleoside Triphosphate

o       DNA Thymine Nucleoside Triphosphate

(also referred to as Thymidine Triphosphate, TTP)

 

Nucleic Acids

• chains of nucleotides each containing ribose or deoxyribose, a phosphate group, and a nitrogenous base
• RNA – Ribonucleic acid
• DNA – Deoxyribonucleic acid

 

© 2006 David G. Ward, PhD All rights reserved, Last modified 30 August, 2006