The Chemical Level of Organization

What is matter? It is anything that takes up space and has mass (weight). Types Solids – definite shape and volume Liquids – definite volume Gases – no definite shape and volume Changes Physical changes – do not change the basic nature of a substance (ice melting) Chemical changes – change the composition of a substance (food digestion)

What is the composition of matter? Elements – unique substance that cannot be broken down into simpler substances (112 in existence) Four Common Elements (96% of body) Carbon Oxygen Hydrogen Nitrogen

What is an atom? It is the building block of elements shown by one or two letters found on a periodic table Structure Protons – positively charged Electrons – negatively charged Neutrons – no charge

Atomic Vocabulary Molecules – two or more atoms that combine chemically (H2O) Compound – two or more different atoms bind together to form a molecule (CH4) Chemical reactions – when atoms unite chemically forming chemical bonds

What are chemical bonds? It is an energy relationship that involves interactions between the electrons of the reacting atoms. The valence shell or outer energy level is involved in this bonding. First energy shell – holds 2 electrons Second energy shell – holds 8 electrons Third energy shell – holds 8 electrons

What are two types of chemical bonds? Ionic bond – when electrons are completely transferred from one atom to another. This forms two oppositely charged ions (+ and -) NaCl – sodium chloride (table salt) Na = (11p+,12n0,11e-) Cl = (17p+,18n0,17e-)

Type of chemical bond 2. Covalent bond – sharing of electrons between atoms CH4 (methane), H2 (hydrogen gas), Cl2 (chlorine gas)

What is energy? It is the ability to do work or to put matter into motion. Types Kinetic energy – actually doing work (moving objects) Potential energy – inactive or stored energy (batteries)

What are the energy forms? Chemical energy – stored in chemical substances Electrical energy – movement of charged particles Mechanical energy – moving matter Radiant energy – travels in waves

What are inorganic compounds? Compounds that lack carbon Three Types: Water – most abundant compound in body and universal solvent Salts (electrolytes) – nerve transmission, muscle contraction, blood clotting and metabolism Acids – proton donors (H+) Bases – proton acceptors (OH-)

What is pH? It is the concentration of hydrogen and hydroxide ions in various body fluids. The scale runs from 0 to 14. pH below 7 = acidic pH above 7 = basic or alkaline pH at 7 = neutral

pH scale

What are organic compounds? Carbon-containing compounds Contains the four elements – carbon, hydrogen, oxygen, and nitrogen (CHON) Major Types: Carbohydrates Lipids Proteins Nucleic acids

What are carbohydrates? Sugars and starches Contain carbon, hydrogen, and oxygen Classification: Monosaccharides – simple or one sugar (glucose) b) Disaccharides – double sugars (sucrose, lactose, maltose) c) Polysaccharides – long branching sugars ( starch and glycogen)

What are lipids? Neutral fats or triglycerides (glycerol and three fatty acid chains) – most abundant source of energy Phospholipids – found in cell membrane Steroids (cholesterol) – found in cell membrane

What are proteins? 50% of organic matter in body Building blocks are amino acids (20) Classification: Fibrous proteins or structural proteins (collagen and keratin) Globular proteins or functional proteins (enzymes, hemoglobin, and hormones)

What are nucleic acids Building block is nucleotide Nitrogenous base Sugar (ribose or deoxyribose) Phosphate group Deoxyribonucleic acid (DNA) – genetic material of the cell nucleus Ribonucleic acid (RNA) – directs protein synthesis

Nucleic Acid Diagrams nucleotide DNA structure

What are enzymes? Functional proteins that act as biological catalysts Increase rate of chemical reaction End with the suffix (ase)

What is ATP? Adenosine triphosphate Chemical energy for all body cells Structure: Adenine base Ribose sugar Three phosphate groups