Ch. 2 Part 2 The Chemical Level of Organization

Inorganic vs. Organic Inorganic – Usually lack carbon – Structurally simple – Include: Water Salts Acids Bases – Exceptions Carbon dioxide (CO 2 ) Bicarbonate (HCO 3 - ) Carbonic acid (H 2 CO 3 ) Organic – Always contain carbon – Usually contain hydrogen – Always have covalent bonds – Most are large molecules made up of long chains

Role of Water in the Body Most important inorganic compound for life Almost all chemical reactions in the body need water to occur Water is a solvent – dissolves important substances Water has high heat capacity – doesn’t change temperatures easily Water also acts as a lubricant (mucus) for joints, food movement, and between thoracic organs

Acids and Bases This is also a review pH scale – 0-14 Acids (0-6) – Dissociate into hydrogen (H + ) ions – Example: HCl Bases (0-14) – Dissociate into hydroxide (OH - ) ions – Example: NaOH

Acids and Bases in the Body Buffer system – the body’s ability to control pH of certain fluids Example: – Blood should have a pH of – If the pH of blood gets to high or too low, serious complications can occur – A buffer system can help correct a pH imbalance Does this by converting strong acids or bases into weak acids or bases

Organic Compounds of the Body Organic compounds contain carbon Organized into various structures – Macromolecules – large molecules – Polymers – built by putting together repeating monomers

Organic Compounds in the Body In order to make a macromolecule – Dehydration synthesis must occur – Removing a water molecule, bind to monomers together – XOH + YOH → XOY + H 2 O In order to break a macromolecule – Hydrolysis must occur – Adding a water molecule, break to monomers apart – XOY + H 2 O → XOH + YOH

4 Major Groups of Organic Compounds Carbohydrates Lipids Proteins Nucleic Acids

Carbohydrates Include: sugars, glycogen, starches, cellulose Examples in our diet – Bread, pasta, rice, cereal Function as a source of chemical energy (quick energy) Made of carbon, hydrogen, and oxygen 3 major groups – Monosaccharides – Disaccharides – polysaccharides

Carbohydrates Monosaccharides – one sugar (sweet) – Glucose, fructose, galactose Disaccharides – two sugars (sweet) – Sucrose, lactose, maltose Polysaccharides – many sugars (not sweet) – Glycogen, starch, cellulose

Lipids Include: triglycerides, phospholipids, steroids Examples in our diet: – Fats, oils Function as a source of energy storage Made of carbon, hydrogen, and oxygen Are hydrophobic – do not dissolve in water Lipids are made of repeating fatty acids

Lipids Triglycerides – Saturated fats – only single covalent bonds – Monounsaturated fats – one double bond – Polyunsaturated fats – more than one double bond Phospholipids – Important part of cell membrane Steroids – Important part of cell membrane, not all steroids are anabolic

Proteins Include: proteins and enzymes Examples in our diet: – Meat, fish, eggs, milk Function as catalysts, protect against invaders, hormones, cell transport, building blocks of body Made of carbon, hydrogen, oxygen, nitrogen, sulfur Proteins are made of repeating amino acids

Proteins 20 different amino acids Amino acids are joined by peptide bonds to create polypeptide chains Enzymes – Speed up chemical reactions within the body

Nucleic Acids Include: DNA and RNA Examples in our diet: – none – but we eat the building blocks (amino acids) Function as inherited genetic material Made of carbon, hydrogen, oxygen, nitrogen, and phosphorous Made of repeating chains of nucleotides

Nucleic Acids Nucleotides have 3 parts – Sugar – Phosphate – Nitrogenous base

ATP Adenosine triphosphate ATP is not one of the 4 major groups of organic molecules ATP is essential to life – energy source