Anatomy & Physiology - The Chemical Basis of Life

HUMAN ANATOMY AND PHYSIOLOGY LECTURE • CHAPTER 2 - THE CHEMICAL BASIS OF LIFE • • • • • • • • • • • • • • • • • • • COMPOSITION OF MATTER Matter - anything that occupies space and has mass (solid, liquid, or gas) Mass - amount of matter in an object Weight - gravitational force acting on object Element o simplest form of matter o Ex. C, H, O, N, Ca, K, Na, Cl Atom o smallest particle of an element o contains protons, electrons, and neutrons o Proton - + charge, inside nucleus o Electron - - charge, outside nucleus o Neutron - neutral, inside nucleus Atomic Number - number of protons in each atom Mass Number - number of proton and neutrons in each atom CHEMICAL BONDS occurs when outermost electrons are transferred or shared between atoms Ionic bonding - attraction between two oppositely charged ions; Ex. NaCl o Ion - charged particle; Ex. Na+ Covalent bonding - atoms share one or more pairs of electrons; Ex. Hydrogen molecule Polar covalent bonds - Unequal sharing of electrons; Ex. Water (H2O) Polar molecules - asymmetrical electrical charge Nonpolar molecules - symmetrical electrical charge Hydrogen bonds o Polar molecules have a positive end and a negative end o Hydrogen bond forms when positive end of one polar molecule is weakly attracted to negative end of another polar molecule o Weaker bond than ionic or covalent Molecule - 2 or more atoms chemically combine; Ex. Water (H2O) Compound - chemical combination of 2 or more different types of atoms; Ex. NaCl CHEMICAL REACTIONS formation or breaking of chemical bonds Reactants - what is put into reaction Products - end result of reaction A+B → C+D Reactants Product TYPES OF CHEMICAL REACTIONS • Synthesis reaction o build a new molecule o energy-requiring o Ex. ADP + P → ATP • • • • • • • • • • • • • • • Decomposition reaction: o break down molecule o energy-releasing o Ex. ATP → ADP + P Exchange reaction: o combination of synthesis and decomposition reactions o Ex. AB + CD → AC + BD o Ex. HCl + NaOH → NaCl + H2O Enzymes - proteins that speed up reactions ENERGY ability to do work Kinetic energy - energy in motion Potential energy - stored energy Chemical energy - energy stored in chemical bonds (food) Glucose: o sugar found in food o glucose is used to make ATP (energy) o Major metabolic fuel; best fuel for energy Glycogen: o stored glucose o stored in liver, skeletal muscle, and fat ATP o adenosine triphosphate o stored energy o When ATP is broken down (ATP → ADP + P) energy is released. Acids: o donate H+ (proton) o pH below 7 o Ex. HCl (hydrochloric acid) Bases: o accept H+ (proton) o pH above 7 o Ex. NaOH (sodium hydroxide) Neutral - pH of 7 Inorganic Chemistry o substances that do not contain carbon or hydrogen; Ex. O2 and CO2 ORGANIC CHEMISTRY Metabolism o Sum total of lung processes o Catabolism – break down protein; uses peptidase o Anabolism – build-up proteins o Neutralization rxn – H2O + NaCl o Glycolysis – breaks down to Carbohydrates o Hydration of carbon o Contain C, H, O o H:O is a 2:1 ratio o Ex. C6H12O6 o • • Monosaccharides are the building blocks. ▪ 3 important saccharides • Sugar - sucrose; glucose + fructose • Lactose - milk; glucose + galactose • Maltose - grains; glucose + glucose • Glycosylic bond – the bond that produce a saccharide ▪ Monosaccharide: • simple sugar (1 sugar) • Ex. Glucose and fructose ▪ Disaccharide: • 2 sugars • Ex. Glucose + fructose = sucrose • Ex. Glucose + galactose=lactose ▪ Polysaccharide: • many sugars • Starch, grain, vegetables, glycogen o Functions: ▪ Short-term energy storage ▪ Converted to glucose quickly ▪ Glucose is used to make ATP (energy) ▪ Brain cells require glucose Proteins o Contains C, H, O, N o Amino acids are the building blocks. o 20 different amino acids o Amino acids ▪ contain an amine (NH2) group and carboxyl group ▪ aren’t stored so a daily supply is required ▪ can be divided into essential and nonessential o Functions: ▪ Used to make skin, hair, nails, muscles ▪ Hemoglobin ▪ Act as enzymes ▪ Immune system functions ▪ Muscle contractions (actin and myosin) ▪ Part of cell membrane Lipids o Contain C, H, O o No 2:1 ratio of H:O o Insoluble in water o Ex. Fats, oils, cholesterol, triglycerides, phospholipids o Glycerol and fatty acids are the building blocks. o Fatty Acids ▪ Long chain of monocarboxylic acid ▪ Made with even number of carbon atoms o Glycerol – trihydric alcohol o Functions: ▪ Long term energy storage ▪ Insulates against heat loss ▪ Protective cushion for organs ▪ Cholesterol is part of the cell membrane structure o o • Saturated - single covalent bonds between carbon atoms; Beef, port, whole milk, cheese, eggs Unsaturated - one or more double covalent bonds between carbons; Ex. Olive oil, fish oil, sunflower oil ▪ Monounsaturated - one double bond ▪ Polyunsaturated - two or more double bond ▪ Omega 3 - location of double bond Nucleic Acids o Composed of C, H, O, N, P o Ex. DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) o Nucleoside - n-base + sugar o Nucleotides ▪ building blocks ▪ composed of nitrogen base, phosphate, and 5 carbon sugar ▪ Nitrogen base • PyOUT (Pyrimidine, Cytosine, Thyronine) • PuGA (Purine, Guanine, Adenine) ▪ Sugar • D – deoxyribose; pentose • R – ribose; pentose o DNA ▪ Polynucleotide – joined by polymerized phosphodiester bond ▪ Base pairing – composed of phosphodiester bond, glycosidic bond, and hydrogen bond