Power Point Presentation to Accompany 2010 Delmar Cengage

Power. Point Presentation to Accompany © 2010 Delmar, Cengage Learning

Chapter 2 The Chemistry of Life © 2010 Delmar, Cengage Learning 2

Introduction • Cells, tissues and organs composed of chemicals • Chemical reactions important for function • Chemistry is the study of: – Elements, compounds, chemical reactions, molecular structure © 2010 Delmar, Cengage Learning 3

Atomic Structure © 2010 Delmar, Cengage Learning 4

Atomic Structure (cont’d. ) • Atoms – Smallest particles of elements – Maintain all characteristics of element – Nucleus contains protons and neutrons – Electrons orbit nucleus in shells © 2010 Delmar, Cengage Learning 5

Elements, Isotopes, Compounds © 2010 Delmar, Cengage Learning 6

Elements, Isotopes, Compounds (cont’d. ) • Element: atoms contain same numbers of protons and electrons • Compound: contains two or more elements • Isotope: number of neutrons varies • Periodic table of the elements – Arranges elements by increasing atomic number © 2010 Delmar, Cengage Learning 7

Elements, Isotopes, Compounds (cont’d. ) • Orbital: area where electron is found • Energy levels: grouping of orbitals – Represented as concentric circles surrounding nucleus © 2010 Delmar, Cengage Learning 8

Bonds and Energy © 2010 Delmar, Cengage Learning 9

Bonds and Energy (cont’d. ) • Ionic: one atom gains and one atom loses electrons • Covalent: atoms share electrons • Hydrogen: weak bonds, hold water molecules together • Electron donors vs. acceptors vs. carriers • Bonds are energy containing © 2010 Delmar, Cengage Learning 10

Bonds and Energy (cont’d. ) © 2010 Delmar, Cengage Learning 11

Bonds and Energy (cont’d. ) © 2010 Delmar, Cengage Learning 12

Common Substances in Living Systems © 2010 Delmar, Cengage Learning 13

Water • • • Most abundant substance in cells Universal solvent Transport of materials Absorbs and reduces heat Protects body structures © 2010 Delmar, Cengage Learning 14

Carbon Dioxide • Waste product of cellular respiration • Used in photosynthesis to produce usable energy sources • Must be removed quickly from cells • Carbon in molecules comes from carbon dioxide gas © 2010 Delmar, Cengage Learning 15

Molecular Oxygen • Formed from covalent bond of two oxygen atoms • Required by all organisms that breathe air • Necessary to convert food into ATP • Level in atmosphere is 21% © 2010 Delmar, Cengage Learning 16

Ammonia • By-product of amino acid breakdown – Amino acids are building blocks of proteins – Amino acids contain nitrogen • Converted to urea in the liver © 2010 Delmar, Cengage Learning 17

Mineral Salts • Composed of small ions • Calcium: muscle contraction and strong bones • Phosphate - ATP synthesis • Sodium, potassium, and chloride are necessary for muscle contraction and nervous transmission © 2010 Delmar, Cengage Learning 18

Carbohydrates • 1: 2: 1 ratio of carbon, hydrogen and oxygen • Five- and six-carbon simple sugars are smallest – Five-carbon: deoxyribose and ribose – Six-carbon: glucose and fructose • Functions: energy storage and cell structure © 2010 Delmar, Cengage Learning 19

Lipids • Insoluble in water • 95% of fats in body are triacylglycerols • Saturated fat: fatty acids have single covalent bonds • Unsaturated fat: fatty acids have one or more double covalent bonds • Functions: energy, insulation and protection © 2010 Delmar, Cengage Learning 20

Proteins • Contain carbon, oxygen, hydrogen, nitrogen and sulfur • Amino acids are building blocks of proteins • Functions: energy and structure • Enzymes: protein catalysts for chemical reactions © 2010 Delmar, Cengage Learning 21

Proteins (cont’d. ) • Structure – Primary: amino acid sequence – Secondary: determined by hydrogen bonds – Tertiary: folding caused by interactions within peptide bonds and sulfur atoms – Quaternary: determined by spatial relationships between units © 2010 Delmar, Cengage Learning 22

Nucleic Acids • Deoxyribonucleic acid: genetic material of the cell • Ribonucleic acid: protein synthesis – Messenger RNA – Transfer RNA • Structure – DNA: double helical chain – RNA: single chain © 2010 Delmar, Cengage Learning 23

Nucleic Acids (cont’d. ) • Nucleic acids are made up of chains of nucleotides – Nucleotide: nitrogen base, sugar and phosphate group – Nitrogen bases: purines (two) and pyrimidines (three) © 2010 Delmar, Cengage Learning 24

Adenosine Triphosphate • Fuel for cell function and maintenance • Molecule consists of sugar, adenine, and three phosphates – Energy is stored in the second and third phosphates • Breakdown of glucose provides energy to make ATP © 2010 Delmar, Cengage Learning 25

Movement of Materials Into and Out of Cells © 2010 Delmar, Cengage Learning 26

Introduction • Plasma membrane is selectively permeable – Only selected materials can enter and exit – This is because of chemical structure – Water can enter and exit with ease © 2010 Delmar, Cengage Learning 27

Diffusion • Movement of molecules from area of high concentration to low concentration • Brownian movement: random collision of diffusing molecules • Accelerated by increased temperature • O 2 - CO 2 exchange is an example of diffusion © 2010 Delmar, Cengage Learning 28

Osmosis • Movement of water through semipermeable membrane from high concentration to low concentration – Isotonic solution: salt concentration is the same outside the cell as inside – Hypotonic solution: salt concentration inside cell is higher than outside cell – Hypertonic solution: salt concentration higher outside the cell than inside © 2010 Delmar, Cengage Learning 29

Osmosis (cont’d. ) © 2010 Delmar, Cengage Learning 30

Osmosis (cont’d. ) • Active transport – Used by cells to obtain sugars, amino acids, larger proteins and fats – Needs energy in the form of ATP – Molecules move from areas of low concentration to areas of high concentration © 2010 Delmar, Cengage Learning 31

p. H © 2010 Delmar, Cengage Learning 32

p. H (cont’d. ) • Negative logarithm of hydrogen ion concentration • Acids: p. H values below 7 • Bases: p. H values above 7 • Buffers: help maintain p. H levels © 2010 Delmar, Cengage Learning 33

p. H (cont’d. ) © 2010 Delmar, Cengage Learning 34

Summary • Discussed basic chemical concepts such as bonds and energy and how they apply to living systems • Discussed specific chemical substances and how they are used in living systems • Described three ways that substances move into and out of cells • Introduced p. H and acids/bases © 2010 Delmar, Cengage Learning 35