1. Chemistry of Life

2. Objectives Define the terms atom, element, molecule, and compound.
Describe the structure of an atom.
Compare and contrast ionic and covalent types of chemical bonding.
Distinguish between organic and inorganic chemical compounds.

3. Objectives Discuss the chemical characteristics of water.
Explain the concept of PH.
Discuss the structure and function of the following types of organic molecules:
Carbs
Lipids
Proteins
Nucleic acid

4. Levels of Chemical Organization
Matter
Anything that occupies space and has mass.
Molecules are particles of matter, made up of atoms.

5. Atoms Nucleus Central core of the atom Contains subatomic particles:
Protons = positively charged
Number of protons determines type of atom. (atomic number)
Neutrons = no charge

6. Atoms
Orbiting around the nucleus are negatively charged particles called electrons.
Energy levels (shells)
Outer level may hold up to 8 electrons.
Energy increases with distance from the nucleus.
Number of electrons in the outer shell affects the atoms ability to unite with other atoms.

7. Elements, Molecules, and Compounds
Pure substance; made up of only one kind of atom.
Molecule
Group of atoms bound together.
Compound
Substances whose molecules have more than one kind of atom.

8. Elements, Molecules, and Compounds
Compounds are written in formulas containing symbols and number of atoms in subscript.
Example: Carbon Dioxide
CO2

9. Elements, Molecules, and Compounds
Four kinds of atoms make up approx. 96% of the human body.
Oxygen
Carbon
Hydrogen
Nitrogen
20 or more trace elements.

10. Chemical Bonding Chemical bonds form to make atoms more stable.
Considered stable when the outer energy level is full. (8 electrons)
Atoms will share, donate, or borrow electrons to fill the outermost energy level.

11. Ionic Bonds
Ions form when atoms gain or lose electrons in the outer energy levels.
Positive Ions
Have lost electrons becoming positively charged.
Negative Ions
Have gained electrons becoming negatively charged.

12. Ionic Bonds Example: (Fig 2-2) Sodium – Na
Containing 1 electron in outer shell.
Chlorine – Cl
Contains 7 electrons in outer shell.
Donating or borrowing electrons make sodium positively charged and chlorine negatively charged forming a bond NaCl or Sodium Cloride.

13. Electrolytes
Ionic molecules dissociate easily in water forming electrolytes.
Examples:
Sodium – Na+
Chloride – Cl-
Calcium – Ca++
Potassium – K+

14. Covalent Bonds
Atoms that share electrons, rather than donate or receive them form covalent bonds.
Bonds are not easily broken and do not break apart in water.

16. Organic/Inorganic Compounds
Living organisms contain both organic and inorganic compounds.
Organic compounds contain:
Carbon to Carbon covalent bonds
And/Or
Carbon to Hydrogen covalent bonds
Inorganic compounds lack these bonds.

17. Inorganic Compounds Water Most abundant compound in the body.
Solvent that other solutes are dissolved.
Aqueous solution
Essential in many important chemical reactions.

18. Chemical Reactions Fig 2-4
Dehydration synthesis
Water is removed from smaller molecules so larger ones can be created.
Hydrolysis
Water is added to larger molecules to break them apart into smaller ones.

19. Chemical Reactions Chemical reactions involve energy transfers.
Some of the energy used to build the molecules are stored as potential energy and released when broken apart.
Example:
Adenosine Triphosphate (ATP)
Needed for muscle contraction.

20. Chemical Reactions
Chemical equations show how reactants interact to form products.
Written with “arrows” to separate and show products.
Example:
K+ + Cl KCL

21. The pH Scale

22. Acids, Bases, and Salts
Water molecules dissociate to form equal amounts of Hydrogen Ions/Hydroxide Ions.
Neutral pH 7.0
Acids are higher in Hydrogen Ions (< 7.0)
Bases/Alkalines are lower in Hydrogen Ions (>7.0)

23. Acids, Bases, and Salts
Strong acids or strong bases are neutralized when mixed with each other and form salts.
Buffers are chemical systems that absorb excess acids or bases and thus maintain a relatively stable pH.

24. Organic Compounds More complex than inorganic compounds. Carbohydrates
Lipids
Proteins
Nucleic acids

25. Organic Compounds Carbohydrates Sugars and complex carbohydrates
Monosaccharide (Glucose/Dextrose)
Disaccharide (Sucrose/Lactose)
Polysaccharides (Glycogen/Starches)
Contains Carbon, Hydrogen, Oxygen
Uses for energy or stores for later use.

26. Organic Compounds Lipids - Fats and oils Triglycerides
Glycerol and 3 fatty acids.
Stores energy.
Phospholipids
Phosphorus unit with 2 fatty acids
Forms cell membranes
Cholesterol
Transports lipids
Basis for making steroid hormones

27. Organic Compounds Proteins
Very large molecules composed of amino acids held together in long folded chains by peptide bonds.
Structural proteins
Functional proteins
Can bond with other compounds to form mixed molecules:
Glycoproteins
Lipoproteins

28. Organic Compounds Structural Proteins Form structures in the body.
Collagen is a fibrous protein that holds many tissues together.
Keratin forms tough, waterproof fibers in the outer layer of the skin.

29. Organic Compounds Functional Proteins
Participate in chemical processes.
Examples:
Hormones
Cell membrane channels/receptors
Enzymes

30. Organic Compounds Enzymes Catalysts Assist with chemical reactions
Lock and Key model
Each enzyme fits a particular molecule that it acts on as a key fits into a lock.

31. Organic Compounds Nucleic acids
Direct proteins for overall body structure and function.
Basic building blocks are called nucleotides.
Phosphate, sugar, and nitrogen base.
Deoxyribonucleic Acid (DNA)
Ribonucleic Acid (RNA)

32. Nucleic Acids Deoxyribonucleic Acid (DNA) Nucleotide bases: Adensine
Thymine
Guanine
Cytosine
Used as a master code for assembling proteins.

33. Nucleic Acids Ribonucleic Acid (RNA) Nucleotide bases: Adensine Uracil
Guanine
Cytosine
Used as a temporary working copy of a gene.
Portion of DNA code

34. Are you as confused as I am?
Any Questions?