1. Chemical Basis of Life
Chapter 2: Section 3

2. Organic vs. Inorganic Chemicals in the Human Body
Organic: chemicals that contain carbon and hydrogen atoms
Compounds dissolve in organic liquids, such as ether or alcohol.
Can dissolve in water but do not release ions and are called nonelectrolytes.
Inorganic: chemical substances that lack carbon and hydrogen atoms.
Dissolve/react with water to release ions; electrolytes

3. Inorganic Substances
Water
Oxygen
Carbon Dioxide
Salts

4. Inorganic Substances: Water
Most abundant compound in living material and accounts for 2/3 of the weight of an adult human.
Important solvent because substances dissolve in it
Solute: substance dissolved in water and broken down into smaller and smaller pieces.
Moves chemicals within the body
Aqueous portions of blood carry substances such as oxygen, sugars, salts, and vitamins, from digestive organs to respiratory organs.
Can absorb and transport heat
Blood carries heat released from muscle cells during exercise from deeper parts to the surface.

5. Inorganic Substances: Oxygen
Oxygen enters through respiratory organs and transported by blood
RBCs bind and carry oxygen
Cellular organelles use oxygen to release energy from sugar glucose and other nutrients.
Released energy drives the cell’s metabolic activities

6. Inorganic Substances: Carbon Dioxide
Simple, carbon-containing compound
Produced as a waste-product when certain metabolic processes release energy, and it is exhausted by the lungs

7. Inorganic Substances: Salts
Salt is a compound composed of oppositely- charged ions
Abundant in tissues and fluids
Provide necessary compounds such as:
Refer to handout 
Important in metabolic processes:
Transport of substances into and out of cells
Muscle contraction
Nerve impulse conduction

8. Organic Substances
Carbohydrates
Lipids
Proteins
Nucleic Acids

9. Organic Substances: Carbohydrates
Carbohydrates: provide much of the energy cells require
Supply materials to build certain cell structures and often are stored as reserve energy supplies
Consist of carbon, hydrogen, and oxygen
Contain twice as many hydrogen as water; think of H2O, C6H12O6, and C12H22O11.

10. Organic Substances: Carbohydrates
Carbon atoms of carbohydrate molecules join in chains whose lengths vary with the type of carbohydrate
Shorter chains = sugars
Sugars w/6-carbon atoms= simple sugars or monosaccharides, and are the building blocks of complex carbohydrates
Examples of simple sugars: glucose, fructose, galactose

11. Organic Substances: Carbohydrates
Complex carbohydrates: number of simple sugar molecules link to form molecules of varying sizes.
Disaccharides: (double sugars) molecules contain two simple sugar building blocks
Examples: sucrose and lactose
Polysaccharides: made up of many simple sugar units joined together
Example: plant starch; and animals (humans) synthesize glycogen

12. Organic Substances: Lipids
Lipids: insoluble in water but soluble in certain organic solvents, such as ether or chloroform.
Include a variety of compounds that are vital to cell functions:
Fats (most common)
Phospholipids
Steroids

13. Organic Substances: Lipids
Fats: primarily to store energy for cellular activities
Store more energy, gram for gram, than carbohydrate molecules.
Composed of carbon, hydrogen, and oxygen atoms.
Unlike carbohydrates, fats have a much smaller portion of oxygen atoms.

14. Organic Substances: Lipids
Building blocks of fat molecules are:
Fatty Acids
Glycerol
Each glycerol binds with 3 fatty acid molecules to produce a single fat, or triglyceride, molecule.
Glycerol portions are identical but fatty acid portions are different because there are many kinds of fatty acids.
Variations in fatty acid chains create different kinds of fatty acids.

15. Organic Substances: Lipids
Saturated
Each carbon atom is bound to as many hydrogen atoms as possible and is thus saturated with hydrogen atoms
Unsaturated
Fatty acids with double bonds
Polysaturated
Fatty acids with MANY double bonds

16. Organic Substances: Lipids
Like fatty acids, there are different kinds of fat molecules.
Saturated fats
Made of saturated fatty acids
Unsaturated fats
Made of unsaturated fatty acids

17. Organic Substances: Lipids
Phospholipids: contains a glycerol portion and a fatty acid portion, but it only has a two fatty acid chains.
Place for third chain is replaced by a phosphate group
Hydrophilic head- water-loving
Hydrophobic tails- water-hating
Important in cellular structure

18. Organic Substances: Lipids
Steroid: complex structures that contain 4 connected rings of carbon atoms
Cholesterol is a very important steroid for body cells and is used to synthesize other steroids
Other steroids include:
Sex hormones (estrogen, progesterone, testosterone)
Several hormones from adrenal gland

19. Organic Substances: Proteins
Protein: wide variety of functions; structural materials, energy sources, hormones.
Glycoproteins: proteins and carbohydrates that serve as a receptor on a cell’s surface and bond to specific molecules.
Antibodies detect and destroy foreign substances in the body.
Enzymes make metabolism occur faster and are EXTREMELY important.

20. Organic Substances: Proteins
Proteins composed of carbon, hydrogen, and oxygen, plus nitrogen and sometimes sulfur atoms.
Building blocks of proteins are called amino acids.
There are 20 different kinds of amino acids that occur commonly in living organisms.

21. Organic Substances: Proteins
Protein structure:
Primary
Secondary
Tertiary
Quaternary
Each level of structure increases complexity
Protein 3D shape = conformation
When hydrogen bonds holding protein shape break because of heat, radiation, electricity, pH, or chemicals, the protein denatures.

22. Organic Substances: Nucleic Acids
Nucleic Acids: form genes and take part in protein synthesis
Usually large and complex molecules
Contain carbon, hydrogen, oxygen, nitrogen, and phosphorus, which form the building blocks of nucleotides.
5-carbon sugar, phosphate group, and one of several nitrogenous bases

23. Organic Substances: Nucleic Acids
Two kinds of Nucleic Acids
RNA (ribonucleic acid)
Nucleotides contain ribose
Single chain but can fold into various shapes to control when genes are accessed
DNA (deoxyribonucleic acid)
Nucleotides contain deoxyribose
Double chain that is held together by hydrogen bonds