Biochemistry Chapter 3

Water Section 2.3

Structure of Water  Most abundant molecule  Held together by covalent bonds  2 atoms of H, 1 atom of O

Water is a Polar Molecule  Definition: a molecule with an uneven distribution of charge but a net charge of zero  Water bonds at an angle

Water’s ability to dissolve  “Like Dissolves Like”  Polar substances can dissolve polar substances, nonpolar substances can dissolve nonpolar substances  “Universal solvent”

Questions:  Why don’t oil and water mix?  Why can water dissolve sugar or salt?  How does water dissolve a polar substance?

Answer:  The + end of water attracts to the – ion of the substance  The – end of water attracts to the + ion of the substance  This breaks the ionic bond of the substance thus dissolving it

Water’s special bond:  Hydrogen Bond: a weak chemical bond that exists between the H atoms and a – charged part of a different molecule

Water’s special properties: Due to H-bonds: 1. Water can cling to itself and other substances 2. Water is able to absorb large amounts of energy without changing temperatures quickly (high boiling point)

Cohesion:  When like molecules are attracted to each other  Ex) surface tension in water

Adhesion:  Definition: the attractive forces between unlike substances

Capillarity:  Definition: cohesion and adhesion working together to move water molecules up a narrow tube against the force of gravity

Homeostasis? 1. The H-bonds in water are the first bonds to break when an increase in energy (temp) is applied 2. It takes a LARGE amount of energy to break/move water molecules 3. Thus, the temperature of water stays fairly constant in a cell even though there might be a drastic temperature change outside

Lab time….yeah!

Carbon Compounds SECTION 3.1

Organic Compounds  Organic compounds contain carbon atoms  Form covalent bonds with other C atoms or to other elements - N, H, and O.

Carbon Bonding  C readily covalently bonds (a bond forms when electrons are shared)  Each C forms 4 covalent bonds

Large Carbon Molecules  Polymers are made up of many small, repeating molecules called monomers.  Macromolecules- large polymers

Condensation Reaction  A chemical reaction that links monomers to form polymers  One water molecule is produced  A.k.a. dehydration synthesis Ex) Glucose and Fructose combine to make Sucrose, table sugar

Condensation Reaction:  The formation of larger molecules by removing a H + from one monomer and a OH - from the other monomer.  The H + and the OH - combine to form the bi-product H 2 O.

Hydrolysis  A chemical reaction that breaks down polymers  Reversal of condensation reaction  Usually done by adding water

ATP – Adenosine Triphosphate  All of life’s functions require energy  Energy compounds found in cells

Biochemistry The stuff life is made of! Section 3.3

The Four Molecules of Life  1. Carbohydrates  2. Proteins  3. Lipids  4. Nucleic Acids  All of your body is made up of these four types of molecules!

The Building Blocks  Each type of molecules is made up of smaller parts called monomers.  When 3 or more monomers are linked together, they form a polymer.

How to make a macromolecule.  How do you make a polymer from many monomers?  CONDENSATION REACTION!

What will break up a large molecule?  The opposite reaction of condensation……  HYDROLYSIS REACTION! The use of water to break apart polymers back into monomers.

 Condensation/Hydrolysis Condensation/Hydrolysis

Monomers of the 4 Life Molecules  1. Carbohydrates - Monosaccharide  2. Proteins – Amino Acids  3. Lipids – Fatty Acids  4. Nucleic Acids - Nucleotides  How do you make macromolecules of each monomer? CONDENSATION REACTION

1. Carbohydrates  Used for “fuel” and structural material  Monosaccharide = monomer, simple sugar, ex) fructose, galactose, & glucose C 6 H 12 O 6  Disaccharide = 2 monomers, double sugar ex) sucrose (table sugar)

________________________________________ Examples)

 Polysaccharide = too many to count ex) starch & cellulose (in plants) glycogen (in animals)

2. Protein  Amino Acid = monomer, 20 different types  Peptide bond holds amino acids together  Polypeptide = chains of amino acids  Protein = the final functional form, 1 or more polypeptides

Most DIVERSE group of molecules: structures such as antibodies, hormones, muscles, skin, hair, and biological catalysts (enzymes) are made of proteins.

Enzymes  Protein molecules that catalyze (increase the rate of) biochemical reactions  How Do Enzymes Work? How Do Enzymes Work?  Animation: How Enzymes Work Animation: How Enzymes Work

3. Lipids  Fatty Acids = monomer Hydrophilic carboxyl head - polar Hydrophobic fatty acid tail – nonpolar, not soluble in water Ex) saturated (solid) and unsaturated (liquid)

Complex Lipids  Triglycerides (fats) Ex) butter  Phospholipids Ex) cell membrane  Waxes Ex) earwax  Steroids Ex) testosterone, cholesterol

4. Nucleic Acids  Nucleotide = monomer  Found in the genetic material DNA & RNA  carries out all of the functions of the cell