Integrated Science Chapter 6: Chemistry in Biology

Atoms  The building blocks of matter

Atoms Protons  Positive (+)  Inside the nucleus  Mass of 1 Neutrons  No Charge  Inside the nucleus  Mass of 1 Electrons  Negative (-)  Outside the nucleus  No mass

Elements  A pure substance that cannot be broken down.  Most commonly found in living things are CHONPS.

Elements

Isotopes: Atoms of the same element that have different numbers of neutrons.  Carbon 14 is used for radioactive dating of organic material.  Cesium 137 is used to treat cancerous tumors. (55 protons, 82 Neutrons)  Iodine 123 is widely used to diagnose thyroid disorders and other metabolic disorders including brain function.

Compounds: a pure substance formed when two or more different elements combine.

Chemical Bonds: the force that holds substances together  Covalent: electrons are shared.  Form molecules  Example: Water  Ionic: Electrons are transferred  Form ionic compounds:  Example: Salt

Chemical Bonds MoleculeIonic Compound

Water  Water is polar  It has a positive end and a negative end  This causes hydrogen bonding

Hydrogen Bonds  The attraction between the positive hydrogen end and the negative oxygen end in water

Why is water Important?  Solvent  Dissolves polar compounds  Example: Salt dissolves in water

Why is Water Important? It is sticky. Cohesion- water sticks to itself Adhesion- water sticks to other things

Why is Water Important? High specific heat – water can hold a lot off heat. Good evaporative coolant – Water carries heat from you body by sweating.

Why is Water Important?  Water is less dense when it is frozen  Ex: glaciers

Acids, Bases and ph

Universal ph indicator

Organic compounds A compound containing Carbon Exceptions: CO 2 CO CaCO 3 All living organisms are made up of organic compounds

Organic Compounds Carbon = 4 covalent bonds Carbon can bond to itself Results in a variety of important organic compounds

Organic Molecules Carbon based molecules form straight chains, branched chains and rings.

Macromolecules: four classes of organic compounds 1. Carbohydrates 2. Lipids 3. Proteins 4. Nucleic Acids

Macromolecules Polymer = many units Monomer = one unit

Carbohydrates  carbon, hydrogen and oxygen  Includes sugars, starches and cellulose Uses Energy storage Build cell walls Usually end in “-ose”

Monosaccharide Single (simple) sugar Monomers of carbohydrates Ex: Glucose (energy in cells)(from the sun), Fructose(fruit sugar), Galactose

Disaccharides Double sugar C 12 H 22 O 11 (sucrose) Example: Sucrose Lactose (milk sugar)

Polysaccharides Many sugars Starch- plants Glycogen- animal starch

cellulose Long chains of starch Very strong Function: plant cell walls

Lipids What are they?  Fats, oils, waxes, steroids Function  Energy storage  Insulation  Cell membrane  Coatings  Hormones

Lipid Structure Triglyceride = Glycerol 3 Fatty Acid Chains

Saturated vs. Unsaturated Fats

Lipids  Saturated  Solid  Straight  Unsaturated  Liquid  Bent

What are trans fats? (isomer) Chemically altered unsaturated fats Not found in nature Your body doesn’t know how to break them down

Phospholipid function  Phospholipid bilayer in the cell membrane

Steriods

Proteins  Contain C, H, N, O (S)  Enzymes (Amylase)  Antibodies  Hormones-regulate body functions (insulin)

Types of Proteins 1. Structural: 1. Keratin (hair, nails) 2. Collagen 2. Contractile 1. Actin/myosin (muscles) 3. Pigments (skin, hair, iris)

Protein Structure  1. Amino Acids  20 different kinds

Peptide Bond  Joins two amino acids ( dehydration Rxn)  Polypeptide = many amino acids ← Primary Structure

Levels of Protein Structure 1. Primary- amino acid sequence 2. Secondary- helix or pleated sheet 3. Tertiary- a.a. interact to form the polypeptide into 3D shape 4. Quaternary- two or more tertiary polypeptides

What are enzymes and why are they important?  Specialized proteins.  Speeds up a reaction (not consumed)

How do enzymes work?  Enzymes bind with a substrate and break it into two or more products.

What are some examples of enzymes?  Lipase – breaks down fat  Helicase- unwinds DNA  Amylase – breaks down food in your mouth  DNA Polymerase- assemble nucleotides in DNA replication  Pepsin – breaks down proteins

What do all Enzymes have in common?  1. Active Site  Location that the substrate binds to.

What do all enzymes have in common?  2.Very specific  Lipase only breaks down fat  Helicase unwinds DNA for replication

What do all enzymes have in common?  3. Recycled  Can be used over and over  Only a small amount is needed to speed up thousands of reactions.

What is activation energy?  Amount of energy needed to start a reaction

How do enzymes affect activation energy?  Enzymes lower activation energy

How is enzyme activity affected by pH?  Too high/low = denatures

How is enzyme activity affected by temperature ?  Too high = denatures  Too low = inactive

How is enzyme activity affected by enzyme concentration?  More Enzymes = faster rate of reaction

How is enzyme activity affected by substrate concentration?  The rate of reaction will gradually increase until it levels off.

The Enzyme Song  QhPurj-k QhPurj-k

Nucleic Acids DNA  Contains hereditary info (genes)  Double helix RNA  Protein synthesis  Single helix

Flow of information  DNA → RNA → Proteins