Biology 30

Biology 30Unit 1:The Chemical Basis of LifeChemistry Involved in Life ProcessesRefresher from Chem 201. Atoms:All matter has mass and takes up spaceAll matter is composed of atomsAtoms are composed of three particles:Proton (+)Neutrons (no charge)Electrons (-)

1. Atoms:Nucleus of the atom is made of protons and neutronsNumber of protons and electrons in an atom are the same making the charge neutralElectrons circle the nucleus at different energy levels to form an energy cloud

2. ElementsAn element is a substance composed of only one type of atomEvery atom in the element has the same number of protonsIsotopes occur when atoms of the same element have a different number of neutrons

3. MoleculesMolecule: when atoms join with other atoms of the same or different elementsStable molecules are created when outermost energy levels are completely filledCovalent Bonds: the forces involved in the sharing of electrons to fill up an energy level

3. MoleculesBonds are held together by energy and when broken that energy is releasedWeakest chemical bond is hydrogen because it has only one electron

4. CompoundsCompounds: substances composed of different kinds of atoms chemically bonded togetherThere are two main types of compounds:Inorganic compoundsOrganic compounds4. CompoundsInorganic Compounds: contain no carbonOnly a single carbon atom per moleculeContain energy that is not useful for organisms

4. CompoundsOrganic compounds:Built with long carbon-to-carbon chainsLarge molecules containing stored energy Energy can be used by organismsEx: CHOs, Proteins, Lipids

5. Chemical ReactionsChemical Reaction: results from rearranging atoms and molecules of the materials involvedEx: burning wood adds oxygen to the wood substances

5. Chemical ReactionsReactions can be written as chemical equationsReactants: beginning substancesProducts: end of reactionLaw of Conservation of Mass: same number of atoms at the beginning and the end of a reactionEnergy is either required or produced when a reaction occurs

6. IonsIons: atoms that gained or lost electrons have an imbalance of charged particlesPositive Ions: atoms that donate electrons have an excess of positive chargeNegative Ions: atoms that accept electrons have an excess of negative chargeIonic bonds form when electrons are transferred

7. Acids and BasesWater is made of 2 H atoms and 1 O atom A hydrogen atom breaks away from water molecule:Positive hydrogen ionNegative hydroxide ionNeutral solutions have the same number of hydrogen and hydroxide ions

7. Acids and BasesWater is made of 2 H atoms and 1 O atom A hydrogen atom breaks away from water molecule:Positive hydrogen ionNegative hydroxide ionNeutral solutions have the same number of hydrogen and hydroxide ions

7. Acids and BasesAcids: concentration of hydrogen ions > concentration of hydroxide ionsHave a sour taste... Lemon juiceBasic: concentration of hydroxide ions > concentration of hydrogen ionsAmmonia, soap, oven cleanerpH scale 1-141-6 Acids7 Neutral8-14 BasicProperties of MacromoleculesCarbohydratesThese are composed of carbon, hydrogen, and oxygen with the ratio of H:O=2:1Monosaccharides (C6H12O6) are called simple sugars because they are made of only one sugar unit.Glucose is formed by plants during photosynthesis and is the form of energy most easily used by cells. Monosaccharaides link together to form other types of sugars

CarbohydratesDisaccharides (C12H22O11 ) are called double sugars because they are formed when two monosaccharides join together. Sucrose is made when a glucose and a fructose are joined together. Whenever monosaccharides link together, a molecule of water is released. This is called a dehydration reaction.Polysaccharides (C6H12O6)n are called many sugars because they are formed when three or more monosaccharides are linked together.4 calories per gramHow to Identify CarbohydratesOnly carbons, hydrogens, and oxygensTwice as many Hs as OsDehydration reaction has H2O as a productHydrolysis reaction has H2O as a reactantThe names end in oseLab Tests:Benedicts solution changes from blue to a variety of other colors to indicate percentage of sugarIodine turns blue black to indicate starchExamples of CharbohydratesGlucose Sucrose Starch Cellulose Glycogen Chitin Diagrams of Charbohydrates

ProteinsThese are composed of carbon, hydrogen, oxygen, and nitrogen ( and sometimes sulphur)Built from a combination of twenty subunits called amino acidsThe long chains (thousands of subunits) are called polypeptideGreen plants can synthesize all amino acids from simple materialsAnimals cannot so they must get them from their diet

ProteinsThe particular combination of amino acids and the 3D folded shape it forms determines the function of the protein.Important in living organisms because each type of chemical reaction is controlled by a different type of enzyme, which is formed from proteinsEnzymes are complex proteins that cause a specific chemical change in all parts of the body.The production of many different enzymes makes thousands of chemical reactions4 Calories per gramHow to Identify ProteinsMust contain NSometimes contains SMost labeled molecules end in ineLab Test:The Bluret Test indicates peptide bonds when color changes from blue to pink purplesExamples of Proteinshair NailsSteak (animal flesh)Milk wheySilkWebsScabsBlood cellsEnzymeshormones

Diagrams of Proteins

LipidsThese are oily or waxy substances that are composed of carbon, hydrogen, and oxygen but the ratio of H:O is always greater than 2:1Fats are made of two types of lipid building blocks:Glycerole which is a single sugarFatty acids which are chains of carbon and hydrogen with an acid grouping on one end Different fatty acids produce different lipids.

LipidsLipids can be grouped into:Fats (animals)Oils (plants)Waxes (animals & plants)Generally fats are used as a concentrated source of stored energy but can also be found in cell membranes and as cushions around body organs.

How to Identify LipidsOnly carbons, hydrogens, oxygens but more than double Hs than OsSeveral carbons with double bondsLab Test:Sudan IV solution identifies most lipids with a color change from pinks to redsTranslucence test indicates lipids by making untreated paper to transmit lightExamples of LipidsFats:MargarineButterLardBlubberOils:Canola oilFlax oilVegetable OilWaxes:Bee waxEar waxCuticle on leaves

Diagrams of Lipids

Nucleic AcidAnother important group is nucleic acids (DNA, RNA)They are part of chromosomes and the reading of chromosomes