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EOC Review BIOCHEMSITRY/CHEMISTRY OF LIFE Atoms Atoms are the basic unit of matter Composed of: Part Proton Neutron Electron Charge + Positive 0 Neutral - Negative Location Nucleus Nucleus Circling the nucleus In order to be stable Atoms need 8 valence electrons To do this they will create bonds! Covalent Bonds Between ATOMS – 2 non-metals Sharing electrons Strong bond! Ex: CH4, H2O Most important in biology! ◦ Found in the bonds of DNA Atoms to Ions Atoms become ions when they lose or gain electrons (negative charge) Lose electrons= positive ion - cation ◦ Ex: Na+, K+ Gain electrons= negative ion - anion ◦ Ex: Cl- (chlorine ion), F- (fluorine ion) Ionic Bonds Between ATOMS-metal and non-metal Transferring electrons Ex: NaCl (salt), KF Water One of the most important molecules on Earth! Universal solvent: dissolves more substances than other liquids Helps maintain a stable global temperature because of its high heat capacity Ice floats! The solid is less dense than the liquid It has high surface tension! Water and Polarity POLAR Electrons are unequally shared Oxygen atom: more electronegative, pulls the electrons away from hydrogen O slightly negative (more e-) H slightly positive (less e-) Hydrogen bonds Hydrogen Bonds An attractive force between polar molecules H atom of one molecule is attracted to an electronegative atom of another molecule (especially, N, F, or O) Weak bonds Ex: Water, between the strands of DNA Properties of Water 1. Cohesion between water molecules ◦ H2O transport in plants ◦ High surface tension 2. Adhesion between water and other substances pH pH: measure of acidity – the amount of H+ ions in a solution 0 -6 = acidic, 7 = neutral, 8-14 = basic Acids contain more H+ ions Bases contain more OH- ions Changing the pH is exponential 10x Organic Compounds Organic Compounds are essential for life! They are made of carbon and hydrogen backbone ◦ They also contain oxygen Carbon is able to make 4 bonds which makes it a variety of structures All organic compounds are made from CO2 – converted during photosynthesis! Is Carbon Dioxide organic? Why or why not? Organic Compounds Organic compounds are considered polymers (chain of identical units) because they are made of many monomers (single unit) Carbohydrates Monomer: Monosaccharide (simple sugar) ◦ Ex. Glucose Polymer: 1. Disaccharide: 2 monosaccharide rings joined together a) Ex: lactose 2. Polysaccharide: macromolecule consisting of simple sugars a) Starch (plant) & glycogen (animal): store energy b) Cellulose (plants) and Chitin (fungi): provides structure Function – immediate energy for the organism and structural support in plants Lipids Monomer: fatty acids Polymer: 1. Fats (triglycerides) - Glycerol + 3 fatty acids a) b) Saturated – max # of H’s. Solid. Unsaturated – have C=C double bonds. Liquid. 2. Phospholipids - Phosphate group + 2 fatty acids 3. Steroids – 4 fused rings 1. Cholesterol 2. Hormones Function – long term energy storage and component of cell membranes and hormones Proteins Monomer: Amino Acid (20 different ones) Polymer: ◦ Polypeptide – made of amino acids. Bonded by a peptide bond. Function: Shape = function Make up all tissues, enzymes, muscle tissue, transport proteins in the cell membrane, hormones, antibodies in the immune system Building blocks of our body! Nucleic Acids Monomer: nucleotide Function: ◦ Stores genetic information Polymer: ◦ DNA and RNA Found in all living things What is an enzyme? A catalytic protein Speed up chemical reactions without being used in the reaction. They lower the Activation Energy (EA) – the energy required to start a reaction 5. Recyclable and reusable 4. bind to specific substrate; lock-and-key fit 1. Lower activation energy 2. Speed up chemical reactions ENZYMES (special proteins) Ex: Without enzymes digestion would take weeks instead of hours 3. Without them, reactions would take a long time Enzymes are specific Substrate : reactant that enzyme acts on The enzyme binds to its substrate, forming an enzyme-substrate complex Active site : region on the enzyme where the substrate binds Induced fit of a substrate brings chemical groups of the active site into positions that enhance their ability to catalyze the reaction Enzyme Activity An enzyme’s activity can be affected by ◦ General environmental factors, such as temperature and pH ◦ Chemicals that specifically influence the enzyme Each enzyme has an optimal temperature & pH at which it can function Even slight changes in pH and temperature can “denature” enzymes ◦ Denature= change the shape of the protein ◦ When the shape is changed, the active site is no longer the same and the substrate can not fit! Practice Biochemistry With a partner or group of 3: Read the three statements about molecule X and Y Analyze the evidence about organic molecules Write a CER about which statement is the best! *Yes this is for a grade*