Transcript Main Notes
Biochemistry Chapter 2 Background • Organic molecules contain both the elements carbon and hydrogen – Glucose C6H12O6 • Inorganic molecules do not contain both carbon and hydrogen – Water H2O – Carbon Dioxide CO2 Background • Dehydration Synthesis Reaction – A reaction that builds larger molecules from smaller molecules – A water molecule is released during the process – Small + Small Large + H2O (water) Background • Hydrolysis Reaction – A reaction that breaks down larger molecules into smaller molecules – A water molecule is used up during the process. – Large + H2O (water) Small + Small Background Dehydration Synthesis Reaction Small + Small Large + H20 Large + H20 Small + Small Hydrolysis Reaction Chemistry Review- THE ATOM • Atom is the basic unit of matter – Remember • Proton = positive charge • Electron = negative charge • Neutron = neutral charge • Compound-combo of 2 or more elements • Molecule- formed when atoms joined together; smallest unit of most compounds Chemical Bonds • Ionic bond – 1 or more electrons transferred • Covalent Bond – electrons shared • -Van der Walls Forces – weak intermolecular forces – Can develop when molecules are close together Water is Essential to Life • Water Polarity – polar molecule-the charges are unevenly distributed – like a magnet with poles • A water molecule is polar because there is an uneven distribution between the O and H atoms – negative near O positive between H Polarity allows water Polarity allows water mo molecules to attract each other Hydrogen bonds- bonds between H molecules -weak -allow for special properties of water Mixtures: Solution and Suspensions • Mixture- 2 or more elements or compounds – -physically mixed together but not chemically combined – -can be separated – ex: salt and pepper, sugar and sand • Solutions- mixture of 2 or more substances in which the molecules are evenly distributed – ex: table salt in water – table salt= solute- substance that is dissolved – water= solvent- does dissolving • Suspension-mixtures with non- dissolved material – ex: -water and sand Acids, Bases and pH • Remember: ion = charged particle – pH= “potential of Hydrogen” – indicates the concentration of H+ ions pH scale- ranges from 0 – 14 pH 7 = concentration of H+ ions and OH- equal Below 7 = acidic = more H+ ions Above 7 = basic = more OH- ions • Controlling pH= buffers • buffers= weak acids or bases – -can react w/strong acids or bases – prevent sudden changes in pH Chemistry of Carbon • I. The Chemistry of Carbon A. Characteristics of Carbon 4 valence electrons allows C to form strong covalent bonds 2. Can form C to C bonds a. Types of bonds i. single C-C ii. double C=C ii. triple C=C • 3. Very versatile (can make many different compounds) Macromolecules A. Formed by polymerization – 1. Process of joining many monomers B. Types of Biological macromolecules 1. Carbohydrates 2. Lipids 3. Nucleic Acids 4. Protein The Macromolecules of Life 1. Carbohydrates 2. Lipids (Fats) 3. Proteins 4. Nucleic Acids Carbohydrates • Function: molecules that contain energy and give structure • Composed of which 3 elements? – Carbon, Hydrogen, and Oxygen • The ratio of hydrogen to oxygen is 2:1 Carbohydrates • Basic Building block is a Monosaccharide, which is a simple sugar – Example: C6H12O6 (Glucose) • Glucose - made during photosynthesis; main source of energy for plants and animals Carbohydrates • Diagram of Glucose Carbohydrates Fructose - in fruits, sweetest of the simple sugars Galactose - in milk Carbohydrates • Disaccharides are formed when 2 monosaccharides combine in a dehydration synthesis reaction: – Examples of disaccharides • • Lactose = glucose + galactose Sucrose (table sugar) = glucose + fructose Carbohydrates Carbohydrates • Polysaccharides are 3 or more monosaccharides joined together • 3 biologically important examples: – Glycogen in animals – Starch in plants – Cellulose in plants • These molecules have a lot of energy stored in them repeating glucose units Carbohydrates • Polysaccharide Lipids (Fats) • Function: these molecules store long-term energy and make up the cell membrane of cells (phospholipids) • Lipids are made of which elements? – Carbon, Hydrogen, and Oxygen • There are many carbon and hydrogen atoms but only a few oxygen atoms • Do lipids dissolve well in water? – No - they are therefore considered hydrophobic (water-fearing) • Some examples of lipids: oils, fats, waxes, steroids, phospholipids Lipids (Fats) Lipids Examples of lipids 1. Steriods- act as chemical messengers 2. Fatty acids i. Saturated- all single bond ii. unsaturated (olive oil)- one C=C iii. polyunsaturated (cooking oils: corn, peanut, sesame, canola) – many C=C Proteins • Function: control the rate of reactions, transport materials, form bone and muscle, transport materials. Fight disease, act as enzymes • Composed of which 4 elements? – Carbon, Hydrogen, Oxygen, Nitrogen and sulfur • Basic building block: amino acid (AA) Proteins • Basic building block: amino acid (AA) • Question: How many different amino acids are there? – 20 Proteins • Dipeptide – 2 amino acids bonded together with a peptide bond. They are joined by dehydration synthesis reactions • Polypeptide – long chain of AA bonded together • Proteins are composed of 2 or more polypeptide chains Proteins • Enzymes are biological catalyst made of protein • What is a catalyst? – A substance that speeds up a chemical reaction without being altered • How does an enzyme speed up a reaction? – It lowers the activation energy needed to start the reaction • Substrate - the molecule(s) that are acted upon by the enzyme • Active site - the spot on the enzyme where the substrate fits Proteins - Enzymes • Lock and Key Model: Proteins - Enzymes • Lock and Key Model: Proteins - Enzymes • Lock and Key Model: http://waynesword.palomar.edu/molecu1.htm#lock Proteins • How many times can a single enzyme be used? – Thousands • Enzymes work at specific pH values and temperatures. If the pH or temperature goes too high or too low, the enzyme won’t work properly – ex. Lactase catalyzes (speed up) the breakdown of lactose into glucose and galactose – ex. Catalase speeds up the breakdown of hydrogen peroxide Nucleic Acids • Nucleic Acids are composed of Carbon, Hydrogen, Oxygen, and Nitrogen, Phosophorous • Nucleic Acids function in living things as the structure of DNA and RNA – The blueprint of life • Monomers- Nucleotides – Composed of a 5-Carbon Sugar, Phosphate group, and Nitrogen Base – Store genetic information – Held together by covalent bonds • Polymers- Nucleic Acids – A string of nucleotides – DNA or RNA Nucleic Acids • There are four nitrogen bases, meaning there are four “types” of nucleotides – Adenine, Thymine, Guanine, Cytosine • RNA is a single strand nucleic acid • In DNA, two strands of nucleic acid bond – Double Helix – Adenine always bonds with Thymine – Guanine always bonds with Cytosine Nucleic Acids NUCLEOTIDE DNA RNA Biochemistry THE END