Chemical Reactions in Living Cells Chemical Reaction –Involves the making and breaking of chemical bonds –Represented as a “short statement”: H 2 O H 2 + O 2 How would you balance this? 22 Does this happen on its own? Activation Energy: The amount of energy needed to initiate a reaction Biochemistry: Chemical Reactions in Living Cells

δ + δ - Water molecules are polar covalent bonds. Biochemistry: The unique properties of water They are attracted to other water molecules through relatively weak Hydrogen bonds.

Can water form ions? Yes, at a very small rate (1 out of 500,000,000!) H2OH2O H+H+ OH How would you quantify (count) this ionic disassociation? The pH scale powerHydrogen The “power of Hydrogen” scale pHpH Biochemistry: The unique properties of water

Stomach Acid, lemon juice Vinegar, cola Tomato juice Black coffee; Rainwater Urine Pure water; Human blood Seawater Milk of magnesia Household ammonia Household bleach Oven cleaner Increasingly Acidic   Increasingly Basic Neutral [OH - ] [H + ] = [OH - ] >[H + ] <[OH - ]

Besides water, what elements and compounds are essential to life? Organic compounds 1.Mostly contain Carbon, Hydrogen, Oxygen, Nitrogen, Phosphorus and Sulfur* *For Homework: Left Side IntNB Assignment: Write an Acrostic Poem for the six elements often found in organic compounds Carbon CCCCCC HHHHHHH O H O HHHH O O O O Organic Compounds: An Overview

Organic compounds (continued…) 2.Four categories of organic compounds: a.Carbohydrates b.Lipids c.Proteins d.Nucleic Acids 3.All formed and separated in similar ways a.Formation (Polymerization): Dehydration Synthesis b.Separation: Hydrolysis Hey Sugar, I sure am happy that you’re a Carbohydrate like me. Awww, how sweet! Hurry up, Lipids! You should have more energy stored up than this! Does this bond structure make me look fat? Hi there! My name is Polly Peptide. Can you believe that each of your cells contains about 2 meters of me? Organic Compounds: Carbohydrates

Polymerization Polymerization (definition): –Forming of large organic macromolecules by the joining of smaller repeating units called monomers Bonding: Polymerization

Dehydration Synthesis Dehydration Synthesis is the removal of a water molecule to form a new bond. HO H H2OH2O H H Short PolymerMonomer Dehydration removes a water molecule forming a new bond Bonding: Polymerization: Dehydration Synthesis

Hydrolysis HO H H2OH2O H H Short Polymer Monomer Hydrolysis adds a water molecule to break a bond Polymers are broken by adding water. Literally, “Water Splitting” Bonding: Polymerization: Hydrolysis

CC C C C C Carbon = The element of life Carbon’s Valence has ____ electrons Can bond with ____ elements Can form chains, rings, branches, & isomers 4 4 C C HO OHH H C C HOOH HH What biological impact do you think isomers have on living systems? Bonding: Carbon

Thalidomide: an optical isomer Bonding: The importance of chemical structure

Bond energy When bonds are made, energy (E) is stored. When bonds are broken, energy (E) is released for use. Bonding: Bond Energy Glucose: A MonosaccharideFructose: A Monosaccharide Sucrose: A Disaccharide

Carbohydrates Carbohydrates are: –an important energy (E) source –Cellular structures Carbon, Hydrogen and Oxygen in a ratio of 1:2:1 General Formula (CH 2 O)n Organic Compounds: Carbohydrates CH2OH2O Water = hydrate Carbon hydrate

Organic Compounds: Carbohydrates: Monomers Carbohydrates Monosaccharides (simple sugars) –Contain 3-7 Carbons each Examples: Glucose, Galactose, Fructose Glucose

Organic Compounds: Carbohydrates: Dimers Carbohydrates Disaccharides (two sugars) Examples: Sucrose, Maltose, Lactose –Maltose = Glucose + Glucose –Lactose = Glucose + Galactose Sucrose GlucoseFructose

Organic Compounds: Carbohydrates: Polymers Carbohydrates Polysaccharides (many sugars) Examples: Starch, Glycogen, Cellulose Starch Cellulose ChloroplastStarch Glycogen Liver Cell Plant Cells Cellulose

Lipids Organic Compounds: Lipids Lipids function in: –Energy (E) storage, –forming cell membranes, –and as chemical messengers (e.g., hormones) Nonpolar (hydrophobic) Made up mostly of Carbon and Hydrogen (with a few Oxygen)

Lipids 1.Fats (Triglycerides) –G–Glycerol + 3 Fatty Acids –S–Saturated = No Double Bonds (solid) –U–Unsaturated = Double Bonds (liquid) Organic Compounds: Lipids: Fats OH Ester Bonds

Lipids 2.Phospholipids –G–Glycerol with Phosphate Head + 2 Fatty Acid Chains –A–Amphiphilic (“Both” “lover”) Hydrophilic head Hydrophobic tail –F–Forms 2 layers in water –M–Makes up cell membranes Organic Compounds: Lipids: Phospholipids Phosphate Glycerol Fatty Acids

Organic Compounds: Lipids: Sterols Lipids OH O Testosterone HO O Estrogen 3.Sterols –L–Lipids whose Carbon Skeleton consists of 4 fused rings –I–Includes: Hormones Cholesterol Cortisol –M–Makes up cell membranes HO OH O O

Proteins Made up of Carbon, Hydrogen, Oxygen and Nitrogen (and some Sulfur) Many functions represented through different types of proteins Organic Compounds: Proteins

Proteins Enzymes: Catalysts that speed up the rate of a chemical reaction –Build up or break down substrate Fit together like a “lock” and a “key” –Not used up in the reaction –Work in a very specific biological range –Usually end with “-ase” Organic Compounds: Proteins: Functions Hi sweeties, Do you remember me? In addition to what you know. I am a substrate. I am an enzyme. I am going to try to convert you. I am now a product. I am a glucose now. I am a product, too. I am a fructose now. I am completely unchanged, and ready for some more sucrose! I am the active site. The substrate binds to me.

Proteins Structural Proteins –Provides mechanical support to cells and tissues Transport Proteins –Transports small ions or molecules Motor Proteins –Enables structures to move Organic Compounds: Proteins: Functions

Proteins Hormones (signaling proteins) –Carries signals from cell-to-cell –e.g., insulin Storage –Stores small molecules or ions –e.g., iron is stored in the liver in ferritin Other specialized functions –Defense (antibodies), –Receptor proteins (in eyes and muscles to detect stimulus) Organic Compounds: Proteins: Functions

Proteins Monomers: Amino Acids –Peptide Bond: Bond between 2 Amino Acids: Amino end (NH 2 ) and the Carboxyl end (COOH) Organic Compounds: Proteins: Monomers H2OH2OH2OH2O Side Chains Backbone R Group = Amino end Carboxyl end

Proteins R Groups (Side chains) –Differ in: Size Charge Polarity There are 20 protein-building Amino Acids –9 Essential Amino Acids Can’t be synthesized by the body, but are necessary for life Organic Compounds: Proteins: Monomers Hydrophilic Amino Acid Hydrophobic Amino Acid

Proteins Polymers: Polypeptides “Many Peptides” Four Levels of Structure –Primary (1°) –Secondary (2°) – H bonds –Tertiary (3°) –Quaternary (4°) – several polypeptides These specific shapes allow proteins to function Organic Compounds: Proteins: Polymers Polypeptides

Organic Compounds: Proteins: Denaturation Proteins Denaturation –When the protein loses its shape, and becomes non- functional due to: –Changes in temperature pH salinity (salt concentration) alcohol concentration

Nucleic Acids –Informational Polymers: Code for all of the proteins in an organism –Monomers: Nucleotides Phosphate Group 5-Carbon Sugar Nitrogenous base Organic Compounds: Nucleic Acids

Nucleic Acids DNA (Deoxyribonucleic Acid) –Backbone sugar: Deoxyribose –Four Bases Adenine (A) Guanine (G) Thymine (T) Cytosine (C) RNA (Ribonucleic Acid) –Messenger RNA: mRNA conveys the instructions to build proteins from the genetic information in DNA –Differences from DNA: Backbone sugar: Ribose Uracil in place of Thymine Organic Compounds: Nucleic Acids Deoxyribo AdenineGuanine ThymineCytosine Uracil

Flow of Information DNA RNA Protein Organic Compounds: Nucleic Acids and Proteins