Biochemistry Introduction

Biochemistry of Cells :1 Biochemistry of Cells


Uses of Organic Molecules :2 Uses of Organic Molecules Americans consume an average of 140 pounds of sugar per person per year Cellulose, found in plant cell walls, is the most abundant organic compound on Earth


Uses of Organic Molecules :3 Uses of Organic Molecules A typical cell in your body has about 2 meters of DNA A typical cow produces over 200 pounds of methane gas each year


Water :4 Water About 60-90 percent of an organism is water Water is used in most reactions in the body Water is called the universal solvent


Water Properties :5 Water Properties Polarity Cohesiveness Adhesiveness Surface Tension


Carbon-based Molecules :6 Carbon-based Molecules Although a cell is mostly water, the rest of the cell consists mostly of carbon-based molecules Organic chemistry is the study of carbon compounds


Carbon is a Versatile Atom :7 Carbon is a Versatile Atom It has four electrons in an outer shell that holds eight Carbon can share its electrons with other atoms to form up to four covalent bonds


Hydrocarbons :8 Hydrocarbons The simplest carbon compounds … Contain only carbon & hydrogen atoms


Carbon can use its bonds to:: :9 Carbon can use its bonds to:: Attach to other carbons Form an endless diversity of carbon skeletons


Large Hydrocarbons: :10 Large Hydrocarbons: Are the main molecules in the gasoline we burn in our cars The hydrocarbons of fat molecules provide energy for our bodies


Shape of Organic Molecules :11 Shape of Organic Molecules Each type of organic molecule has a unique three-dimensional shape The shape determines its function in an organism


Functional Groups are: :12 Functional Groups are: Groups of atoms that give properties to the compounds to which they attach Gained Electrons Lost Electrons


Common Functional Groups :13 Common Functional Groups


Giant Molecules - Polymers :14 Giant Molecules - Polymers Large molecules are called polymers Polymers are built from smaller molecules called monomers Biologists call them macromolecules


Examples of Polymers :15 Examples of Polymers Proteins Lipids Starch Nucleic Acids


Most Macromolecules are Polymers :16 Most Macromolecules are Polymers Polymers are made by stringing together many smaller molecules called monomers Nucleic Acid Monomer


Linking Monomers :17 Linking Monomers Cells link monomers by a process called dehydration synthesis (removing a molecule of water) This process joins two sugar monomers to make a double sugar Remove H Remove OH H2O Forms


Breaking Down Polymers :18 Breaking Down Polymers Cells break down macromolecules by a process called hydrolysis (adding a molecule of water) Water added to split a double sugar


Macromolecules in Organisms :19 Macromolecules in Organisms There are four categories of large molecules in cells: Carbohydrates Lipids Proteins Nucleic Acids


Carbohydrates :20 Carbohydrates Carbohydrates include: Small sugar molecules in soft drinks Long starch molecules in pasta and potatoes


Monosaccharides: :21 Monosaccharides: Called simple sugars Include glucose, fructose, & galactose Have the same chemical, but different structural formulas C6H12O6


Monosaccharides :22 Monosaccharides Glucose is found in sports drinks Fructose is found in fruits Honey contains both glucose & fructose Galactose is called “milk sugar”


Isomers :23 Isomers Glucose & fructose are isomers because they’re structures are different, but their chemical formulas are the same


Rings :24 Rings In aqueous (watery) solutions, monosaccharides form ring structures


Cellular Fuel :25 Cellular Fuel Monosaccharides are the main fuel that cells use for cellular work ATP


Disaccharides :26 Disaccharides A disaccharide is a double sugar They’re made by joining two monosaccharides Involves removing a water molecule (dehydration)


Disaccharides :27 Disaccharides Common disaccharides include: Sucrose (table sugar) Lactose (Milk Sugar) Maltose (Grain sugar)


Disaccharides :28 Disaccharides Sucrose is composed of glucose + fructose Maltose is composed of 2 glucose molecules Lactose is made of galactose + glucose GLUCOSE


Polysaccharides :29 Polysaccharides Complex carbohydrates Composed of many sugar monomers linked together Polymers of monosaccharide chains


Examples of Polysaccharides :30 Examples of Polysaccharides Starch Glycogen Cellulose Glucose Monomer


Starch :31 Starch Starch is an example of a polysaccharide in plants Plant cells store starch for energy Potatoes and grains are major sources of starch in the human diet


Glycogen :32 Glycogen Glycogen is an example of a polysaccharide in animals Animals store excess sugar in the form of glycogen Glycogen is similar in structure to starch


Cellulose :33 Cellulose Cellulose is the most abundant organic compound on Earth It forms cable-like fibrils in the tough walls that enclose plants It is a major component of wood It is also known as dietary fiber


Cellulose :34 Cellulose SUGARS


Dietary Cellulose :35 Dietary Cellulose Most animals cannot derive nutrition from fiber They have bacteria in their digestive tracts that can break down cellulose


Sugars in Water :36 Sugars in Water Simple sugars and double sugars dissolve readily in water They are hydrophilic, or “water-loving” WATER MOLECULE SUGAR MOLECULE


Lipids :37 Lipids Lipids are hydrophobic –”water fearing” Includes fats, waxes, steroids, & oils Do NOT mix with water FAT MOLECULE


Function of Lipids :38 Function of Lipids Fats store energy, help to insulate the body, and cushion and protect organs


Types of Fatty Acids :39 Types of Fatty Acids Unsaturated fatty acids have less than the maximum number of hydrogens bonded to the carbons (a double bond between carbons) Saturated fatty acids have the maximum number of hydrogens bonded to the carbons (all single bonds between carbons)


Types of Fatty Acids :40 Types of Fatty Acids Single Bonds in Carbon chain Double bond in carbon chain


Triglyceride :41 Triglyceride Monomer of lipids Composed of Glycerol & 3 fatty acid chains Glycerol forms the “backbone” of the fat Organic Alcohol


Triglyceride :42 Triglyceride Glycerol Fatty Acid Chains


Fats in Organisms :43 Fats in Organisms Most animal fats have a high proportion of saturated fatty acids & exist as solids at room temperature (butter, margarine, shortening)


Fats in Organisms :44 Fats in Organisms Most plant oils tend to be low in saturated fatty acids & exist as liquids at room temperature (oils)


Fats :45 Fats Dietary fat consists largely of the molecule triglyceride composed of glycerol and three fatty acid chains Glycerol Fatty Acid Chain Dehydration links the fatty acids to Glycerol


Steroids :46 Steroids The carbon skeleton of steroids is bent to form 4 fused rings Cholesterol is the “base steroid” from which your body produces other steroids Estrogen & testosterone are also steroids Cholesterol Testosterone Estrogen


Synthetic Anabolic Steroids :47 Synthetic Anabolic Steroids They are variants of testosterone Some athletes use them to build up their muscles quickly They can pose serious health risks


Proteins :48 Proteins Proteins are polymers made of monomers called amino acids All proteins are made of 20 different amino acids linked in different orders Proteins are used to build cells, act as hormones & enzymes, and do much of the work in a cell


Four Types of Proteins :49 Four Types of Proteins Structural Contractile Storage Transport


20 Amino Acid Monomers :50 20 Amino Acid Monomers


Structure of Amino Acids :51 Structure of Amino Acids Amino acids have a central carbon with 4 things boded to it: Amino group -NH3 Carboxyl group -COOH Hydrogen -H Side group -R Amino group Carboxyl group R group Side groups Leucine -hydrophobic Serine-hydrophillic


Linking Amino Acids :52 Linking Amino Acids Cells link amino acids together to make proteins The process is called dehydration synthesis Peptide bonds form to hold the amino acids together Carboxyl Amino Side Group Dehydration Synthesis Peptide Bond


Proteins as Enzymes :53 Proteins as Enzymes Many proteins act as biological catalysts or enzymes Thousands of different enzymes exist in the body Enzymes control the rate of chemical reactions by weakening bonds, thus lowering the amount of activation energy needed for the reaction


Enzymes :54 Enzymes Their folded conformation creates an area known as the active site. Enzymes are globular proteins. The nature and arrangement of amino acids in the active site make it specific for only one type of substrate.


Enzyme + Substrate = Product :55 Enzyme + Substrate = Product


How the Enzyme Works :56 How the Enzyme Works Enzymes are reusable!!!


Primary Protein Structure :57 Primary Protein Structure The primary structure is the specific sequence of amino acids in a protein Amino Acid


Protein Structures :58 Protein Structures Secondary protein structures occur when protein chains coil or fold When protein chains called polypeptides join together, the tertiary structure forms In the watery environment of a cell, proteins become globular in their quaternary structure


Protein Structures :59 Protein Structures Hydrogen bond Pleated sheet Amino acid (a) Primary structure Hydrogen bond Alpha helix (b) Secondary structure Polypeptide (single subunit) (c) Tertiary structure (d) Quaternary structure


Denaturating Proteins :60 Denaturating Proteins Changes in temperature & pH can denature (unfold) a protein so it no longer works Cooking denatures protein in eggs Milk protein separates into curds & whey when it denatures


Changing Amino Acid Sequence :61 Changing Amino Acid Sequence Substitution of one amino acid for another in hemoglobin causes sickle-cell disease (a) Normal red blood cell Normal hemoglobin 1 2 3 4 5 6 7. . . 146 (b) Sickled red blood cell Sickle-cell hemoglobin 2 3 1 4 5 6 7. . . 146


Nucleic Acids :62 Nucleic Acids Store hereditary information Contain information for making all the body’s proteins Two types exist --- DNA & RNA


Slide 63 :63


Nucleic Acids :64 Nucleic Acids Nitrogenous base (A,G,C, or T) Phosphate group Thymine (T) Sugar (deoxyribose) Phosphate Base Sugar Nucleic acids are polymers of nucleotides Nucleotide


Bases :65 Bases Each DNA nucleotide has one of the following bases: Thymine (T) Cytosine (C) Adenine (A) Guanine (G) Adenine (A) Guanine (G) Thymine (T) Cytosine (C)


Nucleotide Monomers :66 Nucleotide Monomers Form long chains called DNA Backbone Nucleotide Bases DNA strand Nucleotides are joined by sugars & phosphates on the side


DNA :67 DNA Two strands of DNA join together to form a double helix Base pair Double helix


RNA – Ribonucleic Acid :68 RNA – Ribonucleic Acid Ribose sugar has an extra –OH or hydroxyl group It has the base uracil (U) instead of thymine (T) Nitrogenous base (A,G,C, or U) Sugar (ribose) Phosphate group Uracil


Summary of Key Concepts :69 Summary of Key Concepts


Nucleic Acids :70 Nucleic Acids


Macromolecules :71 Macromolecules


Macromolecules :72 Macromolecules


End :73 End