Biochemistry of Cells PDF

Biochemistry of Cells Copyright Cmassengale 1  What is an organic compound? Contains carbon skeleton Is covalently bonded  Organic Compounds Always contain carbon and hydrogen Usually contain covalent bonds Usually large, unique molecules with complex functions...

Biochemistry of Cells Copyright Cmassengale 1  What is an organic compound? Contains carbon skeleton Is covalently bonded  Organic Compounds Always contain carbon and hydrogen Usually contain covalent bonds Usually large, unique molecules with complex functions The two major characteristics of the chemistry of life are: 1. Living things contain organic molecules 2. Living things are made mostly of water Uses of Organic Molecules Humans 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 Copyright Cmassengale 4  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 Copyright Cmassengale 5  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 Copyright Cmassengale 6  Water Properties Polarity Cohesiveness Adhesiveness Surface Tension Copyright Cmassengale 7  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 Copyright Cmassengale 8 Carbon bonds easily Carbon is very flexible in the structures it forms  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 Copyright Cmassengale 11  Hydrocarbons The simplest carbon compounds … Contain only carbon & hydrogen atoms Copyright Cmassengale 12 Carbon can use its bonds to:: Attach to other carbons Form an endless diversity of carbon skeletons Copyright Cmassengale 13  Large Hydrocarbons: Are the main molecules in the gasoline we burn in our cars The hydrocarbons of fat molecules provide energy for our bodies Copyright Cmassengale 14 Shape of Organic Molecules Each type of organic molecule has a unique three-dimensional shape The shape determines its function in an organism Copyright Cmassengale 15  Functional Groups Active portion of the molecule that determines what properties that compound has.  Functional Groups are: Groups of atoms that give properties to the compounds to which they attach Gained Electrons Copyright Cmassengale Lost Electrons17 Common Functional Groups Copyright Cmassengale 18  Many monomers join to form polymers Polymers are made from many of the same basic subunits Most Macromolecules are Polymers Polymers are made by stringing together many smaller molecules called monomers Nucleic Acid Monomer Copyright Cmassengale 21 Linking Monomers Cells link monomers by a process called condensation or dehydration synthesis (removing a molecule of water) Remove H H2O Forms Remove OH This process joins two sugar monomers to make a double sugar Copyright Cmassengale 22  Breaking Down Polymers Cells break down macromolecules by a process called hydrolysis (adding a molecule of water) Water added to split a double sugar Copyright Cmassengale 23 Dehydration (Condensation Reaction) Building polmers… Monomers link together to forms chains of polymers Each time monomer is added to chain, a water molecule is released = Dehydration Condensation Reactions take water out to join molecules Glucose + Fructose → Sucrose Reactants Products + → + Condensation Reaction (dehydration) water is released Hydrolysis Breaking polmers… Water used to break polymer H20 breaks bond linking each monomer Reverse of dehydration Hydrolysis Reactions add water & split molecules apart Breakdown of polymer involves… Hydrolysis! (adding water to break polymer)  What is a condensation reaction (dehydration)? What is hydrolysis? Glucose + Fructose  Sucrose Products Reactants + → + Hydrolysis – water is added Macromolecules in Organisms There are four categories of large molecules in cells: Carbohydrates Lipids Proteins Nucleic Acids Copyright Cmassengale 32 Giant Molecules - Polymers Large molecules are called polymers Polymers are built from smaller molecules called monomers Biologists call them macromolecules Copyright Cmassengale 33 Examples of Polymers Proteins Lipids Carbohydrates Nucleic Acids Copyright Cmassengale 34 Carbohydrates Carbohydrates include: Small sugar molecules in soft drinks Long starch molecules in pasta and potatoes Copyright Cmassengale 35  Monosaccharides: Called simple sugars Include glucose, fructose, & galactose Have the same chemical, but different structural formulas C6H12O6 Copyright Cmassengale 36 Monosaccharides Glucose is found in sports drinks Fructose is found in fruits Honey contains both glucose & fructose Galactose is called “milk sugar” Copyright Cmassengale 37 -OSE ending means SUGAR Isomers Glucose & fructose are isomers because they’re structures are different, but their chemical formulas are the same Copyright Cmassengale 38 Rings In aqueous (watery) solutions, monosaccharides form ring structures Copyright Cmassengale 39  Cellular Fuel Monosaccharides are the main fuel that cells use for cellular work ATP Copyright Cmassengale 40 Disaccharides Common disaccharides include: Sucrose (table sugar) Lactose (Milk Sugar) Maltose (Grain sugar) Copyright Cmassengale 41 Disaccharides Sucrose is composed of glucose + fructose Maltose is composed of 2 glucose molecules Lactose is made of galactose + glucose GLUCOSE Copyright Cmassengale 42 Polysaccharides Complex carbohydrates Composed of many sugar monomers linked together Polymers of monosaccharide chains Copyright Cmassengale 43 Examples of Polysaccharides Glucose Monomer Starch Glycogen Cellulose Copyright Cmassengale 44 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 Copyright Cmassengale 45  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 because BOTH are made of glucose monomers Copyright Cmassengale 46  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 Copyright Cmassengale 47  Cellulose SUGARS Copyright Cmassengale 48  Dietary Cellulose Most animals cannot derive nutrition from fiber They have bacteria in their digestive tracts that can break down cellulose Copyright Cmassengale 49  Digesting starch vs. cellulose starch easy to enzyme digest cellulose hard to enzyme digest Why do we eat cellulose if we can’t digest it?? Fiber = Cellulose We can't digest it, but it's really good for us because it helps keep our insides clean. It also helps to keep everything moving through just like it should, helping to carry all the body's waste on out of your system. Whole grains and vegetables have a lot of this kind of fiber.  Cow can digest cellulose well; no need to eat other sugars Gorilla can’t digest cellulose well; must add another sugar source, like fruit to diet  Sugars in Water Simple sugars and double sugars dissolve WATER readily in water MOLECULE They are hydrophilic, or “water- loving” -OH groups SUGAR make them MOLECULE water soluble Copyright Cmassengale 53  Lipids Lipids are hydrophobic –”water fearing” Do NOT mix with water Includes fats, waxes, steroids, & oils FAT MOLECULE Copyright Cmassengale 54 Function of Lipids Fats store energy, help to insulate the body, and cushion and protect organs Copyright Cmassengale 55  Triglyceride Monomer of lipids Composed of Glycerol & 3 fatty acid chains Glycerol forms the “backbone” of the fat Organic Alcohol (-OL ending) Copyright Cmassengale 56  Triglyceride Glycerol Fatty Acid Chains Copyright Cmassengale 57 Fats in Organisms Most animal fats have a high proportion of saturated fatty acids & exist as solids at room temperature (butter, margarine, shortening) Copyright Cmassengale 58 Fats in Organisms Most plant oils tend to be low in saturated fatty acids & exist as liquids at room temperature (oils) Copyright Cmassengale 59  Fats Dietary fat consists largely of the molecule triglyceride composed of glycerol and three fatty acid chains Fatty Acid Chain Glycerol Condensation links the fatty acids to Glycerol Copyright Cmassengale 60 Types of Fatty Acids Saturated fatty acids have the maximum number of hydrogens bonded to the carbons (all single bonds between carbons) Unsaturated fatty acids have less than the maximum number of hydrogens bonded to the carbons (a double bond between carbons) Copyright Cmassengale 61 Types of Fatty Acids Single Bonds in Carbon chain Double bond in carbon chain Copyright Cmassengale 62 Saturated and unsaturated fats Essential Details #3: Saturated = full of carbon atoms Essential Details #4: Unsaturated = not entirely full of carbon atoms  Lipids & Cell Membranes Cell membranes are made of lipids called phospholipids Phospholipids have a head that is polar & attract water (hydrophilic) Phospholipids also have 2 tails that are nonpolar and do not attract water (hydrophobic) Copyright Cmassengale 64  Steroids The carbon skeleton of steroids is bent to form 4 fused rings Cholesterol Cholesterol is the “base Estrogen steroid” from Testosterone which your body produces other steroids Estrogen & testosterone are also steroids Copyright Cmassengale 65 Synthetic Anabolic Steroids They are variants of testosterone Some athletes use them to build up their muscles quickly They can pose serious health risks Copyright Cmassengale 66  Anabolic Steroids Steroids occur in animals in something called hormones. Many body builders and athletes use anabolic steroids to build muscle mass. The steroids make their body want to add more muscle than they normally would be able to. The body builders wind up stronger and bulkier (but not faster). Never take drugs to enhance your body. Those body builders are actually hurting their bodies. They can't see it because it is slowly destroying their internal organs and not the muscles. When they get older, they can have kidney and liver problems. Some even die.  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 Copyright Cmassengale 68  Four Types of Proteins Storage Structural Contractile Transport Copyright Cmassengale 69 20 Amino Acid Monomers Copyright Cmassengale 70  Structure of Amino Acids Amino Carboxyl Amino acids have a group group central carbon with 4 things boded to it: R group Amino group –NH2 Carboxyl group -COOH Hydrogen -H Side groups Side group -R Serine-hydrophillic Leucine -hydrophobic Copyright Cmassengale 71 Linking Amino Acids Carboxyl Cells link amino acids together to make Amino proteins Side Group The process is called condensation Dehydration or dehydration Synthesis Peptide bonds form to hold the amino acids together Peptide Bond Copyright Cmassengale 72 Different combinations 1. Change the sequence (order) 2. Change the length (number of amino acids) Shape is everything to a protein!  Protein order & number Function depends on specific order of amino acids, which affects shape of protein Just like 26 letters of the alphabet form infinite numbers of words, 20 amino acids form infinite numbers of proteins! Sickle Cell Hemoglobin Anemia is made of 574 amino acids! If just 1 of the 600 amino acids is the wrong one, your red blood cells will sickle Hemoglobin is protein in red blood cells that transports oxygen  Primary Protein Structure The primary structure is the specific sequence of amino acids in a protein Called polypeptide Amino Acid Copyright Cmassengale 76 Protein Structures Secondary protein structures occur when protein chains coil or fold When protein chains called polypeptides join together, the tertiary structure forms because R groups interact with each other In the watery environment of a cell, proteins become globular in their quaternary structure Copyright Cmassengale 77  Protein Structures or CONFORMATIONS Hydrogen bond Pleated sheet Polypeptide Amino acid (single subunit) (a) Primary structure Hydrogen bond Alpha helix (b) Secondary (c) Tertiary structure structure (d) Quaternary structure Copyright Cmassengale 78  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 Copyright Cmassengale 79  Changing Amino Acid Sequence Substitution of one amino acid for another in hemoglobin causes sickle-cell disease 2 7... 146 1 3 6 4 5 (a) Normal red blood cell Normal hemoglobin 2 7... 146 1 3 6 4 5 (b) Sickled red blood cell Sickle-cell hemoglobin Copyright Cmassengale 80  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 Copyright Cmassengale 81  Enzymes Enzymes are globular proteins. Their folded conformation creates an area known as the active site. The nature and arrangement of amino acids in the active site make it specific for only one type of substrate. Copyright Cmassengale 82 Enzyme + Substrate = Product Copyright Cmassengale 83  How the Enzyme Works Enzymes are reusable!!! Active site changes SHAPE Called INDUCED FIT Copyright Cmassengale 84  Enzymes Enzyme binds a particular reactant or substrate Substrate fits into part of enzyme like a key fits into a lock This is called the “Lock and Key” model  Other Important Proteins Blood sugar level is controlled by a protein called insulin Insulin causes the liver to uptake and store excess sugar as Glycogen The cell membrane also contains proteins Receptor proteins help cells recognize other cells Copyright Cmassengale 86 INSULIN Cell membrane with proteins & phospholipids Copyright Cmassengale 87  Nucleic Acids Store hereditary information Contain information for making all the body’s proteins Two types exist --- DNA & RNA Copyright Cmassengale 88 Copyright Cmassengale 89  Nucleic Acids Nitrogenous base (A,G,C, or T) Nucleic acids are polymers of Phosphate group Thymine (T) nucleotides Sugar (deoxyribose) Phosphate Base Sugar Nucleotide Copyright Cmassengale 90 DNA Structure Double Stranded Deoxyribose sugar A-G-T-C (Nitrogenous Bases) 3 parts of DNA Structure Nitrogenous base (A-G-T-C) Phosphate Group 5 Carbon Sugar Nitrogenous Bases DNA = A-G-T-C Adenine Guanine Thymine Cytosine RNA = A-G-U-C Adenine Guanine Uracil Cytosine  DNA Bonds Strong, covalent bonds are used to bond monomers together along one chain Weak, hydrogen bonds are used to bond the chains across the double helix The weak hydrogen bonds hold the DNA in a double strand, but then allow the DNA to split into two strand to be replicated (copied).  RNA Structure Single Stranded ribose sugar Uracil instead of thymine DNA: Most important molecule on Earth It’s found in all humans and all other organisms, in every cell It provides the starting template for every new life It codes for many of the traits that make you, you! DNA codes determine the sequence of the amino acids DNA codes are passed on to our children Humans have about 6 billion codes in each cell! So What? (What’s important to understand about this?) Contain all genetic info (codes) for cell activities and building proteins Nucleotide – Nucleic acid monomer Copyright Cmassengale 100 Nucleic Acids Copyright Cmassengale 101 Bases Each DNA nucleotide has one of the following bases: Thymine (T) Cytosine (C) –Adenine (A) –Guanine (G) –Thymine (T) –Cytosine (C) Adenine (A) Guanine (G) Copyright Cmassengale 102 Nucleotide Monomers Backbone Form long chains Nucleotide called DNA Nucleotides are joined by sugars & phosphates on the side Bases DNA strand Copyright Cmassengale 103 DNA Two strands of DNA join together to form a double helix Base pair Double helix Copyright Cmassengale 104 RNA – Ribonucleic Acid Nitrogenous base (A,G,C, or U) Ribose sugar has an extra – OH or hydroxyl group Uracil It has the Phosphate group base uracil (U) instead of thymine (T) Sugar (ribose) Copyright Cmassengale 105  ATP – Cellular Energy ATP is used by cells for energy Adenosine triphosphate Made of a nucleotide with 3 phosphate groups Copyright Cmassengale 106  ATP – Cellular Energy Energy is stored in the chemical bonds of ATP The last 2 phosphate bonds are HIGH ENERGY Breaking the last phosphate bond releases energy for cellular work and produces ADP and a free phosphate ADP (adenosine Diphosphate) can be rejoined to the free phosphate to make more ATP Copyright Cmassengale 107 Summary of Key Concepts Copyright Cmassengale 108 Macromolecules Copyright Cmassengale 109 Macromolecules Copyright Cmassengale 110  End Copyright Cmassengale 111