2. Molecules of life - 24-25.pptx

Nucleic Acids Lipids Proteins Carbohydrates 2. Introduction to important molecules of life : structure and function  Of the 92 naturally occurring elements, 16 are known to be important constituents of living systems: C, H, O, N, P, S, K...

Nucleic Acids Lipids Proteins Carbohydrates 2. Introduction to important molecules of life : structure and function  Of the 92 naturally occurring elements, 16 are known to be important constituents of living systems: C, H, O, N, P, S, K, Ca, Na, Cl, Mg, Fe, Cu, I, Mo, Zn  Organic compounds - a large class of Carbon-containing chemical compounds in which one or more atoms of carbon are covalently linked to atoms of other elements, most commonly H, N, or O.  Why is carbon the backbone of life? Why is it special? Simple organic compound Found natural Digestive tracts of Grazing animals It is possible to construct an endless diversity of C skeletons varying in size and branching pattern  Variation in carbon skeletons contributes to the diversity of organic molecules. Carbon chains form the skeletons of most organic molecules. The skeletons vary in length & may be straight, branched, or arranged in closed rings.... Atoms of other elements can be bonded to the atoms of the carbon skeleton. 2. Branched Chain 3. Ring 1. Straight Chain Carbon skeleton may vary in length C skeletons may have double bond in different locations Animation: Carbon Skeletons Carbon skeleton may be Carbon skeleton may be unbranched / branched arranged in rings Each biomacromolecule has one or more characteristic functional group(s) which give the molecule its specific properties and functions - they are often the centers of chemical reactivity. DNA – Phosphate; Proteins – Amino and carboxyl; Carbs – hydroxyl; Lipids – all of the above?  Biological Molecules to Consider Subunits that serve as building blocks Connected by Dehydration Synthesis Process (condensation) Break down by Hydrolysis Process Covalent bonding Solubility in Water Monomer Polymers Dehydration Synthesis Process Monomers H HO H HO Polymer H2O H from one monomer (Glucose) & OH from another monomer (Fructose) are taken out. They form H2O. If dehydration synthesis continues for a long time, a long & complex carbohydrate chain a polysaccharide is formed. The bond between two carbohydrates is called a Glyosidic Linkage.  Hydrolysis Giant Molecules from Smaller Building Blocks Monomers H 2O Hydrogen hydroxide cation anion H HO C12H22O11 + H2O C6H12O6 + C6H12O6 A chemical reaction in which water reacts with a compound to produce other compounds; involves the splitting of a bond and the addition of the hydrogen cation & the hydroxide anion from the water. breaks bonds between monomers, adds a molecule of water, and reverses the dehydration reaction. Animation: Polymers Dehydration Synthesis- Bonds are formed through the removal of water. It is the chemical reaction in which two molecules are joined covalently by the removal of -OH from one molecule and -H atom from the other molecule. It is also known as condensation. Examples include reactions joining monomers to form polymers. Carbs - Monosaccharide + Monosaccharide -> Disaccharide + H20 Lipid - 1Glycerol + 3 Fatty Acids -> Lipid + 3 H2O Protein - 2 Amino Acids -> Dipeptide + H2O Nucleic Acid- Nucleotides -> Nucleic Acid + H2O Hydrolysis - Bonds are broken through the addition of water. It is the chemical reaction in which a molecule is split into smaller units by the reaction with water's addition. Examples include reactions which split polymers into monomers. It is how we break down food into smaller units that can be used for our cells. Carbs - Disaccharide + H2O -> Monosaccharide + Monosaccharide Lipid- Lipid + 3 H2O -> 1 Glycerol + 3 fatty Acids Protein- Dipeptide + H2O -> 2 Amino Acids  1) CARBOHYDRATES © 2016 Pearson Education, Inc. Characteristics of Carbohydrates Carbohydrates = sugars (Saccharide means simple sugar) Sugars, Starches & Others Suffix used = -ose. Principle Elements: C, H, & O Characteristic formula Cn H2n On From Photosynthesis (1:2:1) Monomers: Monosaccharaides Polymers: Polysaccharides Water Soluble (Hydrophilic) Functions of Carbohydrates Energy Metabolism Structural Components Cell-to-Cell Contacts & Recognition Elimination of wastes (fiber) Trioses - 3 carbon atoms C3 H6 O3 glyceraldehyde Tetroses - 4 carbon atoms C4 H8 O4 erythrose Pentoses - 5 carbon atoms C5 H10 O5 ribose Hexoses - 6 carbon atoms C6 H12 O6 glucose, fructose, galactose What is Dextrose? Glucose dissolved in water; (mono) Dextrose is the name of a simple sugar made from corn or wheat that's chemically identical to glucose, or blood sugar  Monosaccharides Disaccharides C5H10O5 C5H10O5 C6H12O6 C6H12O6 Glucose Fructose glucose + galactose = Lactose Milk sugar glucose + glucose = Maltose Malt sugar Isomers? Different forms of a compound having different arrangements of atoms but the same molecular weight glucose + fructose = Sucrose Animation: Disaccharides Common sweetener - High-fructose Corn Syrup (HFCS) made by chemically treating sugars extracted from corn  Glucose in the form of starch in sweet corn - processed by the enzyme glucose isomerase to convert it into fructose, which is much sweeter The average 20 oz. soda contains 15 teaspoons of sugar, all of it as HFCS Dangers of High Fructose Corn Syrup: Tooth decay Weight Gain Cancer Increased Cholesterol Levels Diabetes High Blood Pressure Heart Disease Empty calories? Calories derived from food containing NO nutrients. Seems like a bit of a contradiction, doesn’t it? Calories are supposed to give us energy, so how can they be empty? Well, an empty calorie does supply energy but is not nutritionally balanced. Most sweeteners contain only negligible amount of nutrients other than carbohydrates. If you’re trying to maintain / lose weight. It’s better to keep these at a minimum level.  Polysaccharides - “complex carbohydrates” Cellulose Glycogen granules in muscle tissue Amylose Commonly known as “starch” is the way many plants store sugars – found commonly in rice, potatoes, corn, wheat, beans and so forth - Storage carb. There are no starches in meat, fish, eggs and none in your own body. So, what happens if you eat starch? Starch gets digested & broken down into individual glucose molecules and that’s what you absorb. Cellulose is made up of glucose monomer, just like starch. We as humans cannot digest or break apart these sugar molecules. Hence, it is referred to as “indigestible fibre,” “roughage,” or “insoluble fibre” - Structural carb. When you eat grains, celery, carrots, or any plant material, the outer plant cell walls are crushed by our teeth and only the contents of the cells are digested. The cellulose however, will remain unchanged and exit along with stools. Our digestive tract needs a certain amount of this indigestible fibre to keep it healthy. When we don’t have enough of this, it makes our digestive tract thin & weak. Easy bowl movements prevents constipation. Remember that cellulose (just like starch) exists only in plants. Glycogen = “animal starch”; The same way plants store sugar by creating starch, animals store sugar using glycogen. A long chain of glucose molecules - Storage carb! This is primarily stored in our liver and muscles. Athletes such as long-distance runners / cyclists, require endurance, and hence often indulge in ’carb-loading’. Eating lots & lots of carbs before an event, helps in absorbing these simple sugars & store it as glycogen in our liver & muscles for energy reserves. These stored sugars can then be broken down easily during the event. Another If you keep carb-loading, how­ever, and don’t expend the energy within the next important cou­ple days, whatstru will happen? a polymer of -glucose  It will be turned into fat!! functional group. Chitin = A polymer of beta-glucose molecules having a nitrogen containing functional group – an important structural polysaccharide!!  It is also indigestible like cellulose  Used to build cell walls in fungi and exoskeletons in arthropods  Classified as a carbohydrate even though it does not strictly follow the structural formula - Cn H2n On 2) Lipids © 2016 Pearson Education, Inc.  Characteristics of Lipids Oils, fats, waxes, phospholipids, steroids Principle Elements: C, H, & O Some With P & N Water Insoluble (Hydrophobic) Functions of Lipids Energy Storage Protection & Cushioning of Body Organs Structural Components of Membranes Chemical Messengers (hormones)  MAJOR TYPES OF LIPIDS Major types include Fats and Oils, Waxes, Phospholipids, and Steroids Phospholipids (Any of various compounds composed of fatty acids & phosphoric acid and a nitrogenous base; an important constituent of membranes) Triglycerides (neutral fats) Sterols (also known as steroid alcohols. They occur naturally in plants, animals, and fungi, with the most familiar type of animal sterol being cholesterol. Cholesterol is vital to cellular function, and a precursor to fat-soluble vitamins and steroid hormones). Phospholipid TRIGLYCERIDES Bilayer Waxes FATTY ACIDS GLYCEROLES Hydrophilic head Hydrophobic tails Phospholipids  Saturated Fats Glycerol Saturated with H+ Fatty Acids Most animal fats are saturated, eg. butter Tend to be Solid at room temp (37oC) Unsaturated Fats Has one or more double bonds between carbons Most vegetable fats Tend to be Liquid at room temp DEHYDROGENATION is a chemical reaction that involves the removal of hydrogen from a molecule. It is the reverse process of hydrogenation. Dehydrogenation reactions are conducted both on industrial and laboratory scales. Dehydrogenation converts saturated fats to unsaturated fats. HYDROGENATION complete or partial, is a chemical process in which hydrogen is added to liquid oils to turn them into a solid form. Partially hydrogenated fat molecules have trans fats, and they may be the worst type of fat you can consume. Figure 3.12 TYPES OF FATS Saturated Fats Unsaturated Fats Margarine Plant oils Trans fats Omega-3 fats Cholesterol Steroids is an organic compound with four rings arranged in a specific molecular configuration. Eg. i) Dietary lipid cholesterol, ii) Sex hormones Estradiol (estrogen) &Testosterone. (Anatomical & physiological differences are brought in by these hormones) How do steroids affect the body? Some athletes take a form of steroids — known as Anabolic-Androgen Steroids / just anabolic steroids — to increase their muscle mass & strength. The main anabolic steroid hormone produced by our body is Testosterone. Testosterone has two main effects on our body Anabolic effects promote muscle building. Synthetic anabolic steroids  are variants / alternatives of testosterone,  mimic some of its effects,  may be prescribed to treat diseases such as cancer and AIDS,  are abused by athletes to build up their muscles quickly, and  can cause serious physical and mental problems. Side effects of oral corticosteroids 1. Fluid retention, causing swelling in your lower legs. 2. High blood pressure. 3. Problems with mood swings, memory, behavior, and other psychological effects, such as confusion or delirium. 4. Upset stomach. 5. Weight gain, with fat deposits in your abdomen, your face and the back of your neck. How long do steroids stay in your system? If taken orally, steroids can show up in a urine test for up to 14 days. If injected, steroids can show up for up to 1 month. Proteins are polypeptides - polymers of amino acids.  Characteristics of Proteins Amino Acid Structure Principle Elements: C, H, O, & N Monomers: Amino Acids Polymers: Polypeptides or Proteins Generally Water Soluble Functional Groups of Amino Acids [hydroxyl (Alcoholic), Carbonyl, Amino, Sulfhydryl, Phosphate, Methyl ] Carboxylic Acid (-COOH) Amine (-NH2) R-Groups (variable - 20 different kinds)  Formation of Peptide Bonds Dehydration synthesis process Carboxyl group of one aa + Amino group of another aa Peptide bond Two Different Polypeptides The variation in R groups gives amino acids different properties Figure 3.15 Some of the varied roles played by proteins MAJOR TYPES OF PROTEINS Structural Proteins Storage Proteins Contractile Transport Proteins Enzymes (provide support) (provide amino Proteins (help transport (help chemical acids for growth) (help movement) substances) reactions)  Functions of Proteins Enzymes Structural Proteins Chemical Messengers Hormones Antibodies The bond between two amino acids is called a Polypeptide / dipeptide bond The bond between fatty acids and glycerol is called an Ester linkage The bond between two carbohydrates (monosaccharides) is called a Glycosidic bond  The diversity of protein function results from diversity of protein structure which is the result of variation in the sequence of amino acids  Functional proteins can vary in length from about 50 amino acids to several thousand amino acids  The diversity of amino acid sequence results in diversity of protein structure  Protein structure can be classified at several different levels: primary, secondary, tertiary, and quaternary  Levels of Protein Structure Primary structure: Linear sequence of amino acids NH3 Leu Cys Val Asp Phe COO Alpha helix Beta Pleated skirt Secondary structure: (likely to twist) (Hair) (Silk) H-Bonds Tertiary: highly coiled & Pleated – interact to form globular (153 amino acids) 3D configuration Weak bonds between side chains (Myoglobin & Cytochrome) Quaternary: Two or more polypeptides e.g. Hemoglobin (Hb) (immunoglobins / antibodies – involved in fighting infectious diseases like Flu, mumps, chicken pox etc.,) Primary structure Secondary structure Tertiary structure Quaternary structure  The form and function of protein If a protein is to do its job effectively, it is vital to maintain a particular shape, sequence, 3D shape. e.g. Normal Hb found in RBC consist of 2 kinds of polypeptide chains– Alpha & Beta chains. The beta chain is 146 aa long, just one of these amino acids is replaced by different one cause drastic change CLASSIC EXAMPLES Sickle cell anemia – 6th aa in beta chain usually glutamic acid changes to valine BSE-Bovine Spongiform encephalitis (Mad Cow Disease) it is an infectious disease believed to be due to a misfolded protein, known as a PRION. An infectious protein particle similar to a virus but lacking nucleic acid Chronic Wasting Disease (CWD) is a contagious neurological disease affecting deer. CJD – Creutzfeldt Jacob Disease (caused by prions) brain cells damaged. CJD is a rare, degenerative, invariably fatal brain disorder. It affects about one person in every one million people/ year worldwide; in US there are about 300 cases / year. Characterized by progressive dementia & gradual loss of muscle control Denature of the egg white Medicines to be stored in brown bottle (light interactions) refrigerated (low temp) – otherwise loose the potency Characteristics of Nucleotide Nucleic Acids Structure Principle Elements: C, H, O, N, & P Monomers: Nucleotides Nitrogen Base Phosphate Polymers: Nucleic Acids Generally Water Soluble Sugar Nucleotide Components: Ribose (5-C) Sugar Phosphate Nitrogenous Base Functions of Nucleic Acids Genetic Instruction Set (DNA) Protein Synthesis (DNA & RNA) Energy Metabolism (ATP)  Nucleotide Bases Nucleotide Sugars Nucleotide Bases Purines Pyrimidines Polynucleotides = Nucleic Uracil Double-Stranded DNA Acids  DNA RNA Polymers made up of individual nucleotides The components of RNA are somewhat similar Nucleotides contain to DNA with 3 major differences. Phosphate group 1. The pyrimidine base uracil replaces thymine Five carbon sugar 2. ribose sugar replaces deoxyribose. 3. RNA mostly forms single stranded structure. Ring shaped nitrogen base DNA contains information for almost all cell activities There are 3 types of RNA directly involved in protein synthesis: Messenger RNA (mRNA) carries the instructions from the nucleus to the cytoplasm. The other two forms of RNA, ribosomal RNA (rRNA) and transfer RNA (tRNA), are involved in the process of ordering the amino acids to make the protein.  ATP Role of ATP in Energy Metabolism Role of ATP in Energy ATP ADP + Pi + Metabolism Energy 1) Passing the information to the next generation (Cell division - DNA replication) 2) Protein synthesis (Translation & Transcription. In a cell, this involves the synthesis of new molecules from food) MAJOR CLASSES