Biochemical Compounds You are what you eat! Why Do We Eat? We need to eat… •For energy •For nutrients Carbon: The Central Atom • Atoms of 4 elements make up roughly 99% of mass of most cells – Hydrogen – Nitrogen – Carbon – Oxygen • With a few exceptions, molecules containing carbon atoms are called organic compounds – Most also contain hydrogen and oxygen Carbon – The Glue!! • Carbon’s ability to bond covalently with other carbon atoms enables it to form a variety of geometrical structures including straight chains, branched chains, ring structures of various sizes and complexity. (Only C and H = hydrocarbons) Functional Groups – In biological systems, atoms may attach to a carbon backbone to form reactive clusters of atoms called Functional Groups • • • • • • CARBON Hydrogen Oxygen Nitrogen Phosphorus Sulfur Functional Groups • Functional groups possess certain chemical properties that they impart to the molecules to which they are attached • These groups are more reactive than the hydrocarbon portions of the biological molecule • Many compounds have more than one functional group in their structure. • These functional groups are hydrophilic (except phosphate group) and as such, are polar and increase the solubility in water of the organic molecules to which they are attached. • Each functional group has a specific role in cell metabolism. • OH and –COOH are polar because of the electronegative oxygen atoms they contain, therefore sugars and alcohols are highly soluble in H2O because they contain polar hydroxyl groups • -COOH makes molecule acidic (organic acids called carboxylic acids) • -NH2makes molecule basic (called amines) • Amino acids contain an amino group and a carboxyl group Molecules of Life • • • • Carbohydrates Fats (Lipids) Proteins DNA CARBOHYDRATES Refers to the “sugar” family • Contain C, H, & O • Examples: – Glucose, fructose, sucrose, lactose, etc. – Starch, cellulose, etc. CARBOHYDRATES • The body’s most important source of energy. • Comes from plants, synthesized from carbon dioxide using energy from the sun. • Made up of single sugar molecules or chains containing many sugar molecules. • Names usually end in “ose” Simple CHO’s: • Simple sugars monomers • Monomer: Mono = 1 – One building block of a larger molecule – Exists in a chain or a ring • Monosaccharide: – 1 molecule of a sugar (e.g. 1 glucose) • Glucose contains C, H, and O in the ratio 1:2:1 (C6H12O6) Glucose: (C6H12O6) This is the fundamental unit of energy used by the mitochondria in cellular respiration!! Can be in a chain or ring! Simple CHO’s: • Disaccharide: Di = 2 – 2 sugars linked together through a process called Dehydration Synthesis. Dehydration Synthesis • One monosaccharide loses a hydroxyl group (OH) and one loses a hydrogen atom (-H). • These two monosaccharides join, produce water (H2O) and a disaccharide is formed. • The opposite reaction is called “Hydrolysis". Water and enzymes are added and the disaccharide is broken down. Dehydration Synthesis • glucose + glucose = maltose • glucose + galactose = lactose Aldoses p 29 Ketoses Complex CHO’s • Polymer: “Poly” = many – 2 or more monomers linked together • Polysaccharide: (aka oligosaccharide) – 3 or more sugars linked together in chains by glycosidic linkages Complex CHO’s in Plants • Amylose (Starch) is made up of thousands of glucose molecules in a long chain. • Starch is a storage molecule for plants. • We break it down into glucose monomers when we eat it! Complex CHO’s in Plants • Cellulose is a molecule made up of many glucose molecules linked differently than in starch. • It is a component of cell walls. • Humans cannot digest it but it is important to us as dietary fibre. Isomers • All C6H12O6 just arranged differently! Isomers – Structural Isomers • Two or more compounds with same atoms bonded differently – Stereoisomers • Two or more compounds wither their atoms bonded in same way. But atoms arranged differently in space – Can be » Geometrical » Different physical properties, tend to have the same chemical properties » Optical » non-superimposable mirror images » usually have similar chemical and physical properties » enzymes or cell proteins can distinguish between them Alpha vs Beta Glucose! Complex CHO’s in Plants Complex CHO’s in Animals • Glycogen is a storage molecule for animals. • Stored in the liver/muscles. (Marathon runners) • Glycogen converted back to individual glucose units when concentration of glucose in blood begins to drop. Complex CHO’s in Animals Why CARB’s? • CHO’s provide the body with immediate energy needs. • Should be 50-55% of your calories • Sources: – Fruits, vegetables, grains, breads, pasta, cereals, etc. Low CARB Diets??? The End!!! Homework! • P 27 #1 • P 34 #2-8, 10 LET’S TALK LIPIDS • Hydrophobic molecules composed of C, H, & O • Insoluble in water! • Used by organisms to – Store energy (Long term) – Build membranes and other cell parts – As chemical signalling molecules • Can be divided into three families of lipids – Fats – Phospholipids – Steroids FATS – Most common energy-storing molecules in living organisms…should be 30% of daily intake. – 1 gram stores 9 calories compared to 1 g of carbohydrate (4 calories). – Animals convert excess carbohydrate to fat. – Fat stored as droplets in cells of adipose (fat) tissue. – Most common fats in plants & animals are Triglycerides (1 Glycerol molecule and three fatty acid chains). – Have more non-polar O-H bonds than carbs so they are insoluble in water Blocked Arteries Types of Fatty Acids 1. Saturated Fatty Acids(SFA’s…all single bonds b/w carbons.) -Animal (Bad) Fats! Saturated Fats • Solid at room Temp due to the tight fitting chains and van der Waals forces! Types of Fatty Acids 2. Monounsaturated fatty acids (MUFA’s)…one double bond. -Veggie (Good) Fats! Types of Fatty Acids 3. Polyunsaturated fatty acids (PUFA’s). Many C double bonds. • Industrial process called hydrogenation adds hydrogen atoms to the double bonds in unsaturated fatty acid chains of liquid fats, converting them into a semisolid material. This creates trans-fat!! VERY BAD! Kekule Structure Diagrams Triglycerides • When glycerol reacts with fatty acids, a condensation reaction takes place between a hydroxyl group of glycerol and the carboxyl group of a fatty acids. Esterification – Ester Linkages WELL NOT EXACTLY BUT…. LAST YEAR AMERICANS DID SPEND $150 BILLION ON FAST FOOD! Obesity is on the rise PHOSPHOLIPIDS • The cell membrane is composed mainly of phospholipids – A glycerol molecule attached to two fatty acids and highly polar phosphate group • Polar head hydrophilic • Non-polar tails hydrophobic – Phospholipids form spheres called micelles when added to water • • A phospholipids bilayer separating two water compartments, as in cell membranes Essential Fatty Acids • Some lipids are essential. • This means that your body cannot make the molecule… you must eat it!! • Eg. Linoleic, Linolenic fatty acids Steriods Also found in membranes! • Compact hydrophobic molecules containing four fused hydrocarbon rings and several different functional groups. (P 39) • Secreted into blood stream (golgi vesicles) for distribution. – cholesterol • builds up in bloodstream…dangerous! – other steroids include • sex hormones » testosterone » estrogens » Progesterone Homework • P. 41 • #11-18 The End!!! The Power of Proteins • Proteins account for more than 50% of the dry weight of most cells and are involved in almost everything the cell does. • The recommended daily intake is 20%. Most of us are eating double that!! • Dietary sources include meat, eggs, peanuts etc. The 7 Classes of Proteins 1. Structural proteins function in the cell membrane, muscle tissue, and includes the silk of spiders, the hair of mammals and the fibers that make up our tendons and ligaments. 2. Contractile proteins work with structural elements. They provide muscular movement. 3. Storage proteins, such as albumin, the main substance of egg white, which serves as a source of amino acids for developing embryos. 4. Defensive proteins, includes the antibodies which fight infection and are carried in the blood. 5. Transport proteins, include hemoglobin, the iron-containing protein in the blood that transports oxygen from our lungs to other parts of the body. 6. Enzymes, perhaps the most important class. Enzymes promote and regulate virtually all chemical reactions in cells. 7. Hormones, such as Insulin act as chemical messengers. Building Proteins • All proteins are made from the same 20 Amino Acids (A.A.’s). • DNA codes for the A.A. order. Change the A.A. order and a different protein is created. • The A.A. monomers form polypeptide chains held together by peptide bonds (dehydration synthesis reaction). The General Structure of an A.A. 1. Amino group (NH2) 2. Carboxyl Group (COOH) 3. R group (side chain)…this is different in each amino acid. NOTE: 9 Amino Acids are considered Essential! (histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine.) http://www.youtube.com/watch?v=haDNTOooXk&feature=related R Groups • Determine chemical properties! • i.e. Cysteine (SH portion of the R-group combines with others to make “disulfide bridges”! Protein Structure • Protein length can vary from 8 amino acids long to 4000!! • 1 A.A. = 1 A.A. monomer • 2 A.A.’s = a dipeptide molecule • Many A.A.’s = a polypeptide chain • 1 or more polypeptide chains = a protein molecule. http://www.youtube.com/watch?v=lijQ3a8y UYQ&feature=related Levels of Structure (p.44) • Primary • A polypeptide chain of A.A’s. Secondary Structure • A.A. chain will pleat or coil or form a helix. • H bonds! Secondary Structure • Alpha helix • Flexibility • Polypeptide chain tightly coiled held by H bonds • i.e. Keratin http://www.youtube.com/watch?v=eUS6CE n4GSA&feature=related Secondary Structure • Beta pleated sheet • Strength • Parallel polypeptide chains • H-bonds • i.e. silk proteins http://www.youtube.com/watch?v=wM2LW CTWlrE&feature=related Tertiary Structure • Folded to form a specific shape (enzymes) Fibrous Vs. Globular • Fibrous proteins are strong and insoluble in water • eg. collagen, silk, keratin (main component in hair) • Globular proteins are spherical in shape, • Have a hydrophobic group on the inside, hydrophilic group on the outside. • Soluble in water. • eg. enzymes, antibodies, hormones Tertiary Structure • Di-sulfide bridges occur between neighbouring cysteine amino acids Have you Always Wanted Curly Hair? • Although it may seem incredible, in order for hair to grow 6 inches in one year, 9-1/2 turns of a -helix must be produced every second. Permanent Wave Hair • Reducing Agent breaks down disulfide bridges • Curlers re-form the hair • Oxidizing Agent (H peroxide) helps reform bridges • Hair is wavy until it grows out! Levels of Structure • Quaternary • 2 or more polypeptide chains linked together. Hemoglobin • C3032H4816O872N780S8Fe4 Build it!!! Denatured Proteins • Protein can’t carry out fxn. • Chemicals and or heat disrupt the h bond, ionic bonds, disulfide bridges and hydrophopic interactions. Protein Supplements • Additional protein beyond diet…usually a powder that is mixed into a PRO shake. • These are usually not needed b/c you can ingest enough PRO through a balanced diet! Homework • Worksheets • P. 50 #19-26 The End!!! Nucleic Acids • • • Nucleic Acids (DNA, RNA) are essential to all living things. They are polymers formed from monomer molecules called nucleotides. A nucleotide contains: 1) A nitrogenous base 2) A 5 carbon pentose sugar 3) A Phosphate group Nucleic Acids • The nitrogenous bases in DNA are Adenine (A), Thymine (T), Guanine (G), and Cytosine (C). • In RNA, Thymine is replaced by Uracil (U) • Single ring – Pyramidines • Two rings - Purines • The phosphate groups and sugar molecules form the backbone of the chain, and the bases stick out like the teeth on a zipper. 2 Types of Nucleic Acids 1. DNA (Deoxyribonucleic Acid) • The genetic code for all proteins and life functions. 2 nucleotide strands linked by Hydrogen bonds between nitrogenous bases (A & T, C & G). A double helix. Unique genetic information is determined by the sequence of nucleotides. • • • 2 Types of Nucleic Acids 2. RNA (Ribonucleic Acid) • A template of 1 gene…a code for 1 protein. • RNA carries the “protein blueprint from nucleus to the ribosome during PRO synthesis. • Usually 1 nucleotide strand containing A, U, C & G. • mRNA – Messenger • tRNA – Transfer Antiparallel Strands How long is DNA? • There are 3.1 billion base pairs in each DNA molecule. • If you were to read the code continuously it would take you 31 years! • The total length of DNA in each cell is 2 metres! • Your total DNA is long enough to reach the moon and back… 6000 times!! http://www.youtube.com/watch?v=qy8dk5i S1f0 Adenosine Triphosphate • ATP is a monomer • It is a nucleotide • ATP is the energy providing molecule of the cell. • ATP ADP + P + Energy Nucleotide Coenzymes • NAD+ • FAD • NADP+ • “Taxis” • Move H+ ions and electrons around • Drive chemical rxns Homework Review chart on page 54 Page 56, Q 1-19 The End!!!
