3B - Biological Molecules.pdf
Transcript
Biological Molecules What’s left for Week 3 Today - Functional groups - Biomolecules / Macromolecules → same for lab! Tomorrow - Water quiz due **Carbon quiz due next Tuesday Functional Groups What’s attached to the Carbon Skeleton? Hydrocarbons are usually not found alone in living systems. Ca...
Biological Molecules What’s left for Week 3 Today - Functional groups - Biomolecules / Macromolecules → same for lab! Tomorrow - Water quiz due **Carbon quiz due next Tuesday Functional Groups What’s attached to the Carbon Skeleton? Hydrocarbons are usually not found alone in living systems. Carbon Skeletons serve as a backbone for functional groups to attach and branch off. What’s attached to the Carbon Skeleton? Functional groups: Small molecules which are directly involved in chemical reactions In biology: We study the ones commonly found in living systems and biological reactions Structure → Function! Hydrocarbon? Carbon Skeleton? Functional group? The ones you should know (see book) Hydroxyl –OH Carbonyl >C=O Carboxyl –COOH Amino –NH2 Sulfhydryl –SH Phosphate –OPO3 Methyl –CH3 Hydroxyl –OH or HO– Compounds with hydroxyl groups called alcohols Names end in “-ol”: methanol, ethanol, etc. Mixes well with water DON’T confuse with OH- (a hydroxide ion) Carbonyl C=O Compounds with carbonyl groups called: Aldehydes if carbonyl at the END (formaldehyde) Ketones if carbonyl is in the MIDDLE (acetone) Carboxyl –COOH Hydroxyl + Carbonyl! Compounds called carboxylic acids or organic acids. Acid from H+ ion, which floats in and out. Amine –NH2 Compounds called amines (easy)! Acts as a base (don’t ask me why). Sulfhydryl –SH Compounds called thiols. Form cross-links (S-S bonds) in hair proteins, making them stay straight/curly. Relaxers change! Phosphate –OPO3 Compounds called organic phosphates. Make up the backbone of DNA, and store energy in ATP – both extremely important! Methyl –CH3 Compounds called methylated compounds. Change the expression of genes – epigenetics Macromolecules Zooming out from Carbon The building blocks of life are built off of carbon skeletons and functional groups. These come together to form macromolecules. Macro = large Molecule = group of atoms bonded together 4 Types of Macromolecules Carbohydrates Proteins Lipids Nucleic Acids The first 3 are probably familiar if you’ve taken nutrition classes. You’re made of macromolecules! Carbohydrates (Carbs) Give cells fuel, like sugars Give cells simple structure, like cellulose Proteins Have multiple levels of structure Make up most of the complex structures in cells Lipids Hydrophobic = repels water Make up fats, cell membranes, and hormones Nucleic Acids DNA & RNA Store, move, and process genetic information Macromolecule Structure Most macromolecules are chains of smaller molecular units, linked together. Smaller unit: monomer (mono = single) Chain: polymer (poly = many) Fusing macromolecules When monomers (or polymers) fuse together, it’s called dehydration synthesis. Dehydration: losing water Synthesis: putting together Splitting macromolecules When monomers (or polymers) split apart, it’s called a hydrolysis reaction. Hydro: water Lysis: splitting Reverse of a DS reaction Macromolecule nomenclature Nomenclature = how something is named All macromolecules have specific names for: - Bonds formed during dehydration synthesis - Their monomers & polymers* *except lipids Carbohydrates Also called sugars or saccharides Made up of carbon, hydrogen, oxygen Look like rings with NO nitrogen Carbohydrates Monomer: monosaccharide Polymer: polysaccharide Dehydration synthesis: glycosidic linkage Carbohydrates Most important carb: Glucose - monosaccharide that gets broken down for energy during cell respiration Carbohydrates Glucose makes up: Starch - long branching polysaccharide used to store energy (in things like potatoes) Carbohydrates Glucose also makes up: Cellulose - long straight polysaccharide that gives plants structure (in things like celery) Proteins Look like branching chains with Nitrogen Proteins Monomer = amino acid Polymer = polypeptide Dehydration synthesis = peptide bond Proteins Hundreds of uses Make up most of structures you find in cells 20 different amino acids, each with slightly different functions Lipids Defined by the fact that they repel water No consistent structure, 3 main types DON’T have monomers or polymers. Can clump together, but don’t form bonds with each other. DO have a dehydration synthesis: ester bond which forms between subunits (not monomers) Lipids Steroids: testosterone, estrogen, and cholesterol Look like 4 fused rings Lipids Fats: glycerol + 3 fatty acids, store energy Lipids Phospholipids: phosphate + glycerol + 2 fatty acids Similar-looking to fats. Make up cell membranes. Nucleic Acids DNA & RNA Most complex of macromolecules, which makes sense. Stores info on how to build proteins so cells can grow, function, and replicate. Nucleic Acids Monomer = nucleotide Polymer = polynucleotide Dehydration synthesis = phosphodiester bond Nucleic Acids Nucleotides are made of: - Phosphate - Sugar (DNA v RNA) - Nitrogenous base (A,T,C,G) Sugar & nitrogenous base both look like rings, but nitrogenous bases have nitrogen in them! Recap Carbs, lipids, proteins, and nucleic acids are all macromolecules, the basic building blocks of cells. Activity Map out what you’ve learned so far about macromolecules. Leave room to add more from future lessons! Green slide = brainstorming time! Write 3 multiple-choice questions based on what we learned today. Need at least 4 answer choices each. Swap with a partner to quiz! Submit your best question before you leave class for a chance at extra credit.
