Chapter 3 - Chapter 3 Marcomolecules and the Origin of Life...

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Chapter 3: Marcomolecules and the Origin of Life What kinds of molecules characterize living things? Section 3.1 1. Proteins, carbohydrates, lipids and nucleic acids- large polymers constructed by covalent bonding of monomers. Monomers that make up each one have similar chemical structures. Macromolecules are polymers with over 1,000 molecular weight- proteins, polysaccharides, and nucleic acids 2. Functional groups- small groups of atoms. Hydroxyl- polar, attracts water. Ketone- electronegative and attracts hydrogen to form hydrogen bond 3. Isomers- molecules with same chemical formula but the atoms are arranged differently a. Structural isomers- differ how atoms are joined together b. Optical isomers- when carbon atom has 4 different atoms or groups of atoms attached to it- allows two different ways of making the attachments, so they are mirror images- asymmetrical carbon 4. Structure- function of macromolecule is same as function in plants- biochemical unity. When eat something, you get those macromolecules. Both carbs and proteins have structural roles in cells while only nucleic acid can store info. Macromolecules contain multiple functional groups- related to 3d shape- chemical properties. 5. Condensation reaction ~ dehydration- loss of water when polymers are constructed from monomers. Results in covalently bonded monomers- release water mol for each covalent bond that has been formed. Polymers only form if energy is added 6. Hydrolysis- reverse- digest polymers and produce monomers. Water reacts with covalent bonds and products are free. Hydrogen and oxygen become part of products What are the chemical structures and functions of proteins? Section 3.2
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1. Proteins are used for structural support, protection, tansport, catalysis, defense, regulation, and movement- made of 20 amino acids. Range in size and made of single unbranched polymer of amino acids- polypeptide chain- which is then folded into 3D shapes 2. Composition- refers to relative amount of different amino acids while sequence- refers to the diversity in protein structures and functions 3. Amino acids have both a carboxyl group and an amino functional group attached to one carbon- carboxyl has lost a H+ and amino has gained an H+ so an amino acid is both and acid and base simultaneously. Attached to carbon is one hydrogen and a side chain (R group) which can also contain functional groups- this determines 3D shape and function of the molecule. a. 5 amino acids have electrically charged side chains will attract water and are oppositely charged ions of all sorts b. 5 amino acids have polar side chains and tend to form hydrogen bonds with water, are hydrophilic c. 7 amino acids have side chains that are nonpolar hydrocarbons, are hydrophobic d. Special cases- cysteine- terminal –SH group can react and form disulfide bridges (-S-S-) which help determine how a polypeptide chain folds; hydrophobic. Glycine- single hydrogen atom side chain, fits into small spaces. Proline- has modified amino group (has H2N+ instead of H3N+) which limits
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Chapter 3 - Chapter 3 Marcomolecules and the Origin of Life...

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