Chapter 3

Chapter 3 - Chapter 3 Proteins, Carbohydrates, and Lipids...

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Chapter 3 – Proteins, Carbohydrates, and Lipids 3.1 – What kinds of molecules characterize living things? Proteins, Carbohydrates, Lipids and Nucleic acids characterize living things o All these molecules except the lipids are polymers Proteins are formed from the different combinations of 20 amino acids Carbohydrates can form giant molecules by linking many monosaccharides together Nucleic acids are formed from four kinds of monomers that link to form long chains Lipids can make large molecules, but the interactions between lipid molecules are noncovalent Polymers with molecular weights exceeding 1000 are called macromolecules Although large lipids aren’t polymers, we still treat them as special macromolecules Functional groups: o Hydroxyl – alcohols – polar, hydrogen bonds with water to help dissolve molecules, enables linkage to other molecules by dehydration o Aldehyde – aldehydes – C=O groups is very reactive, important in building molecules and in energy releasing reactions o Keto – ketones – C=O group is important in carbohydrates and in energy reactions o Carboxyl – carboxylic acids – acidic, ionizes in living tissues to form –COO- and H+. enters into dehydration synthesis by giving up –OH, some carboxylic acids are important to energy releasing reactions o Amino – amines – basic, accept H+ in living tissues to create –NH 3 +, enters into dehydration synthesis by giving up H+ o Phosphate – organic phosphates – negatively charged. Enters into dehydration synthesis by giving up –OH, when bonded to another phosphate, hydrolysis releases much energy o Sulfhydryl – thiols – by giving up H, two –SH groups an react to form a disulfide bridge, thus stabilizing protein structure Isomers are molecules that have the same chemical formula, but different atomic arrangements o Isomers have different chemical properties o Structural isomers have their atoms joined differently o Optical isomers occur when a carbon atom has 4 different atoms bonded to it (asymmetrical carbon), allowing two different patterns to be created (mirror images) Biochemical unity refers to how macromolecules like proteins have similar functions in all organisms due to their chemical structure o Advantage is that if one organism doesn’t have certain material, it can eat other organisms who have the molecule Only nucleic acids store and transmit information Macromolecule specialization has to do with its 3D shape o Long macromolecules like proteins can contract, making movement Polymers are formed when monomers combine via condensation/dehydration reactions
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o Reverse reaction is called hydrolysis, when water reacts with the covalent bonds holding the polymer together 3.2 – What are the chemical structures and functions of proteins? Important types of proteins include
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Chapter 3 - Chapter 3 Proteins, Carbohydrates, and Lipids...

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