Biological Macromolecules and Lipids Lesson 4 PDF

Biological Macromolecules and Lipids Lesson : 4 Biol 101  OBJECTIVES Define Macromolecules, polymers ,and monomers Know the structure, types and function of Carbohydrates Know the structure, types and function of Lipids Know the structure, types...

Biological Macromolecules and Lipids Lesson : 4 Biol 101  OBJECTIVES Define Macromolecules, polymers ,and monomers Know the structure, types and function of Carbohydrates Know the structure, types and function of Lipids Know the structure, types and function of 2 Proteins  Macromolecules Definition Macromolecules are large molecules composed of thousands of covalently connected Atoms. There are 4 main classes: Carbohydrates, Proteins and Nucleic Acids consisting of polymers. And Lipids with no polymers. A polymer is a long molecule consisting of many similar building blocks linked by covalent bonds (train consists of a chain of cars) The repeating units that serve as the building blocks of polymer are smaller molecules = monomers Biol 101  Making and Breaking Polymers Synthesis of polymer by: Dehydration reaction : two monomers covalently bonded to each other by removing water. Break down of polymers by: Hydrolysis reaction: polymers are disassembled (broken) to monomers using water. Biol 101  Example of hydrolysis and dehydration working within our bodies The process of digestion Enzyme Enzyme Polymers =food s Monomers s Hydrolysi Dehydratio New Polymers s n At the beginning of digestion process, water is added to food particles (ex: protein) to break down the bonds between the monomers. After digestions water is removed to build the polymer. Biol 101  1. Carbohydrates 1 Carbonyl group (C=O) Carbohydrat and multiple Hydroxyl group (─OH) es Monomers of Polymers of sugars sugars Simple Double Complex sugars sugars sugars Monosaccharid Disaccharid Polysaccharid es es es Glucos 2 Monosaccharides joined e by a glycosidic linkage Starch, Cellulose (plants) Glycogen (animals) Biol 101 Summary Biol 101  2. Lipids Lipids are not composed of polymers They mix poorly with water, they have hydrophobic behavior based on molecular structure (nonpolar covalent bond) They consist mostly of hydrocarbon regions There are three types of lipids: o Fats o Phospholipids o Steroids Biol 101  Fats Joined by ester linkage= 1 3 Fatty Bond between hydroxyl + carboxyl Glycerol Acid group Alcoho Long hydrocarbon skeleton Triacylglycerol= l with carboxyl group at one end Triglyceride C─H nonpolar= Reason that fats are hydrophobic Triglyceride: predominant form in diet. The Head: 1 molecule of Glycerol The tails: 3 Fatty Acids Function of fats is energy storage. A gram of fats stores more than twice as much energy as a gram of polysaccharide such as starch. Biol 101  Types of Fats 1.Saturated Fatty Acids: single bonds between carbon atoms Solid at room temperature. Example: Beef Fat, butter, … A diet rich in saturated fats may contribute to cardiovascular disease (atherosclerosis) 2. Unsaturated Fatty Acids: 1 or more double bonds between carbon atoms Liquid at room temperature. Example: Linseed oil, olive oil Some Unsaturated Fatty Acids must be supplied in the human diet because they cannot be synthesized in the body. Example: Omega-3 required for normal growth and protect against Cardiovascular disease. Biol 101  Phospholipid - Phosphate group + 2 Fatty Acids+ glycerol. - Phospholipid compose the lipid bilayer of cell membranes. Biol 101  Steroids Are composed of 4 fused rings with attached chemical groups. There are tow types of steroids and both of them are natural body components: Sex Hormones : - are signaling molecules that travel through the body. Cholesterol : - is common component of animal cell membranes - is a precursor from which other steroids are synthesized Biol 101 Summary Biol 101  3- Proteins Every dynamic function of a living organism depends on proteins. Its monomer: Amino Acids Composed from the same set of 20 Amino Acids. Proteins have many functions: Speed up chemical reactions Defense, storage, and transport. Cellular communication, movement, and structural support. Biol 101  Amino acids structure All Amino Acids share a common structure: alpha (ὰ) carbon with : o Amino Group (H-N-H) o Carboxyl Group (O=C-OH) Backbo ne o Hydrogen atom o Variable group (R side chain) R= hydrogen atom, or carbon skeleton The amino acids are grouped according to the properties of their side chains. Biol 101 Amino acids structure Biol 101  Levels of Protein’s Structure 1. Primary structure is a chain of amino acids linked together by Peptide Bonds. 2. Secondary structure = hydrogen bonds are forming between adjacent amino acids (backbone) composing a polypeptide 3. Tertiary structure = Vander Waals interactions formed between R groups of amino acids composing a coiled and folded polypeptide 4. Quaternary structure : aggregation of two or more polypeptides will form biologically functional molecule called “Protein” Biol 101  Protein’s structure and function Protein structure depends on the physical and chemical conditions of the protein’s environment : pH, salt concentration, temperature,… Protein function depends on its structure. Any change in physical or chemical conditions can affect the protein’s structure and function. The affected protein is biologically inactive, it is called denatured protein. Biol 101  4- Nucleic Acids Nucleic acids have two classes: DNA and RNA Nucleic acids are polymers made of monomers called nucleotides Each nucleotide is composed of: o Phosphorus Group o Sugar (pentose) o Nitrogenous base Biol 101  DNA (DeoxyriboNucleic Acid) The DNA is archival copy of genetic code. It is a double strand (Double Helix), complementary (A—T / C—G) and antiparallel (5’3’) It is composed of Genes which are composed of Nucleotides The sugar of DNA nucleotides is Deoxyribose The nitrogenous bases of DNA are: o Adenine A o Thymine T o Cytosine C o Guanine G Biol 101  RNA (RiboNucleic Acid) The RNA is single strand The sugar of RNA nucleotides is Ribose The nitrogenous bases of RNA are: o Adenine A o Uracil U o Cytosine C o Guanine G Biol 101  Both DNA & RNA have code which specifies sequence of amino acids in proteins. Biol 101