Ch 5: Structure and Function of Large Biological Molecules

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What is the subunit of the following macromolecules? Polysaccharide, Protein, Nucleic Acid
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Terms in this set (57)
What is the subunit of the following macromolecules? Polysaccharide, Protein, Nucleic Acid
Sugar
Amino Acid
Nucleotide
What do lipids not include?
True polymers
Are lipids hydrophobic or hydrophilic? Why?
They are HYDROPHOBIC
Because they consist mostly of hydrocarbons, which form non polar covalent bonds
What are the most important lipids?
Fats
Phospholipids
Steroids
What are fats made of?
3 fatty acids joined by a glycerol by an ester linkage, making a triacylglycerol
What is glycerol?
3 carbon alcohol with hydroxyl group on each C
What is a fatty acid?
A carboxyl group attached to a long carbon skeleton(usually even #, around 14-22)
What are saturated fatty acids?
-NO double bonds between carbon atoms in the tail
-carbon is FULL with hydrogen atoms
-often solid at room temperature
What are unsaturated fatty acids?
-almost always in cis formation, which produces a kink in the molecule... this prevents fatty acids from packing tightly together
-SOME double bonds between carbon atoms in tail
-carbon is NOT FULL with hydrogen atoms
-often liquid at room temperature
What are trans fats?
-unsaturated fats with trans double bonds
-allows for s more dense arrangement of fat molecules, so they remain solid at room temperature
-most are manmade, NOT GOOD, increases LDL cholesterol
What are essential fatty acids?Bodies need these acids but cannot produce them, they have to be consumed Omega-3 and Omega-6What do phospholipids consist of?2 fatty acids and a phosphate group attached to a glycerol -tails are hydrophobic, but phosphate group form hydrophilic head... "amphipathic"What happens when phospholipids are in an aqueous environment?They are in a bilayer formation, provides boundary around cellWhat are steroids?Carbon skeleton consisting of 4 fused rings -steroid hormones control development, behavior, and biochemical process (derived from cholesterol)Sterols?Steroids with a polar -OH group on one end, and a non polar hydrocarbon on the other (amphipathic)Cholesterol?important in animal cell membranes produced by liver or dietLipoproteins?Transport cholesterol through the blood stream (HDL, LDL) have internal hydrophobic and external hydrophilicFunctions of proteins: Metabolismcatalyzing chemical reactionsFunctions of proteins: SignalingDelivering chemical messages throughout cells and tissues of an organismFunctions of proteins: TransportCarrying molecules into and out of cells throughout the body (transport proteins)Functions of proteins: StructureForming organelles and other structures like basic macromolecules***Functions of proteins: MovementMoving substances, cells, body partsFunctions of proteins: DefenseDefending body against disease-causing agents (antibodies)What is a. protein?-has 1 or more polypeptides... twisted, folded, and coiled into a unique shape (influences its activity)What determines a proteins structure and function?Amino acidsWhat do the polymers of amino acids contain?20 amino acids: amino group and carboxyl group always the same, but different R-groupsWhat do R- groups determine?if amino acid is polar, non polar, or electrically charged (+ or -) -the sequence of the protein -how the protein folds itselfWhat its a peptide bond?Formed between the carboxyl and amino groups of 2 adjacent amino acidsWhat are the levels of protein structure?primary, secondary, tertiary, quaternaryPrimary structureamino acid sequence from N-term to C-termSecondary StructureEither an alpha helix or beta pleated sheet -found in most proteins -coils and folds in polypeptide chain -hydrogen voids between amino and carbonyl groups in the polypeptide backbone (C, O, N, H, R-group)Tertiary structuredetermined by interactions among varies side chains (R-groups), results from 4 kinds of bonds with R-groupsQuarternery structureAggregation of tertiary structure (Ex. collagen) -made up of 3 alpha helices woven into a durable triple helix, good for pulling -structure stabilized by hydrogen bonds that form between each of the 3 initial polypeptide chainsHow is protein conformation determined?-physical and chemical conditions can affect it -Alterations in pH, salt concentration, temperature, or other environmental factors can cause protein to "unravel" or denature -a denatured protein is inactiveUsing X-ray crystallography to determine protein's conformation-crystallize the proteins by preparing a concentration, pure solution of a protein sample and allow it t crystallize on a slide -bombard protein crystals with x-rays, which diffract when they interact with atoms in the crystal -measure angle and intensity of diffracted x-raysWhat are the 2 types of nucleic acid?DNA and RNADNA-contains information for making proteins. Directs complex structures and functions of the cell -double stranded helical structure protects genome -complementary base pairs provides a way for DNA to be replicated and for genome to be passed on to progeny with little change -without DNA, RNA would have no information to produce important cell components -A and T, C and G -complimentary strands, running in opposite directions (antiparallel)RNA-single stranded, base pairs can occur between 2 RNA molecules -U and A, C and G -different types (mRNA, tRNA, rRNA, etc.) -Without RNA, cell would have no way to make proteinsWhat do genes along a DNA molecule direct?synthesis of a messenger RNAWhat does mRNA do?Interacts with the cell's protein synthesizing machinery to direct production of a polypeptide (gene expression)Nitrogenous bases:Pyrimidine= six ring with 2 N and 4 C (G,A) Purine= double ring formed from a 6 ring and 5 ring fused together, contain 4 N (C,T,U)phosphodiester linkageconnects the phosphate group linked ti the 5' position carving on one sugar with the hydroxyl group attached to the 3' carbon on the next sugarWhat does the orientation of the phosphodiester bond give?polynucleotide directionalityWatson and Crick 1953Proposed structure of DNA as a double helixChargaffPredicted A-T and G-CFranklinpredicted helical structure of DNASecondary structure of RNA:-complex, form though intra-strand hydrogen bonds -ribosomal RNA, ribozyme -the additional hydroxyl group is more reactive, and alters the angle of the bases relative to the backbone, making the nucleotides more accessible to non-covalent interactionsWhat do carbohydrates do? What do they contain?-fuel and building materials -include sugars and polymers of sugarsWhat is the simplest carb?monosaccharide, or simple sugars (most common is glucose)What are monosaccharides classified by?The location of the carbonyl group (aloes or ketoses) and the # of carbons in the carbon skeletonThe two forms of carbs:linear or ring (cyclic) -in water they fold into a ring, due to a reaction between kept-aldehydee group and hydroxyl groupHow do disaccharides form?By dehydration synthesis (lose H2O) -the covalent bonds is called a glycosidic linkageWhat are polysaccharides?large macromolecules formed from monosaccharides -polymers of sugars -can be structural or for energy storageHow is the function of a polysaccharide determined?BY its sugar monomers and the positions of glycosidic linkagesPolysaccharides: Energy StoragePolymers of alpha-glucose Ex 1. Starch- plastids in potato cell--amylose (50 um) Ex 2. Glycogen-granules in muscle tissue (1 um)Polysaccharides: StructuralPolymers of beta-glucose Ex. Plants- cellulose (parallel strands joined by hydrogen bonds- cell wall)Energy Storage Plants Vs Animals:Plants: store energy in polysaccharide molecules. Exception is plants storage of oils as long-term food source in seeds. Polysaccharides are adequate for plants because they do not move Animals: Require a more compact energy source. Animals store a lot of energy in fats. Fats hold 2x as much energy as polysaccharide. Adipose cells store fat