Chapter 5 The Structure and Function of Large Biological Molecules

Categories: Lipids ProteinsNucleic Acids Carbohydrates Biological Compounds

Principle Elements Ratio of Various Elements Special Functional Groups

Hydroxyl ( -OH ) Carboxyl ( -COOH ) Carbonyl (C=O) OHCO C O OH Alcohols Aldehydes, Ketones Carboxylic acids N H H AminesAmino ( -NH 2 )

Phosphate ( -H 2 PO 4 ) O H P O O H O SH Sulfhydryl ( -SH) Organic phosphates Thiols

Monomer Subunits that serve as building blocks Connected by condensation reactions (dehydration) Polymers Covalent bonding occurs Solubility in Water

Monomer Polymer

Monomers HHO H H2OH2O

C 6 H 12 O 6 + C 6 H 12 O 6 C 12 H 22 O 11 + H 2 O

H2OH2O

Monomers HHO H2OH2O

C 12 H 22 O 11 + H 2 O C 6 H 12 O 6 + C 6 H 12 O 6

Principle Elements: C, H, & O H:O = 2:1 Many Hydroxyl Groups (-OH) Monomers: Monosaccharides Polymers: Polysaccharides Water Soluble

Energy Metabolism Structural Components Cell-to-Cell Contacts and Recognition Elimination of wastes (fiber) APT cell Helper- T cell

Chemical Formulas C 6 H 12 O 6 From corn syrup

Chemical Formulas C 5 H 10 O 5 C 5 H 10 O 4 deoxyribose

Maltose Sucrose glucose + fructose glucose + glucose Lactose glucose + galactose

glycogen

Fig. 5-6 (b) Glycogen: an animal polysaccharide Starch Glycogen Amylose Chloroplast (a) Starch: a plant polysaccharide Amylopectin Mitochondria Glycogen granules 0.5 µm 1 µm

Chitin, another structural polysaccharide, is found in the exoskeleton of arthropods Chitin also provides structural support for the cell walls of many fungi Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Fig The structure of the chitin monomer. (a) (b) (c) Chitin forms the exoskeleton of arthropods. Chitin is used to make a strong and flexible surgical thread.

Principle Elements: C, H, & O Some With P & N H:O >>> 2:1 Diverse Group of Biological Molecules Water Insoluble

Energy Storage Protection & Cushioning of Body Organs Structural Components of Membranes Chemical Messengers (hormones)

Triglycerides (neutral fats) Phospholipids Sterols Waxes Vitamins (D, E, K)

Glycerol Fatty Acid

Glycerol Fatty Acids Saturated with H + Most animal fats are saturated, ex. butter Solid at room temp

Has one or more double bonds between carbons Most vegetable fats Liquid at room temp

Hydrophilic head Hydrophobic tails phosphorous carbon hydrogen oxygen

Nonpolar hydrophobic tails (fatty acids) exposed to oil Polar hydrophilic heads exposed to water

cholesterol Bacon grease

Cholesterol: < 175 mg/dl Triglycerides: mg/dl HDL: >35 LDL: <130 Cholesterol/HDL ratio: <4.5 indicates heart disease

Family history of vascular disease High levels of blood cholesterol Smoking Diabetes Hypertension Obesity

Eat healthy Exercise Lose wt. Quit smoking 1 glass wine or beer Medication Surgery

Principle Elements: C, H, O, & N Monomers: Amino Acids Polymers: Polypeptides or Proteins Generally Water Soluble

Functional Groups of Amino Acids Carboxylic Acid (-COOH) Amine (-NH 2 ) R-Groups (variable - 20 different kinds)

Enzymes Structural Proteins Chemical Messengers (Hormones) Contractile Antibodies

Levels of Protein Structure Primary structure Secondary structure Tertiary structure Quarternary structure

Primary structure: Linear sequence of amino acids Levels of Protein Structure Alpha helix H-Bonds Secondary structure: Beta Pleated sheet NH 3 LeuCysValAspPheCOO

Levels of Protein Structure Tertiary: 3D configuration Weak bonds between side chains Quartenary: Two or more polypeptides e.g. Hemoglobin (Hb)

Peptide bond DipeptideWater AA1 AA2

GLYSERALATYRILEGLNLEUMET GLYSERASPGLUILEGLNHISASN

Sickle-Cell Disease: A Change in Primary Structure A slight change in primary structure can affect a protein’s structure and ability to function Sickle-cell disease, an inherited blood disorder, results from a single amino acid substitution in the protein hemoglobin Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Fig Primary structure Secondary and tertiary structures Quaternary structure Normal hemoglobin (top view) Primary structure Secondary and tertiary structures Quaternary structure Function  subunit Molecules do not associate with one another; each carries oxygen. Red blood cell shape Normal red blood cells are full of individual hemoglobin moledules, each carrying oxygen. 10 µm Normal hemoglobin     Val His Leu ThrPro Glu Red blood cell shape  subunit Exposed hydrophobic region Sickle-cell hemoglobin   Molecules interact with one another and crystallize into a fiber; capacity to carry oxygen is greatly reduced.   Fibers of abnormal hemoglobin deform red blood cell into sickle shape. 10 µm Sickle-cell hemoglobin GluPro Thr Leu His Val

Fig. 5-22c Normal red blood cells are full of individual hemoglobin molecules, each carrying oxygen. Fibers of abnormal hemoglobin deform red blood cell into sickle shape. 10 µm

Fig mRNA Synthesis of mRNA in the nucleus DNA NUCLEUS CYTOPLASM 1

Fig mRNA Synthesis of mRNA in the nucleus DNA NUCLEUS mRNA CYTOPLASM Movement of mRNA into cytoplasm via nuclear pore 1 2

Fig mRNA Synthesis of mRNA in the nucleus DNA NUCLEUS mRNA CYTOPLASM Movement of mRNA into cytoplasm via nuclear pore Ribosome Amino acids Polypeptide Synthesis of protein 1 2 3

Principle Elements: C, H, O, N, & P Monomers: Nucleotides Polymers: Nucleic Acids Generally Water Soluble

Nucleotide Components: Ribose (5-C) Sugar Phosphate Nitrogenous Base

Genetic Instruction Set (DNA) Protein Synthesis (DNA & RNA) Energy Metabolism (ATP)

Polymers made up of individual nucleotides Nucleotides contain Phosphate group Five carbon sugar Ring shaped nitrogen base DNA contains information for almost all cell activities

ATP

Role of ATP in Energy Metabolism ATP  ADP + P i + Energy

Role of ATP in Energy Metabolism

INQUIRY 1.Describe the difference between saturated and unsaturated fats. 2.Where are phospholipids found? 3.Cholesterol is the base molecule for what type of lipids? 4.Name a polysaccharide used to store energy. 5.Name the currency molecule for all the cells activities.

You should now be able to: 1.List and describe the four major classes of molecules 2.Describe the formation of a glycosidic linkage and distinguish between monosaccharides, disaccharides, and polysaccharides 3.Distinguish between saturated and unsaturated fats and between cis and trans fat molecules 4.Describe the four levels of protein structure Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

You should now be able to: 5.Distinguish between the following pairs: pyrimidine and purine, nucleotide and nucleoside, ribose and deoxyribose, the 5 end and 3 end of a nucleotide Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings