BIO L112 CUMULATIVE PORTION STUDY GUIDE CHAPTER 3 3 Complete the following table Type of Covalent Bond Example Will it form H bonds with water Yes Polar Nonpolar Between Oxygen and Hydrogen O H Between Nitrogen and Hydrogen N H Between Carbon and Hydrogen C H Between Hydrogen and Hydrogen H H Yes No No In a water molecule why does the oxygen atom carry a partial negative charge and why do each of the two hydrogen atoms carry a partial positive charge Oxygen O is more electronegative than hydrogen H This means that an oxygen atom has a stronger ability to attract electrons towards itself than a hydrogen atom The shared electrons in an O H covalent bond are pulled towards oxygen causing a partial charge on this atom In contrast the pull of these shared electrons away from hydrogen cause this atom to have a partial charge 5 What is unique about the hydrogen bonds present in liquid water These bonds are very fragile and break easily 1 20th the strength of a covalent bond Liquid water is constantly moving and forming breaking and reforming hydrogen bonds with different water molecules 12 Use the information in figure 3 10 9th and 10th editions to complete the following table Aqueous Solution Seawater Lemon Juice Urine Household Bleach pH 8 2 6 13 H 10 8 M 10 2 M 10 6 M 10 13 M OH 10 6 M 10 12 M 10 8 M 10 1 M Acid Base or Neutral Base Acid Acid Base 13 How much more acidic is the gastric juices of the stomach lumen compared to the cytosol of parietal cells found in the villus of the stomach The pH of gastric juices is 2 while the pH of the cytosol of a parietal cell is 7 However the gastric juices of the stomach are 100 000 times 10 2 10 7 105 more acidic than the cytosol of parietal cells 14 What is a buffer Buffer Substances that allow biological fluids to maintain a relatively constant pH despite additions of acids or bases Buffers contain a weak acid and its corresponding base Cite an example of a blood buffer that is a weak acid and identify its corresponding base In blood Carbonic Acid H2CO3 is a weak acid donates H and the Bicarbonate ion HCO3 is its corresponding weak base accepts H 15 When the airways of the lungs become partially blocked failure to properly ventilate the lungs can occur This change in ventilation can cause acute respiratory acidosis a condition where the blood pH decreases slightly 7 35 for a short period of time Explain how the blood buffer carbonic acid and its corresponding weak base bicarbonate ion function to quickly return the pH of the blood to normal physiological levels 7 4 Once H increases in the blood the bicarbonate ion HCO3 accepts H to form carbonic acid H2CO3 which decreases H and thus increases the pH of the blood See slide last slide from Chapter 3 handout CHAPTER 4 1 What four large biological molecules are found in all living organisms Proteins lipids fats carbohydrates and nucleic acids 2 What is carbon s valence 4 Why does this number make carbon such a major component of organic molecules Carbon can readily form up to 4 covalent bonds with four o t he molecules This allows for an enormous amount of molecular diversity What are the other three major atomic components of organic molecules Oxygen nitrogen and hydrogen Know the structure of urea and explain how the arrangement of its atoms completes the valance shell of all the atoms in the molecule r atoms or Carbon has a valance of 4 and in this molecule it forms 4 covalent bonds 2 single 1 double Oxygen has a valance of 2 and in this molecule it forms 2 covalent bonds 1 double bond Nitrogen has a valance of 3 and in this molecule it forms 3 covalent bonds Hydrogen has a valance of 1 and in this molecule it forms 1 covalent bond 3 What is a hydrocarbon A hydrocarbon is a molecule that consists of only hydrogen and carbon Are these molecules found in living organisms No hydrocarbons are found in fossil fuels Fossil fuels consist of the partially decomposed remains of organisms that lived millions of years ago 8 Complete the following table Functional Group Draw the chemical structure Name of compound s containing the functional group see p 64 65 of Biology Alcohols Ketones when carbonyl is within carbon skeleton Aldehydes when carbonyl is at the end of the carbon skeleton Carboxylic acids acid donate H Amines base accept H Thiols Organic Phosphates Methylated compounds Hydroxyl Carbonyl Carboxyl Amino Sulfhydryl Phosphate Methyl CHAPTER 5 1 What are the four classes of large molecules discussed in this chapter Carbohydrates lipids proteins nucleic acids Which three classes of large molecules are composed of monomers linked by covalent bonds Carbohydrates Proteins and Nucleic Acids are made up of linked monomers Fats such as triacylglycerol are a bit more complex 3 fatty acid chains connected to a glycerol molecule What is the name of the monomer unit in each of these large molecules Monosaccharide carbohydrates Amino Acids protein Nucleotide nucleic acids 2 What type of biochemical reaction is involved in the synthesis of polymers Dehydration What type of biological reaction is involved in the breakdown of polymers Hydrolysis Which type of biological reaction requires a water molecule Hydrolysis Which type of biological reaction generates a water molecule Dehydration 5 What two monosaccharide monomers make up maltose glucose and glucose lactose galatose and glucose and sucrose glucose and fructose What type of bond is present in maltose 1 4 glycosidic bond A dehydration reaction is involved in the formation of this bond Below is a picture of two glucose molecules Circle the atoms that are removed by the dehydration reaction Cellulose Glycogen Starch 6 What is a polysaccharide A macromolecule made from 100 to 2000 monosaccharides The following table is designed to help you identify key differences between glycogen starch and cellulose molecules Fill in the missing parts Type of Polysaccharide Structure Where is it found Major Function Can humans digest this macromolecule No Flat forms micro fibrils Helical only branched Helical both branched and non branched Plant cell walls Structural Liver cells Energy Storage Yes Plant tubers and grains Energy Storage Yes 7 Why are lipids considered hydrophobic molecules They contain hydrocarbons which are molecules composed of only nonpolar C H covalent bonds What is a triacylglycerol triglyceride Triacylglycerol is a fat molecule composed of a glycerol molecule with three fatty acids attached to each carbon via an ester linkage Is water added or