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Chapter 19
Biochemistry
19-01
Title
 The cell: the smallest structural unit in living organisms
Caption
 Physically, cells consist primarily of a nucleus, a cell membrane, and cytoplasm. Chemically, cells consist primarily of carbohydrates, lipids, proteins, and nucleic acids.
Notes
 A cell can be an independent organism, or part of a larger organism.
Keywords
 cell, organism, nucleus, cell membrane, cytoplasm, carbohydrate, lipid, protein, nucleic acid
19-01-03d
Title
 Glucose: a key carbohydrate in living systems
Caption
 The structural formula and spacefilling model presented here represent glucose, a carbohydrate. Glucose is involved in short-term energy storage.
Notes
 Glucose is an aldehyde that also contains many -OH groups. The -OH groups make glucose soluble in water-based systems, such as blood. The solubility of glucose facilitates its mobility in living systems, allowing glucose to "carry" energy where it is needed.
Keywords
 cell, organism, carbohydrate, aldehyde, alcohol , glucose
19-02
Title
 Glucose can assume a chain or ring structure
Caption
 Glucose is easily convertable from one form to another, by interaction of a terminal -OH with the aldehyde part of the straight-chain molecule. The forms are all isomers.
Notes
 Glucose is an aldehyde that also contains many -OH groups. The -OH groups make glucose soluble in water-based systems, such as blood. The solubility of glucose facilitates its mobility in living systems, allowing glucose to "carry" energy where it is needed.
Keywords
 cell, organism, carbohydrate, aldehyde, alcohol, ring, chain, isomer, glucose
19-02-01e
Title
 The structural formula and spacefilling model presented here represent glucose, a monosaccharide
Caption
 Glucose is an example of a monosaccharide, a carbohydrate that cannot be broken into simpler carbohydrates.
Notes
 Glucose is an example of a hexose, a six-carbon sugar.
Keywords
 glucose, carbohydrate, aldehyde, alcohol, ring, chain, isomer, monosaccharide
19-02-02un
Title
 Structures of fructose and galactose
Caption
 Fructose and galactose are two examples of monosaccharides that can assume a ring form.
Notes
 Glucose and galactose have very similar structures: in the ring form, they differ only in the placement of a single -OH group.
Keywords
 glucose, carbohydrate, ring, isomer, monosaccharide, fructose, galactose
19-02-05un
Title
 Monosaccharides can join to form disaccharides
Caption
 The structural formulas show that pairs of monosaccharides can join together through a glycoside linkage to form a disaccharide. A disaccharide is a carbohydrate that can be broken into two simpler carbohydrates.
Notes
 As an example: glucose and fructose can join to form the disaccharide sucrose, common table sugar.
Keywords
 glucose, carbohydrate, aldehyde, alcohol, ring, chain, isomer, monosaccharide, glycoside linkage, disaccharide, sucrose, fructose
19-03
Title
 Digestion converts disaccharides into monosaccharides
Caption
 An important function of digestion is to break the glycoside linkage in disaccharides, converting them to monosaccharides that can be used for energy storage.
Notes
 As an example, the disaccharide sucrose (table sugar) is broken into glucose and fructose during digestion.
Keywords
 glucose, carbohydrate, aldehyde, alcohol, ring, chain, isomer, monosaccharide, glycoside linkage, disaccharide, sucrose, digestion, fructose
19-03-02un
Title
 Starch is an example of a polysaccharide
Caption
 Many monosaccharides can form glycoside linkages to build what amounts to a sugar polymer: a polysaccharide. Starch is one example that consists of repeating glucose units.
Notes
 Cellulose and glycogen are other examples of polysaccharides.
Keywords
 glucose, carbohydrate, monosaccharide, glycoside linkage, polysaccharide, cellulose, glycogen
19-04
Title
 Digestion converts polysaccharides into monosaccharides
Caption
 An important function of digestion is to break the glycoside linkages in disaccharides, converting them to monosaccharides that can be used for energy storage.
Notes
 As an example, the polysaccharide starch is broken into glucose molecules during digestion.
Keywords
 glucose, carbohydrate, monosaccharide, glycoside linkage, polysaccharide, digestion
19-04-01un
Title
 Example 19.1: Identifying carbohydrates
Caption
 Which of the structures, (a), (b), (c), (d) are carbohydrates? Classify the carbohydrates as monosaccharides, disaccharides, or polysaccharides.
Notes
 Carbohydrates are either aldehydes or ketones with multiple -OH groups present. Structures (a), (b), and (d) all fit this definition. Structure (c) is a carboxylic acid. A disaccharide will have one glycoside linkage; a polysaccharide will have many. Structures (a) and (b) are monosaccharides; (d) is a disaccharide.
Keywords
 carbohydrate, monosaccharide, aldehyde, ketone, glycoside linkage, disaccharide, polysaccharide
19-04-02un
Title
 Skillbuilder 19.1: Identifying carbohydrates
Caption
 Which of the structures, (a), (b), (c), (d) are carbohydrates? Classify the carbohydrates as monosaccharides, disaccharides, or polysaccharides.
Notes
 Carbohydrates are either aldehydes or ketones with multiple -OH groups present. Structures (b), and (d) fit this definition. Structure (a) is an amino acid, and (c) is a carboxylic acid. A disaccharide will have one glycoside linkage; a polysaccharide will have many. Structures (b) is a monosaccharide; (d) is a disaccharide.
Keywords
 carbohydrate, monosaccharide, amino acid, carboxylic acid, aldehyde, ketone, glycoside linkage, disaccharide, polysaccharide
19-04-03un
Title
 General structure of fatty acids: a type of lipid
Caption
 Fatty acids are carboxylic acids with a long hydrocarbon tail. In the general structure, "R" represents the large hydrocarbon tail.
Notes
 R generally represents a hydrocarbon chain of 3 to 19 C atoms.
Keywords
 general structure, fatty acid, lipid, carboxylic acid, hydrocarbon
19-04-04j
Title
 The structural formula and spacefilling model represent myristic acid, a fatty acid
Caption
 Fatty acids are carboxylic acids with a long hydrocarbon tail. In the general structure, "R" represents the large hydrocarbon tail. In this example, the hydrocarbon tail has 13 carbons.
Notes
 Myristic acid is in butterfat and coconut oil. It is a saturated fatty acid: the hydrocarbon tail has no double bonds.
Keywords
 structural formula, spacefilling model, fatty acid, lipid, carboxylic acid, hydrocarbon, myristic acid
19-04-05k
Title
 The structural formula and spacefilling model represent oleic acid, a fatty acid
Caption
 Fatty acids are carboxylic acids with a long hydrocarbon tail. In the general structure, "R" represents the large hydrocarbon tail. In this example, the hydrocarbon tail has 17 carbons.
Notes
 Oleic acid is in olive oil, peanut oil, and human fat. It is an unsaturated fatty acid: the hydrocarbon tail has a double bond. Since there is only one double bond, the fatty acid is monounsaturated.
Keywords
 structural formula, spacefilling model, fatty acid, lipid, carboxylic acid, hydrocarbon, oleic acid
19-04-05un
Title
 Structure of glycerol, a compound that reacts with fatty acids
Caption
 The -OH groups on glycerol can react with the -COOH groups on fatty acids, causing the fatty acid to join to the glycerol, and releasing water.
Notes
 The glycerol and fatty acids react to form triglycerides.
Keywords
 structural formula, fatty acid, carboxylic acid, glycerol, alcohol, triglyceride
19-04-06l
Title
 Glycerol and fatty acids form triglycerides
Caption
 The -OH groups on glycerol can react with the -COOH groups on fatty acids, causing the fatty acid to join to the glycerol, and releasing water.
Notes
 The glycerol and fatty acids react to form triglycerides.
Keywords
 structural formula, fatty acid, carboxylic acid, glycerol, alcohol, triglyceride
19-04-07un
Title
 General formulas show how glycerol and fatty acids form triglycerides
Caption
 The -OH groups on glycerol can react with the -COOH groups on fatty acids, causing the fatty acid to join to the glycerol, and releasing water.
Notes
 The glycerol and fatty acids react to form triglycerides.
Keywords
 general formula, fatty acid, carboxylic acid, glycerol, alcohol, triglyceride
19-04-08un
Title
 Structural formulas show how glycerol and stearic acid forms tristearin, a triglyceride
Caption
 The -OH groups on glycerol can react with the -COOH groups on stearic acid, causing the stearic acid to join to the glycerol, and releasing water.
Notes
 The glycerol and stearic acid react to form tristearin, a triglyceride.
Keywords
 structural formula, fatty acid, carboxylic acid, glycerol, alcohol, triglyceride
19-04-11un
Title
 Example 19.2: Identifying triglycerides
Caption
 Identify the triglycerides and classify each as saturated and unsaturated.
Notes
 (a) not a triglyceride; this is a carboxylic acid. (b) triglyceride: the glycerol backbone is present. It is saturated, because there are no double bonds in the hydrocarbon chains. (c) triglyceride: the glycerol backbone is present. It is unsaturated, because there is a double bond in the hydrocarbon chains. (d) not a triglyceride; this is a monosaccharide.
Keywords
 structural formula, fatty acid, carboxylic acid, glycerol, alcohol, triglyceride, saturated, unsaturated
19-04-12un
Title
 Skillbuilder 19.2: Identifying triglycerides
Caption
 Identify the triglycerides and classify each as saturated and unsaturated.
Notes
 (a) not a triglyceride; this is an amine. (b) triglyceride: the glycerol backbone is present. It is unsaturated, because there is a double bond in the hydrocarbon chains. (c) not a triglyceride; this is a monosaccharide. (d) triglyceride: the glycerol backbone is present. It is saturated, because there are no double bonds in the hydrocarbon chains.
Keywords
 structural formula, fatty acid, carboxylic acid, glycerol, alcohol, triglyceride, saturated, unsaturated
19-04-13o
Title
 Triglycerides are broken down by digestion
Caption
 Digestion breaks down triglycerides into glycerol, monoglycerides, diglycerol, and fatty acids. These products pass through the intestine walls, where they reassemble into triglycerides as they pass into the blood.
Notes
 Digestion of triglycerides is slower than digestion of other food types.
Keywords
 structural formula, fatty acid, carboxylic acid, glycerol, alcohol, triglyceride, monoglyceride, diglycerol
19-04-15q
Title
 The structural formula and spacefilling model presented here represent tristearin, a triglyceride
Caption
 The -OH groups on glycerol can react with the -COOH groups on stearic acid, causing the stearic acid to join to the glycerol, and releasing water.
Notes
 The glycerol and stearic acid react to form tristearin, a triglyceride.
Keywords
 structural formula, spacefilling model, fatty acid, lipid, carboxylic acid, glycerol, stearic acid, triglyceride, tristearin
19-04-16r
Title
 The structural formula and spacefilling model presented here represent trilinolenin, a triglyceride
Caption
 The -OH groups on glycerol can react with the -COOH groups on linolenic acid, causing the linolenic acid to join to the glycerol, and releasing water.
Notes
 The glycerol and linolenic acid react to form trilinolenin, a triglyceride. The triglyceride contains unsaturated fatty acids.
Keywords
 structural formula, spacefilling model, fatty acid, lipid, carboxylic acid, glycerol, linolenic acid, triglyceride, trilinolenin
19-04-17s
Title
 Phospholipids are like a triglyceride in which phosphate has replaced a fatty acid
Caption
 The phosphate group makes the phospholipid polar.
Notes
 Phospholipids are found in cell membranes.
Keywords
 structural formula, fatty acid, phosphate, triglyceride, phospholipid, polar
19-04-17un
Title
 Structure of phosphatidyl choline: a phospholipid
Caption
 The substituted phosphate group makes the phospholipid polar.
Notes
 This phospholipid is found in cell membranes of higher animals.
Keywords
 structural formula, fatty acid, phosphate, triglyceride, phospholipid, polar, phosphatidyl choline
19-05
Title
 Phospholipids have a polar head and nonpolar tails
Caption
 How would a phospholipid orient itself if placed in water?
Notes
 The polar head would point into the water; the tails would point away from the water.
Keywords
 structural formula, fatty acid, phosphate, triglyceride, phospholipid, polar, water
19-06
Title
 Cell membranes are formed from lipid bilayers
Caption
 The polar heads point into the cell, and outward, into the cell's environment. The nonpolar tails point toward one another.
Notes
 Both phospholipids and glycolipids can form lipid bilayers.
Keywords
 structural formula, fatty acid, phosphate, triglyceride, phospholipid, polar, water, glycolipid, bilayer, cell membrane
19-06-01un
Title
 Steroids have a four-ring structure
Caption
 Steroids are important biological compounds. Like phospholipids and glycolipids, steriods are found in cell membranes.
Notes
 Steroids include cholesterol, testosterone, and estrogen.
Keywords
 general formula, steroid, phospholipid, glycolipid, cell membrane
19-06-01.01un
Title
 Structural formulas of three common steroids
Caption
 Steroids include cholesterol (part of cell membranes), testosterone (principal male hormone), and estrogen (principal female hormone).
Notes
 Steroids are important biological compounds.
Keywords
 structural formula, steroid, cell membrane, cholesterol, testosterone, hormone, estrogen
19-06-05un
Title
 General structure of amino acids
Caption
 Amino acids combine a carboxylic acid group, an amine group, and a hydrocarbon group (R) in a single molecule.
Notes
 Amino acids can polymerize to form proteins.
Keywords
 general structure, amino acid, carboxylic acid, amine, hydrocarbon, protein
19-06-06w
Title
 Structural formula and spacefilling model of alanine, an amino acid
Caption
 Alanine combines a carboxylic acid group, an amine group, and a hydrocarbon group (-CH3) in a single molecule.
Notes
 Alanine is a common amino acid in living organisms.
Keywords
 structural formula, spacefilling model, alanine, amino acid, carboxylic acid, amine, hydrocarbon, protein
19-06-07x
Title
 Structural formula and spacefilling model of serine, an amino acid
Caption
 Serine combines a carboxylic acid group, an amine group, and a hydrocarbon group (actually an alcohol, -CH2OH) in a single molecule.
Notes
 Serine is a common amino acid in living organisms.
Keywords
 structural formula, spacefilling model, serine, amino acid, carboxylic acid, amine, hydrocarbon, protein
19-06-08y
Title
 Structural formula and spacefilling model of aspartic acid, an amino acid
Caption
 Aspartic acid combines a carboxylic acid group, an amine group, and a hydrocarbon group (actually a carboxylic acid, -CH2COOH) in a single molecule.
Notes
 Aspartic acid is a common amino acid in living organisms.
Keywords
 structural formula, spacefilling model, aspartic acid, amino acid, carboxylic acid, amine, hydrocarbon, protein
19-06-09z
Title
 Structural formula and spacefilling model of lysine, an amino acid
Caption
 Lysine combines a carboxylic acid group, an amine group, and a hydrocarbon group (actually an amine. -CH2CH2CH2CH2NH2) in a single molecule.
Notes
 Lysine is a common amino acid in living organisms.
Keywords
 structural formula, spacefilling model, lysine, amino acid, carboxylic acid, amine, hydrocarbon, protein
19-06-10_T02
Title
 Table 19.2: Common amino acids
Caption
 The 20 amino acids in this table are all common in living organisms. They all combine a carboxylic acid group, an amine group, and a hydrocarbon group in a single molecule.
Notes
 Amino acids react with incredible variety to form proteins. These are considered to be the 20 "essential" amino acids. Students might be asked to research why these are "essential".
Keywords
 structural formula, amino acid, carboxylic acid, amine, hydrocarbon, protein, Histidine, Phenylalanine, Tyrosine, Tryptophan, Asparagine, Glutamine, Lysine, Arginine, Serine, Threonine, Aspartic acid, Glutamic acid, Isoleucine, Proline, Methionine, Cysteine , Glycine, Alanine, Valine, Leucine
19-06-11un
Title
 Amino acids react with one another by forming a peptide bond
Caption
 The peptide bond is a bond that forms between the amine group on one amino acid molecule, and the carboxylic acid group on an adjacent amino acid. Water is released when the bond forms.
Notes
 Amino acids react with incredible variety to form proteins.
Keywords
 structural formula, amino acid, carboxylic acid, amine, hydrocarbon, protein, peptide bond
19-06-12un
Title
 Glycine and alanine react with one another by forming a peptide bond
Caption
 The peptide bond is a bond that forms between the amine group on one amino acid molecule (alanine), and the carboxylic acid group on an adjacent amino acid (glycine). Water is released when the bond forms.
Notes
 Amino acids react with incredible variety to form proteins.
Keywords
 structural formula, amino acid, carboxylic acid, amine, hydrocarbon, protein, peptide bond, glycine, alanine
19-06-13un
Title
 Glycine and alanine react with one another by forming a dipeptide and water
Caption
 The peptide bond is a bond that forms between the amine group on one amino acid molecule (alanine), and the carboxylic acid group on an adjacent amino acid (glycine). Water is released when the bond forms.
Notes
 Amino acids react with incredible variety to form proteins.
Keywords
 structural formula, amino acid, carboxylic acid, amine, hydrocarbon, protein, peptide bond, glycine, alanine
19-06-14un
Title
 Valine and leucine react with one another by forming a dipeptide and water
Caption
 The peptide bond is a bond that forms between the amine group on one amino acid molecule, and the carboxylic acid group on an adjacent amino acid. Water is released when the bond forms.
Notes
 Amino acids react with incredible variety to form proteins.
Keywords
 structural formula, amino acid, carboxylic acid, amine, hydrocarbon, protein, peptide bond, valine, leucine
19-06-15un
Title
 Valine and leucine react with one another by forming a dipeptide and water
Caption
 The peptide bond is a bond that forms between the amine group on one amino acid molecule, and the carboxylic acid group on an adjacent amino acid. Water is released when the bond forms.
Notes
 Amino acids react with incredible variety to form proteins.
Keywords
 structural formula, amino acid, carboxylic acid, amine, hydrocarbon, protein, peptide bond, valine, leucine
19-07
Title
 Protein structure is expressed at four levels
Caption
 Proteins are made up of amino acid sequences. The sequences organize into recognizable shapes: pleated sheet, helix, random coil. These structures fold into a polypeptide chain that is ultimately arranged in a distinct position with respect to one or more other polypeptide chains.
Notes
 The four levels of structure allow proteins to display extremely specific properties in living organisms.
Keywords
 amino acid, protein, peptide bond, primary, secondary, tertiary, quaternary, polypeptide, pleated sheet, helix, random coil
19-08
Title
 Hemoglobin displays typical protein structure
Caption
 Proteins are made up of amino acid sequences. The sequences organize into recognizable shapes: pleated sheet, helix, random coil. These structures fold into a polypeptide chain that is ultimately arranged in a distinct position with respect to one or more other polypeptide chains.
Notes
 The protein surrounds four heme units, the iron-containing groups that reversibly bind with oxygen.
Keywords
 amino acid, protein, peptide bond, primary, secondary, tertiary, quaternary, polypeptide, pleated sheet, helix, random coil, heme, hemoglobin
19-09
Title
 Secondary structure in proteins: the alpha-helix
Caption
 Proteins are made up of amino acid sequences. In many proteins, the sequences organize into the alpha-helix shape.
Notes
 The shape is largely due to the interaction between peptide backbones of amino acids that are close to each other in the chain.
Keywords
 amino acid, protein, peptide bond, secondary, peptide, helix
19-10
Title
 Secondary structure in proteins: the beta-pleated sheet
Caption
 Proteins are made up of amino acid sequences. In many proteins, the sequences organize into the beta-pleated sheet shape.
Notes
 The shape is largely due to the interaction between peptide backbones of amino acids on neighboring protein chains.
Keywords
 amino acid, protein, peptide bond, secondary, polypeptide, pleated sheet
19-11
Title
 Block diagram of DNA
Caption
 DNA consists of nucleotide units bonded in a specific pattern. Each nucleotide is composed of a sugar, a phosphate group, and a base.
Notes
 The nucleotides join together through the phosphate groups. The sugar is deoxyribose.
Keywords
 DNA, nucleotide, sugar, phosphate, base, deoxyribose
19-11-01un
Title
 The sugars in DNA and RNA
Caption
 In DNA, the sugar is deoxyribose; in RNA, the sugar is ribose.
Notes
 The sugar is deoxyribose for every nucleotide in DNA. Likewise, the sugar is ribose for every RNA nucleotide.
Keywords
 structural formula, DNA, RNA, nucleotide, sugar, phosphate, base, deoxyribose, ribose
19-11-02un
Title
 DNA uses four bases
Caption
 In DNA, the four bases, adenine, cytosine, guanine, and thymine, code genetic information.
Notes
 In DNA, neither the sugar (deoxyribose) nor the phosphate group differ among the nucleotides. Only the base pairs differ.
Keywords
 DNA, nucleotide, sugar, phosphate, base, deoxyribose, adenine, cytosine, guanine, thymine, genetic
19-11-03un
Title
 Like DNA, RNA uses four bases, one of which is uracil
Caption
 In DNA, the four bases, adenine, cytosine, guanine, and thymine, code genetic information. RNA also uses four bases, but thymine is replaced by uracil.
Notes
 In RNA, neither the sugar (ribose) nor the phosphate group differ among the nucleotides. Only the base pairs differ.
Keywords
 DNA, RNA, nucleotide, sugar, phosphate, base, ribose, adenine, cytosine, guanine, thymine, uracil
19-12
Title
 A codon is a sequence of three nucleotides
Caption
 Codons are three-nucleotide sequences that code for an amino acid.
Notes
 Sequences of codons in a DNA molecule make up the genes.
Keywords
 DNA, nucleotide, sugar, phosphate, base, adenine, cytosine, guanine, thymine, codon, amino acid, gene
19-13
Title
 Chromosome structures within cell nucleus to nucleotide
Caption
 A codon is a sequence of three nucleotides. A gene is a sequence of codons that code for a protein. A chromosome is a collection of genes.
Notes
 Genetic information instructs matter in its organization into proteins and, ultimately, to a living organism.
Keywords
 DNA, nucleotide, sugar, phosphate, base, codon, amino acid, gene, chromosome, protein
19-14
Title
 DNA has a double-helix structure
Caption
 The strands of the double helix are complementary to each other. This is so because the bases interact in pairs: adenine with thymine (A and T), and cytosine with guanine (C and G).
Notes
 The base pairs interact through hydrogen bonds.
Keywords
 DNA, nucleotide, adenine, thymine, cytosine, guanine, base, double helix
19-14-01un