Campbell Biology: Concepts & Connections Chapter 3 - PDF

Campbell Biology: Concepts & Connections Tenth Edition Chapter 3 The Molecules of Cells Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Introduction Most adults cannot properly digest dairy products. – These peop...

Campbell Biology: Concepts & Connections Tenth Edition Chapter 3 The Molecules of Cells Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Introduction Most adults cannot properly digest dairy products. – These people are lactose intolerant, because they lack the enzyme lactase. – This illustrates the importance of biological molecules, such as lactase, in the daily functions of living organisms. Copyright © 2020 Pearson Education, Inc. All Rights Reserved. 3.1 Life’s Molecular Diversity Is Based on the Properties of Carbon (1 of 2) Carbon’s ability to bond with four other atoms is the basis for building large and diverse organic compounds. Carbon chains form the backbone of most organic molecules. Isomers have the same molecular formula but different structures. Hydrocarbons are composed of only carbon and hydrogen. Copyright © 2020 Pearson Education, Inc. All Rights Reserved. 3.1 Life’s Molecular Diversity Is Based on the Properties of Carbon (2 of 2) Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Figure 3.1b Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Animation: Isomers 2 Copyright © 2020 Pearson Education, Inc. All Rights Reserved. 3.2 A Few Chemical Groups are Key to the Functioning of Biological Molecules (1 of 2) An organic compound’s properties depend on the – size and shape of its carbon backbone and – atoms attached to that skeleton. Hydrophilic functional groups give organic molecules specific chemical properties. Table 3.2 illustrates six important chemical groups. Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Important Chemical Groups Of Organic Compounds Functional Groups animation Copyright © 2020 Pearson Education, Inc. All Rights Reserved.  3.2 A Few Chemical Groups Are Key to the Functioning of Biological Molecules (2 of 2) The sex hormones testosterone and estradiol (a type of estrogen) differ only in the groups of atoms highlighted in Figure 3.2. Copyright © 2020 Pearson Education, Inc. All Rights Reserved. 3.3 Cells Make Large Molecules from a Limited Set of Small Molecules The four classes of biological molecules contain very large molecules. – They are often called macromolecules because of their large size. – They are also called polymers because they are made from identical or similar building blocks strung together. – The building blocks of polymers are called monomers. Copyright © 2020 Pearson Education, Inc. All Rights Reserved. 3.3 Cells Make Large Molecules from a Limited Set of Small Molecules Monomers are linked together to form polymers through dehydration synthesis (condensation) reactions. Polymers are broken apart by hydrolysis. These reactions are mediated by enzymes, specialized macromolecules that speed up reactions. Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Figure 3.3 Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Figure 3.3_1_2 Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Figure 3.3_2_2 Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Animation: Polymers Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Carbohydrates Copyright © 2020 Pearson Education, Inc. All Rights Reserved. 3.4 Monosaccharides are the Simplest Carbohydrates Carbohydrates range from small sugar molecules (monomers) to large polysaccharides. – Sugar monomers are monosaccharides. – A monosaccharide generally has a formula that is a multiple of C H 2 O and contains hydroxyl groups and a carbonyl group. Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Figure 3.4b Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Figure 3.4c Copyright © 2020 Pearson Education, Inc. All Rights Reserved. 3.5 Two Monosaccharides Are Linked to Form a Disaccharide Two monosaccharides (monomers) can bond to form a disaccharide in a dehydration reaction. Checkpoint question Lactose, as you read in the chapter introduction, is the disaccharide sugar in milk. It is formed from glucose and galactose. The formula for both these monosaccharides is C 6 H 12 O 6. What is the formula for lactose? Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Figure 3.5_2 Copyright © 2020 Pearson Education, Inc. All Rights Reserved. 3.6 Connection: Are We Eating Too Much Sugar? The F D A recommends that only 10% of daily calories come from added sugar. Research supports the correlation between high sugar intake and adverse health effects. Checkpoint question Sugars are often described as “empty calories.” What do you think that means from a nutrition standpoint? Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Figure 3.6 Copyright © 2020 Pearson Education, Inc. All Rights Reserved. 3.7 Polysaccharides Are Long Chains of Sugar Units Starch and glycogen are storage polysaccharides. Cellulose is structural, found in plant cell walls. Chitin is a component of insect and crustacean and fungal cell walls. Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Animation: Polysaccharides Carbohydrates video animation Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Lipids Copyright © 2020 Pearson Education, Inc. All Rights Reserved. 3.8 Fats Are Lipids That Are Mostly Energy-Storage Molecules (1 of 2) Lipids are diverse hydrophobic (water-fearing) compounds composed largely of carbon and hydrogen. – Fats (triglycerides) consist of glycerol linked to three fatty acids. – Some fatty acids contain one or more double bonds, forming unsaturated fatty acids. Unsaturated fatty acids are typical of plant oils. – Fats with the maximum number of hydrogens are called saturated fatty acids. Saturated fatty acids are found in animal fats like butter or lard. Copyright © 2020 Pearson Education, Inc. All Rights Reserved. 3.8 Fats Are Lipids That Are Mostly Energy-Storage Molecules Hydrogenated vegetable oils are unsaturated fats that have been converted to saturated fats by adding hydrogen. This hydrogenation creates trans fats, which are associated with health risks. Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Figure 3.8c Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Animation: Fats Copyright © 2020 Pearson Education, Inc. All Rights Reserved. 3.9 Scientific Thinking: Scientific Studies Document the Health Risks of Trans Fats By the 1990s, partially hydrogenated oils were common in countless foods. Recent research has shown that trans fats pose an even greater health risk than saturated fats. The scientific studies establishing the risks of trans fats were of two types. 1. In experimental controlled feeding trials, diets contained different proportions of saturated, unsaturated, and partially hydrogenated fats. 2. Many other scientific studies on dietary health effects are observational. Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Figure 3.9 Copyright © 2020 Pearson Education, Inc. All Rights Reserved. 3.10 Phospholipids and Steroids Are Important Lipids with a Variety of Functions Phospholipids are components of cell membranes. Steroids include cholesterol and some hormones. Cholesterol is a common component in animal cell membranes and is also the precursor for making other steroids, including sex hormones. Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Figure 3.10a Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Figure 3.10b Copyright © 2020 Pearson Education, Inc. All Rights Reserved. 3.11 Connection: Anabolic Steroids Pose Health Risks Anabolic steroids are synthetic variants of the male hormone testosterone that are abused by some athletes with serious consequences. Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Proteins Copyright © 2020 Pearson Education, Inc. All Rights Reserved. 3.12 Proteins Have a Wide Range of Functions and Structures (1 of 2) Proteins are involved in nearly every dynamic function in your body and are very diverse. Proteins function as – enzymes, – transport proteins embedded in cell membranes, – defensive proteins, such as antibodies, – signal proteins such as many hormones, – receptor proteins, – contractile proteins found within muscle cells, – structural proteins such as collagen, and – storage proteins. Copyright © 2020 Pearson Education, Inc. All Rights Reserved. 3.12 Proteins Have a Wide Range of Functions and Structures Proteins are composed of differing arrangements of a common set of just 20 amino acid monomers. The functions of different types of proteins depend on their individual shapes. In the process of denaturation, a protein unravels, loses its specific shape, and loses its function. Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Figure 3.12c Copyright © 2020 Pearson Education, Inc. All Rights Reserved. 3.13 Proteins Are Made from Amino Acids Linked by Peptide Bonds (1 of 2) Protein diversity is based on different sequences of amino acids, monomers that contain – an amino group, – a carboxyl group, – an H atom, and – an R group, all attached to a central carbon. Copyright © 2020 Pearson Education, Inc. All Rights Reserved. 3.13 Proteins Are Made from Amino Acids Linked by Peptide Bonds (2 of 2) Amino acid monomers are linked together in a dehydration reaction, – joining the carboxyl group of one amino acid to the amino group of the next amino acid, and – creating a peptide bond. Additional amino acids can be added by the same process to create a chain of amino acids called a polypeptide. Copyright © 2020 Pearson Education, Inc. All Rights Reserved.  Figure 3.13b The R groups distinguish 20 amino acids, each with specific properties. Copyright © 2020 Pearson Education, Inc. All Rights Reserved. 3.14 Visualizing the Concept: A Protein’s Functional Shape Results from Four Levels of Structure (1 of 2) A protein can have four levels of structure: 1. A protein’s primary structure is the sequence of amino acids in its polypeptide chain. 2. Its secondary structure is the coiling or folding of the chain, stabilized by hydrogen bonds. 3. The tertiary structure is the overall three-dimensional shape of a polypeptide, resulting from interactions among R groups. 4. Proteins made of more than one polypeptide have quaternary structure. Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Figure 3.14_1 Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Figure 3.14_2 Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Figure 3.14_3 Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Figure 3.14_4 Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Figure 3.14 Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Animation: Protein Structure Introduction Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Nucleic Acids Copyright © 2020 Pearson Education, Inc. All Rights Reserved.  3.15 The Nucleic Acids D N A and R N A Are Information-Rich Polymers of Nucleotides The monomers that make up nucleic acids are nucleotides. Nucleotides are composed of a sugar, a phosphate group, and a nitrogenous base. – D N A is a double helix. – R N A is a single polynucleotide chain. – D N A and R N A serve as the blueprints for proteins and thus control the life of a cell. – D N A is the molecule of inheritance. Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Figure 3.15a Nucleic Acid structure Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Figure 3.15b Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Figure 3.15d_1 Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Figure 3.15d_2 Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Figure 3.15d_3 Copyright © 2020 Pearson Education, Inc. All Rights Reserved. 3.16 Evolution Connection: Lactose Tolerance Is a Recent Event in Human Evolution Different mutations in D N A have led to lactose tolerance in several human groups whose ancestors raised dairy cattle. Researchers identified three new mutations in 43 ethnic groups in East Africa that keep the lactase gene permanently turned on. Copyright © 2020 Pearson Education, Inc. All Rights Reserved. THE END Copyright © 2020 Pearson Education, Inc. All Rights Reserved. You Should Now Be Able to (1 of 2) 1. Describe the importance of carbon to life’s molecular diversity. 2. Describe the chemical groups that are important to life. 3. Explain how a cell can make a variety of large molecules from a small set of molecules. 4. Define monosaccharides, disaccharides, and polysaccharides and explain their functions. 5. Define lipids, phospholipids, and steroids and explain their functions. Copyright © 2020 Pearson Education, Inc. All Rights Reserved. You Should Now Be Able to (2 of 2) 6. Explain how trans fats are formed in food. Describe the evidence that suggests that eating trans fats is more unhealthy than consuming saturated fats. 7. Describe the chemical structure of proteins and the importance of proteins to cells. 8. Describe the chemical structure of nucleic acids and explain how they relate to inheritance. 9. Explain how lactose tolerance has evolved in humans. Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Figure 3.10 Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Table 3.2 Important Chemical Groups of Organic Compounds (2 of 3) Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Table 3.2 Important Chemical Groups of Organic Compounds (3 of 3) Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Figure 3.UN01 Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Figure 3.U N02 Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Figure 3.U N02_1 Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Figure 3.U N02_2 Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Figure 3.U N03 Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Figure 3.U N04 Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Figure 3.U N05 Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Figure 3.U N06 Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Copyright This work is protected by United States copyright laws and is provided solely for the use of instructors in teaching their courses and assessing student learning. Dissemination or sale of any part of this work (including on the World Wide Web) will destroy the integrity of the work and is not permitted. The work and materials from it should never be made available to students except by instructors using the accompanying text in their classes. All recipients of this work are expected to abide by these restrictions and to honor the intended pedagogical purposes and the needs of other instructors who rely on these materials. Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Figure 3.2_1 Copyright © 2020 Pearson Education, Inc. All Rights Reserved.