Chapter 3 Biochemistry Modern Biology Textbook Holt

1. Chapter 3 BiochemistryModern Biology TextbookHolt

2. Section 1 Carbon Compounds Chapter 3 Objectives • Distinguish between organic and inorganic compounds. • Explain the importance of carbon bonding in biological molecules. • Identify functional groups in biological molecules. • Summarize how large carbon molecules are synthesized and broken down. • Describe how the breaking down of ATP supplies energy to drive chemical reactions.

3. Section 1 Carbon Compounds Chapter 3 Carbon Bonding • Organic compounds contain carbon atoms and are found in living things. • Most inorganic compounds do not contain carbon atoms.

4. Section 1 Carbon Compounds Chapter 3 Carbon Bonding, continued • Carbon atoms can readily form four covalent bonds with other atoms including other carbon atoms. The carbon bonds allow the carbon atoms to form a wide variety of simple and complex organic compounds.

5. Section 1 Carbon Compounds Chapter 3 Carbon Bonding

6. Section 1 Carbon Compounds Chapter 3 Functional Groups • Functional groups are groups of atoms that influence the properties of molecules and the chemical reactions in which the molecules participate. • Condensation reactions join monomers (small simple molecules) to form polymers. A condensation reaction releases water as a by-product. • In a hydrolysis reaction, water is used to split polymers into monomers.

7. Section 1 Carbon Compounds Chapter 3 Energy Currency • Adenosine triphosphate (ATP) stores and releases energy during cell processes, enabling organisms to function.

8. Section 2 Molecules of Life Chapter 3 Objectives • Distinguish between monosaccharides, disaccharides,and polysaccharides. • Explain the relationship between amino acids and protein structure. • Describe the induced fit model of enzyme action. • Compare the structure and function of each of the different types of lipids. • Compare the nucleic acids DNA and RNA.

9. Section 2 Molecules of Life Chapter 3 Carbohydrates • Carbohydrates are organic compounds composed of carbon, hydrogen, and oxygen in a ratio of about one carbon to two hydrogen atoms to one oxygen atom. • Carbohydrates are a source of energy and are used as structural materials in organisms.

10. Section 2 Molecules of Life Chapter 3 Carbohydrates, continued • Monosaccharides • Carbohydrates are made up of monomers called monosaccharides. • Disaccharides and Polysaccharides • Two monosaccharides join to form a double sugar called a disaccharide. • A complex sugar, or polysaccharide, is made of three or more monosaccharides.

11. Section 2 Molecules of Life Chapter 3 Proteins • Proteins are organic compounds composed mainly of carbon, hydrogen, oxygen, and nitrogen. • Proteins have many functions including structural, defensive, and catalytic roles.

12. Section 2 Molecules of Life Chapter 3 Proteins, continued • Amino Acids • Proteins are made up of monomers called amino acids. The sequence of amino acids determines a protein’s shape and function. • Dipeptides and Polypeptides • Two amino acids are joined by peptide bonds to form a dipeptide. • A long chain of amino acids is called a polypeptide.

13. Section 2 Molecules of Life Chapter 3 Structure of Proteins

14. Section 2 Molecules of Life Chapter 3 Proteins, continued • Enzymes • Enzymes speed up chemical reactions and bind to specific substrates. • The binding of a substrate with an enzyme causes a change in the enzyme’s shape and reduces the activation energy of the reaction.

15. Section 2 Molecules of Life Chapter 3 Enzyme Activity

16. Section 2 Molecules of Life Chapter 3 Lipids • Lipids are nonpolar molecules that store energy and are an important part of cell membranes.

17. Section 2 Molecules of Life Chapter 3 Lipids, continued • Fatty Acids • Most lipids contain fatty acids, unbranched carbon molecules that have a hydrophilic end and a hydrophobic end. • Triglycerides • Triglycerides consist of three fatty acids and one molecule of glycerol.

18. Section 2 Molecules of Life Chapter 3 Lipids, continued • Phospholipids • Phospholipids, which make up cell membranes, consist of two fatty acids and one glycerol molecule. • Waxes • A wax is made of one long fatty acid chain joined to one long alcohol. • Steroids • A steroid is composed of four fused carbon rings.

19. Section 2 Molecules of Life Chapter 3 Nucleic Acids • A nucleic acid is a large and complex organic molecule that stores and transports information. • The nucleic acid deoxyribonucleic acid (DNA) contains genetic information for cell activities. • Ribonucleic acid (RNA) molecules play many key roles in building of proteins and can act as enzymes.

20. Section 2 Molecules of Life Chapter 3 Structure of Nucleic Acids

21. Section 2 Molecules of Life Chapter 3 DNA Overview

22. Chapter 3 Standardized Test Prep Multiple Choice 1. Which of the following is not a function of polysaccharides? A. energy source B. energy storage C. structural support D. storage of genetic information

23. Chapter 3 Standardized Test Prep Multiple Choice, continued 2. Which of the following statements is false? F. A wax is a lipid. G. Starch is a lipid. H. Saturated fats are solid at room temperature. J. Unsaturated fats are liquid at room temperature.

24. Chapter 3 Standardized Test Prep Multiple Choice, continued 3. Which of the following molecules stores hereditary information? A. ATP B. DNA C. protein D. carbohydrates

25. Chapter 3 Standardized Test Prep Multiple Choice, continued 4. What is the name of the molecule in plants that stores sugars? F. starch G. protein H. cellulose J. glycogen

26. Chapter 3 Standardized Test Prep Multiple Choice, continued The figure below illustrates the basic structure of a cell membrane. Use the figure to answer the questions that follow. 5. Which of the following molecules make up the basic structure of a cell membrane? A. waxes B. steroids C. fatty acids D. phospholipids

27. Chapter 3 Standardized Test Prep Multiple Choice, continued The figure below illustrates the basic structure of a cell membrane. Use the figure to answer the questions that follow. 6. The “tails” of the molecules in the figure orient away from water. Which of the following describes the tail’s movement away from water? F. polar G. adhesive H. hydrophilic J. hydrophobic

28. Chapter 3 Standardized Test Prep Multiple Choice, continued 7. simple sugars : carbohydrates :: amino acids : A. lipids B. proteins C. nucleic acids D. amino acids

29. Chapter 3 Standardized Test Prep Multiple Choice, continued The figure below represents the structural formula of a molecule. Use the figure to answer the question that follows. 8. What is the name of the functional group circled in the structural formula? F. amino G. hydroxyl H. phosphate J. carboxyl

30. Chapter 3 Standardized Test Prep Short Response, continued Proteins are affected by environmental conditions such as heat and pH. Explain why the process of cooking an egg cannot be reversed. Answer: The heat that is added to the egg changes the bonds in the proteins and other molecules that make up the egg to such a large extent that the original protein shape can no longer be distinguished.

31. Chapter 3 Standardized Test Prep Extended Response Enzymes are essential for the functioning of all cells. Part A Explain what enzymes do that is essential for cell function. Part B Explain the induced fit model of enzyme action. Answer: Part A Enzymes catalyze chemical reactions that are involved in important cell processes. Part B Bonding of the substrates to enzymes causes a slight change in the enzyme’s shape, thereby weakening some of the bonds and lowering activation energy.