CHAPTER 5 THE STRUCTURE AND FUNCTION OF MACROMOLECULES

1. CHAPTER 5 THE STRUCTURE AND FUNCTION OF MACROMOLECULES

2. Chapter 5 Objectives After reading this chapter, completing the study guide, and participating in class, you should be able to: • List the levels of biological organization from subatomic particles through macromolecules • Describe the distinguishing characteristics of carbohydrates and explain their classification

3. Describe the important biological functions of polysaccharides • Explain what distinguishes lipids from other classes of biological macromolecules • Describe the unique properties, building blocks and biological roles of fats, phospholipids and steroids • Distinguish proteins from the other classes of macromolecules and list the biological functions which members of this class perform • List and be able to recognize the four major components of a typical amino acid and explain how amino acids may be grouped according to the nature of their side chain

4. Identify a peptide bond and describe how it is formed • Explain what determines protein conformation and why it is important • Name the four levels of protein structure and briefly describe from what aspect of protein structure each is derived • Define denaturation and explain how proteins may be denatured

5. Describe the characteristics that distinguish nucleic acids from the other classes of macromolecules • Summarize the functions of nucleic acids • Juggle three flaming batons...just checking that you're still paying attention (smile!) • List the major components of a nucleotide and describe how these monomers are linked together to form a nucleic acid

6. 16. Distinguish between a pyrimidine and a purine and name those which occur in nucleic acids. • Describe at least one function of nucleotides other than their inclusion in nucleic acids  • Briefly describe the three-dimensional structure of DNA

7. Introduction • Cells join smaller organic molecules together to form larger molecules. • These larger molecules, macromolecules, may be composed of thousands of atoms and weigh over 100,000 daltons. • The four major classes of macromolecules are: carbohydrates, lipids, proteins, and nucleic acids.

8. Polymer Key Principles 1. Most macromolecules are polymers • An immense variety of polymers can be built from a small set of monomers • Pgs. 58-60

9. 1. Most macromolecules are polymers • Three of the four classes of macromolecules form chainlike molecules called polymers (greek poly = many, mer = parts). • Polymers consist of many similar or identical building blocks linked by covalent bonds. • The repeated units are small molecules called monomers (mono = one). • Some monomers have other functions of their own.

10. Making or Breaking Polymers • The chemical mechanisms that cells use to make and break polymers are similar for all classes of macromolecules. • See figure 5.2, pg 59

11. Making Polymers • Monomers are connected by covalent bonds via a condensation reaction or dehydration reaction. • One monomer provides a hydroxyl group and the other provides a hydrogen and together these form water. • This process requires energy and is aided by enzymes.

12. Breaking Down Polymers • The covalent bonds connecting monomers in a polymer are disassembled by hydrolysis. • In hydrolysis as the covalent bond is broken a hydrogen atom and hydroxyl group from a split water molecule attaches where the covalent bond used to be. • Hydrolysis reactions dominate the digestive process, guided by specific enzymes.

13. 2. An immense variety of polymers can be built from a small set of monomers • Each cell has thousands of different macromolecules. • These molecules vary among cells of the same individual, even more among unrelated individuals of a species, and are even greater between species. • This diversity comes from various combinations of the 40-50 common monomers and other rarer ones. • These monomers can be connected in various combinations like the 26 letters in the alphabet can be used to create a great diversity of words. • Biological molecules are even more diverse.

14. Objective 1 • List the levels of biological organization from subatomic particles through macromolecules