The Chemistry of Living Things

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The Chemistry of Living Things

Objectives

After studying this chapter, students will be able to

Describe elements and atoms in terms of their components
Discuss chemical bonding
Describe the relationship between water and life
Discuss acids and bases in relationship to hydrogen bonds
Describe the basic structure of organic molecules and their synthesis and dissolution
Discuss the roles of carbohydrates, lipids, proteins, and nucleic acids in living organisms

Suggested Lecture Outline

2.1All Matter Consists of Elements

A.Atoms: smallest functional unit

B.Isotopes: same element, different number of neutrons

2.2Atoms Combine to Form Molecules

A.Energy as Fuel

B.Potential Energy of Electrons

C.Chemical Bonds: link atoms; form covalent, ionic, hydrogen bonds

D.Elements of Living Organisms

2.3Life Depends on Water

A.Water as a Biological Solvent

B.Body Temperature Regulation

2.4The Importance of Hydrogen Ions

A.Acids Donate and Bases Accept Hydrogen Ions

B.The pH Scale Is the Hydrogen Ion Concentration

C.Buffers: minimize pH change

2.5The Organic Molecules of Living Organisms

A.Carbon: common building block

B.Macromolecules: made and broken, dehydration synthesis and hydrolysis

2.6Carbohydrates Are Used for Energy and Structural Support

A.Monosaccharides: simple sugars, glucose, fructose, ribose, deoxyribose

B.Oligosaccharides: short chains of monosaccharides, disaccharides

C.Polysaccharides: store energy, starch, glycogen, cellulose

2.7Lipids Are Insoluble in Water

A.Triglycerides: energy storage

B.Phospholipids: cell membranes

C.Steroids: ring structures, cholesterol

2.8Proteins Are Complex Structures Constructed of Amino Acids

A.Structure: primary, secondary, tertiary, quaternary

B.Enzyme Function

2.9Nucleic Acids Store Genetic Information and Make Proteins

A.DNA

B.RNA

2.10ATP for Energy Transport

Additional Sections

A.Try It Yourself: Oil and Water Don’t Mix

B.Directions in Science: Why Protein Folding Is Important

C.Try It Yourself: Demonstrating an Enzyme in Your Saliva

D.Current Issue: Antioxidants: Hope or Hype?

Lecture Hints

Students usually do not like any chemistry component. Try emphasizing the importance of some chemistry background to understand biologically important macromolecules such as sugars, proteins, and lipids.
Many students have studied this material previously; try to elicit what you can from the class.
Describe what it’s like to follow a young child (2–4) down a supermarket isle as they dart back and forth and take up much more room than their little body’s would justify. Use this as an example of the movement of electrons that are extremely small, but take up lots of room around an atom’s nucleus.
Several publications list the annual worth of a human organism according to the worth of the elements in people. Try applying this to the list of elements.
The hydrogen bonds are extremely important in water. They help form a matrix that must include anything “dissolved” in it. The vibrations of the bonds move things through the solution and assist in functioning as a heat sink.
There are various definitions of acids and bases; use the one with which you are most comfortable.
The pH is a logarithmic scale; try comparing it to the Richter scale for earthquakes to explain the differences in magnitude.
When dealing with buffers, you could emphasize the very narrow range within which our buffer systems maintain our body pH.
Describe the buffers found in the blood that maintain our body’s pH.
When explaining the structural uses of carbon, a split-rail fence can be used to illustrate the “straight” line arrangement; it is more accurate than a truly straight line.
It should be emphasized that sugar does not just mean table sugar.
When a protein is made, the transition from primary to tertiary is continuous, not fragmented, as the use of separate terms might imply. You might try explaining this as analogous to cooking a single strand of spaghetti: first straight, then a bit bent, then folded into a more-or-less ball-shaped structure.

Media Guide

Listed below are the portions of Interactive Physiology for Human Biology and the Instructor Resource DVD that are relevant to this chapter.

Instructor Resource DVD

Human Biology Animations: Atoms, Ions, and Bonding; Water and Chemistry; Monomers and Polymers; Lipid Structure and Function; Protein Structure; Nucleic Acids
BLAST Tutorials: Covalent Bonds; Hydrogen Bonds in DNA; Hydrogen Bonds in Water; Building Proteins; Protein Primary Structure; Protein Secondary Structure; Protein Tertiary Structure and Quaternary Structure; Unfolding and Refolding a Protein; Alpha Helix; DNA and RNA Compared, Structure of DNA Double Helix; Structure of ATP; ATP/ADP Cycle; Enzyme Regulation: Allosteric; Enzyme Regulation: Chemical Modification; Enzyme Regulation: Competitive Inhibition; How Enzymes Work: Activation Energy; How Enzymes Work: Reaction Types and Specificity
All Images and Tables (labeled and unlabeled in JPEG and PPT formats)
PPT presentations
Active Lecture (“Clicker”) Questions
Interactive Physiology for Human Biology
Fluids & Electrolytes/Introduction to Body Fluids
Class Demonstrations and Student Activities
Explore the Human Biology Place Web site.
See the Fluid Balance topic on the IP for HB CD-ROM.
See Try It Yourself: Demonstrating an Enzyme in Your Saliva, and Oil and Water Don’t Mix.
Bring in models of atoms and electron orbitals.
Have the class figure out, on an atomic level, why a square inch of aluminum weighs so much less than a square inch of iron.
Ask a local radiologist to visit the class to explain medical uses of isotopes.
Test the pH of common solutions by using pH paper.
Have students collect the nutritional panels from their food. Construct posters illustrating the relative amounts of nutrients. Describe how these contribute to our body’s biochemistry.

Suggestions for Possible Assignments

Any of the following questions or topics can be used as a starting point for a discussion, abstract, paper, debate topic, or poster session:

Assign the exercises and questions in Chapter 2 of the Human Biology, 5th edition Study Guide as homework.
See Directions in Science: Why Protein Folding Is Important. When would mass and weight not be the same? Explain.
Why is it that only outer shells of atoms might have unpaired electrons?
Explain why some isotopes can be safely used for medical or research testing.
Why are covalent bonds so much stronger than ionic or hydrogen bonds?
Explain the possible role of free radicals in cancer.
What is the role of diffusion in normal cell functions?
Why is carbon so important to the chemical structure of our macromolecules? Is there a substitute?
What are the common uses and sources of the monosaccharides, disaccharides, and polysaccharides listed in the textbook?
If lipids are relatively insoluble in water, how can they be held in a water-based solution like blood?
Illustrate the transformation of a protein through its various structural forms.
What happens if an enzyme is not working? What if it is working just a little?
Why is an enzyme not affected by the chemical reaction related to it?
How would you prove that DNA is the storage molecule for genetic information?
How is the genetic code like a language?

Case in Point

For the following Case in Point discussion question and answer, see the new Case in Point section that follows Chapter 24 of this Instructor Guide.

I’ll Take a Bag of Labs on Chips

Answers to Concept Review

1.Protons and neutrons have appreciable weight; protons and electrons have charges.

2.The electron of each completes the orbital of the other.

3.They are capable of forming hydrogen bonds with water.

4.Electrons are shared and rotate around both atoms in covalent bonds, forming a strong attraction between the two atoms. The charges in ionic bonds form the basis of the attraction, forming a weaker bond.

5.Potential energy is energy that is not actively doing anything, but can be stored or used, as in the energy in glucose or ATP. Kinetic energy is working energy that is actively facilitating work, as in the energy removed from ATP to help an endothermic reaction occur.

6.Saturated fats have all the possible hydrogens attached to carbons; unsaturated fats are missing some of these hydrogens. Saturated fats tend to be “stiffer” than unsaturated. Saturated fats tend to be solid at room temperature; unsaturated tend to be liquid. Saturated fats tend to stay attached to their protein carrier molecules, while unsaturated fats do not.

7.Cholesterol is found as a component of cell membranes. It’s also used in the manufacture of reproductive hormones estrogen and testosterone.

8.Enzymes help chemical reactions to occur fast enough for life to proceed. Without them, reactions do happen, but not fast enough.

9.ATP functions like a rechargeable battery, temporarily storing energy until it gets to where it is needed for chemical reactions.

10.DNA contains different sugars (deoxyribose in DNA and ribose in RNA). DNA has the bases ATCG, while RNA has the bases AUCG. DNA is double stranded, and RNA is single stranded. DNA comes in the form of a double helix, while RNA has three forms: messenger, transfer, and ribosomal.

Answers to Test Yourself

1.d2.a3.f4.b5.c6.e7.alkaline8.proteins9.glycogen10.denaturation11.fatty acids12.oils13.false14.true15.true.

Answers to Apply What You Know

Answers to Apply What You Know questions can be found at the Human Biology Place,

Integrating MJ’s Human Biology Blog

The author posts recent articles from the news or scientific journals on MJ’s Human Biology Blog. This material covers chapter-relevant topics and could be assigned as extra reading associated with the chapters or used as a starting point for class discussions. Given the timeliness of the topics and the possible controversial nature of some of them, opposing opinions should be easy to generate.

Blog URL:

Sample blog posts related to Chapter 2

A Healthy Tan?

Stunting a Child’s Growth

Stem Cell Breakthrough

Example of Classroom Application

Using the posting for Stunting a Child’s Growth, have the class research the subject further, including the effects of hormone therapy for pre-teens and the effects of contact sports on bone growth. Break up the topics for this subject and assign them to separate groups in the class; have each group present their findings.

Additional Resources

Books

Blackburn, Williams, Gait, Loakes (Editors), Nucleic Acids in Chemistry and Biology, Rsc Publishing, 2006.
Devlin & Devlin, Textbook of Biochemistry with Clinical Correlations; Wiley, John & Sons, Inc., 2005.
Di Pasquale, Amino Acids and Proteins for the Athlete: The Anabolic Edge, Second, CRC Press, 2007.
Harols, F., Way of the Cell: Molecules, Organisms and the Order of Life,OxfordUniversity Press, 2001.
Lechtanski, V.L., Inquiry-Based Experiments in Chemistry, American Chemical Society, 2000.
Lide, D.R., Jr., CRC Handbook of Chemistry and Physics, 84th ed., CRC Press LLC, 2004.
Malone, L.J., Basic Concepts of Chemistry, John Wiley & Sons, Inc., 2000.
Morris, R., The Last Sorcerers: The Path from Alchemy to the Periodic Table,NationalAcademy Press, 2003.
Snyder, C., The Extraordinary Chemistry of Ordinary Things, Laboratory Manual, John Wiley & Sons, Inc., 2003.
Whitford, D., Proteins: Structure and Function, Wiley, John & Sons, Inc.
Widmaier, E., The Stuff of Life: Profiles of the Molecules that Make Us Tick, Times Books, 2002.
Williams, R.J.P., Bringing Chemistry to Life: From Matter to Man, Oxford University Press, Inc., 2000.
Van Loon, Duffy & Duffy, Environmental Chemistry: A Global Perspective, OxfordUniversityPress, USA, 2005.

Web Sites

Find the URLs and links to these Web sites on the Human Biology Place.

Chemistry of Living Things

This Web site explores and discusses the chemistry involved in all living organisms.

Web Chemistry Resources

This Web site contains complete lists of chemistry resources available through the Web for both research and educational applications.

Journal of Biological Chemistry

Journal of the professional society dedicated to the research and educational issues affecting biological chemistry.

Links for Chemists: Virtual Library Chemistry Section

A Web site containing a virtual library of experiments, research, and educational illustrations.

Chemistry

This Web site contains a variety of resources such as articles, homework help, demonstrations, news, periodic tables, educational resources, suppliers, and annotated links.

Chapter 2The Chemistry of Living Things