The Molecules of Cells

1. The Molecules of Cells Chapter 3

2. We live in a world of molecules. You eat food, not atoms. You breathe atmospheric oxygen (O2), not atomic oxygen (O2-). There are main categories of molecules, and you need to understand what they are, and what they generally do.

3. Organic or inorganic? • Organic molecules contain carbon. • Sugars, fats/lipids, proteins, DNA. • Inorganic molecules lack carbon. • Water, atmospheric oxygen.

4. Building molecules. • Small molecules (monomers) are combined to form larger (polymers) molecules. • Polymers are also broken down into monomers. • This is called metabolism.

5. C6H12O6? • These three molecules all have the same molecular formula, but different structures. What are they called?

6. Functional Groups • Functional groups are small areas on a larger molecule that actually participate in a reaction. • Know these examples, and how they function.

7. Pay attention to how… • Atoms make molecules. • Inorganic molecules and organic molecules. • Monomers and polymers interact. • Think of how molecules can be made and broken apart. • Be able to describe dehydration synthesis and hydrolysis.

8. Macromolecules • These are large molecules with specific functions. • There are many types, but in biology there are four primary categories. • Carbohydrates (short term energy source) • Lipids (long term energy; cell structure). • Proteins (perform the cells work) • Nucleic acids (contain genetic information).

9. Carbohydrates • These give short-term energy to the cell. • They are used in almost all energy reactions. • Monosaccharides are single sugar units. • Simple sugars like Glucose. • Disaccharides have two sugars. • Table sugar (sucrose). • Polysaccharides are large and complicated sugars. • Cellulose is a structural carbohydrate found in plants. • Starch and glycogen are energy-storing carbohydrates.

10. Example Carbohydrates

11. Lipids • These macromolecules provide long-term sources of energy. • Contain twice the calories that carbohydrates and proteins have. • They are also important in cell membrane structure. • Pay attention to the types and functions of lipids.

12. Basic Lipid Structure

14. This is Artherosclerosis, which is a leading cause of heart disease.

15. Proteins • Carbohydrates and lipids provide the energy for the cell. • Proteins perform the “work” of the cell. • Metabolism is what the cell does. • Amino Acids • Polypeptides.

16. This is one amino acid. • It has an “amine” and a “carboxyl” functional groups, hence its name. • It also contains an “R” group, described on page 42 of your text.

17. Functions of proteins:

18. Proteins are also are made through dehydration synthesis.

19. Protein function depends on its shape. There are four primary shapes of proteins.

20. Your assignments. • The following questions are due at the beginning of your next lecture. • 1, 2, 3, 6, 7, 10, 12, 16, 17, 18, 19.

21. Nucleic Acids • Contain genetic information of the cell. • DNA and RNA. • Know the differences between these two types of nucleic acids. • Genetic information produces proteins to do the work. • This is part of what is known as the “central dogma” in biology.

22. Nucleic Acids

23. Your assignment. • Finish the following questions, and turn them in at the beginning of next lecture. • 1, 2, 3, 6, 7, 10, 12, 16, 17, 18, and 19.