1. Stern - Introductory Plant Biology: 9th Ed. - All Rights Reserved - McGraw Hill Companies The Nature of Life Chapter 2 Copyright © McGraw-Hill Companies Permission Required for Reproduction or Display

2. Stern - Introductory Plant Biology: 9th Ed. - All Rights Reserved - McGraw Hill Companies Outline Attributes of Living Organisms Chemical and Physical Bases of Life Molecules Bonds and Ions Acids and Bases Energy Carbohydrates, Lipids, Proteins Enzymes Nucleic Acids

3. Stern - Introductory Plant Biology: 9th Ed. - All Rights Reserved - McGraw Hill Companies Attributes of Living Organisms Composition and Structure  Cells - Structural units of organisms. - Cytoplasm - Interior cell matrix.  Nucleus - Houses genetic material (DNA) suspended in cytoplasm. - Cell Wall - Bounds cytoplasm.

4. Stern - Introductory Plant Biology: 9th Ed. - All Rights Reserved - McGraw Hill Companies Attributes of Living Organisms Growth  Increase in mass accompanied by an increase in volume. - Most growth results from production in new cells and includes variation in form. Reproduction  Producing offspring. - Always resemble parents.

5. Stern - Introductory Plant Biology: 9th Ed. - All Rights Reserved - McGraw Hill Companies Attributes of Living Organisms Response to Stimuli  Plants respond to stimuli such as light, temperature, and gravity. - Callose and callus are two substances that may accumulate at wound sites in plant cells.

6. Stern - Introductory Plant Biology: 9th Ed. - All Rights Reserved - McGraw Hill Companies Attributes of Living Organisms Metabolism  Collective product of all biochemical reactions in an organism. - Respiration - Energy release. - Photosynthesis - Energy harnessing. - Digestion - Large insoluble food molecules converted to smaller soluble molecules. - Assimilation - Conversion of raw materials into cell substances.

7. Stern - Introductory Plant Biology: 9th Ed. - All Rights Reserved - McGraw Hill Companies Attributes of Living Organisms Movement  Occurs at all levels of organization. - Cytoplasmic streaming. Organization Complexity  Molecules are organized into compartments, membranes, and other structures within cells and tissues. Environmental Adaptation  Natural selection adapts organisms to their environment.

8. Stern - Introductory Plant Biology: 9th Ed. - All Rights Reserved - McGraw Hill Companies Chemical and Physical Bases of Life Matter  Occupies space  Has mass  Composed of elements Atoms - Smallest stable subdivision of an element.  Nucleus - Center of an atom. - Protons - Positively charged particles. - Neutrons - Neutral particles.

9. Stern - Introductory Plant Biology: 9th Ed. - All Rights Reserved - McGraw Hill Companies Oxygen Atom Model

10. Stern - Introductory Plant Biology: 9th Ed. - All Rights Reserved - McGraw Hill Companies Chemical and Physical Bases of Life Atomic Number - Number of protons.  Cannot change within an element. Atomic Mass - Combined number of protons and neutrons.  Electrons - Negative electrical charges circling the nucleus. - Orbitals - Volume of space in which a given electron occurs 90% of the time.

11. Stern - Introductory Plant Biology: 9th Ed. - All Rights Reserved - McGraw Hill Companies Chemical and Physical Bases of Life An electron’s distance from the nucleus depends on its energy level.  Electron Shell - Outermost shell determines the atom’s reactivity.  Moving to an orbital farther away consumes energy.  Moving to an orbital closer in releases energy.

12. Stern - Introductory Plant Biology: 9th Ed. - All Rights Reserved - McGraw Hill Companies Orbital Models

13. Stern - Introductory Plant Biology: 9th Ed. - All Rights Reserved - McGraw Hill Companies Chemical and Physical Bases of Life Isotope - Form of an element that varies in its atomic weight (Varying number of neutrons).  Radioactive isotopes are unstable and spontaneously split into smaller parts.

14. Stern - Introductory Plant Biology: 9th Ed. - All Rights Reserved - McGraw Hill Companies Molecules Molecule - Two or more atoms bound together.  Compound - Two or more elements united in a definite ratio by chemical bonds. Molecules are in constant motion, with a temperature increase or decrease speeding up or slowing down the atoms.

15. Stern - Introductory Plant Biology: 9th Ed. - All Rights Reserved - McGraw Hill Companies Molecules Random collisions between molecules capable of sharing electrons are the basis for all chemical reactions.  Usually controlled by specific enzymes. - When a water molecule is formed, two hydrogen atoms become attached to an oxygen atom.

16. Stern - Introductory Plant Biology: 9th Ed. - All Rights Reserved - McGraw Hill Companies Molecules Polarity affects atom alignment.  Water molecules form a cohesive network as the slightly positive hydrogen atoms are attracted to the slightly negative oxygen atoms. - Cohesion - Attraction of similar molecules.  Capillary movement in plants. - Adhesion - Attraction of dissimilar molecules.

17. Stern - Introductory Plant Biology: 9th Ed. - All Rights Reserved - McGraw Hill Companies Water Molecules Copyright © McGraw-Hill Companies Permission Required for Reproduction or Display

18. Stern - Introductory Plant Biology: 9th Ed. - All Rights Reserved - McGraw Hill Companies Chemical and Physical Bases of Life Valence  Combining capacity of an atom or an ion. Bonds and Ions  Bonds are forces that move molecules by attracting and holding atoms. - Number of electrons in an atom’s outermost orbital determines how many chemical bonds can be formed by that particular atom.

19. Stern - Introductory Plant Biology: 9th Ed. - All Rights Reserved - McGraw Hill Companies Bonds and Ions Covalent Bond  Forms when two atoms complete their outermost energy level by sharing a pair of electrons.  Polar - Electrons are shared equally.  Nonpolar - Electrons are shared unequally.

20. Stern - Introductory Plant Biology: 9th Ed. - All Rights Reserved - McGraw Hill Companies Bonds and Ions Ionic Bond  Forms when electrons in outermost orbital are completely removed from one atom and transferred to another atom. - Ions - Formed when molecules lose or gain electrons.

21. Stern - Introductory Plant Biology: 9th Ed. - All Rights Reserved - McGraw Hill Companies Bonds and Ions Hydrogen Bond  Forms as a result of attraction between positively charged hydrogen atoms in polar molecules and negatively charged atoms in other polar molecules. - Only have 7-10% strength of covalent bonds.

22. Stern - Introductory Plant Biology: 9th Ed. - All Rights Reserved - McGraw Hill Companies Acids and Bases Acids are chemicals that release hydrogen atoms (H + ) when dissolved in water. Bases (alkaline compounds) are compounds that release negatively charged hydroxyl ions (OH - ) when dissolved in water.  pH scale represents measurement of H + ion concentration. - 7 = Neutral - <7 = Acidic - >7 =Alkaline

23. Stern - Introductory Plant Biology: 9th Ed. - All Rights Reserved - McGraw Hill Companies Energy Energy - The capacity to perform work. Thermodynamics - Study of energy and its conversions from one form to another.  First Law - Energy is constant. It cannot be increased or diminished, only converted from one form to another.  Second Law - Energy flow is uni-directional and there will always be less energy remaining after the conversion than existed before.

24. Stern - Introductory Plant Biology: 9th Ed. - All Rights Reserved - McGraw Hill Companies Energy Electrons with the least potential energy are located within the single spherical orbital closest to the atom’s nucleus.  Electrons with the most potential energy are in the outermost orbital.

25. Stern - Introductory Plant Biology: 9th Ed. - All Rights Reserved - McGraw Hill Companies Monomers and Polymers Polymers - Formed when two or more small units (monomers) bond together.  Dehydration Synthesis - Removal of water in the formation of a bond.  Hydrolysis - Occurs when hydrogen becomes attached to one monomer and a hydroxyl group to the other.

26. Stern - Introductory Plant Biology: 9th Ed. - All Rights Reserved - McGraw Hill Companies Carbohydrates Carbohydrates are the most abundant organic compounds in nature.  Monosaccharides - Simple sugars with backbones of three to seven carbon atoms. (Glucose and Fructose)  Disaccharides - Formed when two monosaccharides bond together by dehydration synthesis. (Sucrose)  Polysaccharides - Formed when several to many monosaccharides bond together. (Cellulose)

27. Stern - Introductory Plant Biology: 9th Ed. - All Rights Reserved - McGraw Hill Companies Lipids Lipids are fatty or oily substances that are mostly insoluble in water. (Fats and Oils)  Typically store twice as much energy as carbohydrates. - Most consist of chain with 16-18 carbon atoms.  Saturated - No double bonds.  Unsaturated - At least one double bond between carbon atoms.

28. Stern - Introductory Plant Biology: 9th Ed. - All Rights Reserved - McGraw Hill Companies Lipids Waxes - Lipids consisting of long-chain fatty acids bonded to long chain alcohol other than glycerol. Phospholipids - Constructed like fats, but one of the fatty acids is usually replaced by a phosphate group.

29. Stern - Introductory Plant Biology: 9th Ed. - All Rights Reserved - McGraw Hill Companies Proteins, Polypeptides, and Amino Acids Proteins regulate chemical reactions in cells, and are usually very large and consist of one or more polypeptide chains.  Polypeptides are chains of amino acids. - Each amino acid has two functional groups plus an R group.  Amino group (-NH 2 )  Carboxyl group (-COOH)

30. Stern - Introductory Plant Biology: 9th Ed. - All Rights Reserved - McGraw Hill Companies Proteins, Polypeptides, and Amino Acids Polypeptide Structure  Primary Structure - A sequence of amino acids fastened together by peptide bonds.  Secondary Structure - Coiling of polypeptide chains.  Tertiary Structure - Maintained by coils between R groups.  Quaternary Structure - Occurs when a protein has more than one kind of polypeptide.

31. Stern - Introductory Plant Biology: 9th Ed. - All Rights Reserved - McGraw Hill Companies Storage Proteins Some plant food-storage organs store small amounts of proteins in addition to large amounts of carbohydrates.  Seeds usually contain proportionately larger amounts of proteins in addition to their complement of carbohydrates.

32. Stern - Introductory Plant Biology: 9th Ed. - All Rights Reserved - McGraw Hill Companies Enzymes Enzymes are mostly large, complex proteins that function as organic catalysts under specific conditions.  Work by lowering energy of activation. - Temporarily bonds with potentially reactive molecules at a surface site.

33. Stern - Introductory Plant Biology: 9th Ed. - All Rights Reserved - McGraw Hill Companies Nucleic Acids Nucleic acids are very large, complex polymers.  Vital to internal communication and cell functioning.  Deoxyribonucleic Acid (DNA) composed of nucleotides. - Nitrogenous base, five-carbon sugar, and a phosphate.

34. Stern - Introductory Plant Biology: 9th Ed. - All Rights Reserved - McGraw Hill Companies Review Attributes of Living Organisms Chemical and Physical Bases of Life Molecules Bonds and Ions Acids and Bases Energy Carbohydrates, Lipids, Proteins Enzymes Nucleic Acids

35. Stern - Introductory Plant Biology: 9th Ed. - All Rights Reserved - McGraw Hill Companies Copyright © McGraw-Hill Companies Permission Required for Reproduction or Display