Chapter 6 Chemistry in Biology

2. Chapter 6 Chemistry in Biology Section 1: Atoms, Elements, and Compounds Section2: Chemical Reactions Section 3: Water and Solutions Section 4: The Building Blocks of Life

3. Chemistry in Biology Chapter 6 6.1 Atoms, Elements, and Compounds • Atoms are the building blocks of matter. • What is located at the center of an atom? Nucleus • Protons are positively charged particles. • Neutrons are particles that have no charge.

4. Chemistry in Biology Chapter 6 6.1 Atoms, Elements, and Compounds • Electrons are negatively charged particles that are located outside the nucleus.

5. Chemistry in Biology Chapter 6 6.1 Atoms, Elements, and Compounds Elements • An element is a pure substance that cannot be broken down into other substances by physical or chemical means. • Located on the periodic table

6. Chemistry in Biology Chapter 6 6.1 Atoms, Elements, and Compounds The Periodic Table of Elements

7. Chemistry in Biology Chapter 6 • Atoms of the same element that have the same number of protons and electrons but have a different number of neutrons are called isotopes • Changing number of neutrons does not change the charge, bit it could change the stability

8. Chemistry in Biology Chapter 6 6.1 Atoms, Elements, and Compounds Radioactive Isotopes • When a nucleus breaks apart, it gives off radiation that can be detected and used for many applications.

9. Chemistry in Biology Chapter 6 6.1 Atoms, Elements, and Compounds Compounds • A pure substance formed when two or more different elements combine • Examples: water, salt

10. Chemistry in Biology • A molecule is a compound in which the atoms are held together by covalent bonds. Chapter 6 6.1 Atoms, Elements, and Compounds Chemical Bonds • Covalent bonds • Chemical bond that forms when electrons are shared

11. Chemistry in Biology Chapter 6 6.1 Atoms, Elements, and Compounds Ionic Bonds • Electrical attraction between two oppositely charged atoms or groups of atoms

12. Chemistry in Biology Chapter 6

13. Chemistry in Biology Chapter 6 6.1 Atoms, Elements, and Compounds van der Waals Forces • Attractive forces between the positive and negative regions pull on the molecules and hold them together • What is a common example of this? Water!

14. Chemistry in Biology Chapter 6 6.2 Chemical Reactions Reactants and Products • A chemical reaction is the process by which atoms or groups of atoms in substances are reorganized into different substances. • Chemical bonds are broken Physical changes: alter the substance’s appearance, but not its composition Chemical reaction Physical reaction

15. Chemistry in Biology Chapter 6 6.2 Chemical Reactions Chemical Equations • Reactants are the starting substances, on the left side of the arrow. • Products are the substances formed during the reaction, on the right side of the arrow.

16. Chemistry in Biology Chapter 6 6.2 Chemical Reactions • Glucose and oxygen react to form carbon dioxide and water.

17. Chemistry in Biology Chapter 6 6.2 Chemical Reactions Balanced Equations • The number of atoms of each element on the reactant side must equal the number of atoms of the same element on the product side.

18. Chemistry in Biology Chapter 6 6.2 Chemical Reactions Energy of Reactions • activation energy: the minimum amount of energy needed for reactants to form products

19. Chemistry in Biology Chapter 6 6.2 Chemical Reactions • This reaction is exothermic and released heat energy. • The energy of the product is lower than the energy of the reactants.

20. Chemistry in Biology Chapter 6 6.2 Chemical Reactions • This reaction is endothermic and absorbed heat energy. • The energy of the products is higher than the energy of the reactants.

21. Chemistry in Biology Chapter 6 6.2 Chemical Reactions Enzymes • Catalyst: a substance that lowers the activation energy needed to start a chemical reaction. • Enzymes: speed up the rate of chemical reactions in biological processes. Enzymes are biological catalysts. • Example in saliva: amylase

22. Chemistry in Biology Chapter 6 6.2 Chemical Reactions • The reactants that bind to the enzyme are called substrates. • The specific location where a substrate binds on an enzyme is called the active site.

23. Chemistry in Biology Chapter 6 6.2 Chemical Reactions • Factors such as pH, temperature, and other substances affect enzyme activity.

24. Chemistry in Biology Chapter 6

25. Chemistry in Biology Chapter 6 6.3 Water and Solutions Water’s Polarity • Molecules that have an unequal distribution of charges: polar molecules. • Water: the oxygen end has a slightly negative charge; the hydrogen ends have a slightly positive charge • hydrogen bond: weak interaction involving a hydrogen atom and a fluorine, oxygen, or nitrogen atom. (water= hydrogen-oxygen)

26. Chemistry in Biology Chapter 6 6.3 Water and Solutions

27. Chemistry in Biology Chapter 6 6.3 Water and Solutions Mixture: a combination of 2 or more substances in which each substance retains its properties (sand/salt) Homogenous Mixtures • A mixture that has a uniform composition throughout (kool-aid) • Solute: substance that is dissolved in the solvent. Food coloring dissolved in water forms a homogenous mixture. • Solvent: substance in which another substance is dissolved.

28. Chemistry in Biology Chapter 6 6.3 Water and Solutions Heterogeneous Mixtures • A mixture in which you can always see the distinct components • Example: salad, milk, ink A salad is a heterogeneous mixture.

29. Chemistry in Biology Chapter 6 6.3 Water and Solutions Acids and Bases • Substances that release hydrogen ions (H+) when dissolved: acids. • Substances that release hydroxide ions (OH–) when dissolved in water: bases.

30. Chemistry in Biology Chapter 6 6.3 Water and Solutions pH and Buffers • The measure of concentration of H+ in a solution is called pH. • Acidic solutions have pH values lower than 7. • Basic solutions have pH values higher than 7.

31. Chemistry in Biology Chapter 6 6.3 Water and Solutions • Buffers: mixtures that can react with acids or bases to keep the pH within a specific range.

32. Chemistry in Biology Chapter 6 6.4 The Building Blocks of Life Organic Compounds • Must contain CARBON!

33. Chemistry in Biology Chapter 6 6.4 The Building Blocks of Life • Macromolecules: large molecules formed by joining smaller organic molecules together. • Polymers: made from repeating, identical (or close to identical) monomers

34. Chemistry in Biology Chapter 6 6.4 The Building Blocks of Life Carbohydrates • Compounds composed of carbon, hydrogen, and oxygen in a ratio of one oxygen and two hydrogen atoms for each carbon atom—(CH2O) • Functions: energy source and provide structural support • Plants (cellulose) • Animals (chitin)

35. Chemistry in Biology Chapter 6 6.4 The Building Blocks of Life • Monosaccharides: simple sugars • Example: glucose • Disaccharides: 2 monosaccharides put together • Example: sucrose, lactose • Polysaccharides: long carbohydrates molecules; many put together • Example: glycogen

36. Chemistry in Biology Chapter 6 6.4 The Building Blocks of Life Proteins • Made up of amino acids • Amino acids are small compounds that are made of carbon, nitrogen, oxygen, hydrogen, and sometimes sulfur. • Can have up to 4 levels of structure (primary, secondary, tertiary, quaternary)

37. Chemistry in Biology Chapter 6 6.4 The Building Blocks of Life • Involved in almost every function of body • Function: transport substances, speed reactions, provide structural support, make hormones

38. Chemistry in Biology Chapter 6 6.4 The Building Blocks of Life Lipids • Fats and oils that are insoluble (undissolvable) in water • Made up of fats, oils, and waxes • Composed of fatty acids, glycerols, and others • Triglyceride: a fat if it is solid at room temperature and an oil if it is liquid at room temperature.

39. Chemistry in Biology Chapter 6 6.4 The Building Blocks of Life • Can have saturated fats, unsaturated fats, polyunsaturated fats, steroids • Phospholipids: important fat responsible for structure/function of cell (plasma) membrane • Functions: store energy, provide barriers

40. Chemistry in Biology Chapter 6

41. Chemistry in Biology Chapter 6 6.4 The Building Blocks of Life • Nucleic acids: made up of nucleotides • Function: store and transmit genetic information. • 2 types found in living organism: DNA & RNA