3. Click on a lesson name to select. Chemistry in Biology Section 1: Atoms, Elements, and Compounds Section 2: Chemical Reactions Section 3: Water and Solutions Section 4: The Building Blocks of Life

4. Atoms  Chemistry is the study of matter. Atoms, Elements, and Compounds  Atoms are the building blocks of matter. Section 1 Chemistry in Biology  Neutrons and protons are located at the center of the atom.  Protons are positively charged particles.  Neutrons are particles that have no charge.

5.  Electrons are negatively charged particles that are located outside the nucleus. Chemistry in Biology Atoms, Elements, and Compounds Section 1

6. Elements Chemistry in Biology  An element is a pure substance that cannot be broken down into other substances by physical or chemical means.  Each element has a unique name and symbol. Atoms, Elements, and Compounds Section 1  An element is determined by the number of protons in an atom’s nucleus.

7. Elements Chemistry in Biology Atoms, Elements, and Compounds Section 1  There are over 100 known elements, 92 of which occur naturally.

8. The Periodic Table of Elements Chemistry in Biology  Horizontal rows are called periods.  Vertical columns are called groups. Atoms, Elements, and Compounds Section 1

9. Isotopes Chemistry in Biology  Atoms of the same element that have the same number of protons and electrons but have a different number of neutrons Atoms, Elements, and Compounds Section 1

10. Radioactive Isotopes Chemistry in Biology  When a nucleus breaks apart, it gives off radiation that can be detected and used for many applications.  Nuclear Radiation is the release of energy and matter from the decay of an atom.  Can cause damage to exposed living tissues.  There are 4 Types of Radiation  Alpha particles (+2 charge)  Beta particles (-1 charge)  Gamma ray (no mass, no charge)  Neutron (no charge) Atoms, Elements, and Compounds Section 1

11. Radioactive Isotopes and Nuclear Radiation Chemistry in Biology  When released from the neutron of an atom, Alpha waves and Beta waves can transfer their energy with other atoms that they may collide with by Ionizing matter…..(they can do this because of their charges.)  Gamma rays are very high energy light. They are a form of electromagnetic energy(Like light or x-rays, but even MORE energy) Because they have no mass or electrical charge, they can cause extensive damage with their high energy. They can move through 60cm of aluminum or 7cm of lead. They are not easily stopped by clothing or even most building material.  Neutron radiation can travel much farther than Alpha or Beta wave radiation because of its neutral charge. Can travel through 15cm of lead. Atoms, Elements, and Compounds Section 1

12. Nuclear Radiation Chemistry in Biology  Alpha waves = Loss of 2 Protons and 2 Neutrons  Beta waves = Gain of 1 Proton and Loss of 1 Neutron Atoms, Elements, and Compounds Section 1 Radioactive Decay  We measure half-life because: When ½ of the the decaying process is complete, ½ of the substance remains unchanged, and the other ½ of the sample is changed…(These ratio’s are measurable and comparable! Yay Math!)  Half-lives can be anywhere from a billionth of a second to billions of years.

13. Half-Life Ratio Reasoning Chemistry in Biology  Scientists know what elements decay into.  For Example: Potassium-40 decays in Argon-40. Carbon-14 decays into Carbon-12. Atoms, Elements, and Compounds Section 1

14. Compounds Chemistry in Biology  A pure substance formed when two or more different elements combine  Compounds are always formed from a specific combination of elements in a fixed ratio.  Compounds cannot be broken down into simpler compounds or elements by physical means. Atoms, Elements, and Compounds Section 1

15. Chemical Bonds Chemistry in Biology  Covalent bonds  Chemical bond that forms when electrons are shared  A molecule is a compound in which the atoms are held together by covalent bonds. Atoms, Elements, and Compounds Section 1

16. Ionic Bonds Chemistry in Biology  Electrical attraction between two oppositely charged atoms or groups of atoms Atoms, Elements, and Compounds Section 1

17. Chemistry in Biology Section 1

18. Chemistry in Biology  The elements identified as metals tend to donate electrons.  The elements identified as nonmetals tend to accept electrons. Atoms, Elements, and Compounds Section 1  Some atoms tend to donate or accept electrons more easily than other atoms.

19.  Most ionic compounds are crystalline at room temperature and have higher melting points than molecular compounds formed by covalent bonds. Chemistry in Biology Atoms, Elements, and Compounds Section 1

20. Chemistry in Biology van der Waals Forces  When molecules come close together, the attractive forces between slightly positive and slightly negative regions pull on the molecules and hold them together.  The strength of the attraction depends on the size of the molecule, its shape, and its ability to attract electrons. Atoms, Elements, and Compounds Section 1

21. Reactants and Products  A chemical reaction is the process by which atoms or groups of atoms in substances are reorganized into different substances. Chemical Reactions  Clues that a chemical reaction has taken place include the production of heat or light, and formation of a gas, liquid, or solid. Chemistry in Biology Section 1

22. Chemical Equations Chemistry in Biology  Chemical formulas describe the substances in the reaction and arrows indicate the process of change.  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. Chemical Reactions Section 2

23.  Glucose and oxygen react to form carbon dioxide and water. Chemistry in Biology Chemical Reactions Section 2

24. Chemistry in Biology Balanced Equations  The law of conservation of mass states matter cannot be created or destroyed.  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. Chemical Reactions Section 2

25. Chemistry in Biology  The activation energy is the minimum amount of energy needed for reactants to form products in a chemical reaction. Energy of Reactions Chemical Reactions Section 2

26. Chemistry in Biology  This reaction is exothermic and released heat energy.  The energy of the product is lower than the energy of the reactants. Chemical Reactions Section 2

27. Chemistry in Biology  This reaction is endothermic and absorbed heat energy.  The energy of the products is higher than the energy of the reactants. Chemical Reactions Section 2

28. Chemistry in Biology  A catalyst is a substance that lowers the activation energy needed to start a chemical reaction.  It does not increase how much product is made and it does not get used up in the reaction. Enzymes Chemical Reactions Section 2

29. Chemistry in Biology  A catalyst is a substance that lowers the activation energy needed to start a chemical reaction.  Enzymes are biological catalysts. (made by living organisms) Enzymes Chemical Reactions Section 2

30. Chemistry in Biology  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. Chemical Reactions Section 2

31. Chemistry in Biology  Factors such as pH, temperature, and other substances affect enzyme activity. Chemical Reactions Section 2  The active site changes shape and forms the enzyme-substrate complex, which helps chemical bonds in the reactants to be broken and new bonds to form.

32. Chemistry in Biology Section 2

33. Water’s Polarity Water and Solutions Chemistry in Biology  Molecules that have an unequal distribution of charges are called polar molecules.  Polarity is the property of having two opposite poles.  A hydrogen bond is a weak interaction involving a hydrogen atom and a fluorine, oxygen, or nitrogen atom. Section 3

34. Chemistry in Biology Water and Solutions Section 3 Enzyme-Controlled Reactions

35. Chemistry in Biology Section 3

36. Chemistry in Biology Homogenous Mixtures  A mixture that has a uniform composition throughout  A solvent is a substance in which another substance is dissolved.  A solute is the substance that is dissolved in the solvent. Water and Solutions Section 3

37. Chemistry in Biology Heterogeneous Mixtures  In a heterogeneous mixture, the components remain distinct. Water and Solutions Section 3

38. Chemistry in Biology  Substances that release hydrogen ions (H + ) when dissolved in water are called acids.  Substances that release hydroxide ions (OH – ) when dissolved in water are called bases. Acids and Bases Water and Solutions Section 3

39. Chemistry in Biology  The measure of concentration of H + in a solution is called pH. “Potential for H + ”  Acidic solutions have pH values lower than 7.  Basic solutions have pH values higher than 7. pH and Buffers Water and Solutions Section 3

40. Chemistry in Biology  Buffers are mixtures that can react with acids or bases to maintain solution pH within a particular range. Water and Solutions Section 3

41. Organic Chemistry  The element carbon is a component of almost all biological molecules. The Building Blocks of Life Chemistry in Biology Section 4

42.  Carbon has four electrons in its outermost energy level.  One carbon atom can form four covalent bonds with other atoms. Chemistry in Biology  Carbon compounds can be in the shape of straight chains, branched chains, and rings. The Building Blocks of Life Section 4

43. Macromolecules Chemistry in Biology  Carbon atoms can be joined to form carbon molecules.  Macromolecules are large molecules formed by joining smaller organic molecules together.  Polymers are molecules made from repeating units of identical or nearly identical compounds linked together by a series of covalent bonds. The Building Blocks of Life Section 4

44. Chemistry in Biology Section 4

45. Chemistry in Biology Carbohydrates  Compounds composed of carbon, hydrogen, and oxygen in a ratio of one oxygen and two hydrogen atoms for each carbon atom—(CH 2 O) n The Building Blocks of Life Section 4

46. Chemistry in Biology  Two monosaccharides joined together form a disaccharide.  Longer carbohydrate molecules are called polysaccharides. The Building Blocks of Life Section 4  Values of n ranging from three to seven are called simple sugars, or monosaccharides.

47. Chemistry in Biology Lipids  Molecules made mostly of carbon and hydrogen  A triglyceride is a fat if it is solid at room temperature and an oil if it is liquid at room temperature. The Building Blocks of Life Section 4

48. Chemistry in Biology  Lipids that have tail chains with only single bonds between the carbon atoms are called saturated fats.  Lipids that have at least one double bond between carbon atoms in the tail chain are called unsaturated fats.  Fats with more than one double bond in the tail are called polyunsaturated fats. The Building Blocks of Life Section 4

49. Chemistry in Biology Proteins  A compound made of small carbon compounds called amino acids  Amino acids are small compounds that are made of carbon, nitrogen, oxygen, hydrogen, and sometimes sulfur. The Building Blocks of Life Section 4

50. Chemistry in Biology  Amino acids have a central carbon atom.  One of the four carbon bonds is with hydrogen.  The other three bonds are with an amino group (–NH 2 ), a carboxyl group (–COOH), and a variable group (–R). The Building Blocks of Life Section 4

51. Chemistry in Biology Section 4