Homework. Due in lab this week. Due Monday 10/1/12, beginning of class

Transcription

1 Homework Due in lab this week 1. Homework #1 What Does the Syllabus Say? 2. Basic Principles 9 & 10 Anatomical Terms & Body Cavities Due Monday 10/1/12, beginning of class 1. Study Guide Introduction Section, Read pages 5 & 6 Complete Page 7 to turn in (also found as HW #2-Studying for Success) 2. Homework #3 (pages 5, 6 & 7) Composition of Matter

2 Thought Question Greg reaches out to grab a pan on the stove without realizing it is still hot. As the hot metal contacts his fingertips, free nerve endings located in his epidermis send a signal (a nerve impulse) to his spinal cord. The impulse is transferred to a motor neuron which in turn sends an impulse to the flexor muscles of his arm causing him to withdraw his fingers from the hot pan. 1. What is the sensor (receptor)? 2. What is the control center? 3. What is the effector? 4. Is this a negative or positive feedback loop?

3 Biological Molecules Introduction

4 Introduction Organs and tissues of the body are all composed of the same basic materials Chemical elements Examples?

5

6 Elements and Atoms Elements are made of atoms Atoms consist of smaller subunits Subatomic particles Protons Neutrons Electrons

7 Identifying elements Elements and Atoms Atoms of different elements contain different numbers of subatomic particles Let s compare hydrogen, helium and lithium

8 Proton Neutron Electron Hydrogen (H) (1p + ; 0n 0 ; 1e ) Helium (He) (2p + ; 2n 0 ; 2e ) Lithium (Li) (3p + ; 4n 0 ; 3e ) Figure 2.2

9 Chemical bond Bonding Sharing of electrons between adjacent atoms Covalent, ionic, hydrogen 2+ atoms molecule 2+ atoms of different elements compound

10 Covalent bonds form between carbon and hydrogen Reacting atoms Resulting molecules + or Hydrogen atoms Carbon atom Molecule of methane gas (CH 4 ) Structural formula shows single bonds. (a) Formation of four single covalent bonds: carbon shares four electron pairs with four hydrogen atoms. Copyright 2010 Pearson Education, Inc. Figure 2.7a

11 Some atoms achieve stability by ionizing = complete transfer of electrons + Sodium atom (Na) (11p + ; 12n 0 ; 11e ) Chlorine atom (Cl) (17p + ; 18n 0 ; 17e ) (a) Sodium gains stability by losing one electron, and chlorine becomes stable by gaining one electron. Sodium ion (Na + ) Chloride ion (Cl ) Sodium chloride (NaCl) (b) After electron transfer, the oppositely charged ions formed attract each other. Figure 2.6a-b

12 CI Na + (c) Large numbers of Na + and Cl ions associate to form salt (NaCl) crystals. Copyright 2010 Pearson Education, Inc. Figure 2.6c

13 Mixtures Bonding Substances of two or more types of molecules Solutions Solvent Solute

14 Thought Questions 1. Is H 2 considered a compound? 2. How is a mixture different than a compound?

15 H 2 O Examples of Compounds CH 4

16 Chemical Reactions Molecules are made, broken down or rearranged Involves alterations in the bonding patterns between reacting molecules H + H H 2 (hydrogen gas) Reactants Products 4H + C CH 4 (methane) Atoms Molecules

17 Metabolism Chemical Reactions All of the chemical reactions that occur within the body Types of reactions include Synthesis (anabolism) Requires energy = endergonic Decomposition (catabolism) Releases energy = exergonic

18 Chemical Reactions Anabolic reactions Also called? Require input of energy Always involve formation of a bond formation of larger molecules A + B AB Frequently observed in rapidly growing tissues

19 Catabolic reactions Also called? Release energy Chemical Reactions Molecules broken down into constituent atoms Involve breaking of chemical bonds AB A + B Often the energy released is used to fuel subsequent reactions

20 Energy Chemical Reactions Ability to do work Types Kinetic = movement Potential = stored energy

21 Energy Chemical Reactions temperature = kinetic energy Larger molecules have more potential energy stored in their chemical bonds

22 Electronegativity Polarity and Solubility Atom s ability to attract electrons May cause asymmetrical distribution of bonding electrons

23 Polarity and Solubility Sharing of electrons may be equal or unequal Equal sharing = electrically balanced, nonpolar molecules CO 2

24 Polarity and Solubility Sharing of electrons may be equal or unequal Unequal sharing by atoms with different electron-attracting abilities = polar molecules H 2 O ( + )

25 Water Polarity and Solubility 60% 80% of the volume of living cells About 60% of human body weight Most important inorganic compound in living organisms

26 + Hydrogen bond (indicated by dotted line) (a) The slightly positive ends ( + ) of the water molecules become aligned with the slightly negative ends ( ) of other water molecules. Figure 2.10a

27 Polarity and Solubility Properties of water (H-bonds) 1. High heat capacity 2. High heat of vaporization 3. Polar solvent properties 4. Reactivity 5. Cushioning

28 Hydrophilic Water loving Soluble in water Polarity and Solubility Non-polar molecules are hydrophobic Water fearing Not soluble in water Like dissolves like

29 1. Carbohydrates 2. Lipids 3. Proteins 4. Nucleic acids Biological Molecules

30 Biological Molecules Six principle elements 1. Oxygen 2. Carbon 3. Hydrogen 4. Nitrogen 5. Calcium 6. Phosphorous

31 Carbohydrates Includes sugars and starches Types Monosaccharides Disaccharides Polysaccharides General formula (CH 2 O) n

32 Glucose = a simple sugar C 6 H 12 O 6 Empirical Formula Structural Formula Shows bonding patterns and position of atoms

33 Monosaccharides Carbohydrates The simplest carbohydrates Building blocks for larger molecules Consist of 3-7 C atoms glucose

34 Example Hexose sugars (the hexoses shown here are isomers) (a) Monosaccharides Monomers of carbohydrates Example Pentose sugars Glucose Fructose Galactose Deoxyribose Ribose Figure 2.15a

35 Disaccharides Carbohydrates 2 monosaccharides bonded together by dehydration synthesis Broken down by hydrolysis Ex: Sucrose and maltose

36 (b) Disaccharides Consist of two linked monosaccharides Example Sucrose, maltose, and lactose (these disaccharides are isomers) Glucose Fructose Glucose Glucose Galactose Glucose Sucrose Maltose Lactose Figure 2.15b

37 (a) Dehydration synthesis Monomers are joined by removal of OH from one monomer and removal of H from the other at the site of bond formation. + Monomer 1 Monomer 2 Monomers linked by covalent bond (b) Hydrolysis Monomers are released by the addition of a water molecule, adding OH to one monomer and H to the other. + Monomer 1 Monomer 2 Monomers linked by covalent bond (c) Example reactions Dehydration synthesis of sucrose and its breakdown by hydrolysis + Water is released Glucose Fructose Water is consumed Sucrose Figure 2.14

38 Polysaccharides Carbohydrates Long chain of monosaccharides Large, fairly insoluble molecules Much energy stored in bonds

39

40 Polysaccharides Glycogen Carbohydrates Primary storage form for glucose in animals Stored in the liver Broken down into glucose when needed

41 Functions Carbohydrates Major source of cellular fuel (e.g. glucose) Structural molecules (e.g. cellulose, ribose sugar in RNA) Cell recognition

42 General characteristics Lipids Non-polar molecules (insoluble in water) Fatty acids and neutral fats are most common types Contain less oxygen than carbohydrates Types Triglycerides Steroids Phospholipids Eicosanoids Prostaglandins

43 Triglycerides Also called neutral fats Solid fats and liquid oils Lipids Three fatty acids bonded to a glycerol molecule Found mainly beneath the skin Provides insulation

44 (a) Triglyceride formation Three fatty acid chains are bound to glycerol by dehydration synthesis + Glycerol 3 fatty acid chains Triglyceride, or neutral fat 3 water molecules Figure 2.16a

45 Lipids Triglycerides Saturated fatty acids Single bonds between C atoms maximum number of H Solid animal fats Ex. butter Unsaturated fatty acids One or more double bonds between C atoms Reduced number of H atoms Plant oils Ex. olive oil, peanut oil, corn oil

46 Saturation of Fatty Acids

47 Triglycerides & Cardiovascular Health Diets with higher proportions of unsaturated fats = risk of heart disease Trans fats = hydrogenated Omega-3 fatty acids

48 Steroids Phospholipids Eicosanoids Prostaglandins Other Lipids

49 Steroids Other Lipids Structurally very different from other lipids Examples: Estrogen, testosterone & cortisone Cholesterol Functions: Important for synthesis of vitamin D and bile salts Stabilize cell membranes Precursor for steroid hormones

50 (c) Simplified structure of a steroid Four interlocking hydrocarbon rings form a steroid. Example Cholesterol (cholesterol is the basis for all steroids formed in the body) Figure 2.16c

51 Phospholipids Other Lipids Have a polar head and a nonpolar tail Primary building material for cellular membranes

52

53 Prostaglandins Other Lipids Important to several body processes Uterine contractions Control of intestinal motility Control of stomach secretions Involved in pain communication Inflammatory actions blocked by non-steroidal anti-inflammatory drugs (NSAIDS)

54 Lipids Four primary functions of lipids 1. Insulation 2. Protection 3. Energy storage 4. Cell membranes

55 Questions? Complete the following Molecules 21 Exercise 1 Molecules 25 Lipid Crossword