Chapter 02 Lecture Outline

Transcription

1 hapter 02 Lecture utline See separate PowerPoint slides for all figures and tables preinserted into PowerPoint without notes. opyright 2016 McGraw-ill Education. Permission required for reproduction or display. 1

2 hemistry of Life 2

3 Points to ponder ow are living things organized from atoms to molecules? What is p and how is it important to living organisms? What are the four macromolecules found in living organisms? What are the structure (subunits) and function of these four macromolecules? ow are proteins organized and how is their shape important to their function? ow are DA and RA similar and how are they different? 3

4 2.1 From Atoms to Molecules Building blocks from large to small Matter is anything that has mass and takes up space. Elements are the basic building blocks of matter that cannot be broken down by chemical means. Atoms are the smallest units of an element that retain the element s physical and chemical properties. These bond together to form molecules. 4

5 Periods 2.1 From Atoms to Molecules Atomic symbol Atomic mass Atomic number I Elements VIII 1 atomic number 2 1 atomic symbol atomic mass e II III IV V VI VII Li Be B F e a Mg Al Si P S l Ar K a Ga Ge As Se Br Kr Figure 2.1 A portion of the periodic table of elements. Groups 5

6 2.1 From Atoms to Molecules Subatomic particles of atoms eutrons are neutral (uncharged). Protons are positively charged. eutrons and protons make up the nucleus. Electrons are negatively charged and orbit around the nucleus. 6

7 2.1 From Atoms to Molecules Subatomic particles of atoms Subatomic Particles 1p Particle harge Atomic Mass Unit (AMU) Proton +1 1 hydrogen eutron 0 1 Electron 1 0 6p 6n 7p 7n 8p 8n Figure 2.2 The atomic structure of select elements. carbon nitrogen oxygen

8 2.1 From Atoms to Molecules Isotopes Isotopes are atoms that have the same atomic number but a different atomic mass because the number of neutrons differ. Radioisotopes are useful in dating old objects, imaging body organs and tissues through X-rays, and killing cancer cells. Radiation can be harmful by damaging cells and DA and/or causing cancer. 8

9 2.1 From Atoms to Molecules Isotopes missing portion of organ larynx thyroid gland trachea a. Figure 2.3 Medical uses for low-level radiation. b. 2.3a: Biomed ommun./ustom Medical Stock Photo; 2.3b(patient): ational Institutes of ealth; 2.3b(scan): Mazzlota et al./science Source

10 2.1 From Atoms to Molecules Molecules Made of atoms that are bonded together an be made of the same atom or different atoms 10

11 2.1 From Atoms to Molecules Ionic bonds Atoms in this type of bond donate or take on electrons Result in a stable outer shell ccur between particles that are charged (ions) 11

12 2.1 From Atoms to Molecules Ionic bonds Figure 2.5 Formation of an ionic bond. 12

13 2.1 From Atoms to Molecules ovalent bonds Atoms in this type of bond share electrons Result in a stable outer shell 13

14 2.1 From Atoms to Molecules ovalent bonds 1p 1p 8p 8n + 1p 8p 8n 1p oxygen 2 hydrogen 2 water 2 a. When an oxygen and two hydrogen atoms covalently bond, water results. 8p 8n + 8p 8n 8p 8n 8p 8n oxygen 2 oxygen 2 oxygen gas 2 b. When two oxygen atoms covalently bond, oxygen gas results. Figure 2.6 ovalent bonds. 14

15 2.2 Water and Life What are the properties of water? Water is liquid at room temperature. Liquid water does not change temperature quickly. Water has a high heat of evaporation. Frozen water is less dense than liquid water. Molecules of water cling together. Water is a solvent for polar molecules. 15

16 2.2 Water and Life What bond holds water molecules together? ydrogen bonds occur between a hydrogen in a covalent bond and a negatively charged atom. + - hydrogen bond + These are relatively weak bonds. ydrogen bonding between water molecules Figure 2.7b ydrogen bonds and water molecules. 16

17 2.2 Water and Life Acids and bases Acids are substances that dissociate and release hydrogen ions ( + ). Bases are substances that take up hydrogen ions ( + ) or release hydroxide ions ( - ). 17

18 2.2 Water and Life What is the p scale? A measure of hydrogen ion ( + ) concentration Working scale is between 0 and 14 with 7 being neutral A p below 7 is acidic and above 7 is basic The concentration of hydrogen ions between each whole number changes by a factor of 10 18

19 basic acidic 2.2 Water and Life Looking at the p scale Figure 2.10 The p scale. + Ion oncentration p Value Examples hydrochloric acid stomach acid, lemon juice vinegar, cola, beer tomatoes black coffee urine pure water seawater baking soda Great Salt Lake household ammonia household bleach + sodium hydroxide 19

20 2.3 Molecules of Life Making and breaking down organic molecules Dehydration reaction the removal of water that allows subunits to link together into larger molecules ydrolysis reaction the addition of water that breaks larger molecules into their subunits 20

21 2.3 Molecules of Life ow do we build and break down organic molecules? subunit subunit dehydration reaction 2 subunit subunit a. subunit subunit hydrolysis reaction 2 Figure 2.11 The breakdown and synthesis of macromolecules. b. subunit subunit 21

22 2.3 Molecules of Life What organic molecules are found in living organisms? 1. arbohydrates 2. Lipids 3. Proteins 4. ucleic acids 22

23 2.4 arbohydrates 1. What are carbohydrates? Made of subunits called monosaccharides Made of,, and in which the and atoms are in a 2:1 ratio Function as short- and long-term energy storage Found as simple and complex forms 23

24 2.4 arbohydrates What are simple carbohydrates? Monosaccharide 1 carbon ring as found in glucose Disaccharide 2 carbon rings as found in maltose maltose Figure 2.12 The synthesis and breakdown of a disaccharide. 24

25 2.4 arbohydrates What are complex carbohydrates? Polysaccharides are made of many carbon rings Glycogen is the storage form in animals. nonbranched branched Starch is the storage form in plants. starch granule cell wall Figure 2.13 Starch is a plant complex carbohydrate. potato cells Jeremy Burgess/SPL/Science Source 25

26 2.5 Lipids 2. What are lipids? Molecules that do not dissolve in water Used as energy molecules Found in cell membranes Found as fats and oils, phospholipids, and steroids 26

27 2.5 Lipids ow are fats and oils different? Fats Usually animal origin Solid at room temperature Function for long-term energy storage, insulation from heat loss, and cushion for organs ils Usually plant origin Liquid at room temperature 27

28 28 What is the structure of fats and oils? A glycerol molecule and 3 fatty acid tails 2.5 Lipids + 3 fatty acids glycerol fat molecule 3 water molecules dehydration reaction hydrolysis reaction Figure 2.16 Structure of a triglyceride.

29 2.5 Lipids Understanding fats when reading a nutrition label The recommendation for total amount of fat for a 2,000 calorie diet is 65g. Be sure to know how many servings there are. A % DV of 5% or less is low and 20% or more is high. Try to stay away from trans fats. Would you eat the food on the following nutrition label? Why or why not? 29

30 2.5 Lipids Understanding fats when reading a nutrition label Serving Size 1 cup (228g) Servings Per ontainer 2 Start here. Limit these nutrients. Get enough of these nutrients. Amount Per Serving alories 250 Total Fat 12g Trans Fat 1.5g holesterol 30mg Sodium 470mg Total arbohydrate 31g Dietary Fiber 0g Sugars 5g Protein 5g Vitamin A Vitamin alcium Iron alories from Fat 110 %Daily Value 18% 15% Saturated Fat 3g 10% 20% 10% 0% 4% 2% 20% 4% Figure 2.18 Understanding a food label. 30

31 2.5 Lipids What is the structure of a phospholipid? The structure is similar to a triglyceride. ne fatty acid is replaced by a polar phosphate group. Phospholipids are the primary components of cellular membranes. polar head nonpolar tails inside cell outside cell Figure 2.19 Structure of a phospholipid. a. Phospholipid structure b. Membrane structure 31

32 2.5 Lipids What is a steroid? 3 3 A steroid is a lipid The structure is four fused carbon rings. a. holesterol Examples are cholesterol and sex hormones Figure 2.20 Examples of steroids. b. Testosterone c. Estrogen Purestock/Superstock RF 32

33 2.6 Proteins 3. What are proteins? Made of subunits called amino acids Important for diverse functions in the body including hormones, enzymes, antibodies, and transport an denature, undergo a change in shape that causes loss of function 33

34 2.6 Proteins What do amino acids look like? valine (val) (nonpolar) glutamic acid (glu) (ionized, polar) lysine (lys) (ionized, polar) Figure 2.21 The structure of a few amino acids tryptophan (trp) (nonpolar) aspartic acid (asp) (ionized, polar) S cysteine (cys) (polar) 34

35 2.6 Proteins What are the 4 levels of protein organization? Primary the linear order of amino acids Secondary localized folding into pleated sheets and helices Tertiary the 3-D shape of the entire protein in space Quaternary combination of more than one polypeptide All proteins have primary, secondary, and tertiary structure, while only a few have quaternary structure. 35

36 2.6 Proteins What do the levels of organization look like? Primary Structure: sequence of amino acids 3 + amino acid peptide bond Secondary Structure: Alpha helix or a pleated sheet hydrogen bond R R hydrogen bond R R R R R (alpha) helix (beta) sheet = pleated sheet Tertiary Structure: final shape of polypeptide disulfide bond Quaternary Structure: two or more associated polypeptides Figure 2.23 Levels of protein structure. 36

37 2.7 ucleic Acids 4. What are nucleic acids? Made of nucleotide subunits Function in the cell to make proteins Include RA and DA 37

38 2.7 ucleic Acids What are the 3 parts of a nucleotide? phosphate P nitrogencontaining base 5' ucleotide 4' S 1' 3' sugar 2' 38

39 2.7 ucleic Acids What are the 5 bases found in nucleotides? Adenine (A) and guanine (G) are doubleringed purines. ytosine (), thymine (T), and uracil (U) are single-ringed pyrimidines. In DA, A pairs with T and G pairs with. 39

40 2.7 ucleic Acids What are the 5 bases found in nucleotides? T A G A T G Adenine (A) ydrogen bond Thymine (T) (DA only) 3 P S P backbone P S G bases U S A U Uracil (U) (RA only) P S Guanine (G) ytosine () a. DA structure with base pairs: A with T and G with b. RA structure with bases G, U, A, Figure 2.24 The structure of DA and RA. 40

41 2.7 ucleic Acids Summary of DA and RA structural differences DA Sugar is deoxyribose Bases include A, T,, and G Double-stranded RA Sugar is ribose Bases include A, U,, and G Single-stranded 41

42 Summary of the macromolecules rganic molecules Examples Monomers Functions arbohydrates Monosaccharides, disaccharides, polysaccharides 2 Glucose Immediate energy and stored energy; structural molecules Lipids Fats, oils, phospholipids, steroids Glycerol Fatty acid R Long-term energy storage; membrane components Proteins Structural, enzymatic, carrier, hormonal, contractile amino group 2 R group acid group Support, metabolic, transport, regulation, motion Amino acid ucleic acids DA, RA phosphate P S base Storage of genetic information ucleotide 42