Chapter 2 The Chemical Basis of Life PowerPoint Lectures Campbell Biology: Concepts & Connections, Eighth Edition REECE TAYLOR SIMON DICKEY HOGAN Lecture by Edward J. Zalisko
Figure 2.0-1 Warmup: page 17
Figure 2.0-2 Chapter 2 Objectives: You will H O H Describe Elements, Atoms, and Compounds Define Biologically Significant Chemical Bonds Illustrate Water s Life- Supporting Properties
ELEMENTS, ATOMS, AND COMPOUNDS
Table 2.1
Figure 2.1-0 Sodium (Na) Chlorine (Cl) Sodium chloride (NaCl)
Figure 2.2a An iodine deficiency prevents production of thyroid hormones, resulting in goiter
Figure 2.2b Fluoride is usually added to municipal water and dental products to help reduce tooth decay
Figure 2.2b Is this GOOD or BAD?
Figure 2.2b Science only presents data, it does not give a value (good or bad)
Figure 2.2c
Figure 2.3 Nucleus 2e + + + + Electron cloud 2 2 + Protons Neutrons Nucleus 2 Electrons
Table 2.3
2.4 CONNECTION: Isotopes Living cells cannot distinguish between isotopes of the same element. Therefore, radioactive isotopes can act as tracers.
Figure 2.4a Positron-emission tomography (PET) detects the location of injected radioactive materials
Figure 2.4b Healthy person Alzheimer s patient
2.4 Uncontrolled exposure can damage living cells, especially DNA. Chemical bonds are broken by the emitted energy, which causes abnormal bonds to form.
You should now be able to 1. Describe the importance of chemical elements to living organisms. 2. Explain the formation of compounds. 3. Describe the structure of an atom.
CHEMICAL BONDS
Figure 2.0-2 Chapter 2 Objectives: You will H O H Describe Elements, Atoms, and Compounds Define Biologically Significant Chemical Bonds Illustrate Water s Life- Supporting Properties
Figure 2.5a
Figure 2.5b-0 First shell Hydrogen Helium Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon Second shell Sodium Magnesium Aluminum Silicon Phosphorus Sulfur Chlorine Argon Third shell
Figure 2.5b-1 Hydrogen Lithium Beryllium Boron Carbon Sodium Magnesium Aluminum Silicon
Figure 2.5b-2 Helium Nitrogen Oxygen Fluorine Neon Phosphorus Sulfur Chlorine Argon
Figure 2.UN04 F K Fluorine atom Potassium atom
Animation: Covalent Bonds
Figure 2.6-0 Molecular Formula Electron Distribution Diagram Structural Formula Space-Filling Model H 2 Hydrogen H H Single bond O 2 Oxygen O O Double bond H CH 4 Methane H C H H Nonpolar covalent bonds H 2 O Water H O H Polar covalent bonds (slightly ) Polar covalent bonds in a water molecule H O H (slightly +) (slightly +)
Figure 2.6-1 Molecular Formula Electron Distribution Diagram Structural Formula Space-Filling Model H 2 Hydrogen H H Single bond O 2 Oxygen O O Double bond
Figure 2.6-2 Molecular Formula Electron Distribution Diagram Structural Formula Space-Filling Model H CH 4 Methane H C H H Nonpolar covalent bonds H 2 O Water H O H Polar covalent bonds
Figure 2.6-3 (slightly ) O H H (slightly +) (slightly +) Polar covalent bonds in a water molecule
Animation: Water Structure
Figure 2.8 ( ) (+) Hydrogen bond (+) ( ) ( ) (+) (+) Polar covalent bonds ( )
Figure 2.9 Chemical reactions do not create or destroy matter. only rearrange matter. 2 H 2 + O 2 2 H 2 O Reactants Products
Figure 2.7a-1 Na Cl Na Sodium atom Cl Chlorine atom
Figure 2.7a-2 + Na Cl Na + Cl Na Sodium atom Cl Chlorine atom Na + Sodium ion Cl Chloride ion Sodium chloride (NaCl)
Animation: Ionic Bonds
Figure 2.7b-0 Cl Na +
You should now be able to 1. Distinguish between ionic, hydrogen, and covalent bonds. 2. Define a chemical reaction and explain how it changes the composition of matter. 3. List and define the life-supporting properties of water. 4. Explain the ph scale and the formation of acid and base solutions. 2015 Pearson Education, Inc. 2015 Pearson
WATER S LIFE-SUPPORTING PROPERTIES
Figure 2.0-2 Chapter 2 Objectives: You will H O H Describe Elements, Atoms, and Compounds Define Biologically Significant Chemical Bonds Illustrate Water s Life- Supporting Properties
2.10 Water Hydrogen bonds cohesion. adhesion.
Animation: Water Transport
Figure 2.10 high surface tension
2.11 Water s hydrogen bonds moderate temperature Thermal energy is the energy associated with the random movement of atoms and molecules. heat temperature
Ice Water Steam
Figure 2.11 Evaporative cooling. the molecules with the greatest energy leave the surface
Figure 2.12-0 Ice Hydrogen bonds are stable. Hydrogen bond Liquid water Hydrogen bonds constantly break and re-form.
Figure 2.UN02 Liquid water: Hydrogen bonds constantly break and re-form Ice: Stable hydrogen bonds hold molecules apart
2.13 Water is the solvent of life A solution is a liquid consisting of a uniform mixture of two or more substances. solvent. solute.
Figure 2.13 Positive hydrogen ends of water molecules attracted to negative chloride ion Negative oxygen ends of water molecules attracted to positive sodium ion Cl Na + + + + + Na + + + Cl + + Salt crystal
Increasingly BASIC (Higher OH concentration) Increasingly ACIDIC (Higher H + concentration) Figure 2.14-0 ph scale 0 1 2 3 4 Battery acid Lemon juice, gastric juice Vinegar, cola Tomato juice H + H + H + OH H + OH H + H + H H + + Acidic solution NEUTRAL [H + ] = [OH ] 5 6 7 8 9 Rainwater Human urine Saliva Pure water Human blood, tears Seawater H + OH OH H + OH OH OH H + H + H + Neutral solution 10 11 12 13 14 Milk of magnesia Household ammonia Household bleach Oven cleaner OH OH OH OH H + OH OH OH H + Basic solution
Increasingly ACIDIC (Higher H + concentration) Figure 2.14-1 ph scale 0 Battery acid 1 NEUTRAL [H + ] = [OH ] 2 3 4 5 6 7 Lemon juice, gastric juice Vinegar, cola Tomato juice Rainwater Human urine Saliva Pure water
Increasingly BASIC (Higher OH concentration) Figure 2.14-2 NEUTRAL [H + ] = [OH ] ph scale 7 8 Pure water Human blood, tears Seawater 9 10 11 12 13 14 Milk of magnesia Household ammonia Household bleach Oven cleaner
Figure 2.14-3 H + H + H + OH OH H + H + H + H + H + Acidic solution H + OH OH H + OH OH OH H + H + H + Neutral solution OH OH OH OH H + OH OH OH H + Basic solution
2.15 SCIENTIFIC THINKING: CO 2 on coral reefs About 25% of human-generated CO 2 is absorbed by oceans. CO 2 dissolved in seawater lowers the ph of the ocean in a process known as ocean acidification.
2.15 (H + ) combine with carbonate ions (CO 3 2 ) to form bicarbonate ions (HCO 3 ). reduces the carbonate ion concentration available to corals and other shell-building animals.
2.15 SCIENTIFIC THINKING: Scientists study the effects of rising atmospheric CO 2 on coral reef ecosystems In a controlled experiment, scientists looked at the effect of decreasing carbonate ion concentration on the rate of calcium deposition by reef organisms. The lower the concentration of carbonate ions, the lower the rate of calcification, and thus the slower the growth of coral animals. The results from experimental and observational field studies of sites where ph naturally varies have dire implications for the health of coral reefs and the diversity of organisms they support.
Figure 2.15a Calcification rate (mmol CaCO 3 /m 2 day) 20 10 0 220 240 260 280 [CO 2 3 ] (μmol/kg of seawater) Source: Adaption of figure 5 from Effect of Calcium Carbonate Saturation State on the Calcification Rate of an Experimental Coral Reef by C. Langdon, et al., from Global Biogeochemical Cycles, June 2000, Volume 14(2). Copyright 2000 by American Geophysical Union. Reprinted with permission of Wiley Inc.
Figure 2.15b A champagne reef with bubbles of CO 2 rising from a volcanic seep Rising CO 2 bubbles lower the ph of the water
Ocean Acidification Video
2.16 EVOLUTION CONNECTION: The search for extraterrestrial life centers on the search for water Why?
You should now be able to 1. List and define the life-supporting properties of water. 2. Explain the ph scale and the formation of acid and base solutions.
Figure 2.UN03-0 Atoms have positively charged have neutral have negatively charged (a) number present equals atomic number of each element (b) (d) number may differ in (c) number in outer shell determines formation of H Chemical Bonds electron transfer between atoms creates electron sharing between atoms creates Na Cl H H ions (e) attraction between ions creates unequal equal sharing creates sharing creates (f) (g) nonpolar covalent bonds H ( ) O H (+) (+) water example is has important qualities due to polarity and can lead to (h) H (+) ( ) O
Chapter 2 The Chemical Basis of Life Clicker Questions for Campbell Biology: Concepts & Connections, Eighth Edition REECE TAYLOR SIMON DICKEY HOGAN Updated by Shannon Datwyler
Concept Check The reactive properties or chemical behavior of an atom mostly depend on the number of a) the electrons in each electron shell of the atom. b) the neutrons found in the nucleus. c) the filled electron shells. d) the electrons in the outer electron shell of the atom.
Answer The reactive properties or chemical behavior of an atom mostly depend on the number of a) the electrons in each electron shell of the atom. b) the neutrons found in the nucleus. c) the filled electron shells. d) the electrons in the outer electron shell of the atom.
Concept Check Water molecules form hydrogen bonds because a) the water molecule is polar. b) the oxygen molecule is positively charged. c) the water molecule forms a tetrahedron. d) the hydrogen atoms are negatively charged.
Answer Water molecules form hydrogen bonds because a) the water molecule is polar. b) the oxygen molecule is positively charged. c) the water molecule forms a tetrahedron. d) the hydrogen atoms are negatively charged.
Interpreting Data This is the general equation for photosynthesis the process of capturing sunlight energy and converting it to chemical energy. Which of the following are the reactants of this reaction? a) C 6 H 12 O 6 and O 2 b) CO 2 and H 2 O
Answer This is the general equation for photosynthesis the process of capturing sunlight energy and converting it to chemical energy. Which of the following are the reactants of this reaction? a) C 6 H 12 O 6 and O 2 b) CO 2 and H 2 O
Interpreting Data Earth s oceans are immense. Small floating plant-like organisms called phytoplankton contribute to ocean productivity. As ocean productivity (the rate of photosynthesis) goes up, what would you predict would happen to global carbon dioxide levels? a) CO 2 levels should also go up. b) CO 2 levels should go down. c) CO 2 levels should remain constant.
Answer Earth s oceans are immense. Small floating plant-like organisms called phytoplankton contribute to ocean productivity. As ocean productivity (the rate of photosynthesis) goes up, what would you predict would happen to global carbon dioxide levels? a) CO 2 levels should also go up. b) CO 2 levels should go down. c) CO 2 levels should remain constant.
Concept Check What will happen as CO 2 levels in the oceans increase? a) The ocean will become more basic b) The ocean will become more acidic c) Growth rates of organisms such as corals will decrease d) Both a and b e) Both b and c
Answer What will happen as CO 2 levels in the oceans increase? The ocean will become more acidic e) Both b and c rowth rates of organisms such as corals will decrease a) Both a and b
Biology and Society One of the authors of your text once overheard the following: It s paranoid and ignorant to worry about industry or agriculture contaminating the environment with their chemical wastes. After all, this stuff is just made of the same atoms that were already present in our environment anyway. What do you think of this statement? Strongly A B C D E Strongly Disagree Agree
Biology and Society Too little iodine in the diet can lead to goiter the condition afflicting this person. Goiter is not common in developing countries because iodine is added to salt and other foods. Do you think that adding trace elements to food items is a good public policy? Strongly A B C D E Strongly Disagree Agree