Unit 2 Themes And Tools For Studying Biology

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Unit 2 Themes And Tools For Studying Biology

  1. 1. KEY CONCEPTTechnology continually changes the way biologists work.<br />
  2. 2. stoma<br />Imaging technologies provide new views of life.<br />A microscope provides an enlarged image of an object.<br /><ul><li>light microscopes (LM)</li></li></ul><li>stoma<br />Imaging technologies provide new views of life.<br />A microscope provides an enlarged image of an object.<br /><ul><li>light microscopes (LM)
  3. 3. scanning electron microscopes (SEM)</li></li></ul><li>stoma<br />Imaging technologies provide new views of life.<br /><ul><li>A microscope provides an enlarged image of an object.
  4. 4. light microscopes (LM)
  5. 5. scanning electron microscopes (SEM)</li></ul>transmission electron microscopes (TEM)<br />
  6. 6. Imaging technology is used in medicine.<br /><ul><li>X-ray images</li></li></ul><li><ul><li>Imaging technology is used in medicine.
  7. 7. X-ray images</li></ul>magnetic resonance imaging (MRI)<br />
  8. 8. <ul><li>Imaging technology is used in medicine.
  9. 9. X-ray images
  10. 10. magnetic resonance imaging (MRI)</li></ul>functional MRI (fMRI)<br />
  11. 11. Complex systems are modeled on computers.<br />Normal heartbeat<br />Computer models are used to study systems that cannot be studied directly.<br />heart attacks<br /><ul><li>effect of medicines on the human body
  12. 12. movement of water molecules into and out of a cell
  13. 13. spread of a disease through a population</li></ul>Heart attack<br /><ul><li>Computer models are used when experiments are not safe, ethical, or practical.</li></li></ul><li>The tools of molecular genetics give rise to new biological studies.<br />A gene is a segment of DNA that stores genetic information.<br />
  14. 14. Through our understanding of DNA, we can study genetics on a molecular level.<br /><ul><li>molecular genetics
  15. 15. genomics</li></li></ul><li>KEY CONCEPTUnderstanding biology can help you make informed decisions.<br />
  16. 16. Your health and the health of the environment depend on your knowledge of biology.<br />Knowledge of biology helps you understand your health.<br />food allergies<br />potential effects of obesity<br />
  17. 17. brain<br />lungs<br />heart<br />liver<br />kidneys<br /><ul><li>Knowledge of biology helps you understand your health.
  18. 18. food allergies
  19. 19. potential effects of obesity</li></ul>cancer<br /><ul><li>effects of alcohol, tobacco, and other drugs</li></li></ul><li>Knowledge of biology can help you understand environmental issues.<br /><ul><li>interactions in ecosystems
  20. 20. pollution
  21. 21. biodiversity</li></li></ul><li>Biotechnology offers great promise but also raises many issues.<br />Biotechnology is the use and application of living things and biological processes.<br />
  22. 22. <ul><li>Biotechnology is the use and application of living things and biological processes.</li></ul>DNA testing in medicine and forensics<br /><ul><li>transgenic (genetically modified) crops
  23. 23. transgenic bacteria</li></li></ul><li>Questions are raised about the use of biotechnology.<br /><ul><li> safety of genetically modified crops
  24. 24. spread of undesirable genes
  25. 25. decrease in biodiversity
  26. 26. ethical considerations</li></li></ul><li>Biology presents many unanswered questions.<br />Over the past 50 years, biological knowledge has greatly increased.<br />
  27. 27. There are still many questions to answer in biology.<br /><ul><li>How are memories stored in the brain?</li></li></ul><li>capsid <br />nucleic acid <br />lipid <br />envelope<br />surface proteins<br />There are still many questions to answer in biology.<br /><ul><li>How are memories stored in the brain?
  28. 28. How do viruses mutate?
  29. 29. Does life exist on planets other than Earth?</li></li></ul><li>KEY CONCEPTAll living things are based on atoms and their interactions.<br />
  30. 30. H<br />O<br />Living things consist of atoms of different elements.<br />An atom is the smallest basic unit of matter.<br />An element is one type of atom.<br />Hydrogen atom (H)<br />Oxygen atom (O)<br />
  31. 31. Oxygen atom (O)<br />outermost energy level: 6 electrons (-)<br />Nucleus:8 protons (+)8 neutrons<br />inner energy level: 2 electrons (-)<br /><ul><li>An atom has a nucleus and electrons.</li></ul>The nucleus has protons and neutrons.<br />Electrons are in energy levels outside nucleus.<br />
  32. 32. _<br />O<br />H<br />H<br />+<br />+<br /><ul><li>A compound is made of atoms of different elements bonded together.</li></ul>water (H2O)<br />
  33. 33. <ul><li>A compound is made of atoms of different elements bonded together.
  34. 34. water (H2O)</li></ul>carbon dioxide (CO2)<br />
  35. 35. <ul><li>A compound is made of atoms of different elements bonded together.
  36. 36. water (H2O)
  37. 37. carbon dioxide (CO2)</li></ul>many other carbon-based compounds in living things<br />
  38. 38. gained electron<br />Na loses anelectron to CI<br />ionic bond<br />Sodium atom (Na)<br />Chlorine atom (CI)<br />Sodium ion (Na+)<br />Chloride ion (CI-)<br />Ions form when atoms gain or lose electrons.<br />An ion is an atom that has gained or lost one or more electrons.<br />positive ions<br />negative ions<br /><ul><li>Ionic bonds form between oppositely charged ions.</li></li></ul><li>covalent bonds<br />Oxygen atom (O)<br />Carbon atom (C)<br />Oxygen atom (O)<br />Carbon dioxide (CO2 )<br />Atoms share pairs of electrons in covalent bonds.<br />A covalent bond forms when atoms share a pair of electrons.<br /><ul><li>multiple covalent bonds
  39. 39. diatomic molecules</li></li></ul><li>KEY CONCEPTWater’s unique properties allow life to exist on Earth.<br />
  40. 40. _<br />O<br />H<br />H<br />+<br />+<br />Life depends on hydrogen bonds in water.<br />Water is a polar molecule.<br />Polar molecules have slightly charged regions.<br /><ul><li> Nonpolar molecules do not have charged regions.
  41. 41. Hydrogen bonds form between slightly positive    hydrogen atoms and slightly negative atoms.</li></li></ul><li>Hydrogen bonds are responsible for three important properties of water.<br /><ul><li>high specific heat
  42. 42. cohesion
  43. 43. adhesion</li></li></ul><li>solution<br />Many compounds dissolve in water.<br />A solution is formed when one substance dissolves in another.<br />A solution is a homogeneous mixture.<br />Solvents dissolve other substances.<br />Solutes dissolve in a solvent.<br />
  44. 44. “Like dissolves like.”<br /><ul><li>Polar solvents dissolve polar solutes.
  45. 45. Nonpolar solvents dissolve nonpolar solutes.
  46. 46. Polar substances and nonpolar substances generally remain separate.</li></li></ul><li>stomach acid pH between 1 and 3<br />more acidic<br />Some compounds form acids or bases.<br />An acid releases a hydrogen ion when it dissolves in water.<br />high H+ concentration<br />pH less than 7<br />
  47. 47. bile pH between 8 and 9<br />more basic<br />A base removes hydrogen ions from a solution.<br /><ul><li>low H+ concentration
  48. 48. pH greater than 7</li></li></ul><li>pure water pH 7<br />A neutral solution has a pH of 7.<br />

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