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Topic 3: The Chemistry of Life

Topic 3: The Chemistry of Life. 3.1: Chemical elements and water. ★State that the most frequently occurring chemical elements in living things are carbon, hydrogen, oxygen and nitrogen.

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Topic 3: The Chemistry of Life

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  1. Topic 3: The Chemistry of Life

  2. 3.1: Chemical elements and water • ★State that the most frequently occurring chemical elements in living things are carbon, hydrogen, oxygen and nitrogen. • ★State that a variety of other elements are needed by living organisms, including sulfur, calcium, phosphorus, iron and sodium • ★State one role for each of the elements above

  3. 3.1: Chemical elements and water • There are about 25 different elements that are essential for all life. • 4 main elements that make up the majority of living matter are: hydrogen, carbon, oxygen, nitrogen • HCON • These elements are used in the molecular structures of all carbohydrates, proteins, lipids, and nucleic acids (DNA). • In addition, living organisms contain a variety of other elements which are extremely important, but are less common.

  4. 3.1: Chemical elements and water

  5. 3.1: Chemical elements and water

  6. 3.1: Chemical elements and water • ★Draw and label a diagram showing the structure of water molecules to show their polarity and hydrogen bond formation. • Water is the solvent of life and virtually all cells have water within (cytoplasm) and in the surrounding environment (intercellular fluid, pond water, etc) • Water is an incredibly abundant substance on Earth with many interesting properties which depend on its structure.

  7. 3.1: Chemical elements and water • ARTICLE TIME! • Water Lust: Why All the Excitement When H2O is Found in Space? • Is finding water in the solar system enough to assume there is life on other planets?

  8. 3.1: Chemical elements and water • Question #1: Which of the following chemical elements are part of biochemical molecules in living organisms? • A. silicon, helium, oxygen, iron • B. helium, carbon, sulfur, nitrogen • C. lead, oxygen, carbon, phosphorus • D. nitrogen, sulfur, phosphorus, iron • Answer: D, nitrogen/sulfur/phosphorus/iron

  9. 3.1: Chemical elements and water • Question #2: Carbon, hydrogen, nitrogen and sulfur are elements found in living cells. Which is the least common? • A. Carbon • B. Hydrogen • C. Nitrogen • D. Sulfur • Answer: D, sulfur

  10. 3.1: Chemical elements and water • Question #3: What is a role of sulfur in living organisms? • A. Formation of carbohydrates • B. Formation of proteins • C. Formations of teeth • D. Transmission of nerve impulses • Answer: B, formation of proteins

  11. 3.1: Chemical elements and water • Water molecules consist of two hydrogen atoms bonded to an oxygen atom. • hydrogen atoms = slight positive charge • Hint: writing a capital H, is close to a + • oxygen atoms = slight negative charge • So water molecules have 2 poles - a positive hydrogen pole and a negative oxygen pole • This feature is called polarity.

  12. 3.1: Chemical elements and water

  13. 3.1: Chemical elements and water

  14. 3.1: Chemical elements and water • The hydrogen and oxygen atoms in a single water molecule are held together by a polar covalent bond. • Covalent bond = sharing electrons • A bond forms between the positive pole of one water molecule and the negative pole of another.

  15. 3.1: Chemical elements and water • ★Outline the thermal, cohesive and solvent properties of water. • ★Explain the relationship between the properties of water and its uses in living organisms as a coolant, medium for metabolic reactions and transport medium.

  16. 3.1: Chemical elements and water

  17. 3.1: Chemical elements and water • Youtube video: basilisk lizard running on water • These lizards are able to run on top of the water! • The relatively large surface area of their feet does does not break through the surface tension of the water as long as they keep running.

  18. Have students pair up.  Give each pair 4 items --  a regular drinking straw, a red coffee stirrer, a cup/beaker filled with water and a Sharpie marker.  Have students put both the regular straw and the coffee stirrer into the cup.  They should look carefully through the tubes and use the Sharpie marker to draw a line on the tube to mark the height of the water.  Once students have done that, have them analyze their results.  Why was there a difference in the height of the water between the regular straw and the coffee stirrer?   • After some think time, ask different pairs to share.  Which tube had a higher level of water in it?  Was the result the same for every group?  Why or why not?  (lead students to the conclusion that diameter of the tube plays a huge role.  If the diameter gets too large, the adhesive properties between the water and the side of the tube becomes less strong . . . causing the water not to rise as high.)  • In agriculture, it is critically important that plants have incredibly small tubes within the xylem tissue that carry water and nutrients from the roots upwards into the body of the plant.  If those tubes weren't small in diameter, plants would have a difficult time moving water and dissolved nutrients through their xylem tissue by capillary action. This same concept is also true in animals and humans.  Our circulatory systems contain capillaries.  Capillaries are incredibly small tubes that help move blood in our bodies.  Since blood is mostly made of water, capillary action assists the pumping action of the heart to help keep blood moving in our blood vessels.

  19. 3.1: Chemical elements and water • Question #4: Which diagram represents the polarity of a water molecule? • Answer: B

  20. 3.1: Chemical elements and water • Question #5: Which diagram best illustrates the interactions between water molecules? • Answer: B

  21. 3.1: Chemical elements and water

  22. 3.1: Chemical elements and water

  23. 3.1: Chemical elements and water

  24. Discuss lake effect - what do students think it means? • Lake effect snows occur when a mass of sufficiently cold air moves over a body of warmer water, creating an unstable temperature profile in the atmosphere. • As a result, clouds build over the lake and eventually develop into snow showers and squalls as they move downwind. The intensity of lake effect snow is increased when higher elevations downwind of the lake force the cold, snow-producing air to rise even further. • The most likely setting for this localized type of snowfall is when very cold Arctic air rushes over warmer water on the heels of a passing cold front, as often happens in the Great Lakes region during winter. • Winds accompanying Arctic air masses generally blow from a west or northwest direction, causing lake effect snow to fall on the east or southeast sides of the lakes. • For us, it signifies the strength of Lake Michigan's effect on the temperature of the area. During winter, the lake keeps us warmer and, during summer, we are cooler.

  25. 3.1: Chemical elements and water

  26. 3.1: Chemical elements and water • Question #1: Which of the following chemical elements are part of biochemical molecules in living organisms? • A. silicon, helium, oxygen, iron • B. helium, carbon, sulfur, nitrogen • C. lead, oxygen, carbon, phosphorus • D. nitrogen, sulfur, phosphorus, iron • Answer: D, nitrogen/sulfur/phosphorus/iron

  27. 3.1: Chemical elements and water • Question #2: Carbon, hydrogen, nitrogen and sulfur are elements found in living cells. Which is the least common? • A. Carbon • B. Hydrogen • C. Nitrogen • D. Sulfur • Answer: D, sulfur

  28. 3.1: Chemical elements and water • Question #3: What is a role of sulfur in living organisms? • A. Formation of carbohydrates • B. Formation of proteins • C. Formations of teeth • D. Transmission of nerve impulses • Answer: B, formation of proteins

  29. 3.1: Chemical elements and water • Question #4: Which diagram represents the polarity of a water molecule? • Answer: B

  30. 3.1: Chemical elements and water • Question #5: Which diagram best illustrates the interactions between water molecules? • Answer: B

  31. 3.1: Chemical elements and water • Question #6: What property of water makes it a good evaporative coolant? • A. High latent heat of evaporation • B. Relatively low boiling point • C. Volatility • D. Transparency • Answer: A, high latent heat of evaporation

  32. 3.1: Chemical elements and water • Question #7: Blood is a water-based transport medium. Which property of water makes it a good transport medium? • A. Transparency • B. It has its greatest density at 4°C • C. High specific heat • D. Versatility as a solvent • Answer: D, versatility as a solvent

  33. 3.2: Carbohydrates, lipids, proteins • Living things are composed of an amazing array of molecules. • We can start to make sense of all of these molecules by classifying them into a molecule type. • Molecules of the same type have certain qualities in common .

  34. 3.2: Carbohydrates, lipids, proteins • Some biochemically important molecules and their subcomponents/building blocks

  35. 3.2: Carbohydrates, lipids, proteins • ★Distinguish between organic and inorganic compounds. • Organic compounds: contain carbon found in living organisms • ALL organic molecules contain carbon, but not all carbon containing molecules are organic (ex: carbon dioxide is not organic) • Many of the carbons found in food you eat (carbs) will be eliminated from your body as carbon dioxide that you breathe out. • Inorganic compounds: do not contain carbon

  36. 3.2: Carbohydrates, lipids, proteins • 3 types of organic compounds that are found in large amounts in living organisms: • Carbohydrates, lipids, and proteins • The molecules of many organic compounds are large and so are called macromolecules. • They are built up using small and relatively simple subunits.

  37. 3.2: Carbohydrates, lipids, proteins • ★Identify amino acids, glucose, ribose and fatty acids from diagrams showing their structure (specific names of amino and fatty acids not expected).

  38. 3.2: Carbohydrates, lipids, proteins • Amino Acids: Generalized structure because it can be one of 20 amino acids (look for central carbon)

  39. 3.2: Carbohydrates, lipids, proteins • Glucose: A monosaccharide, identified by its 6-carbon sugar (look for hexagon)

  40. 3.2: Carbohydrates, lipids, proteins • Ribose: A monosaccharide, identified by its 5-carbon sugar (look for pentagon).

  41. 3.2: Carbohydrates, lipids, proteins • Fatty Acids: Number of carbon atoms and bonding between carbon atom varies - both pics have same number of carbons, one is just condensed

  42. 3.2: Carbohydrates, lipids, proteins • ★List 3 examples each of monosaccharides, disaccharides and polysaccharides. • ★State one function of glucose, lactose and glycogen in animals, and of fructose, sucrose and cellulose in plants

  43. 3.2: Carbohydrates, lipids, proteins

  44. 3.2: Carbohydrates, lipids, proteins

  45. 3.2: Carbohydrates, lipids, proteins

  46. 3.2: Carbohydrates, lipids, proteins • ARTICLE TIME! • Grassoline at the Pump • If you were just appointed as an environmental advisor to the president in 2013, would you tell him it would be wise to invest in cellulosic biofuels? Explain.

  47. 3.2: Carbohydrates, lipids, proteins • Question #8: Which of the following is an organic compound made by all plants? • A. Carbon dioxide • B. Lactose • C. DNA • D. Oxygen • Answer: C, DNA

  48. 3.2: Carbohydrates, lipids, proteins • Question #9: Which molecule is shown below? • A. Glucose • B. Galactose • C. Ribose • D. Sucrose • Answer: C, ribose

  49. 3.2: Carbohydrates, lipids, proteins • Question #10: Which of the following terms correctly describe the molecule below? • I. Monosaccharide • II. Ribose • III. Carbohydrate • A. I only B. I and III only • C. II and III only D. I, II, III • Answer: B, I and III only

  50. 3.2: Carbohydrates, lipids, proteins • Question #11: Which describes these molecules correctly? • Answer: D

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