1. 2.4 Chemical Reactions Quiz 10. Which of the following chemicals has a monomer chemistry consisting of amino acids? a.Proteins b.Lipids c.Carbohydrates d.Nucleic acids 11. Which of the following is the major difference between the chemistry of lipids and proteins? a.Lipids have a monomer/polymer chemistry b.Lipids are hydrophilic c.Proteins have a monomer/polymer chemistry d.Proteins are a nutrient and lipids are not.

2. 2.4 Chemical Reactions Quiz 12.The presence of many oxygen atoms and the formation of H-bonds in carbohydrates and proteins make their chemistry: a.Polar and hydrophilic b.Nonpolar and hydrophobic c.Acidic d.Neutral or basic

3. 2.4 Chemical Reactions Updates: Takehome essay practice: water due Monday Homework: –Reading: 2.5 –2.5 Unit guide questions due tomorrow –quiz begins Tuesday 2.3 Unit 2 test Thursday!

4. 2.4 Chemical Reactions BiomoleculeMonomer or basic components Polymer or types Function(s)Looks like? Carbohydrate Nucleic acid Protein Lipid

5. 2.4 Chemical Reactions LEQ: How do enzymes catalyze chemical reactions? Activator: –Complete organizer –Compare and contrast carbohydrates, proteins and nucleic acids with lipids. How are they similar? How are they different? Key terms –activation energy, enzyme, lock-and-key model

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7. Polynucleotides (left) have a unique sequences of bases: –Directionality (just like proteins) 5’ end, 3’ end

8. 2.4 Chemical Reactions Nucleic acids: RNA and DNA What are the major differences?

9. 2.4 Chemical Reactions DNA* stores biological information for building proteins LettersSequenceDiversity Alphabet26MESSAGES…26 8 = 2.1 x10 11 DNA nucleotides4GATCATAC…4 8 = 65,536 Amino acids20 standardGly – Val – Asp…20 8 = 2.56 x 10 10 DNA encodes the info for making RNA, proteins Cell processes make proteins from RNA

10. 2.4 Chemical Reactions dehydration/condensation reactions make polymers A high energy bond is formed: endo- or exo-?

11. 2.4 Chemical Reactions Example: Hydrolysis of a polymer A high energy bond is broken: endo- or exo-?

12. 2.4 Chemical Reactions Compare and contrast dehydration synthesis & hydrolysis

13. 2.4 Chemical Reactions Obstacle 1: equilibrium reverses life-sustaining reactions Obstacle 2: activation energy needed to start reaction Organisms require energy and matter for a cell to maintain homeostasis.

14. 2.4 Chemical Reactions A catalyst lowers activation energy. Catalysts are substances that speed up chemical reactions. –decrease activation energy; increase reaction rate

15. 2.4 Chemical Reactions How does a catalyst affect the activation energy of a chemical reaction? How does this help a cell overcome one of the obstacles to managing its own chemistry?

16. 2.4 Chemical Reactions Enzymes perform chemical reactions in metabolism. Enzymes are proteins that catalyze reactions: –Increase reaction rate –Concentration dependent Lock-and-key fit with substrate(s) and active site Enzyme/substrate fit is specific: enzymes specialize!

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22. Updates: 2.5 Unit guide questions due Quiz begins Tuesday: 2.3 Homework: –Reading: 12.3 Toothpickase lab due Wednesday Unit 2 test Thursday!

23. 2.4 Chemical Reactions Quiz 1.Which of the following molecules stores genetic information? a.Lipids b.Carbohydrates c.Proteins d.Nucleic acids 2.Nucleic acid polymers are made of monomers called: a.Fatty acids b.Monosaccharides c.Amino acids d.nucleotides

24. 2.4 Chemical Reactions Quiz 3) How does an enzyme affect a chemical reaction? a)increases activation energy, slows reaction rate b)decreases activation energy, speeds up reaction rate c)Creates equilibrium conditions d)Chemical reactions remain uncatalyzed

25. 2.4 Chemical Reactions LEQ: How do enzymes participate in metabolism? Activator: –Keystone prep essay: biological molecules Key terms – metabolic pathway

26. 2.4 Chemical Reactions Enzymes perform chemical reactions in metabolism. Enzymes are proteins that catalyze reactions. Increase reaction rate: Lock-and-key fit with substrate(s) and active site

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28. Describe the role of an enzyme as a catalyst in regulating a specific biochemical reaction. –What does lock-and-key fit mean? –How does the activation energy change? –Why does concentration matter?

29. 2.4 Chemical Reactions Post lab: enzyme kinetics How will changes affect reaction rate? –Concentration of substrate? High or low? –Amount of enzyme: High or low? Which concentration of substrate/enzyme is best for life?

30. 2.4 Chemical Reactions Enzymes support cell function in metabolic pathways Metabolic pathways create matter and energy “flow” by performing reactions using enzymes: –Products are reacted upon before they decompose –Activation energy needed is low Nutrients/energy continuously required Enzymes work as chemicals…that change the properties of other chemicals!

31. 2.4 Chemical Reactions Catabolic pathways break bonds in monomers/chemicals Anabolic pathways form bonds between monomers/chemicals to cell’s needs

32. 2.4 Chemical Reactions Example: the phenylalanine metabolic pathway

33. 2.4 Chemical Reactions Pathways are regulated through negative feedback Pathway products can turn enzymes “on” and “off.”

34. 2.4 Chemical Reactions Enzymes in pathways are controlled through inhibition: –Inhibitors can be competitive (blocking active site) –or noncompetitive (changing enzyme shape)

35. 2.4 Chemical Reactions Explain how negative feedback, competitive or noncompetitive inhibition changes the activity of a metabolic pathway.

36. 2.4 Chemical Reactions Vitamins and minerals make enzymes function Vitamin/mineral cofactors activate enzyme activity.

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38. Updates: 2.5 Unit guide questions due Quiz begins Tuesday: 2.3 Homework: –Reading: 12.3 Toothpickase lab due Wednesday Unit 2 test Thursday!

39. 2.4 Chemical Reactions Quiz 1.Which of the following molecules stores genetic information? a.Lipids b.Carbohydrates c.Proteins d.Nucleic acids 2.Nucleic acid polymers are made of monomers called: a.Fatty acids b.Monosaccharides c.Amino acids d.nucleotides

40. 2.4 Chemical Reactions Quiz 3) How does an enzyme affect a chemical reaction? a)increases activation energy, slows reaction rate b)decreases activation energy, speeds up reaction rate c)Creates equilibrium conditions d)Chemical reactions remain uncatalyzed

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42. Updates: Toothpickase lab due Wednesday Quiz continues today: 2.5 Homework: –Reading: 12.3 Unit 2 test Thursday!

43. 2.4 Chemical Reactions Quiz 4) Which of the following best describes enzymes? a)Interacts with many different of substrates b)Performs reactions with one substrate c)Slows down reaction rate d)Raises activation energy 5) Which best describes a metabolic pathway? a)A single enzyme catalyzing a reaction b)Many enzymes performing a series of reactions c)Energy being stored in chemical bonds d)Energy being released from chemical bonds

44. 2.4 Chemical Reactions LEQ: Why are enzymes sensitive to change? Activator: –What is an extremophile? –What kinds of extreme environments can life thrive in? –Why do scientists want to study extreme habitats on Earth?

45. 2.4 Chemical Reactions Enzymes are sensitive/adapted to the environment

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47. Enzymes are sensitive to environmental conditions Enzymes lose their shape the presence of certain physical conditions that alter folding: –Enzymes (all proteins) can denature preventing it from functioning

48. 2.4 Chemical Reactions Chaperone proteins can assist in the renaturation or folding and covalent bonding of proteins that have lost their function

49. 2.4 Chemical Reactions Discussion: Life in Antarctica How are the dry valleys of the Antarctic similar to Mars? What did scientists discover when they drilled into the soil and ice in Antarctica? How do you think the microorganisms found in this extreme environment differ from other species?

50. 2.4 Chemical Reactions Discussion: Thriving on the Arctic Seafloor How are the Arctic Ocean and Europa similar? How do these microbes discovered 12,000 feet beneath the Arctic ice sheets survive without energy from the Sun?

51. 2.4 Chemical Reactions Activities Search: learn genetics life in extreme environments Click on link and watch introduction together Activity: Extremophiles cards –Choose which organisms might survive in 5 featured environments as you watch the introduction. Make a table to summarize results (be brief). Writing: –Choose an organism you would use to colonize space or a specific planet or moon. –Explain why Extension: Aterra4 Explorer: –Modification: use extremophile cards for #4

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