Do Now. What is happening in the pictures below? How do you know? What evidence do you have to support your answer?

Transcription

1 Do Now What is happening in the pictures below? How do you know? What evidence do you have to support your answer?

2 Energy and Enzymes

3 Chemical Reactions Lab

4 Clean Up Procedure

5 Sample Data

6 Do Now What is energy? Are both pictures below demonstrating energy? Explain

7 Objectives 1. SWBAT differentiate between kinetic, potential, and chemical energy and provide examples of each. 2. SWBAT describe the two laws of thermodynamics and define entropy. 3. SWBAT differentiate between exergonic and endergonic reactions 4. SWBAT describe the structure and function of ATP

8 Cells transform energy Energy- ability to do work or rearrange matter, go against an opposing force 1. Kinetic Energy - energy of motion a. b. 2. Thermal (Heat) Energy - molecules move Light Energy - photosynthesis Potential Energy - stored energy a. Chemical Energy- potential energy available for release in a chemical reaction

9 Chemical Energy is most important for living organisms Chemical energy can be released to power the work of the cell Ex: Vibrio fischeri use chemical energy to generate bioluminescence in bobtail squid as a camouflage from predators

10 Energy Transformations Thermodynamics: Study of energy changing forms between the system (cell, power plant, etc) and surroundings (environment). 1. First Law of Thermodynamics a. Energy cannot be created nor destroyed but it can be transformed. i. Example: Roller Coaster 2. Second Law of Thermodynamics a. b. Energy cannot be converted without the loss of unusable energy. Entropy: Measure of randomness or disorder in the universe (unusable energy) i. 10% Rule 1. So we can say entropy is always.

11 Fuel Energy conversion Waste products Heat energy Gasolin e Carbon dioxide Combustion Kinetic energy of movement Oxygen Energy conversion in a car Water Heat Glucose Cellular respiration Carbon dioxide Energy for cellular work Water Oxygen Energy conversion in a cell

12 Chemical Reactions in a cell What is a chemical reaction? Chemical Reaction: one or more substance are changed into one or more NEW substances Example: Cellular Respiration and Photosynthesis Chemical reactions can Form larger molecules Form Smaller molecules Require energy to occur Produce energy

13 Do Now Looking back at your lab, which reactions were exergonic? Endergonic? Describe the energy transfer that enabled you to come to that decision.

14 Exergonic Reaction Energy is released as a product Covalent bonds store energy in reactants and released as products. Ex: Wood Burning, Cellular Respiration

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16 Endergonic Reaction Energy is absorbed from surroundings Energy is stored in bonds of products Ex: Photosynthesis

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18 Endergonic or Exergonic? Cooking an Egg Ice cube in your hands Catabolic Reaction ADP becoming ATP Formation of a peptide bond Hydrolysis of a polysaccharide

19 Do Now What do you think the diagram below is demonstrating? Does this look correct? Explain why or why not.

20 Review What type of reaction is being shown? How do you know?

21 Adenosine Triphosphate (ATP) Structure 1. Adenine (nitrogen base), Ribose, and three phosphate groups 2. Bond between 2nd and 3rd phosphate breaks. a. b. c. Energy is released Type of reaction: Becomes Adenosine Diphosphate (ADP + Pi)

22 What are enzymes? n how_enzymes_work.html

23 Enzymes Activation Energy: Amount of energy required to initiate a reaction Ex: Spark to light candle flame Ways to get over the energy barrier Heat Enzymes Proteins that are biological catalysts Reduce the amount of energy needed to initiate the reaction.

24 Enzyme Structure A Substrate (specific reactant) fits into the enzyme s active site (bonding site on protein) and forms an enzyme-substrate complex. One one substrate works with one enzyme Ex: Maltase will break down Maltose into 2 glucose molecules Induced fit takes place between the substrate and the active site that puts strain on the substrate to either make or break bonds.

25 1 Enzyme available with empty active site Active site Enzyme (sucrase)

26 1 Enzyme available with empty active site Active site Substrate (sucrose) 2 Substrate binds to enzyme with induced fit Enzyme (sucrase)

27 1 Enzyme available with empty active site Active site Substrate (sucrose) 2 Substrate binds to enzyme with induced fit Enzyme (sucrase) 3 Substrate is converted to products

28 1 Enzyme available with empty active site Active site Substrate (sucrose) 2 Substrate binds to enzyme with induced fit Glucose Enzyme (sucrase) Fructose 4 Products are released 3 Substrate is converted to products

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30 Enzymes Continued What do you notice about the picture on the right? What does this tell you about the process? Enzymes are not used up in the reaction! They are reusable!

31 Optimal Conditions for Enzymes Enzyme shape is crucial to its function What do you think could cause an enzyme to stop working? 1. ph changes can cause a denaturation of the enzyme (alteration of shape to inhibit function) a. Most human enzymes work best at a ph of High temperatures are good (faster molecular motion and increased rate of reaction) a. b. c. But too high of temperature can also cause denaturation of the enzyme. Most enzymes work best at 35-40C. Freezing can also enzymes to stop working, but not change the shape.

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