1. Topic 5 Chemical reactions and enzymes
Unit 1: Biochemistry and Digestion
Topic 5
Chemical reactions and enzymes

2. Metabolism Collection of all the chemical reactions of an organism
Unit 1: Biochemistry and Digestion
Metabolism
OBJ 23
Collection of all the chemical reactions of an organism
Anabolism – reactions that build up
Catabolism – reactions that break down (CATastrophic…)
Exergonic
Releases energy
Energy-rich reactants  Energy-poor products
Endergonic
Absorbs/requires energy
Energy-poor reactants  Energy-rich products

3. Metabolism Examples Metabolic Pathway - series of chemical reactions
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Metabolic Pathway - series of chemical reactions
Example: Cellular Respiration
Catabolic - Breaks down glucose
Exergonic - Energy released from glucose
C6H12O O CO H2O
Enzymes

4. Metabolism Examples Example: ATP phosphorylation
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Example: ATP phosphorylation
Anabolic - builds ATP molecules from ADP and P
Endergonic - ATP is high energy

5. Exergonic and Endergonic Reactions
Unit 1: Biochemistry and Digestion
OBJ 23
Exergonic and Endergonic Reactions

6. Reading an Energy Graph
Unit 1: Biochemistry and Digestion
OBJ 28
Reading an Energy Graph
Transition state

7. Enzymes Biological Catalysts
Obj 24,28
Biological Catalysts
Enzymes are proteins that lower the activation energy of biochemical reactions
Shape controls function!
One enzyme for substrate

8. Enzymes Obj 24 Characteristics…. They are usually proteins
Speed up reactions
Work by lowering activation energy
Are not used up during the reaction
Are specific to one reaction
Have a precisely shaped active site

9. Induced Fit Model of Enzyme Function
Unit 1: Biochemistry and Digestion
OBJ 25, 26, 27
Induced Fit Model of Enzyme Function
Enzyme active sites changes shape
The new shape puts stress on specific bonds
Bonds will break and form under this stress

10. Enzyme Function and Homeostasis
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Enzyme Function and Homeostasis
What is the main nutritional component of an egg?
What happens to those proteins when they are exposed to high heat?
Denaturation - process that causes proteins and other biochemical molecules to loose there structure.
Shape (structure) controls function!!!!
Pepsin Lab Next Week

11. Unit 1: Biochemistry and Digestion
Topic 7
The Methods of Science

12. Obj 38
Discovery Science
Understanding of a Biological situation is gained through observation
Large numbers of Observation
Identification of patterns
Field work
Ex. Stickleback fish mating behavior

13. Hypothesis-Based Science
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Hypothesis-Based Science
Understanding is gained through logical prediction and experimentation.
Other variables are controlled
Ex. Pavlov’s Dog experiment

14. Scientific Method OBJ 39-42 Observe and state a problem
Unit 1: Biochemistry and Digestion
OBJ 39-42
Scientific Method
Observe and state a problem
What is the rationale?
Form a hypothesis
Testable
Falsifiable
If (the independent variable affects the dependent variable), then (this is my specific prediction).
Write controlled procedure
Experiment - test the hypothesis
Record and analyze data
Form a conclusion
Repeat the experiment (or publish so others can)
Scientific theories are hypotheses that has held up to extreme scrutiny.

15. Scientific Theory Explanations of phenomena in nature
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Scientific Theory
Explanations of phenomena in nature
Formed from large bodies of data
Refined as new discoveries are made
Not a guess

16. Controlled Experiments
Unit 1: Biochemistry and Digestion
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Controlled Experiments
Independent Variable – changed by scientist
Dependent Variable – observed by scientist
Experimental Group
Control Group – used as a baseline to compare to experimental group
Positive Control Group
Negative Control Group
Confounding Variables – outside factors that may correlate with both independent and dependent variables

17. Obj 41-42
If, then hypothesis
Dependent variable – researcher will measure the resulting size of plant (height in cm)
Independent variable – researcher will adjust the amount of fertilizer applied
If the the amount of fertilizer is related to the growth of radish plants, then radish plants that are given more fertilizer will grow taller.
Testable?
Falsifiable?
Prediction – if the association is true you will see this in the data

18. Observation vs Inference
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Observation vs Inference
Observation
what we know
Facts
Evidence
Inference
Logical conclusions based on the observations

19. Sample Size Number of Data points
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Sample Size
Number of Data points
Patterns require several observations

20. Sample Size Number of data points
Obj 43
Sample Size
Number of data points
Patterns require several observations