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

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

Metabolism Examples Metabolic Pathway - series of chemical reactions Obj 23 Metabolic Pathway - series of chemical reactions Example: Cellular Respiration Catabolic - Breaks down glucose Exergonic - Energy released from glucose C6H12O6 + 6O2 6CO2 + 6 H2O Enzymes

Metabolism Examples Example: ATP phosphorylation Obj 23 Example: ATP phosphorylation Anabolic - builds ATP molecules from ADP and P Endergonic - ATP is high energy

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

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

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

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

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

Enzyme Function and Homeostasis Obj 27, 29 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

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

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

Hypothesis-Based Science Obj 38 Hypothesis-Based Science Understanding is gained through logical prediction and experimentation. Other variables are controlled Ex. Pavlov’s Dog experiment

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.

Scientific Theory Explanations of phenomena in nature Obj 39 Scientific Theory Explanations of phenomena in nature Formed from large bodies of data Refined as new discoveries are made Not a guess

Controlled Experiments Unit 1: Biochemistry and Digestion OBJ 43 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

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

Observation vs Inference Obj 40 Observation vs Inference Observation what we know Facts Evidence Inference Logical conclusions based on the observations

Sample Size Number of Data points Obj 43 Sample Size Number of Data points Patterns require several observations

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