Enzymes & The Need for Energy

Section 1: Enzymes

Enzymes are Catalysts speed up chemical Catalysts- substances that speed up chemical reactions without being affected by the reactions themselves. protein that can be a catalyst increase Enzyme- a protein that can be a catalyst to increase the rate of reactions by lowering the activation energy. speed up chemical Catalysts- substances that speed up chemical reactions without being affected by the reactions themselves. protein that can be a catalyst increase Enzyme- a protein that can be a catalyst to increase the rate of reactions by lowering the activation energy.

Enzymes lower AE Activation Energy - the amount of energy needed to start a chemical reaction

Enzyme-Substrate Specificity Substrate- Substrate- molecule on which an enzyme acts An enzyme binds to a substrate and stresses the bonds of that molecule in a way that makes a reaction more likely to occur. Substrate- Substrate- molecule on which an enzyme acts An enzyme binds to a substrate and stresses the bonds of that molecule in a way that makes a reaction more likely to occur. Enzyme

Enzyme-Substrate Specificity shape The KEY to an enzyme’s activity is its shape. Active Site Active Site- location on an enzyme where the substrate binds Each substrate can only bind to one enzyme.

Enzymes can be reused!

Factors that Can Effect Enzymes 1. Temperature 2. pH 3. Concentration of Enzyme 4. Concentration of Substrate 1. Temperature 2. pH 3. Concentration of Enzyme 4. Concentration of Substrate

Effect of Temperature on Enzymes Raising the temperature will increase the speed and energy of collisions Raising the temperature will increase the speed and energy of collisions between molecules. increase the activity of the enzyme Therefore it will increase the activity of the enzyme TO A POINT! The point where the rate is the highest is called the optimum of the enzyme. Every enzyme has its own optimum Every enzyme has its own optimum.

Effect of pH on Enzymes each enzyme has a specific pH at which it works best optimum of pH Like temperature, each enzyme has a specific pH at which it works best. This is called the optimum of pH. Enzyme pH Optimum Lipase (pancreas) 8.0 Lipase (pancreas) Lipase (stomach) Lipase (castor oil) 4.7 Pepsin Pepsin Trypsin Trypsin Urease 7.0 Urease Invertase 4.5 Maltase Maltase Amylase (pancreas) Amylase (pancreas) Amylase (malt) Amylase (malt) Catalase 7.0 Catalase

Denaturation denatured or stop working at all Enzymes become denatured or stop working at all when exposed to high temperatures or adverse pH.

Effect of [Enzyme] on Enzymatic Reactions rate of the reaction increases increase in the enzyme The rate of the reaction increases with an increase in the enzyme

Effect of [Substrate] on Enzymatic Reactions increase the rate of reaction Increasing the substrate on which the enzyme works will also increase the rate of reaction UNTIL the all the enzymes are busy. saturation point This is called the saturation point

Section 2: The Need for Energy

Biochemical Pathways Biochemical Pathway: a series of biochemical reactions Usable energy produced by one reaction may be stored and used in a later reaction. In most cases, this energy is stored in a molecule called adenosine triphosphate (ATP). Biochemical Pathway: a series of biochemical reactions Usable energy produced by one reaction may be stored and used in a later reaction. In most cases, this energy is stored in a molecule called adenosine triphosphate (ATP).

Structure of ATP Structure- the ATP molecule has three parts: 1. adenine (a nitrogen-containing molecule) 2. ribose (a five-carbon sugar) The adenine bonds to ribose, forming adenosine. 3. three phosphate groups Structure- the ATP molecule has three parts: 1. adenine (a nitrogen-containing molecule) 2. ribose (a five-carbon sugar) The adenine bonds to ribose, forming adenosine. 3. three phosphate groups

Structure of ATP

Function of ATP ATP stores energy in the bonds between the phosphate groups (high-energy bonds)

ATP-ADP Cycle ATPase is an enzyme that removes a phosphate from ATP to make it ADP ATP Synthase is an enzyme that adds a phosphate to ADP to make it ATP ATPase is an enzyme that removes a phosphate from ATP to make it ADP ATP Synthase is an enzyme that adds a phosphate to ADP to make it ATP ATP SynthaseATPase

ATP-ADP Cycle ATP Synathase ATPase

ATP-ADP Cycle The breakdown of ATP to ADP may result in: 1. free phosphate ions + energy. OR 2. the transfer of a phosphate group to another molecule (phosphorylation). The phosphorylated molecule gains both the phosphate group and the energy. The breakdown of ATP to ADP may result in: 1. free phosphate ions + energy. OR 2. the transfer of a phosphate group to another molecule (phosphorylation). The phosphorylated molecule gains both the phosphate group and the energy.

Phosphorylation by ATP Phosphorylation- protein gets phospate group and enrgy

ATP-ADP Cycle Photosynthesis, respiration, and the ATP- ADP cycle form a fundamental biological cycle: plants store energy in glucose molecules during photosynthesis → animals and plants release that energy during respiration → the energy is stored in ATP → until it is needed to fuel cell activities Photosynthesis, respiration, and the ATP- ADP cycle form a fundamental biological cycle: plants store energy in glucose molecules during photosynthesis → animals and plants release that energy during respiration → the energy is stored in ATP → until it is needed to fuel cell activities

ATP-ADP Cycle