Grade 9 Enzymes Study Guide 2025 PDF

**2025 Grade 9 Enzymes study guide V1.0** Textbook Biology 3^rd^ edition (Sections 2.4 p. 30-35) Textbook Biology 4^th^ edition (Sections 4.1, 4.2 (Benedict's), 5.1; pp.36-37, 39-42) **What are enzymes?** Enzymes are [protein biological catalysts] that speeds up a chemical reaction (sometimes sl...

**2025 Grade 9 Enzymes study guide V1.0** Textbook Biology 3^rd^ edition (Sections 2.4 p. 30-35) Textbook Biology 4^th^ edition (Sections 4.1, 4.2 (Benedict's), 5.1; pp.36-37, 39-42) **What are enzymes?** Enzymes are [protein biological catalysts] that speeds up a chemical reaction (sometimes slows down a reaction or build molecules). An enzyme stays the same from beginning -\> end. Enzymes are [globular proteins] (water soluble, shaped like a 3-d sphere). [Hydrophilic side] on the outside -\> soluble A diagram of a structure Description automatically generated Enzymes help with splitting substrate into 2 or more or joining products (two molecules) Enzymes have an active site which the substrate molecule can fit in. The substrate molecule is said to have a [complementary shape] to the enzyme's active site. Enzymes are said to be specific to just [one] substrate for this reason. When the substrate and enzyme molecules temporarily combine it is known as an [enzyme-substrate product]. As the enzyme holds the substrate molecule in a certain way it puts tension on the substrate molecule. This lowers the [activation energy] needed for the reaction to take place. This is why reactions can occur at [relatively low temperatures] in living things. During the reaction the substrate is turned into [complex.] This is released from the enzyme's active site and the enzyme molecule is left [unchanged and free to catalyse] more reactions. Each reaction in our body involves a specific enzyme. We have thousands of different enzymes in our body. [Inorganic molecules]; water (e.g.) [Main organic molecules groups]: 1. [Carbohydrates] are found all over the body, inside cells as energy, blood, and in our cells. They are used for quick energy in cellular respiration 2. [Lipids] -- Portion of cells membranes and help control what goes in and out your body cells 3. [Proteins] are found throughout the body, in muscles, bone, skin, hair, tissue, etc. They make new protein to serve as an energy source and help repair body tissue 4. [Nuclei acids] [Hydrolysis] -- Large molecules are broken down into smaller ones by addition of water (H2O) [Condensation] -- large molecules are formed by the buildup of smaller molecules through the removal of water A diagram of a polymerization process Description automatically generated **Enzymes in industry:** Example: lasctose-free-milk = the lacase is purified from yeast or bacteria and then bound to an inert substance **Active site:** The active site is where the reactions are, when they are done with the reactions, they will need to leave the site. The active site is made up of a few amino acids. It is a cleft or depression on the enzyme (space). Substrate fits perfectly to Active Site: [Lock and key] -- fits perfectly [Induced Fit] - When the enzyme changes shape in-order to bind to the substrate better.  **Activation energy:** Energy is needed for the substrate to turn into a product. By holding the substrate and changing their shape slightly, enzymes lower the energy needed [ATP] is needed for any reaction to happen (adensosine triphosate is the source of energy for use or storage at cellular level, or in easier language; provides energy) mitochondria **Temperature:** 37 degrees Celsius is the optimal temperature As temperature increases reaction rate increases Enzyme denatures (permanent) at a very high temperature [Denature] = it falls apart, it is no longer operable Enzymes slows down at low temperature Above 50 degrees = not operable A diagram of a diagram Description automatically generated **PH levels:** Optimal for every is 7 Differs for every enzyme Enzyme concentration: ⬆️Enzyme concentration ⬆️Rate of reaction - *What types of molecules are enzymes?* - *What types of reaction do enzymes catalyze?* - *What are the characteristics of enzymes?* - *How do temperature and pH affect enzyme activity?* - *How does the concentration of the substrate affect the catalyzed reaction/enzyme activity?* - *What is the "active site" and how does it work (induced-fit vs lock-and-key)* - *How do enzymes affect activation energy?* - *What are some examples of reactions catalyzed by enzymes? (You must know the name of the enzyme, the substrate and product)* - *How can enzymes be used by industry? Example Lactose.* - *Correctly explain results using correct scientific reasoning.* **Key words:** Metabolism, biochemistry, hydrolysis, condensation, intracellular enzymes, extracellular enzymes, catabolic reactions, catalysts, lock and key, induced, and lysis