1 / 14

7.6 Enzymes

7.6 Enzymes. Metabolic Pathways. Metabolic pathways are specific sequences of enzyme-catalyzed reactions that often occur in chains or cycles. Glycolysis Calvin Cycle. Remember…. Anabolism – the building of larger organic molecules (condensation reactions)

lorene
Download Presentation

7.6 Enzymes

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. 7.6 Enzymes

  2. Metabolic Pathways • Metabolic pathways are specific sequences of enzyme-catalyzed reactions that often occur in chains or cycles Glycolysis Calvin Cycle

  3. Remember… Anabolism – the building of larger organic molecules (condensation reactions) Catabolism –the breakdown of organic molecules (hydrolysis reactions) All living things MUST • Grow • Reproduce • Respond to stimuli • Maintain Homeostasis • Nutrition • METABOLISM – sum of all chemical reactions inside the living organism Ex: respiration, photosynthesis, digestion

  4. Review Slide

  5. The Induced-Fit Model • The Induced-Fit Model is a more accurate portrayal of enzyme-substrate relationship • Substrate does not fit perfectly into enzyme until it binds to active site • Once it binds the active site shape chages slightly, which weakens the bonds within substrate • Weakened bonds lowers activation energy and allows reaction to happen faster/easier

  6. Activation Energy Activation Energy is the energy necessary to break bonds and/or make new bonds Enzymes lower AE by weakening the bonds in the reactants and allow reaction to take place easier/faster

  7. Competitive Inhibition • Competitive inhibition is when a molecule that is structurally similar to a substrate binds with the needed enzyme; the result is fewer reactions between the “true” substrate and enzyme; affects can be reduced by adding more substrate • Ex: malonate can block succinate from binding with dehydrogenase during Kreb’s cycle

  8. Non-Competitive Inhibition • Non-competitive inhibition is when an inhibitor binds with the enzyme but not at the active site (instead at the allosteric site), however the result can be a change in the shape of the active site • Ex: metal ions like Silver and Mercury bind to sulfur parts of R groups on amino acids which inhibits disulfide bonds and changes shape of proteins Allosteric site

  9. End-Product Inhibition • With assembly line metabolic reactions (metabolic pathways) cells have developed a way to regulate enzyme activity so resources and energy are not wasted • When end products are abundant, the metabolic pathway is shut down by inhibiting the action of the 1st enzyme • Usually, inhibition is achieved when final product binds to 1st enzyme at allosteric site • Then, when more product is needed, the 1st enzyme will be reactivated with removal of product at allosteric site

More Related