Flashcards
Enzyme Action
Flashcards do conjunto (13)
- 1What are enzymes and active siteThey are biological catalysts, and are polypeptides. Its active site is dependent on its tertiary structure as this is specific to each substrate
- 2Intracellular enzymesIn a cell at anytime they could be 1000's of reactions going on at a time catalysed by different enzymes. Catalase is an example containing four polypeptide chains with an iron haem group. It is the fastest acting enzyme and quickly breaks down hydrogen peroxide into water and oxygen. Its optimum pH is 7 and temperature 45
- 3Extracellular enzymesEnzymes such as fungi are found outside the cell and in humans may be used for digestion. Amylase is produces in the salivary glands and breaks down start to maltose. Trypsin is made in the pancreas and in the small intestine breaks down proteins into smaller peptides by hydrolysing hydrogen bonds with an optimum pH of 7.5-8.5
- 4Lock and key hypothesisThis works on the idea substrates are specific to the ESC (enzyme-substrate complex) which are held there by temporary hydrogen bonds, this the same for joining molecules
- 5What are co-factorsThey are substances permanently bound to enzyme molecules by covalent bonds and are also called prosthetic groups
- 6Carbonic anhydraseThis enzyme has a zinc ion prosthetic group, it is found in red blood cells. It helps the interconversion or C02 and H20 to carbonic acid, which then breaks down to form protons and hydrocarbonate ions
- 7Other cofactorsIons may be present with eznymes, for example they may bind with a substrate to form the necessary shape.
They may also change the surface area of form temporary bonds with the ESC to make it easier to form
Amylase needs the presence of Cl- - 8CoenzymesSmall organic non-protein molecules which bind with the ESC during the reaction, they are chemically changed and must be recycled
- 9VitaminsMany co-enzymes are derived from vitamins which are essential
B12- derives cobalamin lack of causes pernicious aneamia
Folic acid - tetrahydrofolate lack of causes megablastic aneamia
B3 - NAD and NADP - 10Induced fit-hypothesisThis states that when a molecule enters the active site it molds around the substrate to form an ESC, held by temporary forces which then detaches and is shown as
enzyme and substrate - enzyme substrate complex - enzyme product complex - enzyme and product - 11How do enzymes lower activation energyThey do this by bringing substrates together which means there is no need for excess heat and pressure which therefore lowers the activation energy
- 12Why is induced fit hypothesis accepted over lock and keyLock and key hypothesis does not explain how the ESC is stabilised
- 13Why are most enzymes solubleThey are globular proteins mainly
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- A-Level A Level Biology (Module 2.4) FlashCards sobre Enzyme Action, criado por Reuben Veysey-Smith em 05-01-2016.
- Criado por
- Reuben Veysey-Smith
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