• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month
  1. 1
  2. 2
  3. 3
  4. 4
  5. 5
  6. 6
  7. 7
  8. 8
  9. 9
  10. 10
  11. 11
  12. 12
  13. 13
  14. 14
  15. 15
  16. 16

The effect of enzyme concentration on the rate of reaction.

Extracts from this document...


THE EFFECT OF ENZYME CONCENTRATION ON THE RATE OF REACTION Maria Mulvany Ashlawn School Candidate number: 8160 THE EFFECT OF ENZYME CONCENTRATION ON THE RATE OF REACTION Aim: To find out how the concentration of enzyme effects changes in the rate of reaction BACKGROUND INFORMATION ON ENZYMES Enzymes are globular proteins, coiled into a precise three-dimensional shape. They are biological catalysts, speeding up chemical reactions without being affected or used up. Enzymes speed up reactions where molecules are split or joined together. The molecule, or molecules in the reaction bind to a special feature on the enzyme called the active site. The enzyme is folded in such a way that the catalytic amino acids are positioned in a region forming the active site. it is usually a depression or groove on the surface of the enzyme The active site has a complimentary shape to that of the substrate, allowing a perfect fit. This is describing the lock and key theory, where the enzyme is the lock and the substrate is the key.(see figure A). This theory has been modified to the induced fit hypothesis. This states that when the enzyme and the substrate bind, it induces the enzyme structure to fit. (see figure B). A Enzyme and Substrate Enzyme-substrate complex Enzyme and released products B Shape changes as enzyme and substrate bind Reaction proceeds as they bind Original shape returns as products are released In the particular example shown in the diagram, the substrate is split into two products. ...read more.


or the ferric (Fe+++) oxidation state. Other enzymes also have variable effects on reactions dependent on the concentration. For example, carbonic anhydrase and maltase. CARBONIC ANHYDRASE Carbonic anhydrases are enzymes that catalyse the hydration of carbon dioxide and the dehydration of bicarbonate in the human body. CO2 + H2O <-----> HCO3- + H+ Carbonic anhydrase isozymes are metalloenzymes consisting of a single polypeptide chain complexed to an atom of zinc. They are incredibly active catalysts, with a turnover rate (kcat) of about 106 reactions per second.3 These carbonic anhydrase-driven reactions are of great importance in a number of tissues where the concentration of the enzyme will affect the rate of reaction. Examples include: Parietal cells in the stomach secrete massive amounts of acid (i.e. hydrogen ions or protons) into the lumen and a corresponding amount of bicarbonate ion into blood. Pancreatic duct cells do essentially the opposite, with bicarbonate as their main secretory product. Secretion of hydrogen ions by the renal tubules is a critical mechanism for maintaining acid-base and fluid balance. Carbon dioxide generated by metabolism in all cells is removed from the body by red blood cells that convert most of it to bicarbonate for transport, then back to carbon dioxide to be exhaled from the lungs. MALTASE Maltase is a glycosidase. It catalyses the hydrolysis of glycoside bonds. The action of maltase on maltose is usually written as:4 maltase Maltose Glucose Increasing the concentration of maltase will affect the rate of production of glucose. ...read more.


clamp B * Attach test tube to clamp A * Put on goggles [**REPEAT EXPERIMENT FROM HERE] * Measure 20 cm3 of Hydrogen peroxide in a measuring cylinder into the test tube * Place the bung and deliver tube into test tube to minimise the evaporation of the hydrogen peroxide * Feed the delivery tube into the inverted measuring cylinder * Place stopwatch in front of clamp A, ready for use * Lift the bung off the test tube and drop the potato with the smallest surface area into the test tube * Push the bung down and start the stopwatch at the same time * Time for three minutes so that a measurable amount of oxygen is produced * Take out delivery tube from the measuring cylinder * Record the volume of oxygen collected/volume of water displaced in the results table and fill in the surface area of the potato, volume of hydrogen peroxide and time period * Take the off the bung from the test tube and detach the test tube from the clamp and place in the test tube rack * Take a clean test tube and attach to clamp A * Tip away the hydrogen peroxide and dispose of potato cubes * Repeat experiment from **asterisked point above. Follow the same method, using a different set of potato cubes with increased surface area. * Repeat the whole method to get a second set of results and record in the repeat column on the same results table. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Life Processes & Cells section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related GCSE Life Processes & Cells essays

  1. Marked by a teacher

    Plan: The effect of the end product, phosphate, on the enzyme phosphatase

    5 star(s)

    * Amount of enzyme solution The reason is the same as above. So each test tube must contain exact 1cm3 enzyme solution by using the accurate 1 cm3 syringes with the accuracy to the nearest 0.1cm3 * The temperature for enzyme activation The temperature will affect the activity of enzyme

  2. Marked by a teacher

    Investigating the effects of surface area on the rate of enzyme reactions.

    4 star(s)

    The size of the pieces doesn't matter because the surface area of the potato will remain the same no matter how long each of the 5 pieces are.

  1. Marked by a teacher

    The aim of this investigation is to find out what effect pH has on ...

    4 star(s)

    with Hydrogen peroxide * If swallowed: wash out mouth and give a glass or two of water. Seek medical attention as soon as possible * If liquid gets in eyes: flood the eyes with gently running tap water for 10 mins.

  2. Investagating the Action of the Enzyme Catalase On the Surface Area of a Potato.

    The molecule of the substrate hydrogen peroxide has to fit in to the contours of a region in the catalase enzyme molecule called the active site. The shape of the catalase enzyme and the active site of the enzyme catalase let the molecule of the substrate fit in and lock as a key.

  1. What influence does pH have on the enzyme Catalase?

    This shows that the optimum pH, where catalase breaks down hydrogen peroxide most effectively, is approximately around pH 8. However, the rate of reaction begins to slow down and effectively flattens out between pH 7 and 8. In fact with potatoes 1, 7 and 8 the results for pH 8 were lower than the results for pH 7.

  2. Investigating the influence of pH on the activity of potato catalase

    at pH5, resulted in a bubble count of 80 during a three minute interval, which was unusually high for the trend of results gained. Another anomaly was in the experiment at pH8 where a very low count of 125 bubbles was recorded.

  1. Investigating the Effect of Substrate Concentration on Catalase

    To get sufficient data to plot on the initial rate of reaction graph, the concentrations will increase in 0.5% so there will be six concentrations to test in total. The pH used, as informed by the preliminary experiment will be pH7 as this is the optimum pH and so will produce the best set of results.

  2. My hypothesis is that the higher the concentration of hydrogen peroxide the more catalase ...

    Then I filled a 50ml measuring cylinder with some water and turned it over inside the bowl of water. One end of the delivery tube was fed into the measuring cylinder and the clamp kept it from falling. The other end was fitted to a bung which would fit into the test tube.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work