Enzymes 2.0 Flashcards
What is an enzyme?
A biological catalyst made from protein used to alter the rate of chemical reactions, without being used up themselves.
What is the shape of a protein that functions as an enzyme?
3D globular
What cell organelle are enzymes produced in?
Ribosomes
What is the first step of the induced fit theory?
An enzyme has a specific active site shape. This means that the active site of an enzyme will only act on one substrate.
What is the second step of the induced fit theory?
When the substrate enters the active site of its correct enzyme, the active site changes shape slightly to ensure that the substrate fits. This is the ‘induced fit’. The substrate and enzyme are now connected; this is called an enzyme-substrate complex.
What is the third step of the induced fit theory?
The enzyme will now change the substrate and release the newly formed product. The active site remains unchanged and can now carry out the same process again.
What is the specificity of an enzyme?
The active site of an enzyme will only work on one specific substrate.
What is a substrate?
A substance an enzyme acts upon.
What is a product in enzymatic reactions?
The substance formed by the action of an enzyme on a substrate.
What is the active site of an enzyme?
The area of an enzyme that binds to the substrate to form an enzyme-substrate complex; it is a specific shape.
What are catabolic enzymes?
An enzyme that breaks down large molecules into smaller molecules.
Give an example of a catabolic enzyme.
Amylase
It breaks starch into smaller substances called maltose.
What are anabolic enzymes?
An enzyme that helps to join small molecules together to form larger ones.
Give an example of an anabolic enzyme.
DNA polymerase
It helps join amino acids into protein during protein synthesis.
What are inhibitors?
Something that disrupts the specificity of an enzyme’s shape or blocks the enzyme’s active site.
What are beneficial inhibitors?
Drugs and antibiotics that can affect enzymes involved in pain or bacteria, causing pain to stop or bacteria to die.
What are denatured enzymes?
An enzyme that has lost its function as a result of an active site changing shape. The change is permanent and irreversible.
What factors impact an enzyme’s activity?
Temperature & pH
What is the optimum condition for an enzyme?
The condition an enzyme works best at.
What is the optimum temperature of a plant enzyme?
25 degrees
What is the optimum temperature of an animal enzyme?
37 degrees
What happens if the temperature falls below the optimum?
They do not collide with the substrate, therefore the rate of enzyme activity is slow.
What happens when the temperature starts to return to the optimum?
It will start to work again.
What happens if the temperature is too high above the optimum?
The enzyme will become denatured; it will no longer work as the active site will change shape.
What happens if you return a denatured enzyme to its optimum temperature?
It will not make any difference as it’s denatured already and this enzyme cannot be used again.
What is the optimum ph of amylase?
7/8
What is the optimum ph of lipase?
7/8
What is the optimum ph of pepsin?
2
What is the optimum ph of catalase?
9
What happens if the pH goes too far above or below optimum?
The enzyme becomes denatured, no enzyme-substrate complex can be formed due to the active site being changed, resulting in no enzyme activity.
What are immobilised enzymes?
Enzymes that have been attached to each other or an inert substance.
What are the advantages of immobilised enzymes?
Reusable, cost-effective, produce purer product.
What is bioprocessing?
The use of enzyme-controlled reactions to produce a product.
What are some substances made by bioprocessing?
Cheese, vaccines, antibiotics.
What is a bioreactor?
The vessel in which bioprocessing takes place.
Give a chemical example of bioprocessing.
Lactase
Lactose ———–> Galactose
Which type of biomolecule are enzymes?
Protein
What are harmful inhibitors?
Inhibitors that can result in human death.
What is the method of investigating the effect of pH?
Chop celery & place it into a graduated cylinder with washing up liquid & pH buffer 1, in a water bath @ 25 degrees. Add hydrogen peroxide to a test tube & place the graduated cylinder & the test tube into a water bath @ 25 degrees. After 10 mins, add the hydrogen peroxide to the graduated cylinder. Record the volume of foam produced per min. Repeat steps 1-4 with buffers 4, 9 & 13.
Why is washing up liquid used?
To produce the foam from the products, H2O & O2.
Why is a water bath at 25 degrees used?
To maintain the constant optimum temperature at 25 degrees.
What is the source of the enzyme? Ph experiment
Celery.
What is the enzyme involved? Ph experiments
Catalase.
What is the substrate? (Ph experiment)
Hydrogen peroxide.
What are the products of the reaction?
Water & oxygen.
How was the pH kept constant?
Using a pH buffer.
How is enzyme rate measured?
Measure the volume of foam produced after 5 minutes.
Why does pH affect enzyme activity?
As the active site has changed shape.
What is the control in this experiment?
Temperature, via water-bath at 25 degrees.
Why would changing the pH affect enzyme activity?
If pH is too far above or below the optimum, the enzyme will be denatured, and as a result, no enzyme activity occurs.
What is the optimum pH?
9.
What factor was varied in the experiment?
Different pH buffers used.
How do you know if the enzyme was denatured?
No enzyme activity.
What is the method to prepare an immobilised enzyme?
- Dissolve sodium alginate in water until a paste is formed. 2. Add yeast to water & stir. 3. Add yeast to the sodium alginate & form a gel. 4. Add calcium chloride to water in a beaker & stir. 5. Using a syringe, draw up some of the yeast/alginate mixture. 6. Drop by drop, add the yeast/alginate mixture into the calcium chloride to form beads. 7. Allow the beads to harden for around 10 min & strain them using a thin wire sieve. 8. Rinse the beads in water using another sieve at least 3 times.
What is the method of application for immobilised enzymes?
- Set up 2 retort stands with separating funnels & add the immobilized beads into one of them. 2. Add a solution of yeast & water to the other separating funnel. 3. Ensure the tap is closed & add in a sucrose (table sugar solution). 4. Open the tap & allow the liquid to flow into the beaker. 5. While the liquid is coming out, use a diastix at least 5 times over a 2 min period & record how long it takes each liquid to produce a colour change. 6. Record the colour of the solution that comes into the beaker.
What is sodium alginate?
Sodium alginate is the substrate used to immobilise the enzyme.
What is the source of the enzyme used?
The source of the enzyme is yeast.
What is the role of calcium chloride in the immobilisation process?
Calcium chloride is one of the substances used to immobilise the enzyme & causes beads to harden.
Why rinse the beads after preparation?
To remove free yeast from the outside of the beads.
What is a diastix used for?
Diastix is used to test for glucose.
What is the appearance of the product when using free yeast?
The appearance of the product is brown.
What is the appearance of the product when using immobilised enzyme?
The appearance of the product is clear / colourless.
What are the advantages of immobilised enzymes?
- Reusable. 2. Purer product.
What enzyme is used in this process? Application of immobilization
The enzyme used is sucrase.
What is the substrate in this process? Application of immobilization
The substrate is sucrose.
What is the product of the reaction? Application of immobilization
The product is glucose.
Why do you always pour the yeast into the alginate and not the other way around?
Because the yeast is a liquid & is easy to pour, but the alginate is a paste.
Why are gloves used during the process?
To protect hands from calcium chloride.
What gel is used in the immobilisation process?
The gel used is sodium alginate.
What substance is used to make the gel insoluble?
The substance used to make the gel insoluble is calcium chloride.
Which is quicker, free yeast or immobilised yeast?
Free yeast is quicker.
Which solution is colourless, free yeast or immobilised yeast?
Immobilised yeast is colourless, as yeast is immobilised so no yeast can fall into the beaker.
What compound are the immobilised beads formed in?
The compound that immobilised beads are formed in is sodium alginate.
Why was the immobilised yeast beaker clear?
Because it only contained the product glucose.
