Bio - Enzymes Flashcards
What is the substrate?
A molecule upon which an enzyme acts. It can be broken down into molecules by enzymes. They are made up of amino acids.
What is are Enzymes and their properties?
Enzymes are biological catalysts that speed up the rate of reaction.
-They don’t get consumed or changed in the reaction
-They are made of proteins (chains of amino acids)
-They are involved in building and breaking down molecules, eg: Components of food
They makes sure that our cells are functioning properly.
What are the different types of reactions that enzymes act as a catalyst for?
Anabolic- the building up of molecules
Catabolic- the breaking down of molecules
Name three types of enzymes, what they break down and what they produce:
Amylase, found in Salivary Glands, are involved in the breakdown of Starch into Sugar
Protease, found in the Stomach, is involved in the breakdown of proteins into amino acids
Lipase, found in the Pancreas, is involved in the breakdown of Lipids into fatty acids and Glycerol.
What is emulsification?
The process in which Bile breaks down fat globules, in the duodenum, into smaller droplets so that they have a greater surface area for the pancreatic enzyme, Lipase, to work. Enzymes can then break the fat down easier.
Name 3 chemical reactions, around the body, that enzymes are involved in:
Digestion, eg: breaking down Proteins and fat
-Metabolic reactions, eg Respiration- which converts sugar to ATP
-DNA replication, during Mitosis
What is the active site?
The active site is the region on the enzyme where the substrate binds. It’s shape complements the substrate.
Describe how an Enzyme and Substrate work together:
An enzyme and substrate bind to form an Enzyme-Substrate complex. The enzyme then converts the substrate into a product, which is then released from the active site, so there is now the Enzyme and it’s products, formed by the substrate-breaking down large insoluble molecules for better digestion.
What does denatured mean?
The change of an enzymes structure, altering the active site and the overall effectiveness so it can no longer bind with the substrate. This may occur because of high temperatures or an extreme pH.
What are Intracellular enzymes? Name some examples of their processes
Enzymes that catalyse reactions within cells, such as:
-Respiration
-Photosynthesis
-Protein Synthesis
-Cell Division
What is an extracellular enzyme?
Produced and secreted by cells to catalyse reactions outside of cells. Eg, Digestive enzymes that are produced by specialised cells in the glands and lining of the gut. They are then secreted out of the cell into the gut, where they come into contact with food molecules.
They catalyse the breakdown of large, insoluble molecules into smaller molecules.
What is Human Body temperature?
Human Body Temperature is 37 degrees. Also the optimum temp for digestive enzymes.
Describe how our body adapts to invading pathogens.
Temperature of our body RISES to kill pathogens that have invaded as they work best at our body temperature. There is a cascade effect and an increase in our human body temperature disable our enzymes to function.
An ——– in temperature leads to an enzyme becoming ———.
This leads to the —— —- changing shape meaning that a ——— cannot be broken down.
Increase, denatured
Active site, Substrate
Describe the Lock and Key theory?
Substrate fits into enzyme’s active site. Active site shape is specific for a substrate.
What happens to the rate of reaction as the temperature increases and why?
As the temperature increases, so does the rate of reaction. This is because all of the molecules will have more kinetic energy and are moving faster, and so more likely to be successful collisions between the substrate and active site and more energy to react.
The enzyme is working at its fastest possible rate at it’s ——- ———-.
Optimum Temperature.
Explain what happens as we increase the temperature past the optimum
As we increase the temperature past the optimum, the activity of the enzyme (rate of reaction) rapidly decreases to zero. This is because high temperatures start to break the bonds holding enzymes together, the active site starts to change and if it changes shape enough, the substrate will no longer be able to fit into the active site. The bonds in an enzyme will change as the enzyme changes shape. The Enzyme has been denatured. The enzyme can no longer catalyse the reaction.
Explain what happens as we increase or decrease from the optimum pH of an enzyme.
As we increase or decrease from the optimum pH of an enzyme, some of the bonds holding the enzyme together start to break. The active site starts to change shape, but not so much so, that the substrate cant fit, only less well. So it slows down the rate of reaction but doesn’t completely stop it.
At extremely high or low pHs, the active site changes so much that the substrate can’t fit- it becomes denatured. It is reverseable until these points, due to the presence of Hydrogen and Hydroxide Ions.
