2.3 - How does CF affect other body systems? Flashcards
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What are biological catalysts?
protein molecules which speed up chemical reactions in living organisms (enzymes are biological catalysts)
What is activation energy?
before a chemical reaction can take place bonds must be broken which requires energy. The activation energy is normally provided by heating the substances involved in the reaction. Enzymes reduce the activation energy for a reaction, so reactions in living organisms can take place at relatively low temperatures
What is an active site?
the part of the enzyme molecules into which a substrate molecule fits during a chemical reaction.
What is an enzyme substrate complex?
in a chemical reaction controlled by an enzyme, one or more substrate molecules fits into the active site of the enzyme to form an enzyme substrate complex
What is a product?
product molecules are produced in enzyme controlled reactions and released while the enzymes is unchanged
What is the lock and key theory?
each enzymes will catalyse only one specific reaction or type of reaction because only a specific shaped substrate is able to fit into its precisely shaped active site
What is the induced fit theory?
when the substrate enters the active site the enzymes molecule changes shape sitting more closely around the active site
What are enzymes?
- Enzymes are globular proteins which act as biological catalysts.
- Enzymes are a complex tertiary and sometimes quaternary shape and catalyse reactions by forming a complex (known as the enzyme substrate complex) at a specific region of the enzyme called the active site.
- Enzyme + substrate -> enzyme substrate complex -> product
What is the process of the induced fit hypothesis?
- Substrate approaches the active site of the enzyme.
- The shape of the active site then changes to fit precisely around the
substrate – in other words, the substrate induces the active site to
change shape. - The reaction is catalysed and products form.
- The products are a different shape from the substrate and therefore
diffuse away from the active site. As they do, the active site reverts to
its original shape.
How does temperature affect enzyme activity?
enzymes have an optimum temperature, temperature increases the kinetic energy of the system, effectively increasing the number of collisions between the substrate and the enzyme’s active site, temperatures above optimum can lead to denaturation
How does pH affect enzyme activity?
each enzyme has an optimum pH, if pH increases or decreases much beyond this optimum, the ionisation of groups at the active site and on the substrate may change.
At extreme pH the bonds and active site are disrupted and the enzyme denatures.
How does enzyme concentration affect enzyme activity?
at low enzyme concentrations there are more substrate molecules than there are available active sites. Increasing the number of active sites by increasing the concentration of the enzyme increases the rate of the reaction
How does substrate concentration affect enzyme activity?
At low substrate concentration the reaction proceeds slowly. This is because there are not enough substrate molecules to occupy all of the active sites on the enzyme. As substrate concentration increases, the rate increases because there are more enzyme substrate complexes formed.
How do cofactors affect enzyme activity?
Many enzymes require cofactors to function properly. There are three
main types of cofactor; co-enzymes, inorganic ions and prosthetic groups.
What are inhibitors?
- Inhibitors slow down the rate of reaction
- two types of reversible inhibitors: competitive and non-competitive
