Enzymes Flashcards
(41 cards)
What’s a catalyst?
Chemical that speeds up the rate of reaction and remains unchanged and reusable at the end of the reaction
What’s extracellular?
Outside the cell
What’s intracellular?
Inside the cell
What is metabolism
The chemical reactions that take place inside living cells or organisms
What’s a product?
Molecule produced from the substrate, by an enzyme catalyses reaction
What’s a substrate?
A molecule that is altered by an enzyme catalyses reaction
What are enzymes and what do they do?
Biological catalysts that speed up metabolic reactions in living organisms
Catalysts
Number of relations an enzyme catalyses per second is turnover number
What metabolic pathways are described as catabolic?
Where metabolites are broken down to smaller molecules and release energy
What metabolic pathways are described as anabolic?
Energy is used to synthesise larger molecules from smaller ones
What’s an active site?
Indented area on the surface of an enzyme molecule, with a shape that is complementary to the shape of the substrate molecule
What’s a cofactors?
A substance that has to be present to ensure an enzyme catalyses reaction takes place at the appropriate rate
What’s an enzyme substrate complex?
Complex formed by temporary binding of enzyme and substrate molecules during an enzyme catalyses reaction
What’s a prosthetic group?
A cofactors that is permanently bound by covalent bonds to an enzyme molecule
Describe carbonic anhydride and its function
Contain a zinc ion prosthetic group permanently bound to its active site
Found in erythrocytes
Catalyses conversion of carbon dioxide and water to carbonic acid which then breaks down into protons and hydrogen carbonate ions
How do unbound cofactors work?
Temporarily bind to enzyme or substrate to ease the formation of the complex therefore increasing rate of reaction
Some act as co substrates. The substrate and ion form correct shape to bind to active site
Some change charge distribution on the surface of substrate or active site and make the temporary complex bonds easier to form
What are coenzymes?
Small organic non-protein molecules that bind temporarily to the active site of enzyme molecules. They are chemically changed during the reaction and need to be recycled
What are enzyme product and enzyme substrate complexes?
An enzyme molecule with the products in its active site. Joined by non covalent force
Same with subtract instead of product
What is Q10
Temperature coefficient
Calculated by dividing the t+10 by t
Why do enzymes denature at high temperatures?
As temperature increases the enzymes vibrate more. This can break weak bonds in the tertiary structure such as hydrogen and ionic bonds.
This will cause the active site to change shape so the substrate will not fit into it.
This is irreversible
The enzymes are denatured
What is a buffer?
Something that resists changes in pH
It can donate or accept hydrogen ions
How does pH effect enzymes?
Excess proton interfere with hydrogen bonds and ionic forces so the active site changes shape. It also alters the charges on the active site as they cluster around negatively charged group
How does pH affect rate of reaction?
Small changes reduce rate
Hydrogen bonds can reform if optimum pH is reached
Change can also be permanent if extreme pHs
What is concentration?
Number of molecules per unit volume
What’s an inhibitor?
Substance that stops or reduces a reaction
