enzymes (biological molecules) Flashcards
learn enzymes pretty please
what is an enzyme
a biological catalyst, biological: function in living systems
catalysts: speed up the rate of chemical reactions (arent used up or permanently changed)
enzyme structure
globular proteins with complex tertiary structures, some formed from one polypeptide, others formed by two or more polypeptides (quaternary structure)
metabolic pathway
biochemical cascade of reactions, catalysed and controlled by enzymes
site of action of enzymes
intracellular- produced and function inside the cell
extracellular- secreted by cells and catalyse reactions outside cells
enzyme action
- enzymes have a specific active site where substrates bind, forming enzyme substrate complexes
- the substrate is then broken down into products and released
factors for enzyme action
- ph level
- temperature
- substrate concentration
- enzyme concentration
temperatures effect on enzymes
extreme highs= denaturation, changing the shape of the active site, preventing substrate binding
extreme lows= reduced kinetic energy, reducing chance of substrates colliding
enzyme specificity
the specific shape of the enzymes active sites mean they can only bind to a specific substrate
enzyme substrate complex
formed when an enzyme and its substrate bind together after a collision at perfect orientation and speed, bond is only formed temporarily as the enzyme breaks the substrate down into products
lock and key hypothesis
- the substrate fits perfectly into the active site as they are an exact match
- like a key to a lock
- proposed in the 1890’s
- rigid structures
induced fit hypothesis
- modified lock and key hypothesis
- suggested that the enzymes active site can change slightly as the substrate molecule enters the enzyme
- conformational changes, ensuring an ideal binding arrangement between the enzyme and substrate
