Organisation Flashcards
(56 cards)
definition of enzyme
biological catalyst that speeds up the rate of a chemical reaction without being altered or used up itself in the reaction
definition of active site
small dent on the surface of the enzyme where the substrate binds and where the chemical reaction takes place.
State what type of molecule enzymes are
Proteins
large molecule made from many amino acids joined together
State 4 factors that affect the activity of enzymes
pH
temperature
concentration of enzyme
concentration of substrate
State the two different types of chemical reaction
Catabolic
Anabolic
Definition of a catabolic reaction
chemical reaction that breaks down larger molecules into smaller molecules
Definition of an anabolic reaction
A chemical reaction that builds up smaller molecules into a larger molecules (the product)
Define the term metabolism
sum total of all chemical reactions that take place inside a cell
(includes all the catabolic and anabolic reactions)
Describe the structure of an enzyme
enzyme has a dip on its surface (called the active site)
The active site has a complementary shape to its specific substrate
Explain why enzymes are specific
Each enzyme has an active site unique to specific substrates for one chemical reaction
active site is only complementary to one substrate
Hence each enzyme can only catalyse one specific reaction
Describe the relationship between the active site and the substrate
complementary to each other
Name the model that describes how enzymes work
Lock and key theory
Explain the lock and key theory model
active site on enzyme acts as a lock
complementary substrate acts as a key that fits into the active site
chemical reaction then takes place
The substrate is converted to the product
The product is released
The enzyme remains unaltered and can carry out further identical reactions
Define the term enzyme-substrate complex
An enzyme that has it specific substrate bound to its active site
Explain the effect of low temperatures on enzyme activity
substrate and enzyme have very little kinetic energy
very few collisions between the substrate and the active site
Very few enzyme-substrate complexes form
very little product is made
enzyme is described as inactive
The rate of reaction is very low
Explain the effect of high temperatures on enzyme activity
substrate and enzyme have a high amount of kinetic energy
many collisions between the substrate and the active site
high temperature changes the shape of the enzyme
alters the shape of the active site
substrate is no longer complementary to the active site
NO enzyme-substrate complexes form
NO product is made
The enzyme is described as denatured
The rate of reaction is zero
Describe the effect the optimum temperatures on enzyme activity
both the substrate and enzyme have very high kinetic energy
many collisions between the substrate and the active site
High numbers of enzyme-substrate complexes form
lot of product is made
enzyme is described as working at its maximum rate
The rate of reaction is at its maximum
What is the typical optimum temperature for human enzymes?
37oC
Name an human enzyme that works at an optimal pH of 1-2 (acidic)
Pepsin
State 2 human enzymes that work at an optimal pH of 7 (neutral)
Amylase
Catalase
Lipase
Carbohydrases
Proteases (except trypsin)
How do you calculate the rate of reaction?
Amount of product formed divided by the time
State the 3 main groups of enzymes that are involved in digestion
Lipases
Carbohydrases
Proteases
Describe the action of a protease enzyme
break proteins down into amino acids
Describe the action of a lipase enzyme
break lipids down into 3 fatty acids and 1 glycerol
