1.4 Enzymes Flashcards
(26 cards)
What is the term for the specific region on an enzyme where substrate molecules bind?
Active site
True or False: Enzymes can catalyze reactions with any substrate.
False
Fill in the blank: The model that describes how an enzyme and substrate fit together is called the __________ model.
lock and key
What is enzyme specificity?
Enzyme specificity refers to the ability of an enzyme to select and catalyze a particular substrate or group of substrates.
True or False: Enzymes can catalyze multiple reactions with different substrates.
False
Fill in the blank: Enzymes that act on a specific type of bond or functional group are known as __________ enzymes.
group-specific
Which of the following best describes the lock and key model of enzyme specificity? A) Enzymes can adapt to substrates, B) Enzymes have a specific shape that fits precisely with a substrate, C) Enzymes can work with any substrate.
B) Enzymes have a specific shape that fits precisely with a substrate.
What term describes the unique region of an enzyme where substrate binding occurs?
Active site
What is metabolism?
the biochemical reactions carried out by a living organism
What do enzymes do to reaction rates and activation energy?
Enzymes increase reaction rates by lowering activation energy. They are specific for their substrate.
what are metabolic pathways?
Metabolic pathways can be described as a series of chemical reactions that start with a substrate and finish with an end product.
What factors affect the rate of an enzyme-controlled reaction?
The rate of an enzyme-controlled reaction is affected by:
The concentration of reactants (substrates)
The concentration of the enzyme
what factors influence enzyme activity?
Temperature
pH
presence of inhibitors
are enzymes used up in the reactions they catalyse?
No
what is activation energy?
All reactant molecules require energy for their bonds to break and the energy needed to do this is known as activation energy. The lower the activation energy is, the more quickly a reaction occurs because less energy is needed to break reactant bonds to initiate the reaction.
why is enzyme activity low at low temperatures?
This is because there a fewer substrates colliding with the enzyme’s active site as they do not have enough energy to overcome the activation energy barrie
As temperature increases, the enzyme activity also increases. WHY?
This is because, according to the kinetic model for matter, enzyme and substrate molecules will move more and more rapidly, resulting in more collisions at the active site and, therefore, a greater rate of reaction.
what is the maximum enzyme activity?
Enzyme activity reaches a maximum at the optimum temperature.
How do enzymes increase reaction rates?
Enzymes increase reaction rates by lowering the activation energy required for the reaction to occur.
Why are enzymes specific for their substrate?
Enzymes are specific for their substrate because their active sites are shaped to bind only specific molecules, ensuring that only certain reactions are catalyzed.
What is the induced-fit model of enzyme-substrate binding?
The induced-fit model suggests that when a substrate binds to an enzyme’s active site, the enzyme changes shape slightly to better fit the substrate, improving the binding and the catalytic process.
How does pH affect enzyme function?
pH affects enzyme function by influencing the charge and shape of the enzyme and substrate. Extreme pH levels can denature enzymes or alter their ability to bind to substrates.
How does temperature affect enzyme function?
Temperature affects enzyme function by influencing the kinetic energy of molecules. At higher temperatures, enzyme activity increases, but if the temperature is too high, the enzyme may denature and lose its function.
How do inhibitors affect enzyme function?
Inhibitors can reduce or stop enzyme activity by binding to the enzyme’s active site (competitive inhibitors) or by binding elsewhere on the enzyme, changing its shape (non-competitive inhibitors).
