Enzymes Flashcards
What is a catalyst?
a substance that increases
the rate of a chemical reaction and is not
changed by the reaction
What is an enzyme?
proteins that are involved
in all metabolic reactions, where they function as
biological catalysts
Describe why enzymes are important in all living
organisms
Enzymes operate by lowering the activation energy of the reaction by providing alternate pathway for the reaction. This saves the energy required to overcome the high activation energy levels and also increases the rates of the reactions. Without the heightened rate of reactions, the human body (or animal bodies) will not be able to carry out the chemical reactions at a fast enough rate to sustain life. It is estimated that enzymes speed up bodily reactions by about 1 million times as compared to body without enzymes.
Explain the effect of changes in temperature on
enzyme activity in terms of kinetic energy, shape
and fit, frequency of effective collisions and
denaturation
as temp increases the chance of substrate molecules and enzyme colliding also increase, so rate of reaction goes up
best temperature for an enzyme is the opnium temperature of 37 degrees (body temp) in which above temp, bonds holding enzymes together start to break so it changes shape. this then deforms the active site, so enzymes and substrate cannot fit together- enzyme has been denatured, but enzymes denature above 50 degrees
Investigate and describe the effect of changes
in temperature on enzyme activity
most of the enzymes in our body work at a temperature of 37 degrees because those are the conditions in most parts of our bodies, and our enzymes are well adapted to function inside us.
the temperature an enzyme works best at the ‘optimum temperature’ (exception is pepsin which is present in our stomach and functions best in our stomach’s acidity at pH 2)
the lower the temp, the slower the enzyme works; the higher the temp the less the enzyme works
define
denaturation
An increase in temperature beyond the optimum causes the enzyme’s active site to become denatured.
define optimum temperature
The temperature, pH or enzyme concentration that allows the enzyme to work at its best.
An enzyme that can break down starch into simple sugars.
amylase
Enzyme that breaks down proteins.
protase
Enzyme that breaks down lipids (fats and oils).
Lipase
What is a substate?
A substance on which enzymes act.
How does pH affect enzyme activity?
Deviating from the optimum pH (too high or too low) causes the enzyme’s active site to become denatured and the active site loses its important shape.
the lower the pH the less the enzyme function; the higher the pH; the less the enzyme works
It can no longer form enzyme-substrate complexes, leading to a decrease in enzyme activity.
normal pH is 7
Explain enzyme action with reference to: active
site, enzyme-substrate complex, substrate and
product
The enzyme-substrate complex is a temporary complex formed when the enzyme and substrate molecules come together at the active site. The active site of the enzyme is a small region that has a specific shape that is complementary to the shape of the substrate molecule. This specific shape allows the enzyme to recognize and bind to the substrate molecule. The binding of the enzyme and substrate forms a temporary enzyme-substrate complex, in which the enzyme catalyzes the chemical reaction that converts the substrate into product.
The substrate is the molecule that is acted upon by the enzyme. Substrates bind to the active site of the enzyme, which then catalyzes the chemical reaction to convert the substrate into product. The specific nature of the active site and its interaction with the substrate allows enzymes to catalyze specific reactions, so each enzyme is typically specific to one particular substrate or a group of closely related substrates.
The product is the molecule that is formed as a result of the reaction. After the enzyme catalyzes the reaction, the product is released from the active site and the enzyme is free to catalyze another reaction.
In summary, enzyme action involves the binding of a substrate to the active site of the enzyme, forming an enzyme-substrate complex. The enzyme catalyzes the reaction to convert the substrate into product, and the product is released from the active site. The specificity of the active site allows enzymes to catalyze specific reactions and control the rate of chemical reactions in living organisms.
Explain the specificity of enzymes in terms of the
complementary shape and fit of the active site
with the substrate
The specificity of enzymes refers to the fact that each enzyme is specific to one particular substrate or a group of closely related substrates. Enzyme specificity is due to the complementary shape and fit of the active site with the substrate.
The active site of an enzyme is a small region that has a specific shape, which is complementary to the shape of the substrate molecule. The active site contains specific amino acid residues that interact with the substrate to form an enzyme-substrate complex. These interactions are highly specific and depend on the three-dimensional shape of the substrate and the active site of the enzyme. This specificity means that enzymes can only catalyze the reaction for which they are specifically designed.
Enzyme specificity is critical to the proper functioning of biological systems. Without the specificity of enzymes, the chemical reactions that take place in living organisms would be too slow to sustain life. The specificity of enzymes allows them to catalyze specific reactions, which are often part of a larger metabolic pathway. This specificity ensures that the products of one reaction are used as substrates for the next reaction in the pathway, and helps to prevent unwanted side reactions.
In summary, the specificity of enzymes is due to the complementary shape and fit of the active site with the substrate. The specific amino acid residues in the active site interact with the substrate to form an enzyme-substrate complex, and this specificity ensures that enzymes can only catalyze the reaction for which they are specifically designed. Enzyme specificity is critical to the proper functioning of biological systems and helps to prevent unwanted side reactions.
