Enzymes Flashcards
What type of reactions are anabolic reactions?
Building up.
What type of reactions are catabolic reactions?
Breaking down.
Enzymes can only increase the rate of reaction up to a certain point. What is this called?
Vmax (maximum initial velocity or rate of the enzyme-catalysed reaction)
What will happen to the molecules when high temperatures or pressures are applied to a solution?
The speed of the molecules will increase, increasing the number of successful collisions and therefore the rate of reaction.
What is the specificity of an enzyme?
Where each enzyme catalyses one specific biochemical reaction.
What is activation energy?
The energy needed for a reaction to start.
What is the lock and key hypothesis?
The idea that only a specific substrate will ‘fit’ into the active site of an enzyme.
What is an enzyme-substrate complex?
When the substrate binds to the active site.
What happens when the R-groups within the active site of an enzyme interact with the substrate?
It forms temporary bonds, which puts a strain on other bonds within the substrate and help speed the reaction up.
What is the induced fit hypothesis?
When the active site changes slightly as the substrate enters.
What are intracellular enzymes?
Enzymes that act within cells.
What are extracellular enzymes?
Enzymes that act outside of cells.
Which organisms rely on extracellular enzymes to make use of polymers for nutrition?
Both single-celled and multicellular organisms.
Name a large molecule that enzymes break down.
Protein.
Name 2 small molecules that enzymes produce.
Amino acids, glucose.
Name 2 extracellular enzymes that are involved in digestion in humans.
Amylase and trypsin.
What happens to the particles when temperature of a reaction environment is increased?
Kinetic energy of the particles increase and the particles move faster and collide more frequently.
What measures how much the rate of a reaction increases?
Temperature coefficient, Q10.
As temperature increases, the vibrations increase until the bonds strain then break. What does this cause the enzyme to do?
Denature.
What is the optimum temperature?
The temperature at which the enzyme has the highest rate of activity.
What is the optimum temperature for enzymes in the human body?
40*C.
Which enzymes have more flexible structures and are less stable?
Enzymes adapted to the cold.
Which enzymes are more stable?
Enzymes adapted to hot environments.
Why are enzymes that are adapted to hot environments more stable?
They have an increased number of hydrogen and sulphur bonds.
More hydrogen ions are present in which pH?
Low (acid).
Fewer hydrogen atoms are present in which pH?
High (alkaline).
What is the optimum pH in terms of ions?
Where a certain hydrogen ion concentration will cause the active site to be the right shape.
What is renaturation?
If the pH returns to the optimum then the protein will resume its natural shape and catalyse the reaction again.
What does the increased number of substrate particles lead to?
A higher collision rate with the active sites of enzymes and the formation of more enzyme-substrate complexes.
What happens when the concentration of the enzyme increases?
More active sites become available which leads to enzyme-substrate complexes forming at a faster rate.
Competitive inhibitor.
Binds to the active site of the enzyme, preventing the substrate from doing this.
Incompetitive inhibitor.
Binds to the allosteric site of the enzyme, which still allows the substrate to bind to the active site, but prevents any products from being produced.
