Enzymes Flashcards
What are extracellular enzymes?
Enzymes that work outside the cell.
Give an example of an intracellular enzyme, what does it do?
Catalase. It catalyses the breakdown of hydrogen peroxide into oxygen and water.
Give two examples of extracellular enzymes?
Amylase and Trypsin
Where is amylase found and what is its function?
It is found in saliva. It catalyses the hydrolysis of starch into maltose.
Where is trypsin found and what is its function?
It is found in the small intestine produced by pancreatic cells. It catalyses the hydrolysis of peptide bonds making polypeptides into smaller ones.
What are enzymes?
They are biological catalysts that speed up metabolic reactions in a cell or organism.
What is the active site?
Part of an enzyme that substrate molecules bind to.
What is the active site’s shape based on?
The tertiary structure of that enzyme.
The active site and substrate molecules are what to eachother?
Complementary.
What is activation energy?
The energy required for a chemical reaction to start.
How do enzymes speed up reactions in the body?
They reduce the overall activation energy by the formation of the enzyme-substrate complex.
What are the two hypothesise for how enzymes work?
Lock and key hypothesis
Induced-Fit hypothesis.
Describe the lock and key hypothesis.
Only a specific substrate can enter the active site of an enzyme in the same way that a specific key fits into a lock.
Describe the induced-fit hypothesis.
The active site of an enzyme changes shape slightly as the substrate molecule enters.
What are the four factors that affect enzyme activity?
Temperature
pH
Enzyme concentration
Substrate concentration
How does an increase in temperature affect the rate of an enzymes activity?
More heat means more kinetic energy so particles move faster and collide more frequently. This increases the chance of successful interactions between substrate and active site.
How is an enzyme denatured by high temperatures?
The vibrations become too strong and cause the bonds holding the active site to break. This changes the shape of the active site, so it can no longer do its job.
What does the temperature coefficient, Q10, mean?
It shows how much the rate of reaction changes when the temperature is raised by 10 *C