enzymes Flashcards
What is the role of enzymes in the digestive system?
Enzymes act as biological catalysts which speed up the rate of biological reactions (the breakdown of food) without being used up.
How does the shape of an enzyme affect its function?
Enzymes have a specific active site which is complementary to their substrate.
What is metabolism?
The sum of all the reactions in an organism
What types of metabolic reactions do enzymes catalyse?
● Building larger molecules from smaller molecules eg.
glucose to starch.
● Changing one molecule to another eg. glucose to
fructose.
● Breaking down larger molecules into smaller
molecules eg. carbohydrates to glucose.
What is the lock and key hypothesis of enzyme function?
The shape of the enzyme active site and the substrate are complementary, so can bind together to form an enzyme-substrate complex.
How does temperature affect enzyme action?
Up to a certain point, increasing temperature increases
enzyme action, as molecules have a higher kinetic
energy. Above a certain temperature, the shape of the
active site is altered and the enzyme becomes
denatured, so it can no longer catalyse the reaction. The
optimum temperature is around 37°.
How does pH affect enzyme function?
The optimum pH for most enzymes is 7 (apart
from proteases in the stomach). If the pH is too
extreme, the shape of the active site may be
altered and the enzyme may no longer work.
Where are carbohydrases, proteases and lipases produced in the body?
● Carbohydrases: amylase - salivary gland and pancreas; maltase - small intestine.
● Proteases: pepsin - stomach; others - pancreas and small intestine.
● Lipases: pancreas and small intestine.
What is the role of carbohydrases in the digestive system?
Carbohydrases break down carbohydrates into
monosaccharides and disaccharides. Amylase
breaks down starch into maltose, and maltase
breaks down maltose into glucose.
What is the role of proteases in the digestive system?
Proteases break down proteins into amino acids
What is the role of lipases in the digestive system?
Lipases break down lipids into fatty acids and glycerol.
How are the products of digestion used?
They are used to build bigger molecules such as carbohydrates and proteins.
Glucose is used as a substrate in
respiration.
where are proteases found?
stomach
pancreas
small intestine
where is amylase found? (a type of carbohydrase)
- saliva
- pancreatic fluid
where is lipase found?
- pancreatic fluid
- small intestine
