2.2 Animal Tissues, Organs and Systems (digestive) Flashcards
What is the main function of the digestive system?
To digest food and absorb the nutrients obtained from digestion.
What is the role of the pancreas and the salivary gland in the digestive system?
The pancreas and the salivary gland are glands which produce digestive juices containing enzymes.
What is the role of the stomach in the digestive system?
Produces hydrochloric acid - which kills any bacteria present and provides the optimum acidic pH for the protease enzyme to function.
What is the role of the small intestine in the digestive system?
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The small intestine is the site where soluble food molecules are absorbed into the bloodstream.
What is the role of the liver in the digestive system?
Produces bile (stored in the gallbladder) which emulsifies lipids and allows the lipase enzyme to work more efficiently.
What is the role of the large intestine in the digestive system?
Absorbs water from undigested food, producing faeces.
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?
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.
