4.2.2.1 The human digestive system Flashcards
(22 cards)
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
they are both glands which produce digestive juices contaning 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 enzymes to function
what is the role of the small intestine in the digestive system
where soluble food molecules are absorbed into the bloodstream
what is the role of the liver in the digestive system
produces bile which is stored in the gall bladder which emulsifies lipids and allows the lipase enzyme to work more efficently
what is the role of the large intestine in the digestive system
absorb water from undigested food
where are carbohydrases,proteases and lipases produced in the body
carbohydrases-amylase-salivary glands and small intestine
protease-pepsin-stomach-others pancreas and small intestine
lipase-pancrease and small intestine
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 an glycerol
where is bile made and stored in the body
bile is made by the liver and stored in the gall bladder
what is the role of bile in the digestive system
bile is an alkaine substance which neutralises the hydrochloric acid secreted by the stomach
4 adaptations of the small intestine
intestine-very long so more time for products to be absorbed
intestine is lined with microvilli which increases surface area so more absorption
lining is one cell thin so shorter diffusion pathway
good blood supply so it maintains a concentration gradient
what is the role of enzymes in the digestive system
enzymes act as biological catalysts which speed up the rate of reactions
how does the shape of an enzyme affect its function
enzymes have a specific active site which is complementary to their substrate
what is the lock and key hypothesis of an enzyme function
the shape of the enzymes active site and the substrate are complementary so can bind together to form an enzyme substrate complex
what two factors affect an enzymes activity?
temperature and pH
how does temperature affect enzyme action
Low temperatures slow down enzyme activity because molecules have less kinetic energy, leading to fewer collisions between the enzyme and its substrate.
As the temperature increases, the rate of reaction speeds up due to more collisions.
describe how you would prepare a sample of food to be tested on
grind up food samples using pestle and mortar
mix with water
filter with funnel and filter paper
What does carbohydrase break down
Carbohydrases break down carbohydrates to simple sugars.
What does protease break down
Proteases break down proteins to amino acids.
What does lipase break down
Lipases break down lipids (fats) to glycerol and fatty acids.
