Human Digestive Learning System Year 9 Flashcards
What is the human digestive system?
Organ system in which several organs work together to digest and absorb food
What are enzymes?
Large proteins made on ribosomes and biological catalysts that speed up chemical reactions in living organisms
What do enzymes catalyse?
A specific reaction due to the shape of the active site
What denatures enzymes?
High temperature and extreme pH due to changes in active site shape
What is amylase?
Enzyme made in salivary glands that breaks starch down into simple sugars
What is lipase?
Enzyme made in pancreas and small intestine that breaks down lipids into fatty acids and glycerol
What is protease?
Enzyme made in pancreas and small intestine that breaks down proteins into amino acids
How does lock and key theory describe relationship between enzyme and substrate?
The lock(the enzyme) has a specific shape that it fits precisely with, the key(the substrate)
What is the primary purpose of digestive enzymes?
To convert food into small soluble molecules that can be absorbed into the bloodstream
What is absorption?
Movement of digested food molecules through intestine wall into the blood
What is the duodenum?
Top section of small intestine where food is neutralised by adding bile
What is carbohydrase?
Enzyme that breaks down carbohydrates into simple sugars
What are the products of digestion used to do?
Make new carbohydrates, lipids and proteins, and some carbohydrates are used in respiration
What does emulsify mean?
To break large droplets into small droplets
Why does bile neutralise acid?
To provide the optimum pH for pancreatic enzymes like lipase in the small intestine
What is the test for glucose?
Grind food with pestle and mortar, place food into test tube, add 1cm of distilled water and Benedict’s solution, put test tube in 80degrees for 5 minutes, green, yellow or brick red is positive
What is the test for starch?
Put small amount of food on white tile, add iodine, blue-black is positive
What is the test for proteins?
Use pestle and mortar to grind food, add food to test tube, add 1 cm of distilled water and sodium hydroxide + biuret solution, shake, purple is positive
What is the test for lipids?
Use pestle and mortar to grind food, add food to test tube, add 2cm of ethanol, shake, transfer liquid from top of mixtures to test tube half filled with water, water turning cloudy is positive
