organisation (T2) Flashcards
what is a cell?
basic building block of a living organism
what is a tissue?
a group of cells with a similar structure and function working together
what is an organ?
a group of tissues working together to perform a particular function
what is an organ system?
a group of organs working together to perform specific functions
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 digestion?
the pancreas and salivary gland are glands which produce digestive juices containing enzymes
what is the role of the stomach in digestion?
produces HCl which kills any bacteria present and provides the optimum pH for protease to function
what is the role of the small intestine in digestion?
the small intestine is the site where soluble food molecules are absorbed into the blood
what is the role of the liver in digestion?
produces bile (stored in the gallbladder) which emulsifies fat and allows the lipase enzyme to work more efficiently on a larger surface area
what is the role of the large intestine in digestion?
absorbs water from undigested food forming faeces
what is the role of enzymes in the digestive system?
enzymes act as biological catalysts, proteins which speed up the rate of biological reactions 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 reaction in a cell or an organism
what type of metabolic reactions do enzymes catalyse?
- Building larger molecules from smaller molecules (glucose -> starch)
- changing one molecule to another (glucose-> fructose)
- breaking down larger molecules to smaller molecules (carbohydrates-> glucose)
what is the lock and key hypothesis of enzyme function?
the shape of an enzyme active site and substrate are complementary so can bind together to form an enzyme-substrate complex
how does temperature affect rate of reaction?
Up to a certain point, increasing temperature increases the rate of reaction as molecules have higher kinetic energy so collisions are more frequent. after the optimum temperature, the enzyme becomes denatured because the active site has changed shape so the substrate no longer fits and so the enzyme cannot catalyse the reaction
how does pH affect rate of reaction?
the optimum pH for most enzymes is 7 (apart from protease), if the pH is too high above or below the optimum pH, the enzyme denatures as the active site has changed shape so the substrate no longer fits.
where is amylase, protease and lipase produced in the body?
- amylase: salivary gland, pancreas, small intestine
- protease: stomach, pancreas and small intestine
- lipase: pancreas and small intestine
what is the role of amylase in the digestive system?
break down carbohydrates into simple sugars e.g. glucose
what is the role of protease in the digestive system?
break down proteins into amino acids
what is the role of lipase in the digestive system?
break down lipids into fatty acids and glycerol
how are the products of digestion used?
- simple sugars to build new carbohydrates
- some of the glucose is used in respiration
- amino acids to build new proteins
- fatty acids and glycerol to build new lipids
where is bile made and stored in the body?
bile is made in the liver and stored in the gallbladder
what is the role of bile in digestive system?
- bile is an alkaline substance which neutralises the hydrochloric acid secreted by the stomach
- bile emulsifies lipids to form droplets - this increases the surface area for the lipase enzyme to work on
what is the heart?
the organ that pumps blood around the body
what is the purpose of the circulatory system?
carries oxygen and useful substances to bodily tissues, and the remove waste substances