chapter 3 - organisation and digestion Flashcards
name the 5 levels of organisation
cells > tissues > organs > organ systems > organisms
what is a tissue?
a group of cells with similar structures and functions
what is an organ?
a group of tissues working together to perform a specific function
function of liver in digestion?
it produces bile, which neutralises hydrochloric acid from, the stomach and emulsifies fat to form small droplets with a large surface area
function of saliva in digestion?
lubrication to help swallowing - contains amylase to break down starch
enzymes produced in pancreas?
amylase, protease and lipase
what are enzymes?
protein molecules that catalyse specific reactions in organisms
why are enzymes described as specific?
each enzymes only catalyses a specific reaction, because the active site only fits together with certain substrates (lock and key)
function of amylase?
to break down starch into glucose
where are amylases produced?
salivary glands, pancreas, and small intestine
function of protease?
to break down proteins into amino acids
where are proteases produced?
stomach, pancreas and small intestine
function of lipase?
to break down lipids into fatty acids and glycerol
where are lipases produced?
pancreas and small intestine
factors that affect rate of activity of an enzyme?
temperature and pH
what does denatured mean?
the shape of an enzymes active site is changed by high temperatures or an extreme pH, so it can no longer bind with the substrate
effect of temperature on enzyme activity?
as temperature increases, rate of reaction increases until it reaches the optimum for enzyme activity - above this temperature enzyme activity decreases and eventually stops
effect of pH on enzyme activity?
different enzymes have a different optimum pH at which their activity is greatest - at a pH much lower or higher than this enzyme activity decreases and stops
why do different digestive enzymes have different optimum pHs?
different parts of the digestive system have very different pHs - the stomach is strongly acidic, and the pH in the small intestine is close to neutral
