!! 4.2.2.1, Digestive System Flashcards
what is an organ system
a group of organs that work together to perform a particular role
which 5 organs make up the digestive system
small intestine
large intestine
liver
glands
stomach
what does the small intestine do in the digestive system
digests food and absorbs soluble food molecules
what does soluble mean
can be dissolved
what does unsoluble mean
can’t be dissolved
what does the large intestine do in the digestive system
absorbs water molecules from remaining undigested food
this allows it to produce faeces
what does the liver do in the digestive system
produces bile
what do glands do in the digestive system
produce digestive juices
2 examples of glands in the digestive system
pancreas
salivary glands
what does the stomach do in the digestive system
digests food
what is an organism
highest level of organisation in a multicellular organism
and consists of several organ systems
what are levels of organisation in multicellular organisms, starting least complex
cell
tissue
organ
organ system
organism
what is an organ
a group of distinct tissues that group together to form a specific function
2 factors that affect rate of enzyme reactions
temperature
PH
how does temperature affect the rate of enzyme action
increasing the temperature of a working enzyme initially increases the reacting activity
enzymes have an optimum temperature, once reached their activity decreases
past a certain temperature, the active site changes shape, and the enzyme is denatured (loses its catalytic activity).
how does PH affect the rate of enzyme action
Enzymes have an optimum PH level
changes away from the optimum PH, then the enzyme activity decreases
PH is too low or too high the enzyme is denatured and will not function
does is the ‘lock and key’ theory
the active site is like a lock and the substrate is like a key
usually only one enzyme for every substrate (or one key for each lock)
what do enzymes do to reactions in the body
speeds them up
often called ‘biological catalysts’
what is the rate of reaction equal to on a graph
what does it show
the gradient
shows mass of the product, plotted against the reaction time
how is the rate of reaction calculated using a graph
(using the gradient)
picking two points on the graph
then dividing the change in mass by the change in time
what must happen in order for an enzyme to catalyse a reaction
how does this happen
the reacting chemical (substrate) must bind to the enzyme’s active site
both the substrate and the active sight are the same shape
lock and key theory
unit for rate of reaction
g/s
where are digestive enzymes made
and by who
specialised cells in the glands and the lining of the gut
what do digestive enzymes do in the body
speed up the breakdown of large, insoluble food molecules into smaller, soluble ones
that are then small enough to be absorbed into the bloodstream
how can digested molecules be used
what happens to some of the glucose produced by digestion
to construct new carbohydrates, proteins and lipids in the body
some is used for respiration
what are the three main digestive enzymes
amylase
lipids
protease
what does the digestive enzyme amylase do
breaks down starch into simple sugars, predominantly maltose
what do carbohydrases
example of a carbohydrase
break down carbohydrates into simple sugars
amylase
which three places is amylase produced
small intestine
pancreas
salivary glands
what are the two sites of action for amylase
small intestine
mouth
constituent
what does the digestive enzyme protease do
breaks down proteins into amino acids
which three places is protease produced
small intestine
pancreas
stomach
what are the two sites of action for protease
stomach
small intestine
what does the digestive enzyme lipase do
breaks down lipids into glycerol and fatty acids
is bile alkaline or acidic
bile is an alkaline substance
where is bile produced
where is bile stored
produced in the liver
stored in the gall bladder
what does bile do in the digestive system
breaks up fats into tiny droplets, through emulsification
the tiny droplets have a higher surface area than the original fat drop
the alkaline condition and larger SA increases the rate of fat breakdown by lipase
what is emulsification
process by which bile breaks up fats into tiny droplets
in which condition to enzymes in the small intestine operate
in alkaline conditions
in which condition to enzymes in the small intestine operate
in alkaline conditions
which role does bile play in the stomach
Bile neutralises hydrochloric acid from the stomach to stop enzymes in the small intestine becoming denatured
what is meant by an enzyme being denatured
it’s active site has changed shape
equation for rate of reaction
change in mass / change in time
