organisation and digestive system Flashcards
what are organelles
things that make up cell eg nucleas
whats a tissue
a group of similar cells that work for a function
what are organs
collection of dif tissues
whats an organ system
group of organs that work together eg the digestive or reproductive system
what happens when food is first eaten
its physically broken down by chewing and saliva acts as an enzyme against carbs then it goes down the asophagos into the stomach
three main traits of stomach
produces pepsin which breaks down protien
hydrochloric acid kills bacteria
contracts muscular walls
what happens in small intestine
digestion takes place and food is absorbed into the blood
why is the small intestine adapted
pancreas pushes enzymes in to break them down
liver sends bile to gall bladder to intestine which neutralises acid and breaks down any fats
the villa largely increases the SA and is thin so there isnt much to get through
carbs general look
made up of sugars, can be simple or complex- complex can be starch, cellulose etc.
most are turned into glucose for energy
lipids general
lipids are fats and oils depending on their melting point. they are made of fatty acids and glycerol
protiens general
made up of amino acids they are the building blocks of cells and tissues. they hold speciific 3d shapes which will become denatured if lost
functions of protiens
structures of muscles and tendons
hormones
antibodies
enzymes
required prac food test starter
take food sample and grind it with some water to form a paste and then put it in water until it dissolves, then funnel out any excess so you have a solution- not with lipids
test for starch
add orange iodine and it will go black
test for sugars
add ten drops of benedict and put the tube in a half filled hot beaker. sugar will go up the rainbow from blue depending on how sugary. only works for reducing sugars
test for protien
add buriet and it will go from blue to lilac
test for lipids
no filter because itll stick. add water and ethanol and it will go white
what is an enzyme
a catalyst made by living organisms and amino acids
what is lock andkey and induced fit
originally it was believed that the active site formed by the amino acids fit perfectly into its subbstrate but now we know it can change
what is metabolism
controlled by enzymes its the sum of all the reactions
effect of temp on enzymes
if theyre above 40c then they can change the active site and it will become denatured
effect of ph on enzymes
a change in ph affects the forces that hold the chain of protien molecule so it will change, often gradually until it becomes fully denatured
enzymes have dif optimal ph
what are digestive enzymes
made in glands and in the system and they speed up the breakdown of foods
what and where breaks down carbs
amalyse/carbohydrase breaks it down from the pancreas and saliva into simple sugars
what and where breaks down protiens
protease are made in the small intestine and the stomach and pancreas and make amino acids
what and where breaks down lipids
lipases from pancreas and small intestine make fatty acids and glycerol- absorbed into blood to needed places from the small intestine
explain required practical amalayse
so you have like apaint palette and you put adrop of orange iodine in each hole and then you fill up three test tubes with 2cm each of amayse starch and a ph buffer. put them in a warm water bath for 30s to soak and then mix the mixture. start timer, every 30sadd a drop to one of the iodines in the pallette and after time it should stop going black because starch has fully reacted. repeat this with other ph bffers
problems with the ph amalayse experiemtn
because its every 30s the time the reaction ended isnt obvious and also its hard to always see when its not blue black so you may need several opinions
what is the ph of stomach and why
the protease enzyme pepsin works best at acidic ph so the stomach produces hydrochloric acid to maintain that. the stomach is also coated in mucus so the acid doesnt attack the walls
how is the ph changed in the small intestine
when the acidic stuff comes from the stomach bile comes from the gall bladder and neutralises the acid
what does bile do for fat
bile physically breaks it up so the SA is larger to break down
things enzymes speed up
breaking down of molecules
changing molecules into dif ones
building large molecules from smaller ones- making starch or glyogen from glucose, co2 and water to make glucose etc
whats the dif between polymers and monomers in biological molecules
lipids are not made of polymers, they are just fatty acids bonded to a glycerol, whilst protien is made of achain of monomer amino acids and carbohydrate polymers like glycerol come from a chain of simple sugars
jobs of dif enzzymes to catalyse
- building large molecules eg starch or glycogen from glucose
- changing molecules into one another
- breaking large molecules into small ones eg amino into urea
