B2 - Organisation Flashcards
what does the human digestive system provide the body with
nutrients
what does the respiatory system do
provides the body w oxygen and removes carbon dioxide
what are cells
the basic building blocks of all living organisms
what is a tissue
a group of cells with similar structure and function
what are organs
aggregations of tissues performing specific functions
why do enzymes only catalyse specific reactions
due to the shape of their active site
what is the lock and key theory
that the enzyme has a unique active site that fits onto the substrate involved in a reaction
why might the enzyme not work anymore if the temp increases too much
as it may break some of the bonds holding that enzyme together, changing the shape of the active site so the substrate doesnt fit anymore. this means its denatured
what are 2 things which can make an enzyme denatured
pH
temp
where is amylase made
salivary glands
pancreas
small intestine
where is protease made
stomach
pancreas
small intestine
where is lipase made
pancreas
small intestine
what do digestive enzymes convert food into
small soluble molecules which can be absorbed into the bloodstream
what do carbohydrases
break down carbohydrase into simple sugars
what does amylase do
break down starch
what do proteases do
break down protiens into amino acids
what do lipases do
break down lipids to glycerol and fatty acids
where is bile made
in the liver
where is bile stored
the gall bladder
why is bile alkaline
to neutralise hydrochloric acid from the stomach
what does bile do
neutralises hydrochloric acid from the stomach
emulsifies fat to form small droplets to increase the surface area
how do we make a food sample
1 - use a pestle and mortar to break up food
2 - transfer this to a beaker and add distillied water
3 - stir w glass rod to dissolve some of the food
4 - filter using a funnel and filter paper to get rid of the solid bits of food
what is the benedicts test used for
to test for sugars
what is the iodine test used for
test for starch
what is the biuret test used for
to test for proteins
what is the sudan iii test used for
to test for lipids
how do we carry out the benedicts test
1 - transfer 5cm3 of food sample to a test tube
2 - prepare a water bath at 75 degrees
3 - add 10 drops of benedicts solution using a test tube using a pipette and pipette filler
4 - place the test tube in the water bath using a test tube holder, leaving it for 5 mins
5 - if the colour changes from blue to green, yellow or brick red then sugars are present
how do we carry out the iodine test
1 - transfer 5cm3 of food sample to a test tube
2 - add a few drops of iodine solution
3 - gently shake
4 - if the colour changes from orange to black or blue-black then there is starch
how do we carry out the sudan iii test
1 - transfer 5cm3 of food sample to a test tube
2 - use a pipette to add 3 drops of sudan iii stain solution and gently shake
3 - if lipids present, there will be two layers and the top layer will be bright red
how do we carry out the biruet test
1 - transfer 2cm3 of food sample to a test tube
2 - add 2cm3 of biuret solution to the sample and shake
3 - if there is starch, the solution will change from blue to purple
