Organisation Flashcards
what is a tissue
a group of cells with a similar structure and function
what are the adaptations of muscle cells
they contain protein fibers that can change their length and have lots of mitochondria which provide the energy for contraction
what is the purpose of digestion
to break down large molecules into smaller ones to be absorbed by into the bloodstream
what is the function of the mouth
to produce saliva which contains amylase to break down carbohydrates and food is chewed to break it down
what is the function of the stomach
the stomach is where the digestion of proteins begins. The stomach contains hydrochloric acid to help the digestion of the proteins. The churning action of the stomach turns the food into a fluid increasing the surface area
what is the function of the small intestine
chemicals are released from the liver and pancreas. the pancreas releases enzymes that digest starch and proteins and start the digestion of lipids. The liver releases bile which helps to speed up the digestion of lipids and also neutralises the hydrochloric acid in the stomach. It absorbs digested molecules into the bloodstream by active transport or diffusion
what is the purpose of an enzyme
enzymes catalyse chemical reaction
what is the purpose of an enzyme
enzymes catalyse chemical reactions and are large protein molecules with a groove on one side called the active site and this is where the substrate attaches to
what enzyme breaks down proteins
proteases which break down amino acids so the body can absorb them and rearrange the amino acids in a different order to make human body cells
what is the enzyme that breaks down carbohydrates
amalayse break down starch into simple sugars
what does a lipid molecule look like
it contains a molecule of glycerol attached to multiple molecules of fatty acids and is broken down by the enzyme lipase
what is the function of bile
bile converts large lipid droplets into smaller lipid droplets. It emulsifies the lipid which massively increases the surface area of the lipid droplets allowing lipase to break it down faster. It can also neutralise the stomach acids increasing the rate of digestion for the lipids
why does the rate of reaction increase as you increase an enzyme catalyses reactions temperature
because the substrate and the enzyme are both moving faster so there are more collisions per second
what do we call it when the shape of the active site changes on an enzye
the active site becomes denatured if the enzymes conditions change too much. this means that the enzyme can no longer catalyse the reaction
how would you conduct a food test
first break down the food using a mortar and pestle then transfer the paste to a beaker and mix it with distilled water to make sure the food dissolves into the distilled water. Then filter the product to remove any food particles
how do you do a test for starch
first add 2cm³ of food solution and add iodine which is orange in colour
If starch is present the solution will turn blue-black
how do you test for sugar
first add 2cm³ of food solution and add 10cm³ of benedicts solution which is blue in colour and then place into a hot water bath
benedicts solution cannot exactly tell you if sugar is present it only indicates how much
green - small amount of sugar
yellow - more sugar
brick red - lots of sugar
benedicts test only works for reducing sugars such as glucose
how to test for protein
first add 2cm³ of food solution and then add biuret solution which is blue in colour
If protein is present then the biuret solution will turn to a purple or lilac colour
how do we test for lipids
grind the food using a mortar and pestle but do not filter it as lipid molecules can stick to filer paper. Then add a few drops of distilled water and ethanol then shake gently. If lipids are present the solution will go cloudy as an emulsion has formed. Ethanol is highly flammable
how to test the effect of pH on amylase
First get a spotting tile and add one drop of iodine to each well
Then get 2cm³ of starch amylase and a pH buffer solution (to alter the pH) in separate test tubes.Then leave these all in a hot water bath (30 degrees) for 10 minutes so they all reach the correct temperature.
Finally mix them all and add a drop of the solution to the spotting tile every 30 seconds. If it no longer turns blue black then starch is not present. repeat the experiment with different pH buffer solutions
what is the function of the small intestine
it absorbs the products of digestion into the bloodstream