B3 organization and the digestive system Flashcards
what is a tissue
A tissue is a group of cells with a similar structure and function.
what is an oragan
a group of tissues carrying out a specific function
what is an organ system
a group of organs working together to carry out a specific job
what is the digestive system
The digestive system is an example of an organ system in which
several organs work together to digest and absorb food.
what is an enzyme
an enzyme is a biological catalyst which speeds up chemical reactions in living organisms
name the properties of enzymes
they are large proteins
the is space within the protein molecule called the active site
each enzyme catalyzes a specific reaction
they work best at a specific temperature and a pH called the optimum
explain the ‘lock and key theory’ as a
simplified model to explain enzyme action.
the chemical that reacts is called the substrate (key) and this fits into the enzymes active site (lock)
high temperatures and extremes of pH cause the enzymes to change shape this is called denaturing
the enzyme does not work once it has been denatured because the substrate no longer fits into the active site
what are digestive enzymes
Digestive enzymes convert food into small soluble molecules that
can be absorbed into the bloodstream.
what are the 3 digestive enzymes
protease lipase and carbohydrase
what do carbohydrase do
break down carbohydrates into simple sugars
what is amalyse
the carbohydrase that breaks down starch into sugar (maltose)
where is amylase produced
salivary glands and pancreas
where is protease produced
stomach pancreas and small intestine
what does protease do
breaks down proteins into amino acids
where is lipase produced
pancreas and small intestine
what does lipase do
breaks down lipids into fatty acids and glycerol
what is bile
a liquid made in the liver and stored in the gall bladder
what are the properties of bile
It is alkaline to neutralize hydrochloric acid from the stomach.
It also emulsifies fat to form small droplets which increases the surface area.
The alkaline conditions and large surface area increase the rate of fat , breakdown by lipase.
what chemical do you use to test for sugars and how
heat in a water bath for two minutes and add benedicts solution
what colour will the solution turn if sugar is present
red
which chemical do you use to test for starch
iodine solution NOT IODINE
what colour will the solution turn if starch is present
blue-black
what chemical do you use to test for proteins
biuret reagent
what colour will the solution turn if protein is present
purple
what are the risks in food tests
do not boil the mixture for a long time because the starch will start to break down into sugar
sometimes the purple is hard to see try holding the test tube in front of a white piece of paper
describe the method used when investigating the effect of pH on the rate of reaction of amylase
enzyme.
put a test tube containing starch solution and a test tube containing amylase into water bath at 37’C
after 5 minutes add the amylase solution to starch
every 30 secs take a drop from the mixture and test it for starch using iodine solution
record how long it takes for starch to be completely digested
repeat the experiment at different pH values using different buffer solutions
when investigating the effect of pH on the rate of reaction of amylase enzyme what are the risks
you could spill iodine solution on the skin
take care when using the Bunsen burner
what is the independent variable when investigating the effect of pH on the rate of reaction of amylase enzyme
the pH
what is the dependent variable when investigating the effect of pH on the rate of reaction of amylase enzyme
time taken for the starch to be digested
what is the control variable when investigating the effect of pH on the rate of reaction of amylase enzyme
temperature, concentration and volume of starch and amylase
