Amylase is an enzyme that breaks
down starch. Depending upon the amount of reducing sugar
present, it can be from light yellow-green to almost brick red in colour after
heating the solution in a boiling water bath. It doesn't detect non-reducing
sugars.
Chew on a bit of bread for a
minute or so. Don’t swallow. The taste of it changes. Can you tell what your saliva, well the
amylase in your saliva, turns the starches into?
SUGAR!
It’s true, you can turn the starch
in your bread to sugar just by chewing it and keeping it in your mouth.
This happens because of an enzyme called Amylase. Amylase
catalyses (catalyses means causes a reaction) the hydrolysis (hydrolysis means
the chemical breakdown of a compound due to a reaction with water) of starch
into sugar.
Amylase is present in human
saliva and in some other mammals and this is where the chemical process of
digestion begins.
Foods like bread, potato and rice
become sweeter as we chew them as they are high in starch and this starch is
turned into sugar by the amylase as we have already discovered in our first
science experiment.
The pancreas and the salivary
gland make amylase to hydrolyse dietary starch.
This is then converted into glucose by other enzymes to supply the body
with energy.
The pancreas produces lots of
digestive enzymes. Enzymes are imperative (that means absolutely
necessary) in the digestive process.
Each enzyme has a specific job.
Like a jigsaw, they will only fit and breakdown the substances they were made to break down:
- An Amylase enzyme will only fit into a
carbohydrate, a starch and break it down into sugar
- A protease, like pepsin, will only fit into a
protein and break it down into amino acids
- A lipase, lipids, will only fit into fat and
break it down into fatty acids or glycerol
We can do an experiment that
proves that starch I turned into sugar, as it happens in the mouth as we mix
food with saliva. To do this you will
need:
- Corn flour
- Amylase
- Iodine - here's how to make your own: click here
- Water
- 2 test tubes with lids, one for the iodine and one for the solution we will make up.
- 6 Petri dishes or a clear plastic bag.
- 2 pipettes
- Optional: Benedict’s solution – if you use this you will also need an extra pipette.
STEP ONE
Add ¼ teaspoon of Amylase and ¼
teaspoon of corn flour ( the corn flour is the starch) to one of your test
tubes.
STEP TWO
Fill the test tube with water,
tap water is fine, so it is 1/3 full.
STEP THREE
Put a lid on your test tube and
give it a gentle shake
STEP FOUR
Test for starch.
Hypothesise about what will happen when you mix the solution you have made
with iodine.
In one your petri dishes (or on a small area of your plastic bag if you
don’t have petri dishes) put a drop of the amylase and starch solution on using
one of your pipettes. Always use this
first pipette only for the amylase and starch solution.
Then, with the second pipette, drop the smallest drop of iodine onto your
drop in you petri dish (or on your plastic bag).
It goes black! This means starch is
present.
STEP FIVE
Leave the solution for 5 minutes.
Repeat STEP FOUR – don’t
forget to your hypothesis.
STEP SIX
Leave for another 5 minutes and repeat STEP FOUR. Do this another 4 times.
On the last test you should notice that when you mix the iodine in with the
solution it’s no longer black but it’s yellow.
You should also notice that each time you test the solution the colours will go from black, to brown, to orange and then yellow. This means that the starch has all been turned into sugar.
If you have the Benedict’s reagent solution you could test to see if simple
sugars are present in the solution. If
there is sugar present the solution will go a green to yellow colour, if you
heat your solution in a bath of boiling water the colour will turn to a brick
red colour.
Benedict’s reagent solution does not detect not-reducing sugars, but will detect
the simple sugars form in the reaction of Amylase and starch.
The initial step of assimilation happens in the mouth. Delectably sweet starches - like cake, treats, bread, and pasta- - begin their breakdown here. Next, the sustenance is transported to the stomach through the throat, a long, limit strong tube that extends from your mouth to your stomach. Once the nourishment gets to the stomach, chemicals and compounds begin to destroy the sustenance. From the stomach, the mushed up nourishment, or chyme, goes into the small digestive tract. Here's the place the activity happens. Sustenance is further separated through substance assimilation and supplements from nourishment are consumed into the blood that flows through our bodies. Extra organs like the pancreas, liver, and gallbladder over here as well. Next, the digestive organ retains water and sends the waste to the rectum for transfer.
ReplyDeleteAs a child I liked to make some experiments with some materials and it was not always successful.
ReplyDeleteIf your child like makiking some experiments you have to halp him and take part in it with them.
ReplyDeleteWow! It's amazing! You should Start Writing A Book about your experiments. Kids would love it!
ReplyDelete