Digestive System Flashcards
Test for sugars
Benedicts test - add drops of benedicts solution into sample and put into 75 degree water bath for 5 mins. If sugar is present it will go from blue to green, yellow or brick red
Test for starch
Iodine solution - put a few drops of iodine solution into sample and shake. If starch is present solution will go from browny orange to blue/black
Tests for protein
Biuret- add even parts of the food sample and biuret solution and mix by shaking. If protein is present solution will go from blue to purple
Test for lipids
Sudan 111 test - add 5cm cubed of food sample into test tube, add a couple drops of Sudan 111 stain solution with a pipettes and shake. If containing lipids the mixture will separate into 2 layers top layer = bright red
Cells
Basic building blocks that make up all living organisms
Tissue
A group of similar cells that work together to carry out a particular function
Organ
A group of different tissues that work together to perform a certain function
Organ system
A group of organs working together to perform a particular function e.g. the liver, glands
Carbohydrases
Convert carbohydrates into simple sugars
Proteases
Convert proteins into amino acids
Lipases
Convert lipids into glycerol and fatty acids
What is bile?
An alkaline as hydrochloric acid in stomach makes the pH too acidic for enzymes in the small intestine to work properly so bile makes the conditions alkaline. The enzymes in the SMALL INTESTINE work best in these alkaline conditions
Where is bile produced?
In the liver
Where is bile stored?
The gall bladder
Where is bile released into?
The small intestine
What does bile do?
- makes conditions alkaline
- emulsified fats creating a bigger surface area of fat for lipase to work on -> makes digestion quicker
What happens in the stomach?
~ pummels food with it’s muscular walls
~ produces the enzyme protease (called pepsin in the stomach)
~ produces hydrochloric acid to kill bacteria and give the right pH for protease to work
What happens in the liver?
Bile is produced
What happens in the gall bladder?
Bile is stored before it is released
What happens in pancreas?
~ produces PROTEASE, AMYLASE, LIPASE and releases these into the small intestine
What happens in the small intestine?
~ produces PROTEASE, AMYLASE, LIPASE to complete digestion
~ digested food is absorbed out of digestive system into the blood
What happens in the large intestine?
Excess water is absorbed from food
What happens in rectum?
Where the faeces is stored before leaving the body
Where are carbohydrases made?
In the salivary glads, pancreas, small intestine
Where are proteases made?
Stomach, pancreas, small intestine
Where are lipase made?
Pancreas + small instestine
What do the digestive enzymes do?
Break down big molecules like starch ,protein + fat into smaller molecules like sugars, amino acids, glycerol and fatty acids. The smaller molecules can pass through the walls of the digestive system easier allowing them to be absorbed into the bloodstream
What are the purpose of enzymes?
They speed up useful chemical reactions in the body
How do enzymes work?
Every enzymes has an active site with a unique shape that fits onto the substance involved in a reaction therefore they only catalyse one chemical reaction.
What could cause an enzyme to denature?
> if the temperature is too high the bonds can break in enzyme causing the active site to change shape and denature
~ if the pH gets too high or too low it will interfere with the bonds holding the enzyme together (enzyme denatures)
Amylase
Converts starch to sugar
