Cell Organisation, Enzymes and Digestion (Food Tests) Flashcards
What is a tissue?
A group of cells with a similar structure and function.
What is an organ?
It is a group of tissues working together for a specific function e.g stomach.
What are the three main nutrients in food?
Carbohydrates
Protein
Lipids
What enzyme is used in the stomach?
Pepsin
Increasing temperature always increases the rate of reaction?
Is this correct?
It increases the rate initially until it hits the optimum temperature and from there it will decline
In mammals what sort of tissue is included?
Muscular tissue - which contracts to move what it’s attached to
Glandular tissue - makes and secretes chemicals like enzymes and hormones
Epithelial tissue - covers some parts of the body e.g the inside of the gut
What is an organ system?
A group of organs working together to perform a particular function
What are enzymes?
Enzymes are catalysts produced by living things. They make reactions occur more quickly
What is a catalyst?
A catalyst is a substance which increases the speed of a reaction without being changed or used up by the reaction.
What is the lock and key theory?
It is the idea enzymes are like keys that only fit a certain reaction and if it doesn’t fit the reaction won’t be catalysed
What enzyme breaks down starch?
Amylase
What do lipases convert Lipids into?
Fatty acids and glycerol
What is bile for and where is it used?
Bile is used in the stomach and neutralises stomach acid.
It’s produced in the liver and stored in the gall bladder before it’s released into the small intestine.
What do the salivary glands do?
These produce analyse enzyme in the saliva that breaks down food.
How does the stomach break down food?
It pummels the food with its muscular walls
It produces the protease enzyme pepsin
It produces hydrochloric-acid to kill bacteria and to give the right pH for the protease enzyme to work
How does the Pancreas break down food?
Produces protease amylase and lipase enzymes and releases them into the small intestine
What does the Gall Bladder do?
Is where bile is stored before it’s released into the small intestine.
What does the Large intestine do?
It absorbs essential vitamins produced by gut bacteria and reclaiming water from faeces.
How do you do the Benedicts test to test for sugars?
[5 steps]
1: Prepare a food sample and transfer 5cm3 to a test tube
2: Prepare a water bath so that it’s set to 75 degrees
3: Add some Benedict’s solution to the test tube with a pipet (10 drops)
4: Place the test tube in the water bath using a test tube holder and leave it there for 5 minutes
5: It will change to green yellow or red if sugar is present
How to use the Biuret test to test for proteins?
[3 steps]
1: Prepare a sample of food and transfer 2cm3 of your sample to a test tube
2: Add 2cm3 of biuret solution to the sample and mix the contents by gently shaking it
3: Of the food sample contains protein the solution will go to pink or purple
