Nutrition & Food Tests Flashcards
Biological molecules
Give us energy.
Carbohydrates
Provide energy.
2 types - Simple and Complex Carbs
Carbohydrates and Fats
Made up of
- Carbon
- Hydrogen
- Oxygen
Cellulose
Found in Plant Cell Walls.
Cannot be digested by humans.
However, as fibre - helps the muscles of intestinal wall to push food through the digestive system.
Cellulose as Fibre
Helps the muscles of intestinal wall to push food through the digestive system.
Cellulose, Starch and Glycogen
Long Chain of Sugars joined together.
Fats/Lipids
A store of energy.
Provide Double the Energy that carbohydrates and proteins do.
Made up of fatty acids and glycerol.
Food
Made up of different biological molecules;
- Which Give us Energy
Contain chemicals we need to:
- Grow and Repair ourselves
- Help our Cells Function
Glucose
Can be used by cells to make energy.
Proteins
Used for the growth and repair of cells
- Used as a source of energy
if carbohydrate and fat reserves are low.
Made up of long chains of amino acids
- which after digestion; are absorbed into the bloodstream
- and brought to cells that reassemble them into proteins needed by the body.
Glycogen
Carbohydrate stored within the liver and skeletal muscle
A Polysaccharide that can be Converted into Glucose when Levels Low.
Reagent
Chemical that indicates the presence of a substance, usually by changing colour.
Proteins contain
- Carbon
- Hydrogen
- Oxygen
- Nitrogen
Starch
Broken down by digestive enzymes into glucose - which can be used by cells to make energy.
Reagents and Food Testing
There are tests which can be used to detect carbohydrates, proteins and lipids.
They involve:
- Adding a reagent to a food sample - changing the colour depending on what biological molecules are present.
- Sometimes it‘s necessary to crush or add water to the food before adding the reagent.
Initial Colour of Benedicts (Reagent)
Blue
Initial Colour of Biuret (Reagent)
Blue
Initial Colour of Ethanol (Reagent)
Colourless
Simple Carbohydrates
Sugars - Glucose and Lactose
Fast Acting Source of Energy.
Complex Carbohydrates
Include - Cellulose, Starch and Glycogen
Source of Slow Releasing.
Complex Carbohydrates Examples
Rice and pasta.
Initial Colour of Iodine (Reagent)
Yellow-brown
Simple Carbohydrates Examples
Biscuits + energy bars.
Biuret (Reagent)
Mixture of Sodium Hydroxide and Copper Sulfate.
Benedict colour - Positive result for Reducing Sugar
Brick red precipitate
Biuret colour - Positive result for Protein/Amino Acid
Lilac/purple
Ethanol colour - Positive result for Fat
White Emulsion
Testing for Protein/Amino Acids
Reagent - Biuret
Method: add Biuret fo the food.
Initial Colour - Blue.
Colour of Positive Result - Lilac/purple.
Testing for Fat
Reagent - Ethanol.
Method: add Ethanol to the food to dissolve the fat then add water.
Initial Colour - Colourless.
Colour of Positive Result - White Emulsion.
Iodine colour of positive result for Starch
Blue-black
Testing for Reduced Sugar
Reagent used - Benedicts
Method: add Benedicts to the food and boil in a water bath.
Initial colour - Blue.
Colour of a positive result - Brick red precipitate.
Testing for Starch
Reagent - Iodine.
Method: add Iodine to the food.
Initial colour - Yellow-brown.
Colour of Positive Result - Blue-black.
The Chemicals in Our Food Are Needed to
- Grow and Repair Ourselves
- Help Our Cells Function
Contain Chemicals We Need To:
- Grow and Repair Ourselves
- Help Our Cells Function
Food in our diet.
In Our Food and Give Us Energy
Biological Molecules
Proteins needed by the body
Enzymes
Essential to Grow and Repair Ourselves + Help Our Cells Function
Chemicals in our Food.
Adding what to a food sample - changes the colour depending on what biological molecules are present
A reagent.
Food Sample Examples
- Reducing Sugar
- Starch
- Protein/Amino Acids
- Fat
Cannot be digested by humans
Cellulose
Sometimes what is necessary before adding the reagent into food
To crush or add water to the food.
Whilst testing for Reducing Sugar:
After adding Benedicts (Reagent) to the food
Boil in a water bath.
Adding a reagent to ? - changes the colour depending on what biological molecules are present.
Food
During tests to detect carbohydrates, proteins and lipids;
Adding a reagent to a food sample - changes the colour depending on what ? are present.
Biological Molecules
Foods high in Fat
- Cheese
- Butter
- Oils
Sometimes it‘s necessary to crush or add water to the food before adding what?
The reagent.
Sometimes it is necessary to crush or add water to what before adding the reagent?
Food
Used as a source of energy if Carbohydrate and Fat reserves are low
Proteins
Whilst testing for Fat:
We add Ethanol to the food to dissolve ? then add water.
Fat
Examples of Reducing Sugar
- Glucose
- Fructose
- Galactose
Whilst testing for Fat: we add Ethanol to the food to dissolve the fat then add ?
Water
Foods high in protein
Fish and eggs.
What is made of biological molecules?
Food (our diet)
Found in Plant Cell Wall
Cellulose
What are absorbed into the bloodstream after digestion?
Amino acids
What are reassembled into proteins in the bloodstream?
Amino acids
When are amino acids absorbed into the bloodstream?
After digestion.
Tests used to detect carbohydrates, proteins and lipids
Involve:
- Adding a reagent to a food sample - changing the colour depending on what biological molecules are present.
- Sometimes it‘s necessary to crush or add water to the food before adding the reagent.
Controlled Variables
A factor kept the same during an experiment in order to keep the experiment valid.
