Nutrition, Food Test and Enzymes Flashcards
Food test for Starch
Starch Test(Iodine)
Food test for Sugar
Benedicts Test
Food Test for Protein
Buiret Test
Food Test for Fats
Ethanol Test
What elements do carbohydrates contain
Carbon Hydrogen And Oxygen
What are Examples Simple Carbohydrates
Glucose
Lactose
Sucrose
Why are simple carbohydrates describes as simple?
Made up of one basic sugar units
Role of Glucose
Respiration
Role of Sucrose
Transportation
Role of Lactose
Sugar and energy source in milk
What is Glucose also called as?
Monosaccharide
What is Sucrose also called as
Disaccharide
Where is Lactose found
Milk
Use of Carbohydrates
They are Fast release energy stores, which means that they can quickly diest to release energy
How to Perform Benedicts Test
1) Grind your Food
2) Mix it with little water
3) Add Benedicts Solution
4) Heat carefully in a water bath
Color Change for Benedicts Test
Blue to Brick Red
Examples of Complex Carbohydrates
Starch
Glycogen
Cellulose
Fibre
Where is Starch Found
Cereal,Pasta,Rice
What is starch used for?
Respiration
Where can you find cellulose
Plants
Use of Cellulose
make cell wall
Use of Fibre
Prevent Constipation
Where is glycogen stored
1) Stored in Liver and Muscle
How to perform Starch test
Add iodine solution to food sample
Color change for starch test
Yellow brown- Blue Black
What does Fat consist
One molecule of Glycerol and three molecules of fatty acids
What are fats also called
Lipids
Uses of fats
Prevents heat Loss
provides Twice the energy of carbs
Sources of fat
oil
Red Meat
What is Required for Emulsion Test
Ethanol
How to perform emulsion Test
Shake the fat with alcohol and add equal amount of water
Colour Changes for Emulsion Test
clear colorless- cloudy white emulsion
What are proteins?
Long chains of amino acids bonded together
Functions of Proteins
Growth and cell repairs
makes Enzymes, hormones and antibodies
Sources of Protein
Meat
eggs
Milk
How to Perform Buiret test
Add sodium hydroxide and then a few drops of copper sulfate and shake
Color Change of Buiret test
Blue to Purple
How are there different types of Protein
There are 20 different types of amino acids, there are many different arrangements in which amino acids can be linked together
What are enzymes?
Enzymes are proteins that function as biological catalysts
What are catalysts?
A catalyst is a substance which increases the rate of a chemical reaction without being changed or used up
Burning Food Practical
How do you ensure the results are valid(fair test)
Use the same mass
Use the same volume of Water
Hold the burning food from the same distance away from the boiling tube
Burning Food Practical
Why do you repeat experiment and calculate average
To get reliable results
Burning Food Practical
Why is the energy value not always accurate?
1) Not all the energy released from the food was transferred to water
2)Most heat energy is lost to surrounding air
3) Some heat is lost in the boiling tube
What does Vitamin C prevent
Scurvy
Why do you need calcium
Strong bones/teeth
Why do you need iron
Make hemoglobin for blood cells
What is a Substrate?
The molecule enzymes acts on is a substrate
What is Active Site
The part of an enzyme which the substrate fits in
What does complementary mean?
The shape of active site matches the substate
What does denaturation mean
An irreversible change in the shape of an enzyme which means that it is no longer complementary to the substrate and cannot catalyze the reaction
Explain the Lock and Key Model
1) Enzymes work because the shape of substrate matches the shape of active site(complimentary)
2) The tight fit between the enzyme and its substrate is called Lock and Key Model
What is the Substrate and Product of Carbohydrase
Substrate= Carbohydrate
Product= Glucose
What is the Substate and Product of Amylase
Substrate= Starch
Product= Glucose
What is the Substate and Product of Protease
Substrate= Protein
Product= Amino Acid
What is the Substrate and product of Lipase
Substrate= Lipids(Fat)
Product= Glycerol and Fatty Acids
Steps of Burning Food Experiment
1) Measure 20cm^3 of Water using a measuring cylinder, and add it to a boiling tube, clamped in a retort stand
2) Record the temperature of the water using a thermometer and weigh the crisps using a top pan balance
3) Secure the crisps using tongs and light the crisps in a Bunsen burner flame and quickly hold it under the boiling tube using tongs
4) Record the maximum temperature of the water after the crisp is burned using thermometer
5) Repeat the experiment and calculate the average energy released per gram
6) Calculate the differences of temperatures
