Biology: Chapter 4 Flashcards
What are the 3 elements that make up carbohydrates?
Carbon, Hydrogen, Oxygen
Carbohydrate components and types
- starch, cellulose and sugar
- made up or carbon, hydrogen and oxygen
- 1 molecule of carbohydrate has 2(carbon + oxygen) = hydrogen
Use of Carbohydrate
In animals:
- transported around body as glucose
- carried in blood plasma
- used for cellular respiration
- stored as glycogen
In plants:
- used in respiration
- transport sucrose around plant body
- stored as starch
- cellulose used to make cell wall
Structure of Starch
Glucose linked together and coil into spiral shape
Structure of Glycogen
Glucose link together to form glycogen
Structure of Cellulose
Glucose links together in a chain to form straight line
Features of Sugar: Monosaccharides
- glucose, fructose, galactose
- simple sugar
- very small
- soluble in water
- sweet
- monomers of carbohydrate
Features of Sugar: Disaccharides
- sucrose (glucose + fructose), lactose (galactose + glucose), maltose (glucose + glucose)
- two simple sugars joined together
- sucrose (used in hot drinks & cereals)
- maltose (malt sugar: sweet potato, honey, barley)
- soluble in water
- sweet
List 3 substance that are included in Carbohydrates
Sugar, Starch, Cellulose
Give one importance of carbohydrates in animals
-Glucose, transported around the body in blood plasma
- needed for energy , cellular respiration
Features of Sugar: Polysaccharides
- starch, cellulose, glycogen
- many simple sugars join together
- contains thousands of sugar molecules joined in a long chain
- insoluble, do not taste sweet
What is the category containing fats and oils?
Lipids
What are lipids made up of?
Carbon, Hydrogen, Oxygen
Use of fats
- making cell membrane
- used as energy stores
- heat insulating layer in some animals (mammals)
What are proteins made up of?
Carbon, Hydrogen, Oxygen, Nitrogen
Features of Protein: Monomer
- made up of amino acids
- 20 different kinds of amino acids
- each protein made up of different amino acid linked together
Function of Protein
- antibodies
- enzymes
- haemoglobin
- cell membrane
- keratin (hair and nails)
Test for Protein
Name: Biuret’s solution
1. Preapre clean test tube
2. Prepare food samples by cutting into small pieces
3. Add small amount of Biuret’s solution into test tube
4. Shake the test tube to mix the food sample with the solution
5. Observe for colour change from blue to violet
Results
Positive: Biuret’s solution turns from blue to violet
Negative: Biuret’s solution remains blue
Test for Lipids (fats & oils)
Name: Ethanol Emulsion Test
1. The food is cut up into small pieces
2. Add food samples to small amount of ethanol and shake it to mix them.
3. Take a clean test tube and add distilled water (same amount as ethanol)
4. Add ethanol mixed with food sample into distilled water
5. Observe for any milky or cloudy emulsion.
Results
Positive: Lipids will form small droplets and make the water cloudy (emulsion)
Negative: No changes to water and ethanol mixture, no milky emulsion
Test for Vitamin C
Name: DCPIP solution
1. Prepare a clean test tube and drop 1ml of DCPIP solution in with syringe
2. FOR SOLID FOODS: grind food sample and mix with distilled water
3. Use a syringe to drop the food sample slowly until the solution becomes clear
4. Record smount of food sample that was added
(The lower the amount of food sample needed to make DCPIP solution clear, the higher the amount of vitamin C in the sample)
Results
Positive: Solution in test tube will turn clear
Negative; Solution remains purple
Test for Starch
Name: Iodine solution
1. Prepare a small piece of food sample
2. Add a few drops of iodine solution on the food samples
3. Observe for change of colour from brown to blue-black
Results
Positive: Iodine solution will turn from brown to blue-black
Negative: Iodine solution will remain brown
Test for Reducing Sugar
Name: Benedict’s solution
1. Prepare two boiling tubes
2. Take a small piece of food sample and grind it
3. Put the food samples into the boiling tubes
4. Add some distilled water into the boiling tube and shake
5. Add a small amount of Benedict’s solution into boiling tube and shake
6. Prepare a water bath to heat the boiling tubes.
7. Observe for colour changes in heated solution
Results
Positive: Benedict’s solution changes colour from blue to green/yellow/orange/brick-red
Negative: Benedict’s solution remains blue
What does DNA stand for?
DeoxyriboNucleic Acid
What determines the sequences of amino acid?
Sequence of bases on DNA
What is DNA made up of/
Nucleotides
Structure of DNA molecules
- 2 chains of nucleotides coiled around each other (double helix)
