Unit 4 - Biological molecules

Question 1

Carbohydrates

Answer 1

• Carbon, Hydrogen & Oxygen - Glucose
• Large Carbs - cellulose, starch, glycogen

Question 2

Fats & oils

Answer 2

• Carbon, Hydrogen, Oxygen
• Fats are solid at room temperature
• Oils liquid at room temperature
• Fats found in animals
• Oil found in plants
• 1 molecule of fat - glycerol + 3 fatty acids

Question 3

Protein

Answer 3

• Carbon, Hydrogen, Oxygen, Nitrogen
• Some have sulfur and selenium
• Made from amino acids

Question 4

Amino Acids

Answer 4

Over 20 types that naturally occur

Question 5

Starch Food test

Answer 5

1. Take 1cm^3 of food solution
2. Add 2/3 drops of iodine
3. Iodine will change from gold –> blue/black if positive

Question 6

Sugar/Reducing sugar food test

Answer 6

1.Take 1cm^3 of food solution
2.Add 1cm^3 of Benedict’s solution
3.Place in 60˚C water bath for 3 minutes
4.Benedict’s will change from Blue (no sugar) –> Green (little sugar) –> Red (lots of sugar)

Question 7

Lipids/ fats & oils food test

Answer 7

1.Take 1cm^3 of food solution
2.Take 1cm^3 of water + 1cm^3 of ethanol, shake solution well - emulsification agent
3.Solution goes from clear –> Milky white if test is positive

Question 8

Protein food test

Answer 8

1.Take 1cm^3 of food solution
2.Add 2-3 drops of Biuret solution
3.Solution goes from Blue –> Lilac if test is positive

Question 9

DCPIP/vitamin C food test

Answer 9

1.Take 1cm^3 of food solution
2.Add 2-3 drops of DCPIP
3.Solution will go from blue –> pink/colorless if positive

Question 10

DNA

Answer 10

• Deoxyribonucleic acid
• Nearly every cell has a complete copy of DNA
• Comes from parents
• Double helix - two spirals wrapped around each other
  -Each strand has phosphates, deoxyribose & nitrogen