ch3 nutrients Flashcards
3 classes of nutrients
- Carbohydrates
- Proteins
- Lipids
Which elements are the 3 classes of nutrients made out of
- Carbohydrates
C, H, O ratio of H:O -> 2:1 - Protein
C, H, O, N - Lipids
C, H, O
3 types of carbo
- Monosaccharides
- Diasaccharides
- Polysaccharides
List the monosaccharides
- Fructose
- Galactose
- Glucose
List the diasaccharides
- Sucrose
- Maltose
- Lactose
List the Polysaccharides
- Cellulose
- Glycogen
- Starch
Tip: Start from the Monosaccharides
List the Reducing Sugars
- Glucose
- Galactose
- Fructose
- Maltose
- Lactose
Sucrose not included in reducing sugars.
List the non-reducing sugars
- Sucrose
I would like to test a wintermelon for reducing sugars. How do I conduct this test?
Benedict’s Test
- Crush 2g, Wintermelon
- Add 2ml, Benedict’s Solution, add 2g crushed wintermelon, into clean test tube
- Shake vigorously
- Heat mixture in boiling water bath, 5min
R:
present: Yellow/orange/brick red precipitate formed
absent: blue Benedict’s solution remained blue
R: Stands for Results:
For R: Must declare the previous colour of the solution unless special cases e.g. precipitate, emulsion formed
I would like to test a sample of milk for starch. What do I do?
Iodine Test
- Add 2ml of milk, onto white tile
- Add 2 drops of iodine solution, on 2 ml of milk
R:
present: brown iodine solution, turned blue-black
absent: brown iodine solution, remained brown
For R: Must declare the previous colour of the solution unless special cases e.g. precipitate, emulsion formed
What are proteins made of? (Not the CHNO, smth else)
one or more polypeptides
What are polypeptides made of?
many animo acids
I would like to test egg yolk (raw) for the presence of proteins. I am given a raw egg. What do I do?
Biuret’s Test
1. Add 2ml, biuret reagent into a clean test tube, with 2ml of egg yolk
2. Shake vigorously
R:
present: blue reagent turned violet
absent: blue reagent remained blue
Yes, raw egg is liquid.
P.S. During actual pract
Please remove the shell (cracc the egg) and separate the white from the yolk
What are lipids made of? (not elements)
1 glycerol
3 Fatty Acids
I would like to test a crushed watermelon for lipids
- Crush 2g, watermelon
- Add 2ml of ethanol to 2g, of crushed watermelon
- shake vigorously
- Decant supernatant, into test tube, containing 2ml, distilled water
R:
present: white emulsion formed
absent: clear mixture remained clear
Crushed watermelon is 2g imo because it still contains fiber
