Lab 2 - Testing for Organics

Question 0

Iodine Test

Answer 0

Tests for starch
Positive: black/blue
Negative: yellow/no change

Add drop of iodine- instant results

Question 1

Benedict’s reaction

Answer 1

Finds reducing sugars (monosaccharides)
Positive: Red/orange
Negative: Blue

Add solution and cook for 3 min

Question 2

Sudan IV Test

Answer 2

Tests for fat
Positive: bright red
Negative: dark red/brown

Add powder to materiel, dissolves in fats. Can wait up to 30 min but can usually see instant results

Question 3

Ninhydrin Test

Answer 3

Tests for amino acids

Positive: purple
Negative: no change

Add clear liquid to test material and cook for 3 min

Question 4

Biuret Test

Answer 4

Tests for protein

Positive: purple
Negative: no change/blue

Add blueish liquid to test material. Instant results

Question 5

pH

Answer 5

7 is neutral
Above 7: H > OH = basic
Below 7: H < OH = acidic

Question 6

Monosaccharide

Answer 6

One sugar- usually 3-7 carbons long

Glucose, fructose, galactose, ribose

Question 7

Disaccharide

Answer 7

2 sugars

Form by removal of water= dehydration/synthesis

Question 8

Hydrolysis

Answer 8

Breaking apart a molecule by adding water to satisfy broken bonds

Question 9

Polysaccharide

Answer 9

Many sugars - more than 3

Starch and glycogen