biological molecules!! Flashcards
YAY
chemicals elements that make up:
carbohydrates
fats
protein
carb - C H O
fats - C H O
proteins - C H O N
sometimes sulfur
large molecules are made from smaller molecules
Describe the structure of a
* lipid/fats and oils
* protein
* starch, glycogen, cellulose
lipid/fats and oils
* 3 fatty acids
* 1 glycerol
protein
* amino acids
starch, glycogen, cellulose
* glucose
What is used to test for starch?
What are the positive and negative results?
Iodine solution
orange-brown in color
Positive result
* blue-black
Negative result
* orange-brown
What is used to test for reducing sugars?
Steps to conduct test
What are the positive and negative results?
Benedict’s solution
* Blue in color
Step
1. Add benedicts solution to food sample, heat in water bath at 80 C
+ve result
* Gradually changes from blue, green, yellow to orange-red/brick red
-ve result
* Stays blue colored.
What is used to test for proteins?
What are the positive & negative results?
Biuret reagent
+ve
Blue to violet
-ve
stays blue
What is used to test for fats and oils?
Steps
What are the positive & negative results?
Ethanol emulsion
Steps
1. Shake test substance with ethanol for a minute until it dissolves, then pour slution to water.
+ve
* fats and oils will precipitate; milky emulsion
-ve
* no emulsion/colorless
What is used to test for VITAMIN C?
Steps
What are the positive & negative results?
**DCPIP **
Steps
1. Add DCPIP solution using dropper pipettes to food sample.
2. Keep adding until blue color no longer disappears when mixed w sample.
3. Vit C reacts w DCPIP solution, making it colorless. Color stops changing when all VIT C is used up.
4. Higher the volume of DCPIP solution added before blue color stops disappearing, the more vitamin C food sample contains.
+ve
* Colorless
-ve
* blue
energy store in animals and plants
Animals
* glycogen in liver
plants
* starch; broken down to glucose when plant needs it.
structure of glucose molecules
small hexagon shape
Describe structure of DNA molecule
- 2 strands coiled together to form a double
helix - Each strand contains chemicals called bases
- Bonds between pairs of bases hold the
strands together - The bases always pair up in the same way:
A with T, and C with G