2c Biological Molecules Flashcards
What is the test for glucose?
Heat solution with Benedict’s solution in a water bath.
Glucose present: blue -> orange
Give 3 features of glucose
It is a monosaccharide (simple sugar)
It is soluble
It provides short term energy
What is the test for starch?
Add drops of iodine solution to the starch
Starch present: orange-brown to blue-black
What do plants store glucose as?
Why not just store as glucose?
Starch.
Glycogen
Starch is insoluble so water won’t enter the cell by osmosis, making it swell.
Starch is compact so take up less space to store
What is cellulose?
A polysaccharide that is a strong molecule. Used to form plant cell walls.
What is glycogen?
A polysaccharide that is a highly branched molecule. How animals + fungi store glucose. Stored in liver and muscles in humans.
What are protein’s constituent elements?
SPONCH
Sulfur
Phosphorus
Oxygen
Nitrogen
Carbon
Hydrogen
What are proteins’ building blocks and how is their order determined?
Amino acids, and their order is determined by DNA
What are proteins used for?
Form enzymes, growth & repair, hormones
What is the test for protein?
Add drops of Biuret solution to solution,
If protein present: blue to purple
Describe what happens when blood sugar levels are high.
Glucose levels are high, so insulin is released to uptake glucose and convert it to glycogen
Describe what happens when blood sugar levels are low.
Glucose levels are low, so glucagon is released to convert glycogen to glucose and release it into the bloodstream.
What synthesizes glucagon and insulin?
Pancreatic alpha cells make glucagon
Pancreatic beta cells make insulin
Why are lipids needed when we already have glycogen as energy store?
- insulation
- longer term storage
- effective: more energy per gram
Describe the structure of a lipid. What enzyme breaks it down?
Glycerol + 3 fatty acids. Lipase breaks it down
What is the test for lipids?
Dissolve solution in ethanol. Add to water.
If lipids present, cloudy emulsion formed
