Bio Molecules Quiz 1

Biomolecules quiz 1 Name the following functional groups:

List the type of biomolecule each of the following represents: cotton: dextrose: glutimate: sucose: wool: bacon fat: Which types of biomolecules are small enough to pass through cell membranes without digestion? Which type of molecule will likely dissolve in only nonpolar solvents? Which monosaccharide tastes the sweetest? Which single test would best identify each listed substance? dextrose: wool: glutamate: triglycerides: starch: Paper and cotton are mostly what type of biomolecule? In your body, you store extra sugar as... Cholesterol (see structural formula) belongs to the class of biomolecules called... A color of a positive Biuret's test is... A color of a positive Benedict's test is... A color of a positive iodine test is... A color of a positive ninhydrin test is...

Which tests do you heat? Identify the types of biomolecules shown:

Which of the molecules shown would be soluble in water?

Answers ...are indicated below by this color. Name the following functional groups:

(1) is an alcohol molecule containing the hydroxyl functional group. (2) is a ketone molecule containing the carbonyl functional group. Note there is NO hydrogen on the carbonyl carbon. (3) is an organic acid containing a carboxyl group. (4) is an amine containing the amino functional group. (5) is an aldehyde containing the carbonyl functional group. Note there IS a hydrogen on the carbonyl carbon. List the type of biomolecule each of the following represents: cotton: a polysaccharide (carbohydrate polymer) dextrose: a monosaccharide (carbohydrate)

glutimate: an amino acid sucose: a disaccharide (carbohydrate) wool: a protein (polymer) bacon fat: a triglyceride (lipid) Which types of biomolecules are small enough to pass through cell membranes without digestion? Only monosaccharides, amino acids, fatty acids, glycerol, and smaller molecules generally can pass through membranes by dialysis. Larger molecules must be digested to smaller molecules. Which type of molecule will likely dissolve in only nonpolar solvents? Other small non-polar molecules such as fatty acids and lipids. Which monosaccharide tastes the sweetest? fructose Which single test would best identify each listed substance? dextrose: Benedicts test turns orange, red, or brown due to Cu2O for monoand disaccharides. wool: Biuret's test forms a purple coordination complete between a Cu2+ a four peptide nitrogen atoms in proteins. Note because of the copper, Biuret may react like Benedict's if heated. glutamate: Any molecule containing an amino group forms a blue compound with Ninhydrin test. triglycerides: Solubility in a non-polar solvent is useful to identify lipids. starch: Iodine is lodged in the alpha helical sturcture found in many (but not all) kinds of starch forming a dark blue or purple complex. The complex will not form when hot. Paper and cotton are mostly what type of biomolecule? cellulose is a type of polysaccharide polymer as are glycogen, starch, and gums. In your body, you store extra sugar as... glycogen Cholesterol (see structural formula) belongs to the class of biomolecules called... a lipid; NOTE the sparsity of functional groups. A color of a positive Biuret's test is...

purple

A color of a positive Benedict's test is... A color of a positive iodine test is...

red

dark blue, purple; nearly black

A color of a positive ninhydrin test is... Which tests do you heat?

blue

Benedict's and Ninhydrin

Identify the types of biomolecules shown:

(1) is a saturated (maximum number of hydrogen due to NO double bonds between carbons) fatty acid. (2) is a mono-unsaturated (due to ONE double bond between carbons) fatty acid. (3) glucose, a monosaccharide (carbohydrate). (4) alanine, one of a couple dozen common amino acids. (5) a tryglyceride (lipid); NOTE the three fatty acids attached by ester bonds to glycerol. Which of the molecules shown would be soluble in water? To be soluble, a molecule needs to be moderately small and contain polar functional groups that bond to water. (3) glucose and (4) alanine are the only ones above to be very soluble. The human body uses soap like molecules in lymph fluid to increase the solubility of fatty acids so they can be transported via the blood. Larger molecules need to be digested to smaller size to transport. Cheers, and good luck on the test!

revised 12/10/2000 by