511. Which of the following will easily dissolve in a polar solvent?
A. gasoline (heptanes& octanes)
B. methane
C. argon
D. sodium chloride

512. The elements oxygen, nitrogen, and carbon
A. can all form covalent bonds with other elements
B. contain protons and neutrons in their atomic nuclei
C. are common elements in the molecules that make up living organisms
D. All of the above

513. When the amino acid alanine (R-group is CH3) is added to a solution with a pH of 7.3, alanine becomes
A. a cation
B. nonpolar
C. a zwitterions
D. an isotope

514. What is the end product of leucine metabolism?
A. Acetyl-CoA
B. Pyruvic acid
C. Oxaloacetic acid
D. Acetyl carnitine

515. What is the heaviest of the twenty amino acids?
A. Phenylalanine
B. Tryptophan
C. Tyrosine
D. Histidine

516. Which of the following amino acids can form hydrogen bonds with their side (R) groups?
A. Asparagine
B. Aspartic acid
C. Glutamine
D. All of these

517. The isoelectric point of an amino acid is defined as the pH
A. where the molecule carries no electric charge
B. where the carboxyl group is uncharged
C. where the amino group is uncharged
D. of maximum electrolytic mobility

518. Molecules that bear charged groups of opposite polarity are known as
A. zwitterions
B. ambions
C. ion conversion
D. amphions

519. What is the product of the catabolic breakdown of Arginine?
A. Alpha-ketoglutarate
B. Fumarate
C. Oxaloacetate
D. Succinate

520. Which amino acids would most likely reside in the membrane-anchoring domain of a membrane embedded protein?
A. Isoleucine, valine and phenylalanine
B. Phenylalanine, valine, and aspartate
C. Leucine, threonine, and lysine
D. Lysine, arginine and histidine