Cell Biology Final Exam Midterm Questions

Front 1

T or F

Proteins are so remarkably diverse b/c each is made from a unique mixture of amino acids that are linked in random order

Back 1

False-the properties of a protein depend on both the amino acids it contains and the order in which they are linked together. The diversity of proteins is due to the almost unlimited number of ways in which 20 different amino acids can be combined in a linear sequence.

Front 2

T or F
Lipid bilayers are macromolecules that are made up mostly of phospholipid subunits.

Back 2

False- lipids assemble into bilayers by noncovalent forces. A membrane is therefore not a macromolecule.

Front 3

T or F
Nucleic acids contain sugar groups

Back 3

True- the backbone of nucleic acids is made up of alternating ribose (or deoxyribose in DNA) and phosphate groups. Ribose and deoxyribose are sugars.

Front 4

T or F
Many amino acids have hydrophobic side chains

Back 4

True. About half of the 20 naturally occurring amino acids have hydrophobic side chains. In folded proteins, many of these side chains face toward the inside of the folded-up proteins, because they are repelled from water.

Front 5

T or F
The hydrophobic tails of phospholipid molecules are repelled from water.

Back 5

True. Hydrophobic hydrocarbon tails contain only nonpolar bonds. Thus, they cannot participate in hydrogen-bonding and are repelled from water.

Front 6

DNA contains the four different bases A, G, U and C

Back 6

False. RNA contains the four listed bases, but DNA contains T instead of U. T and U are very much alike, however, and differ only by a single methyl group.