Macromolecules

What is the chemical mechanism by which cells make polymers from monomers?

• phosphodiester linkages

• hydrolysis

• dehydration reactions

• ionic bonding of monomers

Which of the following best summarizes the relationship between dehydration reactions and hydrolysis?

• Dehydration reactions assemble polymers, and hydrolysis reactions break down polymers

• Macromolecular synthesis occurs through the removal of water and digestion occurs through the addition of water.

• Dehydration reactions can occur only after hydrolysis

All of the following are polysaccharides except

• glucose

• starch

• chitin

• cellulose

Which of the following statements is false for lipids?

• They are soluble in water.

• They are an important constituent of cell membranes.

• They contain more energy than proteins and carbohydrates.

• They are not true polymers.

Which of the following statements is true regarding the molecule shown below?

• It is a saturated fatty acid

• A diet rich in this molecule may contribute to atherosclerosis

• Molecules of this type are usually liquid at room temperature

The molecule shown below is a(n)

• unsaturated fatty acid

• polysaccharide

• saturated fatty acid

• triacylglycerol

Cytosine makes up 42% of the nucleotides in a sample of DNA from an organism. Approximately what percentage of the nucleotides in this sample will be thymine?

• 8%

• 16%

• 31%

• 42%

Which of the following descriptions best fits the class of molecules known as nucleotides?

• a nitrogenous base and a phosphate group

• a nitrogenous base and a pentose sugar

• a nitrogenous base, a phosphate group, and a pentose sugar

• a phosphate group and an adenine or uracil

The difference between the sugar in DNA and the sugar in RNA is that the sugar in DNA

• is a six-carbon sugar and the sugar in RNA is a five-carbon sugar

• contains one less oxygen atom

• is an aldehyde sugar and the sugar in RNA is a keto sugar

• can form a double-stranded molecule

Which bonds are created when amino acids are join together to form a polypeptide?

• peptide bonds

• hydrogen bonds

• phosphodiester bonds

• disulfide bonds