MCAT Physical : Macromolecules

Study concepts, example questions & explanations for MCAT Physical

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Example Questions

Example Question #1 : Proteins

Which of the following amino acids are acidic?

I. Glutamate

II. Proline

III. Glycine

IV. Arginine

Possible Answers:

II and III

I and IV

I, II and IV

I only

Correct answer:

I only

Explanation:

Glutamate (glutamic acid), is the only one of which that contain an acidic functional group (carboxylic acid). Arginine is basic while proline and glycine considered non-polar.

Example Question #192 : Biochemistry, Organic Chemistry, And Other Concepts

What properties of phospholipids make the formation of cell membranes possible?

Possible Answers:

Phospholipids are amphiphatic

Phospholipids are inorganic

Phospholipids are completely non-polar

Phospholipids are completely polar

Correct answer:

Phospholipids are amphiphatic

Explanation:

Phospholipids have two fatty acid tails made of hydrocarbons, which are nonpolar, and a phosphate head, which is polar. Their structure allows phospholipids to group up into a bilayer such that the polar heads face the outside environment while the non-polar fatty tails face inward, protected from the aqueous environment. Phospholipids are not completely polar or non-polar, they are amphiphathic.

Example Question #1 : Carbohydrates

Cellulose is a polymer that is composed of what monomer?

Possible Answers:

Glycerol

Glucose

Fructose

Galactose

Glycogen

Correct answer:

Glucose

Explanation:

Cellulose is a polysaccharide (a sugar). Glucose is the monosaccharide used to generate the structure of cellulose via  linkages. Cellulose is composed of several hundred glucose molecules bound in this chain. Due to the nature of the beta linkage, humans cannot digest cellulose.

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