Question

You are studying two substances that both have very high molecular weights: hyaluronan, a carbohydrate found in the extracellular matrix with a MW of −8×106 daltons, and the bacterial ribosome, with a MW of −2.5×106. Hyaluronan is a single, long-chain polymer, while the ribosome subunit is a complex of 55 different proteins plus three long RNA molecules. Which of the following describes the pattern you would expect to see from ultracentrifugation of these two substances? the sample is loaded as a narrow band at the top of the tube (A) Choose one:

A. Both substances would show smears with wide ranges of molecular weights.
B. The hyaluronan would show a single band at −8×10⁶ daltons, but the ribosome would show a smear with a wide range of molecular weights.
C. The ribosome would show a single band at ∼2.5×10⁶ daltons, but the hyaluronan would show a smear with a wide range of molecular weights.
D. Each would show a single band reflecting the molecular weight: −2.5×10⁶ daltons for the ribosome and ∼8× 10⁶ daltons for hyaluronan.

Answer 1

Ultracentrifugation of hyaluronan would show a single band while the ribosome would show a smear with a wide range of molecular weights.

Step-by-step explanation:

Ultracentrifugation of the two substances, hyaluronan and the bacterial ribosome, would show different patterns. Hyaluronan, being a single, long-chain polymer, would show a single band at -8x10^6 daltons. On the other hand, the ribosome, which is a complex of proteins and RNA, would show a smear with a wide range of molecular weights. Therefore, the correct answer is B - The hyaluronan would show a single band at -8x10^6 daltons, but the ribosome would show a smear with a wide range of molecular weights.

Answer 2

The following describes the pattern you would expect to see from ultracentrifugation of these two substances is C. The ribosome would show a single band at ∼2.5×10⁶ daltons, but the hyaluronan would show a smear with a wide range of molecular weights. (Option C)

Step-by-step explanation:

Ultracentrifugation is a technique that separates particles based on their sedimentation rates in a centrifugal field. The sedimentation rate is influenced by factors like mass, shape, and density. In this scenario, the bacterial ribosome, with a MW of −2.5×10⁶ daltons, would likely form a distinct single band reflecting its molecular weight due to its well-defined structure. On the other hand, hyaluronan, being a long-chain polymer, would exhibit a smear with a wide range of molecular weights as it can exist in various sizes and conformations.

The ribosome, composed of 55 proteins and three RNA molecules, forms a relatively stable complex, resulting in a distinct sedimentation pattern during ultracentrifugation. In contrast, hyaluronan, being a single, long-chain polymer, lacks a defined structure, leading to a range of molecular weights and varied sedimentation rates. The smearing effect in hyaluronan's pattern is indicative of its structural heterogeneity and the presence of molecules with different sizes.

Understanding the principles of ultracentrifugation and the structural characteristics of the substances under study allows for predictions of their sedimentation patterns, providing valuable insights into their molecular properties and behavior in solution.(Option C)