Due to Friction with Molecules of the Surrounding Solution, Sedimenting

question 28

Multiple Choice

Due to friction with molecules of the surrounding solution, sedimenting particles in a mixture reach a terminal velocity when subjected to ultracentrifugation. The sedimentation coefficient (S) for a particle is defined as the ratio of terminal velocity (vt) to the centrifugal acceleration applied to the particle (ac) . S = vt / ac
If each Svedberg unit (S value) is defined as 10-¹³ seconds, approximately how long would it take for a free 50S ribosomal subunit to travel the length of a 9 cm ultracentrifuge tube subjected to a centrifugal force of 50,000 times gravity (g) ? Recall that g is approximately 10 m/s².

• A) 1 min
• B) 10 min
• C) 50 min
• D) 5 h
• E) 10 h

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Definitions:

Profit Maximizing Level of Output

The quantity of production that yields the highest possible profit for a firm, determined by the point where marginal cost equals marginal revenue.

Average Total Cost Curves

Graphs that show the average total cost of producing different quantities of output, typically U-shaped due to economies and diseconomies of scale.

Economic Profits

The difference between a firm's total revenue and its total costs, including both explicit and implicit costs, representing the excess over the opportunity cost.

Perfect Competition

A market structure characterized by a complete lack of friction or impediments to the entry of new firms, where all sellers and buyers have access to the same information and no individual entity can influence the market price.