The Best Possible Analogy Available for the Way in Which

question 65

Multiple Choice

The best possible analogy available for the way in which variable (V) , diversity (D) , and joining (J) antibody gene segments get put together to create the diversity possible in hypervariable regions is

• A) to think of the various segments as a deck of cards-when you get dealt a hand of five cards, you have a very high likelihood of getting a different hand every time. The quality of the hand you have dealt will dictate whether you have a "winning" hand (capable of binding to antigenic epitopes).
• B) to think of the various segments as the pieces of a house-you need a strong foundation first (the joining segments), followed by a frame (the diversity segments), then the interior walls (the variable segments) before the structure is complete.
• C) to think of the various segments as building a highway-you need to prepare the area first by clearing a path (the joining segments do this), then grade/slope the area (the diversity segments) before you can finally lay down the asphalt (the variable segments).
• D) to think of the various segments as a bingo game-each segment is randomly selected, but you're going to need one of each (V, D, and J) to form a functional molecule. The "right" combination varies depending on which antigen is eventually going to be binding to the molecule (i.e., your bingo card would be the eventual antigen, and the random calling out of the number/letter combinations would be the forming of the VDJ hypervariable region).
• E) to think of the various segments as the characters in a game of Clue. Each character is assigned a specific weapon with which to commit a murder (the joining segments), but once that is assigned, the room in which the murder occurs is random (the diversity segments); to get a complete picture, you need to know the name of the victim (variable segments).

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Definitions:

Total Cost

The total of all costs associated with producing goods or services, which encompasses both fixed and variable expenses.

Marginal Revenue

The increase in earnings resulting from the sale of one extra unit of a good or service.

Marginal Cost

The amount needed to make one more unit of a certain product or service.

Total Economic Costs

The sum of all expenses a firm faces, including both explicit costs (direct payments) and implicit costs (opportunity costs).