Chapter 1. DNA Question Suites

1.1 Rubric

Use 1A as a pre-class warm up question. Start the discussion in class with 1B. Ask 1C for discussion. If students choose B as a correct answer, ask them to list all proteins that bind RNA. If they pick C, use it as a lead-in question to ask why this is the case to talk about Chargaff’s rules and structure in general. Follow up with 1D.

To make 1C a fully stand-alone exam question, modify to ask What features of DNA make it a more suitable molecule than RNA? Adjust by asking, what 2 features, what 3 features?

1.2 Pre-class/warm up question 1A:

Question 1.1

Which of the following is true of DNA?

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B.
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D.
E.

1.3 In-class warm up question 1B:

Draw a table comparing the structures and functions of DNA and RNA:

1.4 Questions 1C & 1D

You have been tasked with deciding how best to create, store, and process the genetic information within an artificial cell line. Your team would like to make the most efficient cell possible to keep costs to a minimum.

Question 1.2

One of your colleagues suggests that it may be more convenient to store the cells’ genetic information as RNA, rather than as DNA, because the entire process of transcription (and all of its associated proteins) could be ignored. Your colleague supports his argument by stating that RNA makes up the genome of many different viruses, and was probably the first information molecule in evolutionary history anyway. You can think of numerous problems with this plan. What features of DNA make it a more suitable informational archive than RNA (more than one answer may be correct)?

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B.
C.
D.
E.

Question 1.3

Your colleague’s idea of using RNA as the information storage molecule has numerous other problems. Based on what you know about eukaryotic cells, what are some of the other arguments against using RNA as the genetic storage molecule?

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E.

1.5 Base Pairing Rubric

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1.6 Warm Up Question 2A

Question 1.4

With what does adenine base pair in both DNA and RNA?

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B.
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1.7 2B

Question 1.5

Once you’ve decided that you will go ahead and store the genetic information as DNA, you wonder what proportion of the different nucleotides you will need. To begin to investigate this, you run an assay on the total nucleotide content in a representative eukaryotic cell line. You isolate all the nuclear DNA and begin to run your assays to determine the nucleotide content. If the cytosine content of DNA from your cell line is 17 percent, what is the adenine content?

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B.
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1.8 2C

Question 1.6

In the DNA of certain bacterial cells, 16% of the nucleotides are adenine. What are the percentages of the other nucleotides in the bacterial DNA?

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B.
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1.9 In-Class Activity

2D. Show images of spiral staircases—the kind with the pole in the middle, and the other kind. Which is the better analogy for DNA’s double helix?

2E. How do you build a spiral staircase if you only have planks of two different lengths—one short and one long? How do you keep a constant distance between the two railings? What happens if you put together two short planks in a step, or two long planks? Applying this analogy to the structure of DNA and using what you know about bases, which plank do you think represents A? T? What does the railing represent? What sticks the boards together—how many types of glue do you need to use?