Term
| What is the key difference between the nucleotides of DNA and RNA? |
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Definition
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Term
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Definition
| The 2 ring nitrogenous bases, guanine and adenine |
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Term
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Definition
| The one ringed bases, thymine, cytosine, and uracil |
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Term
| Why do you need complementary base-pairing? |
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Definition
| Because purines are bigger, and pyrimidines are smaller, they match in size. If you have 2 of the same they'd either be too far apart for base-pairing, or they'd be too close. |
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Term
| What's a functional difference between a G-C base pair and a T-A base pair? |
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Definition
| T and A can only form 2 H-bonds, but G and C can form 3. Thus areas of a sequence with a lot of G-C bonds are harder to break. That is why a TATA box is where a DNA strand is opened. |
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Term
| What's on the 5' end of a nucleotide? |
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Definition
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Term
| What's on the 3' end of a nucleotide? |
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Definition
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Term
| How are DNA strands organized? Why? |
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Definition
| Antiparallel, in a double helix. Being antiparallel, the bases are offset, allowing them to interact on the curved spiral. |
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Term
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Definition
| DNA wrapped onto a histone core. It is not available for transcription in this state. |
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Term
| Explain how DNA is semiconservative |
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Definition
| Parents have a total of 4 strands of DNA, but only two are used to make the zygote. Barring recombination, 50% of the parents DNA is thrown out. |
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Term
| How do you PROVE DNA replication is semiconservative? |
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Definition
| Take some E. coli, grow it on media with nitrogen-15. Let it grow a while, take a sample. Then grow a generation on nitrogen-14 media, take a sample. Then let it grow another generation on the same media. Now centrifuge each sample. The first sample has one band, showing DNA that has nitrogen-15. The second sample has one band, but it's lighter because the DNA has one strand with N-15, and one with N-14. The third sample has one band with only N-14, and one with N-14/N-15. |
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