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19 Cards in this Set
- Front
- Back
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Made model of DNA structure |
Who are James Watson and Francis Crick? |
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Cambridge University |
Where did Watson and Crick study? |
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Double helix |
Two strands twisted around each other. |
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It is held together by weak hydrogen bonds between the pairs of bases |
How is the double helix how together? |
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Nucleotides |
Subunits that make up DNA. It is made up of phosphate group, a five carbon sugar molecule deoxyribose, and a nitrogen containing base. |
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Deoxyribose |
The five carbon sugar in DNA nucleotides. |
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Adenine, thymine, guanine, cytosine |
What are the nitrogen bases? |
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Adenine and guanine |
Which nitrogen bases are classified as purines? |
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Thymine and cytosine |
Which nitrogen bases are classified as pyrimidines? |
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Purines |
Nitrogen bases made of two rings of carbon and nitrogen. |
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Pyrimidines |
Nitrogen bases made of a single ring of carbon and nitrogen atoms. |
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Studied at Columbia university in NYC. Measured base pairs and found that the amount of adenine is = to the amount of thymine and the amount of guanine is = to the amount of cytosine |
Who was Erwin Chargaff and what did he contribute to science? |
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X-ray diffraction |
A beam of x-rays is directed at an object. X-rays bounce off the object and scatter in a pattern onto a film. But analyzing the patterns on the film, scientists can determine the structure of the molecule. |
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They worked at Kings College in London. They developed high quality x-ray diffraction photographs of strands of DNA. A photograph suggested that DNA molecule resembles a tightly coiled helix and was composed of two or three chains of nucleotides. |
Who were Maurice Wilkins and Rosalind Franklin? |
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2 hydrogen bonds |
How many hydrogen bonds does adenine form with thymine? |
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3 hydrogen bonds. |
How many hydrogen bonds does cytosine form with guanine? |
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Complementary base pairs |
A characteristic of nucleic acid in which the sequence of bases on one strand is paired to the sequence of bases on the other. |
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Replication forks |
The areas where the double helix separate. Zipper |
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DNA polymerases |
Enzymes that move along each of the strands. They add nucleotides to the exposed nitrogen bases, according to the base pairing rules. As enzymes move along, two new double helixes are formed. They can also proof read and add nucleotides to a growing strand only if the previous nucleotide is correctly paired to its complementary base. If there is an error, this can trace and remove the incorrect nucleotide and replace it with a new one. |
