1. What is the length of a1.5 kb fragment of double-stranded DNA? Give your answ
ID: 5373 • Letter: 1
Question
1. What is the length of a1.5 kb fragment of double-stranded DNA? Give your answer inangstroms. (kb = kilobasepairs)
2. You are studying a DNAmolecule that is 5.0 kb long. You determine that it contains 3500adenine bases.
a. How many guanine basesdoes this molecule contain?
b. How many pyrimidinesdoes this molecule contain?
3. Four samples ofdouble-stranded DNA are analyzed, and the following information isobtained:
a. For each of thesesamples, what can you predict as likely percentages for all of thebases?
b. Is it possible that any of thesesamples represents DNA from the same source?
Explanation / Answer
In the normal B DNA, 10.5 bp have a length of 36angstroms. SO 1bp length is 3.4 angstroms. So 1500bp has a length of 5100 angstroms. length is 5kbp long which is 5000bp. This gives 10000bases. Out of 10,000 , 3500 are adenine. According to chargaff's rules, the number of adenine = no. of thymine The number of guanine = no. of cytosine therefore, as adenine residues are 3500, thymine residues arealso 3500. a. The remainder is 3000bp. out of this 1500 are guanineand 1500are cytosine. b.pyramidines are cytosine and thymine--1500+3500=5000bases. 4. Sample 1: 15% thymine which means 15% adenine. This gives a total of30%. The remainder is 70% out of which 35% is guanine and 35% iscytosine sample 2: 20% guanine which means 20% cytosine. This gives a total of40%. The remainder is 60% out of which 30% is adenine and 30% isthymine. sample 2: 20% guanine which means 20% cytosine. This gives a total of40%. The remainder is 60% out of which 30% is adenine and 30% isthymine. sample 3: 30% adenine which means 30% thymine. This gives a total of60%. The remainder is 40% out of which 20% is guanine and 20% iscytosine. sample 4: 40% cytosine means 40% guanine. This gives a total of80%. The remainder is 20% out of which 10% is adenine and 10% isthymine. yes, samples 2 and 3 are from the same source. If we closelyobserve the % of bases they are same.Related Questions
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