Question

1. dna molecules can be tens of thousands of base pairs in length. mistakes in dna replication lead to mutations, which may or may not be harmful to an organism. how does semi - conservative replication help prevent mutations during dna replication?
2. the proportions of the bases are consistent within a species; however they do vary between species. using the base - pair rules, complete the following table to show the percentage of each type of base in the five different organisms.

Explanation:

Step1: Recall base - pair rules

In DNA, adenine (A) pairs with thymine (T), and guanine (G) pairs with cytosine (C). So \(A = T\) and \(G = C\), and \(A+G + C+T=100\%\)

Step2: For Human

Since \(A = 31\%\), then \(T=31\%\). Given \(C = 19\%\), then \(G = 19\%\)

Step3: For Cow

Since \(A = 28\%\), then \(T = 28\%\). Given \(G=22\%\), then \(C = 22\%\)

Step4: For Salmon

Since \(T = 29\%\), then \(A=29\%\). Given \(C = 21\%\), then \(G = 21\%\)

Step5: For Wheat

Since \(A = 27\%\), then \(T = 27\%\). Let \(G=x\) and \(C=x\). So \(27 + 27+2x=100\), \(2x=46\), \(x = 23\). So \(G = 23\%\) and \(C = 23\%\)

Step6: For Yeast

Since \(A = 31\%\), then \(T = 31\%\). Given \(G = 19\%\), then \(C = 19\%\)

Answer:

Organism	Adenine	Guanine	Cytosine	Thymine
Cow	\(28\%\)	\(22\%\)	\(22\%\)	\(28\%\)
Salmon	\(29\%\)	\(21\%\)	\(21\%\)	\(29\%\)
Wheat	\(27\%\)	\(23\%\)	\(23\%\)	\(27\%\)
Yeast	\(31\%\)	\(19\%\)	\(19\%\)	\(31\%\)