A section of DNA containing 8000 bases has 1200 cytosine bases - Scottish Highers Human Biology - Question 1 - 2019
Question 1
A section of DNA containing 8000 bases has 1200 cytosine bases. The number of adenine bases in this section of DNA is
A 800
B 1200
C 1400
D 2800.
Worked Solution & Example Answer:A section of DNA containing 8000 bases has 1200 cytosine bases - Scottish Highers Human Biology - Question 1 - 2019
Step 1
Determine the total number of bases
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Answer
In this section of DNA, there are a total of 8000 bases.
Step 2
Identify the number of cytosine bases
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Answer
The question states that there are 1200 cytosine bases.
Step 3
Use the base pairing rules
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Answer
In DNA, adenine pairs with thymine, and cytosine pairs with guanine. Therefore, the number of guanine bases will equal the number of cytosine bases.
Step 4
Calculate the number of guanine bases
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Answer
Since there are 1200 cytosine bases, there are also 1200 guanine bases.
Step 5
Calculate the total number of adenine and thymine bases
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Answer
To find the total bases that are adenine and thymine, we first subtract the number of cytosine and guanine bases from the total number of bases:
[ 8000 - (1200 + 1200) = 8000 - 2400 = 5600 ]
This means there are 5600 bases that are either adenine or thymine.
Step 6
Determine the number of adenine bases
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Since adenine and thymine are present in equal amounts, we can divide the 5600 bases evenly:
[ \frac{5600}{2} = 2800 ]
Thus, there are 2800 adenine bases.
Step 7
Select the correct answer
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Answer
The number of adenine bases in this section of DNA is D. 2800.
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