If a DNA has 20 Adenine and 30 cytosine bases. What will be the total number of purine bases in the given sample?

Options

A. 20
B. 50
C. 30
D. 100

Answer

To solve the question, we need to determine the total number of purine bases in the given DNA sample. Here are the steps to arrive at the solution:

### Step 1: Identify the Purine Bases
Purine bases in DNA are Adenine (A) and Guanine (G).

### Step 2: Determine the Number of Adenine Bases
The question states that there are 20 Adenine bases in the DNA sample.

### Step 3: Determine the Number of Cytosine Bases
The question states that there are 30 Cytosine bases in the DNA sample.

### Step 4: Use Base Pairing Rules
According to the base pairing rules in DNA:
- Adenine pairs with Thymine (T)
- Cytosine pairs with Guanine (G)

From the pairing rules, we know:
- The amount of Adenine (A) is equal to the amount of Thymine (T).
- The amount of Cytosine (C) is equal to the amount of Guanine (G).

### Step 5: Calculate the Number of Guanine Bases
Since there are 30 Cytosine bases, there will also be 30 Guanine bases.

### Step 6: Calculate the Total Number of Purines
Now, we can calculate the total number of purines:
- Total Purines = Number of Adenine + Number of Guanine
- Total Purines = 20 (Adenine) + 30 (Guanine) = 50

### Final Answer
The total number of purine bases in the given sample is **50**.

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