Question

If a DNA strand has 30 guanines how much thymine does it have?

Answer 1

✔ It's given that The DNA strand has 30 Guanine.

❋ To solve this , we must know about the pairing of Nitrogen bases.

✔Purine always pairs with Pyrimidine.

✔ Adenine and Guanine are Purines while Thymine and Cytosine are Pyrimidine.

✔ Adenine (A) always pairs with Thymine (T) while Guanine always pairs with Cytosine (C).

✔ Hence, It's clear that the number of Adenine is equal to Thymine and number of Guanine are equal to Cytosine.

✔ The number of cytosine is also 30.

If we consider the number of Guanine as percent of Guanine we can solve this, since the length of DNA strand isn't mentioned.

✔ If Guanine and Cytosine together constitute 60 then remaining 40 are Adenine and thymine.

✔ Adenine and thymine are equal in number. Therefore, Adenine is 20 and Thymine is 20

Answer 2

Deoxyribonucleic acid :-

✧ The genetic information of a cell is stored in molecules of DNA and is a polymer of nucleotides .

✧ A DNA molecule consists of three parts - a nitrogen base , a five-carbon sugar called deoxyribose and a phosphate group .

✧ There are four DNA nucleotides - adenine, thymine , cytosine and guanine .

✧ DNA forms a two-stranded spiral or double helix .

✧ Adenine always bonds with thymine and cytosine always bonds with guanine .

✧ You have 30 Guanine and so there are 30 Cytosine . So there are remaining 40 adenine and thymine .

✧ Thus , there are 20 adenine and 20

Thymine .