Question

A single DNA strand begins with the sequence ATGGACGTATTC. Write the complementary DNA strand sequence. (A is adenine, T thymine, \(G\) guanine and \(\mathrm{C}\) cytosine.)

Short answer

The complementary DNA strand sequence for the given DNA sequence ATGGACGTATTC is TACCTGCATAAG.

Step-by-step solution

Identify the given DNA sequence

The given DNA sequence is ATGGACGTATTC.

Write the pairing rules

Remember the pairing rules: adenine (A) pairs with thymine (T), and guanine (G) pairs with cytosine (C).

Find the complementary nucleotide for each nucleotide

Go through the given DNA sequence and find the complementary nucleotide for each one: A -> T, T -> A, G -> C, G -> C, A -> T, C -> G, G -> C, T -> A, A -> T, T -> A, T -> A, C -> G.

Combine the complementary nucleotides

Combine the complementary nucleotides in the same order as the given DNA sequence: TACCTGCATAAG.

Write the complementary DNA sequence

The complementary DNA strand sequence for the given DNA sequence ATGGACGTATTC is TACCTGCATAAG.

Key concepts

Nucleotide Bases

The building blocks of DNA are known as nucleotide bases. These are molecules that come together to form the genetic code within our cells.
Nucleotide bases include:

• Adenine (A)
• Thymine (T)
• Guanine (G)
• Cytosine (C)

In the structure of DNA, these bases are paired with each other to create the famous double helix shape, resembling a twisted ladder.
This pairing occurs not randomly, but following a strict pattern that ensures the DNA's stability and functionality in encoding genetic information.

Complementary Base Pairing

In the DNA double helix, nucleotide bases pair up using a process known as complementary base pairing. This process is crucial because it provides the mechanism by which the DNA molecule replicates its code each time a cell divides.
The pairing rules are simple:

• Adenine (A) always pairs with Thymine (T)
• Guanine (G) always pairs with Cytosine (C)

These pairs are held together by hydrogen bonds, which are strong enough to hold the strands together but weak enough to allow separation during replication.
By following these pairing rules, DNA strands can replicate accurately, ensuring the transmission of genetic information across generations.

Adenine Thymine Guanine Cytosine

A closer look at the DNA's structure showcases the importance of the four bases: adenine, thymine, guanine, and cytosine, each of which plays a critical role in the genetic coding process.
Adenine and thymine form one pair, and their specific bonding is due to the number of hydrogen bonds they form, which is two.
Guanine and cytosine pair together, creating three hydrogen bonds, hence providing even stronger interaction.

• Adenine (A) - thymine (T) pairs through two hydrogen bonds
• Guanine (G) - cytosine (C) pairs through three hydrogen bonds

These binding patterns not only help in maintaining the DNA structure but also ensure that the genetic code is accurately copied during cell division.
The specific bonding and pairing also enable the correct functioning of DNA in encoding the instructions required for life.