Question

Write the DNA complement for \(5^{\prime}\)-ACCGTTAAT-3'. Be certain to label which is the \(5^{\prime}\) end and which is the \(S^{\prime}\) end of the complement strand.

Short answer

Answer: The DNA complement of the given sequence is \(3^{\prime}\)-TGGCAATT-5'.

Step-by-step solution

Identify Complementary Bases

As mentioned earlier, adenine (A) pairs with thymine (T) and cytosine (C) pairs with guanine (G). With this information, we can easily determine the complementary base pairs for each base in the given sequence.

Write down the complement strand

The complementary bases for the given sequence are: - A -> T - C -> G - C -> G - G -> C - T -> A - T -> A - A -> T - A -> T - T -> A Hence, the complement sequence is: TGGCAATT

Label the \(5^{\prime}\) and \(3^{\prime}\) ends

For the complement strand, we need to reverse the order of the bases, as the original sequence is in \(5^{\prime}\) to \(3^{\prime}\) direction, and the complement sequence should be in the \(3^{\prime}\) to \(5^{\prime}\) direction. So, the final labeled complement strand is: \(3^{\prime}\)-TGGCAATT-5'$

Key concepts

Complementary Base Pairing

In the intricate dance of DNA structure, complementary base pairing plays the leading role by ensuring that the two strands of the DNA double helix fit together perfectly. Imagine DNA as a spiral staircase, with each step consisting of a pair of complementary bases connected across the central axis.

These bases are adenine (A), thymine (T), cytosine (C), and guanine (G). A always pairs with T, like two pieces of a puzzle that only fit together one way, creating a duo dubbed 'A-T'. On the other hand, C always pairs with G, forming the 'C-G' pair. This pairing is governed by the structure of the bases themselves, with hydrogen bonds creating a strong but not irreversible connection.

In one example, if given the DNA sequence 5'-ACCGTTAAT-3', finding the complementary strand would involve swapping A with T and C with G. Correctly identifying these partnerships is crucial in biological processes like DNA replication and transcription, and when studying genetics or performing laboratory work.

DNA Strand Directionality

DNA isn’t just a random string of molecules; it has directionality that is essential for its function and replication. Each strand has a 5' (five-prime) end and a 3' (three-prime) end, denoting the carbon number in the DNA's sugar backbone that the phosphate group is attached to. The 5' end has a phosphate group attached to the fifth carbon of deoxyribose sugar, while the 3' end has a hydroxyl (-OH) group attached to the third carbon.

Directionality is vital because DNA polymerases, the enzymes that replicate and read DNA, can only add new nucleotides to the 3' end of a growing strand. So, when we talk about the complement of the sequence 5'-ACCGTTAAT-3', we must reverse the order and label the ends 3'-TGGCAATT-5' to match the directionality of the original strand. This 5' to 3' orientation is a cornerstone of genetics, ensuring that the genetic information is accurately transmitted and read within a cell.

Nucleic Acid Sequence

The nucleic acid sequence is the precise order of nucleotides in a strand of DNA or RNA. Each nucleotide consists of a sugar, a phosphate group, and a nitrogenous base (A, T, C, or G in the case of DNA). The sequence is like a set of instructions or a language that codes for the synthesis of proteins and dictates the organism's hereditary information.

It is essential to write these sequences correctly, respecting the directionality and the complementary base pairing rules. Incorrect sequences can lead to mutations, resulting in nonfunctional proteins or diseases. For example, if you have the sequence 5'-ACCGTTAAT-3', understanding that each base must be paired with its complement allows us to accurately predict and write down the opposing DNA strand. Digging into nucleic acid sequences is fundamental not only for understanding life's genetic blueprint but also for applications such as forensic analysis, hereditary disease diagnosis, and biotechnology.