Question

Imagine a single DNA strand containing a section with the following base sequence: \(5^{\prime}\) -AGTTACTGG-3'. What is the base sequence of the complementary strand?

Short answer

The base sequence of the complementary strand is \(3^{\prime}\) -TCAATGACC- \(5^{\prime}\).

Step-by-step solution

Identify the given sequence.

The given DNA strand has the following sequence: \(5^{\prime}\) -AGTTACTGG-\(3^{\prime}\).

Determine complementary bases.

For each base in the given sequence, identify its specific complementary base: - A (Adenine) pairs with T (Thymine) - T (Thymine) pairs with A (Adenine) - G (Guanine) pairs with C (Cytosine) - C (Cytosine) pairs with G (Guanine)

Write down the complementary strand.

Using the complementary base pairs from Step 2, write the base sequence for the complementary strand, going from \(3^{\prime}\) to \(5^{\prime}\): The complementary strand: \(3^{\prime}\) - TC A A T GAC C C - \(5^{\prime}\)

Key concepts

complementary DNA strand

In biology, understanding DNA involves knowing how to find a complementary DNA strand for a given sequence. Let's start with what a DNA strand is. DNA strands are like long strings made up of smaller units called nucleotides. These nucleotides line up in a specific order to carry genetic information. The concept of a complementary DNA strand is essential. It means creating a new sequence of nucleotides that can pair up with the original strand. This is like building a matching puzzle, where each piece has only one partner. In the original exercise, the sequence \(5^{\prime} - AGTTACTGG - 3^{\prime}\) needs to match up with its complementary strand, which is \(3^{\prime} - TC AATGACC - 5^{\prime}\).
Creating a complementary strand is vital for processes like DNA replication, where DNA needs to make exact copies of itself. It ensures that each new cell gets the correct genetic information. The process of determining a complementary strand is straightforward once you remember the base pairings.

nucleotide base pairing

Nucleotide base pairing is the heart of the DNA double-helix structure. It is based on the principle that certain nucleotide bases pair exclusively with each other:

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

This might seem complicated at first, but think of it like solving a simple matching game where each base only pairs with its specific partner. In the step-by-step solution, it’s all about switching the bases in the given sequence to their proper partners. For instance, every 'A' in the sequence becomes a 'T' in the complementary strand, and every 'C' turns into a 'G'.
Why is this important? Correct base pairing is crucial because it ensures that the DNA structure remains stable and the encoding of genetic information is accurate and reliable. It keeps the ladder-like structure of DNA, where two strands are held tightly by these base pairs, while still being flexible enough to twist into the double-helix form that is characteristic of DNA.

DNA sequence

A DNA sequence is like a biological code made up of four letters – A, T, G, C, each standing for a nucleotide. These sequences can range in length and carry the genetic information necessary for the development, reproduction, and functioning of all living organisms.
The sequence in the original exercise, \(5^{\prime} - AGTTACTGG - 3^{\prime}\), is a short segment of such code. Each sequence in DNA is important because it determines what proteins can be created. Proteins are essential for almost all functions within a cell.
Reading and interpreting DNA sequences involve moving in the correct direction – typically from the \(5^{\prime}\) end to the \(3^{\prime}\) end. This directionality is also maintained when writing a complementary DNA sequence, as seen in the exercise. Understanding the significance of DNA sequences aids in research, genetic testing, and therapies, contributing to health and medicine advancements.