The organic components known as nucleic acids can be found in the form of DNA or RNA in all living things. These nitrogenous bases, sugar molecules, and phosphate groups are joined by various bonds in a series of sequences to generate these nucleic acids. The fundamental genetic make-up of our body is defined by the structure of our DNA. In actuality, it describes the genetic composition of almost all species on earth.

Table of Contents

What is DNA?

Discovery

Diagram

DNA structure

DNA Organization

The Chargaff Rule

replication of DNA

The role of DNA

Why is DNA referred to as a polynucleotide molecule?

Continue reading to learn more about the meaning, structure, and functions of DNA, as well as its discovery.

What is DNA?

DNA is a collection of molecules that carries and transmits the hereditary information resources or genetic instructions passed on from parents to children.

This holds true for viruses as well, because the majority of these organisms have either RNA or DNA as part of their genetic makeup. For instance, some viruses' genetic material may be RNA, whereas others' genetic material may be DNA. RNA is present in the Human Immunodeficiency Virus (HIV), which, after adhering to the host cell, transforms into DNA.

In addition to ensuring that all living things pass on their genetic information, DNA is essential for the synthesis of proteins. Nuclear DNA is the DNA that is found in the nucleus of each eukaryotic organism's cell. In contrast to mitochondrial DNA and plastid DNA, it codes for the majority of the organism's genomes and manages the remainder.

Mitochondrial DNA refers to the DNA that is found in the cell's mitochondria. It is passed on to the child from the mother. About 16,000 base pairs make up mitochondrial DNA in humans. Similar to this, plastids contain their own DNA and are crucial for photosynthesis.

Also see: mitochondria the power house of a cell

DNA in its whole form

The name "DNA" refers to deoxyribonucleic acid. It is an organic substance with a distinctive molecular make-up. Both eukaryotic and prokaryotic cells contain it.

Types of DNA

There are three varieties of DNA:

The right-handed double helix of A-DNA resembles that of B-DNA. DNA that has been dehydrated adopts an A form that shields it from harmful conditions like desiccation. involving proteins, DNA also loses its solvent, taking on the shape of an A.
B-DNA: A right-handed helix, this DNA conformation is the most prevalent. Under typical physiological settings, most DNA has a B-type shape.
Z-DNA: Z-DNA is a left-handed DNA whose double helix twists zigzag-style to the left. Alexander Rich and Andres Wang made the find. It is thought to play a part in gene regulation since it is located before the start point of a gene.

Also read: Chromosomes in humans| sequence structure, Discovery history and packing of DNA

DNA Discovery

The Swiss biologist Johannes Friedrich Miescher first recognized and named DNA in 1869 while conducting research on white blood cells. the research findings of Francis Crick and James Watson Finally, it was established that DNA is what keeps genetic information in living things.

Also read: Major difference between Eukaryotes and prokaryotes

DNA Chart

The DNA structure is represented by the different portions of the DNA in the diagram that follows. Nucleotide bases and a sugar-phosphate backbone make up DNA (guanine, cytosine, adenine, and thymine).

DNA structure

DNA: A picture of the DNA's structure

DNA Organization

One metaphor for the DNA structure is a twisted ladder. The image above shows what is referred to as this structure's double-helix shape. It is a nucleic acid, and nucleotides are the building blocks of all nucleic acids. The DNA molecule is made up of building blocks known as nucleotides, and

A DNA molecule's double helix structure was later discovered. Three distinct elements, such as sugar, phosphate groups, and nitrogen bases, make up each nucleotide.

Nucleotides, which consist of a sugar group, a phosphate group, and a nitrogen base, are the fundamental components of DNA. Each DNA strand is made up of nucleotides that are joined by sugar and phosphate groups. There are four distinct categories of nitrogen bases: adenine (A), thymine (T), guanine (G), and cytosine (C).

The pairings of these four nitrogenous bases are as follows: A with T and C with G. The DNA's double helix structure, which resembles a twisted ladder, depends on these base pairs.

The genetic code's or DNA's instructions are determined by the nitrogenous bases' order.

DNA Organization

structure of DNA components

One of the three elements Sugar is the component of DNA structure that comprises the DNA molecule's backbone. Additionally known as deoxyribose. A ladder-like structure is created when the nitrogenous bases of the opposing strands establish hydrogen bonds.

DNA structure

DNA's basic building blocks

Adenine (A), thymine (T), cytosine (C), and guanine (G) are the four nitrogen bases that make up the DNA molecule, and together they form a nucleotide. While the C and T are pyrimidines, the A and G are purines.

The two strands of DNA are oriented differently. The hydrogen bond that exists between the two complementary bases holds these strands together. Ten nucleotides make up a turn in the helically twisted strands, each of which forms a right-handed coil. Each helix has a 3.4 nm pitch. As a result, there is a 0.34 nm gap between two base pairs that are hydrogen bound to opposite strands.

DNA structure

One DNA molecule makes up each chromosome, which is formed when the DNA coils up to produce it. In the nucleus of each human cell, there are roughly 23 pairs of chromosomes. Additionally, DNA is crucial for the division of cells.

replication of DNA

Cell division involves a crucial mechanism called DNA replication. DNA copies itself during a process known as "semi-conservative replication."

replication of DNA

There are three phases of DNA replication:

Step 1: Launching

At a location called the origin of replication, DNA replication starts. The DNA helicase divides the two DNA strands. The replication fork is formed by this.

Elongation in Step 2

After reading the nucleotides on the template strand, DNA polymerase III creates a new strand by sequentially adding complementary nucleotides. For instance, if the template strand contains an adenine, it will add The complementary strand contains thymine.

Gaps arise between the strands as nucleotides are added to the trailing strand. The term "Okazaki pieces" refers to these spaces. Ligase fills in these holes or nicks.

Step 3: Finishing

The replication process is ended by the termination sequence that is present opposite the replication origin. DNA polymerase movement is stopped when the TUS protein (terminus utilization substance) attaches to the terminator region. It brings about termination.

DNA Activity

All genetic information is carried in DNA, which is the genetic material. Genes are the short pieces of DNA that typically have between 250 and 2 million base pairs. A gene codes for a polypeptide molecule in which each amino acid is represented by a sequence of three nitrogenous bases.

secondary and tertiary folding of polypeptide chains as well as quaternary structures to create various proteins. Since every creature has a large number of genes in its DNA, various kinds of proteins can be created. The primary structural and functional molecules in the majority of organisms are proteins. In addition to holding genetic data, DNA is involved in:

The replication process involves distributing DNA equally during cell division and transferring genetic information from one cell to its daughters and from one generation to the next.

Mutations: the modifications that take place in DNA sequences

Transcription

Mobile Metabolism

Gene therapy using DNA fingerprinting

Why is DNA referred to as a polynucleotide molecule?

DNA is referred to as polynucleotide molecule because the DNA molecule is made up of the nucleotides deoxyadenylate (A), deoxyguanylate (G), deoxycytidylate (C), and deoxythymidylate (T), which are combined to form DNA, the DNA is known as a polynucleotide. A polynucleotide is a long chain. The DNA is made up of two chains of polynucleotides, according to its structure.

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