What is deoxyribonucleic acid?

Deoxyribonucleic acid (DNA) is usually called the blueprint of life. Deoxyribose is a monosaccharide that has a key function in the synthesis of deoxyribonucleic acid. One less oxygen-containing hydroxyl group occurs in deoxyribose sugar. Nucleic acid, deoxyribonucleic acid, is one of the natural components. Deoxyribonucleic acid is a double-stranded molecule. Watson and Crick postulated the double-stranded model of the helix. A deoxyribonucleic acid is a molecular group that carries and transmits genetic information from parents to offspring. All eukaryotic and prokaryotic cells are involved.

Base pairs of deoxyribonucleic acid

The deoxyribonucleic acid is more stable compared to the ribose nucleic acid molecule. Adenine (A), cytosine (C), guanine (G), and thymine (T) are the four nucleotides or bases found in deoxyribonucleic acid. They are the deoxyribose nucleic acid sequences that create particular base pairs. In deoxyribose nucleic acid base pairs, the nitrogenous bases adenine and thymine (A-T) are paired together, and guanine and cytosine (G-C) are paired together. Adenine and guanine provide a purine base. The structures are made of 5- and 6-sided rings. Cytosine and thymine are pyrimidine structures that are made up of a single six-ring. Adenine always bonds with thymine, and cytosine and guanine bind to each other. The connection of these fundamental pairs shapes the deoxyribonucleic acid structure.

The image represents base pairs of deoxyribonucleic acid

Different forms of deoxyribonucleic acid

A-form DNA, B-form DNA, and Z-form DNA are three important kinds of deoxyribonucleic acid.


Deoxyribonucleotides make up A-DNA, it is a double helix structure and is right-handed. The two strands of A-DNA are not symmetrical and are antiparallel to each other. It occurs in a dehydrated sample of deoxyribonucleic acid, and they are used in the crystallographic experiment. A- DNA is short and broad as compared to B-DNA.


Watson and Crick discovered it using an X-ray diffraction pattern. It is usually present in deoxyribonucleic acid. The double-strand B-DNA runs in opposite directions. B-DNA is narrower than A-DNA.


It is a double helix structure and left-handed, this may be recognized from other forms of deoxyribonucleic acid due to its zigzag pattern. These are found to be present in bacteria, viruses, and eukaryotes.

DNA replication

The deoxyribonucleic acid replication process is self-replication, where deoxyribonucleic acid strands replicate themselves. In the domain of molecular biology, the self-replication of deoxyribonucleic acid is described as a process by which deoxyribonucleic acid strands produce their copies. Deoxyribonucleic acid is synthesized in two strands. The double-strands of the deoxyribonucleic acid will be moved in an antiparallel direction. The double-stranded would split during replication and serve as a template for the formation of the new additional strands. An enzyme such as deoxyribonucleic acid polymerase is used to replicate all sorts of deoxyribonucleic acid. After the completion of replication, each deoxyribonucleic acid molecule would have one parental and one newly formed strand. This is always called semi-conservative replication.

The figure shows the diagrammatic representation of DNA replication

Ribonucleic acid

The significant nuclear acid family member is ribonucleic acid (RNA). The nucleic acid of ribose nucleic acid is ribose. The ribose is inactive compared to deoxyribonucleic acid, and it is not fixed in alkaline conditions. Depending on the kind of ribose nucleic acid production, ribose nucleic acid forms in the kernels and moves into a particular cytoplasmic region. The figure of ribonucleic acid is usually single-stranded. However, double-stranded Ribonucleic acid is also found in some organisms. Ribonucleic acid is seen in single-stranded folded on itself rather than in double-strands. The ribose nucleic acid strands are formed of ribose sugar and phosphate groups. The ribonucleic acid molecule plays an important role in gene expression. Ribose nucleic acid consists of four nitrogenous bases such as adenine, guanine, cytosine, and uracil instead of thymine. In the ribose nucleic acid base pairs, the nitrogen bases are adenine (A) and uracil (U) paired together, and guanine (G) and cytosine (C) are base pairs. The binding of the base pairs forms the structure of ribonucleic acid. Adenine and guanine are purine nucleobases and cytosine, uracil and thymine are pyrimidine nucleobases.

The image represents the ribonucleic acid
PD-user | Image credits: https://commons.wikimedia.org | LadyofHats

Types of ribonucleic acid

There are mainly three types of ribonucleic acid molecules. They are; messenger ribonucleic acid (mRNA), ribosomal ribonucleic acid (rRNA), and transfer ribonucleic acid (tRNA).

Messenger RNA (mRNA)

Messenger ribonucleic acid (mRNA) is one of the significant types of ribose nucleic acid. The mRNA transmits deoxyribonucleic acid genetic information to cytosol-induced ribosomes. Where it is used as a template for protein synthesis.

Transfer RNA (tRNA)

When compared to the other two types of ribose nucleic acids, transfer RNA (tRNA) is the smallest. It plays a crucial role in the translational process. The main function of tRNA is to transfer amino acids during protein synthesis. tRNA is also considered an adapter molecule as it performs as an adapter while mRNA is synthesized into a protein as a gene sequence.

Ribosomal RNA (rRNA)

The ribosomal RNA (rRNA) molecule is a type of non-coding ribonucleic acid, it associates with protein and forms ribosome. The major function of the rRNA is protein synthesis.

Transcriptional Process

In molecular biology, the components of gene expression are transcription and translation. In the transcriptional process, copying segments of deoxyribose nucleic acid into ribonucleic acids produces messenger ribonucleic acid (mRNA). The precursor (mRNA) in the cell nucleus is produced during transcription from a deoxyribonucleic acid template. A deoxyribonucleic acid sequence is read by a ribonucleic acid polymerase, which is an enzyme that is responsible for the transcriptional process. A complementary and antiparallel strand of ribonucleic acid is produced by the enzyme ribonucleic acid polymerase.

Translational Process

The translation is the major secondary step in gene expression. In this process, the messenger ribonucleic acid (mRNA) is decoded by the ribosome to produce a specific amino acid in a polypeptide chain. During the translation process, tRNAs transport amino acids to the ribosome and bind with complementary codons. After translation, post-translational modifications occur. The covalent or usually enzymatic modification of the protein occurs through translation as a result of the synthesis of the protein. Post-translational modification enhances protein specificity and diversity in the human body.

The image represents translational process
CC-BY | Image credits: https://sciencebasedmedicine.org

Context and Applications

This topic is significant in the professional exams for both school level, undergraduate, and postgraduate courses especially for bachelors and masters in biotechnology, bachelors, and masters in microbiology, and bachelors in biochemistry.

Practice Problems

Question 1: Carbohydrates are polymers whose biological molecules are made of ______.

  1. Lipids
  2. Nucleotides
  3. Amino acids
  4. Sugars

Answer: Option 4 is correct.

Explanation: The polymerization of sugar molecules results in the formation of carbohydrates.

Question 2: The term that is used to describe a molecule with more than one double bond is ____.

  1. Saturated
  2. Monosaturated
  3. Polysaturated
  4. None of the above

Answer: Option 3 is correct.

Explanation: The saturated component has just one covalent bond, whereas one with two bonds is described as unsaturated. The 'mono' prefix signifies 'one' so that there is one double bond in the single-unsaturated molecule.

Question 3: Which nuclear base is not present in ribose nucleic acid?

  1. Adenine
  2. Thymine
  3. Guanine
  4. Cytocine

Answer: Option 2 is correct.

Explanation: Deoxyribose nucleic acid and ribose nucleic acid is a mixture of four nucleotides. However, the two nucleic acids are common only in three out of four adenine, guanine, and cytosine bases. The fourth nucleotide is thymine in DNA and thymine is replaced in the RNA by uracil.

Question 4: Both deoxyribose nucleic acid and ribose nucleic acid can form double helices. True or false?

  1. True
  2. False
  3. Given statement is wrong
  4. Maybe true

Answer: Option 1 is correct.

Explanation: Although it is generally known that DNA has a double-helical shape, a two-helical structure may also be formed by adjoining, additional RNA regions. In RNA, the uracil is equally capable as in DNA of base-pairing with adenine.

Question 5: Ribosome are formulating to __________________.

  1. Deoxyribose nucleic acid and ribose nucleic acid
  2. Deoxyribose nucleic acid and protein
  3. Ribose nucleic acid only
  4. Ribose nucleic acid and protein

Answer: Option 4 is correct.

Explanation: A ribosome is composed of RNA, protein, and two different RNA protein complexes, each ribosome is called to consist of small and big subunits. In eukaryotes, protein synthesis fragments of DNA translated to RNAs are arranged by ribosomes from the nucleus (mRNAs).

Want more help with your biology homework?

We've got you covered with step-by-step solutions to millions of textbook problems, subject matter experts on standby 24/7 when you're stumped, and more.
Check out a sample biology Q&A solution here!

*Response times may vary by subject and question complexity. Median response time is 34 minutes for paid subscribers and may be longer for promotional offers.

Search. Solve. Succeed!

Study smarter access to millions of step-by step textbook solutions, our Q&A library, and AI powered Math Solver. Plus, you get 30 questions to ask an expert each month.

Tagged in


Molecular genetics


DNA and RNA Homework Questions from Fellow Students

Browse our recently answered DNA and RNA homework questions.

Search. Solve. Succeed!

Study smarter access to millions of step-by step textbook solutions, our Q&A library, and AI powered Math Solver. Plus, you get 30 questions to ask an expert each month.

Tagged in


Molecular genetics