Anjali Mishra Content Writer-SME
Content Writer-SME
The applications of genes and DNA are widely studied in the fields of biotechnology and genetics. Every living organism contains genetic material as well as genes. The genetic material can be either DNA or RNA. People who do not know the difference between genes and DNA use these terms interchangeably for convenience, but in reality, these genes and DNA are two different components.
- The basic unit of heredity is called gene.
- They are a set of instructions that determine the physical characteristics of an organism.
- Genes are made of a molecule called DNA or deoxyribonucleic acid.
- They store all the genetic information necessary for the growth, development and reproduction of an organism.
In this article, we will look at the major differences between gene and DNA as well as their definitions and functions.
Difference Between Gene and DNA
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Gene and DNA differ in various parameters like function, location, composition etc. The table below highlights the difference between gene and DNA.
| Genes | DNA |
|---|---|
| Genes are DNA segments that encode for various proteins. | DNA is a molecule that preserves the genetic information of an organism. |
| A single gene contains thousands of pieces of DNA. | DNA is a polypeptide with a long chain. |
| Gene research has been going on for a long time. | The research for the same is still in its early stage. |
| The only unique sequence of DNA that determines the characteristics is the gene. | DNA is a component of gene. |
| Genes encode information about heredity and govern characteristics. | It encodes genetic instructions and controls gene regulation. |
| A gene is present on a chromosome. | DNA is present within the nucleus of the cell. |
What is Gene?
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Genes are defined as small stretches of DNA that codes for proteins present inside a genome that are responsible for performing various functions like determining eye colour, hair color, etc. They also play a mjor role in coding RNA to perform other functions.
- We inherit genes from our parents, one gene from the egg and the other from the sperm.
- Once the genes are received they multiply themeselves till our body reaches the maximum limit.
- Approximately 20 to 25 thousand genes are present.
- The inheritance of an organism's phenotypic characteristic is determined by the transfer of genes.
- These genes are crucial in the formation of various DNA sequences called the genotype.
- The genotypes decide which phenotypes will occur based on environmental and developmental variables.
What is DNA?
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DNA is a double-helix molecule that provides genetic instructions for the formation, functioning, growth and reproduction of all known organisms and viruses. The two strands of DNA are made up of simpler monomeric units known as nucleotides.
- Each nucleotide consists of 4 nitrogen-containing nucleobases namely: Adenine, Thiamine, Cytosine, and Guanine.
- The DNA structure also includes a phosphate group and a sugar backbone.
- Covalent bonds called phosphodiester bonds connect the nucleotides together in a chain.
- This connection is formed by the sugar of one nucleotide and the phosphate of another.
- As a result, an alternating sugar-phosphate backbone is formed.
The primary difference between gene and DNA can be best understood with the help of the diagram shown below:
Gene and DNA Diagram
- To form double-stranded DNA, the nitrogenous bases are bonded together by hydrogen bonds.
- This binding is performed in accordance with the base-pairing rules (A with T and C with G).
- The complementary nitrogenous bases are further classified as purines and pyrimidines.
- The pyrimidines in DNA are thymine and cytosine, whereas the purines are adenine and guanine.
Things to Remember
- Gene and DNA are the two terms that are commonly used in biology.
- DNA was first discovered by Friedrich Meischer in 1869.
- A single gene contains thousand to upto million DNA base pairs
- Deoxyribonucleic acid destabilizes in high acidic and high akaline conditions.
- Gene make up only 3% of the DNA.
Previous Year Questions
- A disease caused by an autosomal primary non- disjunction is:….[NEET 2017]
- Which of the following conditions correctly describes the manner of determining the sex in the given example ?...[NEET 2011]
- Lack of independent assortment of two genes- A and B in fruit fly-Drosophila is due to...[NEET 2004]
- A gene is said to be dominant if :-...[NEET 2002]
- A gene pair hides the effect of another gene. The phenomenon is called….[NEET 1999]
- A gene showing codominance has….[NEET 2015]
- A human female with Turner's syndrome….[NEET 2014]
- A woman has an X -linked condition on one of her X chromosomes. This chromosome can be inherited by...[NEET 2018]
- A person with the sex chromosomes XXY suffers from….[NEET 1997]
- A plant of F1 generation with genotype "AABbCC". On selfing of this plant what is the phenotypic ratio in F2 -generation : -...[NEET 2002]
- Identify the wrong statement with reference to the gene T that controls ABO blood groups….[NEET 2020]
- Select the correct match...[NEET 2020]
- One of the parents of a cross has mutation in its mitochondrion. In that cross, that parent is taken as male. During segregation of F2 progenies that mutation is found in...[NEET 2004]
- The recessive genes located on X-chromosomes of humans are always….[NEET 2004]
- What is the probability that their second child will also be an albino?...[NEET 1998]
- Incorrect statement with regard to haemophilia is….[NEET 2013]
- Match the terms in Column-I with their description in Column-II and choose the correct option :….[NEET 2016]
- A colour blind girl is rare because she will be born only when….[NEET 1991]
- What is the probability of their grandson being colour blind ?...[NEET 2015]
- The phenomenon in which an allele of one gene supresses the activity of an allele of another gene is known as….[NEET 1995]
Sample Questions
Ques. What is the composition of DNA? (1 Mark)
Ans. Nucleotides are the building blocks of DNA. A nucleotide is made up of two parts: a backbone composed of the sugar deoxyribose and phosphate groups, and nitrogenous bases such as cytosine, thymine, adenine, and guanine. The genetic code is created by arranging the bases in different ways.
Ques. How are genes different from DNA on the basis of encoding? (1 Mark)
Ans. Genes encode information about heredity and govern characteristics while DNA encodes genetic instructions and controls gene regulation. This is the main difference between them two on the basis of encoding.
Ques. What is the function of DNA? (1 Mark)
Ans. DNA is an organic molecule that includes genetic information as well as protein production instructions. It can be present in the majority of cells in all organisms. DNA is an important component of reproduction in which genetic inheritance is passed down from parent to offspring.
Ques. How was it discovered that the genes are found on chromosomes? (2 Marks)
Ans. According to the chromosomal theory of inheritance given by Bovine and Sutton, genes are present at particular places on a chromosome. Later, Thomas Morgan discovered a mutation in the eye colour of fruit flies and concluded that the gene responsible for the eye colour is situated on the X-chromosome based on the inheritance pattern.
Ques. What is non-coding DNA? (2 Mark)
Ans. A significant portion of DNA does not function as a template for protein sequences. This is referred to as non-coding DNA. The two DNA strands are known as antiparallel. As a result, these strands flow in opposing directions to one another. Sugar is attached using one of four different nucleobases. The sequence of these four nucleobases encodes genetic information.
Ques. How do the alleles of a gene differ from one another? What is its significance? (3 Mark)
Ans. Alleles are distinct versions of the similar gene. A gene for height, for example, consists of two alleles, one for tall (T) and the other for dwarf (D) (t). They differ in nucleotide sequence, resulting in distinct morphologies.
Importance:
- They are critical in the study of heredity and behavioural patterns.
- They exhibit population diversity as a result of different phenotypes of a character.
Ques. How is double stranded DNA formed? (3 Marks)
Ans. To form double-stranded DNA, the nitrogenous bases of two distinct polynucleotide strands are hydrogen-bonded together.
- This binding is performed in accordance with the base-pairing rules (A with T and C with G). The complementary nitrogenous bases are further classified as pyrimidines and purines. The pyrimidines in DNA are thymine and cytosine, whereas the purines are adenine and guanine.
- Both strands of double-stranded DNA store similar biological information. This biological information is replicated during the separation of the two strands. More than 98 percent of humans are made out of DNA.
Ques. How is a gene different from DNA on the basis of presence? (4 Marks)
Ans. A gene is present on a chromosome whereas DNA is present within the nucleus of the cell. This is the main difference between them two on the basis of presence.
Other differences between Gene and DNA are tabulated below:
| Gene | DNA |
|---|---|
| Genes are defined as the DNA stretches. It is used to encode specific proteins. | DNA is defined as a biomolecule. It consists of genetic information. |
| It is a specific sequence present on a short stretch of DNA. | It is made up of two long chains of polynucleotides wound together. |
| Gene helps in regulating the traits of an organism. | DNA helps in regulating gene regulation. |
| Gene is coded with heredity information. | DNA encodes the genetic instructions. |
| A gene is present on a chromosome. | DNA is present within the nucleus of the cell. |
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