Biology

Difference between Gene and Chromosome

Genes and chromosomes play an important and equal role in holding the information. The main difference between genes and chromosomes is that gene is made up of DNA sequences, whereas chromosome is complete strands of DNA that are packed closely together to fit in a cell. Therefore the entire chromosome is covered with genes. In other words, it contains several genes, while it cannot be said the other way around. You should understand that genes and chromosomes are not the same. Another perhaps easier way to think is in an apartment complex. A building and an apartment within the building are not the same things. the gene is represented by the apartments, while the chromosome is the tall buildings that encompass all the apartments. However, the genes and chromosomes are not the same. Let us discuss the difference between genes and chromosomes in detail.

Difference Between Gene And Chromosome In Tabular Form

Gene

Chromosome

What is it?

The functional unit of inheritance Linear DNA packaging structure

Location

On the chromosomes In the nucleus of the cell.

Types

  • Structural genes
  • Regulatory genes
  • Pseudogenes
  • Specialized genes
  • Constitutive genes
According to function, there are two types of chromosomes:

  • Somatic chromosomes
  • X and Y sex chromosomes

According to the location of the centromere, there are four types of chromosomes:

  • Metacentric chromosomes
  • Submetacentric chromosomes
  • Acrocentric chromosomes
  • Telocentric chromosomes

Examples:

  • ACTB gene
  • BRCA1 gene
  • Insulin gene
  • Homo sapiens : 46 chromosomes
  • Mus musculus: 40 chromosomes
  • Gorilla: 48 chromosomes

What are Genes?

Gene is the functional unit of heredity. Genes are defined as a segment of the DNA sequence corresponding to a protein, a set of protein variants, or structural RNA molecules that do not produce proteins. In the human, the genome project determined that humans have 20,000-25,000 genes in their genome in the 3 billion base pairs of DNA. The fruit fly Drosophila melanogaster has about 14 thousand genes in 137 million base pairs and the Arabidopsis thaliana plant has approx. About 26 thousand genes in 142 million base pairs of DNA.

Types of Genes:

Genes can be of the following types:

  • Regulatory genes
  • Structural genes
  • Specialized genes
  • Genes constitutive
  • Pseudogenes

Function OF genes

The major functions of genes are listed below:

  • Genes contain the information that determines the characteristics of the species.
  • Genes control the development and functions of cells.

What are chromosomes?

A chromosome is a threadlike structure found inside the nucleus, made up of DNA and proteins. The eukaryotic cells of each species of living thing contain a characteristic fixed and a constant number of chromosomes. I.e., Homo sapiens has 23 pairs of chromosomes or 46 chromosomes. They are visible under an electron microscope when cells begin to divide. Chromosomes can be identified by their number, size, centromere position, and banding pattern in a given species. The karyotype is the number and appearance of human chromosomes.

What are the 46 chromosomes?

In living beings where there is sexual reproduction, the sex cells/gametes have only one set of the chromosomes of the species, which is, they are haploid. For example, in humans, eggs have 23 chromosomes and sperm also have 23 chromosomes. The number of chromosomes is not related to the complexity of the organism, such as, in somatic cells of humans, there are 46 chromosomes, in mice 42, in bovines 60.

See Also: What exactly is DNA?

Structure of Chromosomes

The chromosomes have the following structures:

  • Centromere – a constricted region of a chromosome that separates it into a short arm (p) and a long arm (q).
  • Telomeres – are the protective caps on the ends of the strands of DNA
  • two arms, a small one or P-arm, and a long one or q-arm.

Functions of Chromosomes

The main functions of chromosomes are listed below:

  • The packaging of DNA within the nucleus is the main function of chromosomes.
  • The DNA of a human comprises more than 3 billion base pairs, that if it could be extended would be 2 meters long, but the nucleus is barely 0.000006 meters long!

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