In this article we are focusing on the topic “Do Chromosomes Contain Genes: 9 Facts You Should Know” enlisting the facts and statements in support with it.
Chromosomes are packed form of DNA which forms genes and are hereditary units containing the genetic information that forms and entire genome of a living organism.
Gene is a basic functional heredity unit which are formed of deoxyribonucleic acids (DNA) and a chromosome contains multiple genes each with its own function and information for protein production. Genes are traits or characteristics that are inherited from parents to their offspring, for instance, a trait of blue eyes, big forehead etc.
Gene Structure
The structure of gene is a cluster of several specialized sequence elements which are organized in a standard way in a DNA. These genes sequences are the information of a life of living cell and its fate.
Structure of genes consists of three regions, a promoter or operator region, coding region and a termination sequence. Four chemicals called nucleotides that forms a gene are A, T, G, and C present repeatedly in a DNA sequence.
How many genes are in a chromosome?
A chromosome contains thousands of genes each having information to make proteins with specific functions. It has been known that approximately 30,000 genes in a genome of human forms around three proteins.
Around 20,000 to 22,000 genes are present in human chromosomes that are also called protein-coding genes. DNA is a very long structure with a length of around 3.0m and it is made up of three chemical units, a ribose sugar, phosphate group and nucleotide bases (A, T, G and C).
Do chromosomes contain many genes?
Yes, chromosomes do possess many genes and the genes are made up of DNA and further DNA is made up of “ATGC” letters, which are present in an organized way. Repeated sequences of ATGC are the information for the production of functional proteins.
There are in total six types of genes that exists, these are, Complementary genes, Duplicate genes, Polymeric genes, Modifying gene, Lethal genes, and Moveable genes.
Do all chromosomes contain genes?
Yes, every cell in a living organism contains chromosome which further possess thousands of genes. Genes are made up of deoxyribonucleic acid, containing ATGC repeats in an organized fashion, some genes are protein coding and some are not.
Genes are known as the building blocks of proteins as they carry the information for protein production. The coding sequences present in genes are called exons while the non-coding sequences are called introns.
How many genes can be inside a chromosome?
There are approximately 25,000 genes inside a human chromosome which codes for proteins and are termed as protein coding genes. The gene number varies in different chromosomes of different species, for instance, in humans around 3000 genes are present in Chromosome 1, 2500 in chromosome 2, and 1900 genes in chromosome 4 and so on.
The circular chromosome of E. coli bacterium carries 5,000 genes which codes for proteins. In humans 23 chromosomes carry around 19,000 protein coding genes. The bacteria “Mycoplasma genitalium” is known for its smallest chromosome size containing approximately 475 genes.
What is the difference between genes and chromosomes?
| Chromosome | Gene |
| Chromosomes are the condensed form of DNA coiled around a protein. | Genes are the small DNA segments present in the chromosome, called locus. |
| Chromosome is composed of DNA and a protein. | A gene can be either DNA or RNA. |
| Mutations are very common in chromosomes as they occur in homologous recombination. | In gene, mutations are not very often and occur during DNA replication and DNA damage. |
| Mutation can cause abnormalities in chromosome number and structure disruptions, for instance, deletion, duplication, insertion and gene inversion. | In gene mutations that occurs are, point and frameshift mutations, insertions and deletions. |
| Chromosomes contains both coding and no-coding genes. | Coding sequences present on genes are exons, and the non-coding sequences are called introns both present on unprocessed proteins. |
Which chromosome has least number of genes?
Chromosome Y contains the fewest genes, 200 genes in total out of which 70 are protein coding genes. The highest number of protein coding genes are present in chromosome 1 and chromosome 2, containing 2,058 and 1,309 genes in total.
Do genes contain Deoxyribonucleic acid (DNA)?
Yes, indeed genes contain DNA. Genes are entirely formed of DNA, some of them code for proteins and some genes do not. Genes exists in different size variation, ranging from a hundred base pairs to higher than 2 million bases.
All the normal cells contain the same amount of DNA located in the cell nucleus and is known as nuclear DNA. Another type of DNA is found in mitochondria which is in circular form and is known as Mitochondrial DNA.
Do Genes contain Ribonucleic nucleic acid (RNA)?
Genes coding for proteins are present in long double stranded DNA in a coiled form, during the process of an mRNA formation from DNA, the information stored in DNA gene is copied into an mRNA, a process called Transcription.
The mRNA transcribed from DNA at the end of transcription process is further translated into a protein by the process called Translation. In human transcription occurs in nucleus and translation occurs in cytoplasm of cells.
Conclusion
To conclude, we can say that chromosomes are important components of a cell which contains the entire genome in a packed form and uncoils when necessary.
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Hey! I am Sneha Sah, I have completed post graduation in Biotechnology. Science has always been fascinating to me and writing is my passion. As an academic writer my aim is to make Science easy and simple to learn and read.
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