Chromosomes and genes

Introduction

Each chromosome is made up of DNA tightly coiled many times around proteins called histones that support its structure. Each chromosome contains hundreds to thousands of genes, which carry the instructions for making proteins. Genes, made up of a tiny stretch of DNA, are the basic functional unit of heredity. Chromosomes are DNA and related proteins that form a complex arrangement and are found in the nucleus as chromatin fibres. During cell division, chromatin fibres twist and condense even more, forming chromosomes.

Let’s talk about the Chromosomes and Genes definition. 

Gene

A gene is a segment of DNA involved in the transmission of information for a specific trait. They’re made of DNA and serve as functional units of heredity. Hereditary features are determined by genes, which is why we all share qualities from both parents, such as eye pigmentation and hair colour. Every cell in the human body contains between 29 and 30 thousand genes. Wilhelm Johannsen, a Danish botanist, was the first to invent the term gene in 1909.

Each cell in the human body contains approximately 25,000-35,000 genes. Only 2% of the genome is made up of DNA found in genes. Many studies have been conducted on the subject, with about 13,000 genes being discovered on each chromosome.

In 1905, William Bateson coined the term genetics. Wilhelm Johannsen, who created the term GENE in 1909, was the first to use it. He was a botanist from Denmark. To represent heredity, he named it ‘Gene’.

Functions of Genes

• Genes regulate DNA and RNA functioning.

• A gene is a little piece of DNA. Genes carry instructions that teach cells how to build protein molecules. Proteins help you stay healthy by performing a variety of activities in your body. Each gene contains instructions for determining your physical characteristics, such as eye colour, hair colour, and height.

• Genes are DNA segments that code for certain enzymes, proteins, and other proteins. We receive expressed proteins at the level of gene transcription, followed by translation in the ribosome. Genes code for enzymes, which is the link between genes and enzymes.

• Genes are made up of a specific collection of instructions or functions. The globin gene, for example, was told to make haemoglobin. Haemoglobin is a protein that aids in oxygen transport throughout the body.

Chromosomes

Chromosomes are multi-stranded structures made up of proteins and a single molecule of deoxyribonucleic acid – DNA. They are mostly found in the nuclei of animal and plant cells. They are passed down through the generations from parents to their children. The word chromosome comes from the Greek word ‘chromosomes’, which means “coloured body.” Every human cell has 46 or 23 chromosome pairs. These chromosomes are crucial in the cell division process because they ensure that DNA molecules are replicated and distributed appropriately.

Reasons for hereditary

Chromosomes are arranged in pairs and genes are present in chromosomes. A human has two copies of genes, and each parent transmits one copy of their genes onto their offspring. This is why the child shares many features with both parents, such as hair colour and eye colour.

Characteristics determined by genes

The chromosomes in a human cell are divided into 23 pairs. A trait is a characteristic that is influenced by one or more genes. Certain features are also caused by abnormal genes and genes generated due to new mutations. The size of genes varies depending on the code or protein they create. The DNA of every cell in the human body is identical. The difference between the cells is due to the different types of activated genes, resulting in a range of proteins being produced.

Chromosome Structure

A homologous chromosome is a pair of each type of chromosomes in each cell. Chromatin, which contains a single molecule of DNA and related proteins, makes up chromosomes. Hundreds of thousands of genes are found on each chromosome, each of which can code for many proteins in the cell. A chromosome’s structure is best seen during cell division.

Types of Chromosomes

Talking about chromosome and gene classification, let’s discuss the classification of chromosomes. On the basis of location of centromere chromosomes are classified as:

Metacentric – The centromere is positioned at one end of the chromosome  Submetacentric- The centromere is located near the centre of the chromosome.

Acrocentric- The centromere is located near the centre of the chromosome.

Telocentric- The centromere is located at the proximal end (tip) of the chromosome.

• Monocentric: Includes one centromere.
• Holocentric: Microtubules are attached along the length of a chromosome, and the centromere is dispersed.
• Acentric: Chromosomes can split and fuse without forming a centromere. It is unable to connect to the mitotic spindle.
• Dicentric: Two centromeres break and fuse, causing chromosomes to split and fuse. They’re also prone to fragmentation since two centromeres tend to move to opposite poles.

Functions of Chromosomes

• The primary function of chromosomes is to pass genetic information from one generation to the next.
• Chromosomes perform a crucial part in the growth, reproduction, repair, and regeneration processes, critical for their survival.
• Chromosomes keep DNA from being twisted or damaged.
• Histone and non-histone proteins play a role in gene regulation.
• The centromere’s spindle fibres aid in the movement of the chromosome during cell division.
• Each chromosome has thousands of genes that code for various proteins found in the body.

Gene Vs. Chromosome 

Let’s talk about the difference between chromosomes and genes: 

Conclusion 

We’ve learned about chromosomes and genes definition, chromosomes and genes classification, and many more.

In nature, genes are the fundamental units of inheritance. This included the nature, structure, and function of genes, DNA, and chromosomes, as well as how chromosomes determine gender and chromosomal disorders.

Reverse genetic approaches can also be used to determine gene function. Any gene can be mutated and re-inserted into a cell’s chromosomes to become a permanent component of the genome using DNA engineering techniques.