Short Answer
Genes are small units of heredity found on DNA. They carry instructions that control the traits and characteristics of living organisms, such as eye color, height, and blood group. Genes are responsible for passing traits from parents to offspring.
Each gene contains specific information needed to make proteins. These proteins control the structure, growth, and functioning of the body. Because of genes, organisms show similarities as well as differences.
Detailed Explanation :
Genes as Units of Heredity
Genes are the basic units of heredity in living organisms. They are small segments of DNA located on chromosomes. Each gene carries a specific set of instructions that decide a particular trait or function. Because genes control inheritance, they play a central role in biology.
DNA is a long molecule, and genes are specific regions on this DNA. Each gene has a unique sequence of nitrogen bases. This sequence stores information in the form of a genetic code. The code is used to produce proteins that control traits.
Genes are present in almost all cells of the body. However, they are passed from parents to offspring through reproductive cells. This transfer of genes explains why children resemble their parents.
Location of Genes
Genes are found on chromosomes, which are present in the nucleus of the cell. Each chromosome contains many genes arranged in a linear order. The position of a gene on a chromosome is called its locus.
Humans have 23 pairs of chromosomes, and each chromosome carries thousands of genes. One set of chromosomes is inherited from the mother and the other from the father. This means each individual has two copies of most genes.
The combination of genes received from both parents determines the traits of an individual.
Structure of Genes
Genes are made of DNA, which is composed of nucleotides. The order of nitrogen bases in a gene forms the genetic code.
This code is read during protein synthesis. First, the gene is copied into RNA. Then, RNA is used to make a specific protein. The structure of the protein depends on the gene sequence.
Even a small change in the gene sequence can change the protein produced. This may result in variation or genetic disorders.
Function of Genes
The main function of genes is to control traits. They do this by controlling protein synthesis. Proteins are responsible for body structure, chemical reactions, and cell functions.
Genes decide physical traits such as skin color, hair type, and eye color. They also control internal traits such as blood group and enzyme production.
Genes also control growth, development, and metabolism. Without genes, cells would not know how to function.
Genes and Inheritance
Genes are passed from parents to offspring during reproduction. Each parent contributes one copy of each gene to the child.
Some traits are controlled by a single gene, while others are controlled by many genes. The combination of genes determines the final appearance of traits.
Genes also explain why siblings are similar but not identical. Each child receives a different combination of genes from parents.
Genes and Variation
Genes are responsible for variation among individuals. Small changes in gene sequences, called mutations, create differences in traits.
These variations are important for adaptation and evolution. Without genetic variation, species would not be able to survive changes in the environment.
Genes also explain inherited diseases. Some genetic disorders occur due to faulty genes passed from parents to children.
Importance of Genes in Modern Biology
Genes are studied in genetics to understand inheritance, diseases, and evolution. Genetic research helps in diagnosing inherited disorders and developing treatments.
Genes are also used in biotechnology, genetic engineering, and medicine. Understanding genes helps improve crops, treat diseases, and study human ancestry.
In simple words, genes are instruction units that control life processes and inheritance.
Conclusion
Genes are the basic units of heredity made of DNA. They carry instructions that control traits, growth, and functioning of organisms. By passing genetic information from parents to offspring, genes ensure continuity of life and explain similarities and variations among individuals.