Law of Segregation ( Genes are Distributed without mixing ) Definition : During fertilization, two members of allelic pair remain together without mixing and these allele pairs separate or segregate, during gamete formation. Introduction : When a pair of contrasting characters or yellow/green factors as in fig. are brought together such as allele pair remain […]
Definition : If inheritance of more than one pairs of characters (two or more) is studied simultaneously, the factors (or genes) for each pair of character as sort out independently of other pairs. Introduction : Whereas the law of segregation applies to the behavior of a single pair of genes, the law of Independent assortment […]
Definition : When the genes of an allelomorphic pair are not expressed as dominant/ recessive but in the hybrid. This phenomenon is called Incomplete dominance. Introduction : The law of dominance is not always found to occur, as there are many examples, where dominance is about viz. (incomplete dominance). In such cases, some characters of […]
Definition: A gene is a functional unit attached to the chromosomal thread that can pass from one cell to another and can be transmitted from one generation to another without any change in its chemical and physical nature. Introduction: A Gene is a hereditary unit (also called hereditary factors of Mendel) and is responsible for […]
Definition : DNA is a senetic material (heritable material) responsible for inheritance. Introduction : Chromosomes are made up of basic proteins and nucleic acids. Nucleic acids discovered by Friedrich Miescher in 1869 ( from nuclei of pus cells) DNA is found in the nucleus as well as cytoplasm. It is the storehouse of genetic material. […]
Introduction : Chargaff Rule of base equivalence was established by Erwin Chargaff. It states that when DNA from any particular species is subjected to chemical hydrolysis in order to release its component purines and pyrimidines (1) The total amount of adenine released is equal to the total amount of thymine and similarly, […]
Introduction : James Watson and Francis Crick a rounded with Nobel Prize for (discovering) DNA structure (1953). X – rays diffraction studies indicated that distances between two paired nucleotides is 3.4 A0 and each turn of the double helix (3600) contains 10 paired nucleotides. Postulates of Watson and Crick’s DNA model : DNA exists as […]
Denaturation of DNA Definition : Denaturation is the transition from native to the denatured state of DNA. Introduction : Denatured Macromolecule results by disrupted state, or coiled conformation while when same molecule present in ordered state/originally present molecular structure in nature called as native. Denaturation is the transition from Native to Denatured state. When […]
Definition : There are five – different types of DNA exist in nature, which differs from each other with a difference in the normal state, molecular difference etc. Types of DNA : (a) A – DNA Found at relative humidity 75%. In high salt concentration or ions concentrations like Na+, K+, Cs+ or in […]
Introduction : It is a clearly stained, network of long and fine threads (called chromatin fibers) suspended in nucleoplasm largely in the interphase nucleus. W. Flemming (1879) first discovered by during cell division, these chromatin fibers condense by spiralization and dehydration into number of rods called chromosomes (Waldayer (1888) DNA is main genetic component of […]
