Refraction of light at a convex surface :- 1. For real image :- The figure shows the geometry of formation of image I of an object O on the principal axis of a spherical surface ( convex ) with centre of curvature C and radius of curvature R. The rays are incident from a medium…
1. Incomplete dominance :- It is a post Mendelian discovery. In the case heterozygous condition of gene results in intermediate phenotype as one allele is only incompletely don’t over the other. The intermediate of flower colour in the Mirabilis jalapa is a good example to understand incomplete dominance. In a cross between true breeding red…
Mendel’s laws of inheritance :- Mendel’s present his paper on principles of heredity at the annual conventy on natural history society at Brun ( Austria ) in 1895. This paper use published in the proceeding on the conference in 1866. Tittle of this paper was experiment in plant hybridization. These principles are – 1. Law…
Monohybrid cross :- Monohybrid is the cross involves one character and single gene pair.It leads to monohybrid offspring in F₁ generation. Mendel proposed that in a true breeding, tall or dwarf pea variety the allelic pair of genes for height are identical or homozygous, TT and tt respectively. TT and tt are called genotype of…
It is a cross which involves two characters and two gene pair. it leads to dihybrid F₁ offspring. Mendel worked with and crossed pea plants that differed in two characters, as is seen in the cross between a pea plant that has seeds with yellow colour and round shape, one that had seeds of green…
Allele or Allelomorph :- Genes which code for a pair of contrasting traits are known as alleles, i.e. They are slightly different forms of the same gene. Example – In case of the character of height, T is used for the tall trait and t for the dwarf, T and t are alleles of each…
Genetics :- Genetics is the branch of biology concerned with the study of genes, genetic variation and heredity in organisms. Heredity :- It is the passing on of traits from parents to their offspring, either through asexual reproduction or sexual reproduction. The traits or characters are called hereditary characters. Gene :- A gene is the…
डीएनए (DNA) क्या है? डीएनए (Deoxyribose Nucleic Acid) न्यूक्लियोटाइड्स का एक लंबा बहुलक है जिसकी लंबाई न्यूक्लियोटाइड के संख्या पर निर्भर करती है न्यूक्लियोटाइड की संख्या अधिक होने पर डीएनए भी अधिक लंबे होते हैं। डीएनए (DNA) की संरचना :- न्यूक्लियोटाइड्स :- न्यूक्लियोटाइड के निम्नांकित तीन घटक होते हैं – नाइट्रोजन क्षारक दो प्रकार के…
RNA and its structure :- RNA molecules are single stranded nucleic acids composed of nucleotides. Fig. 1. Structure of ( a ) DNA and ( b ) RNA. RNA molecules are polymer of nucleotides joined to one another by covalent bonds between the phosphate of one nucleotides and the sugar of another. These linkages are…
Twinkling of stars :- it is is a phenomenon of atmospheric refraction. Stars do not really twinkle they just appear to twinkle when seen from the surface of the earth. The star twinkling in the night because of the effect of our atmosphere. when starling enters our atmosphere it is affected by winds in the…
Total internal reflection :- when light travels from and optically denser medium to rarer medium at the interface, it is partly reflected back into the same medium and partly refracted to the second medium, this reflection is called the internal reflection. Conditions for the total internal reflection :- Critical angle ( Ic ) :- The…
DNA फिंगरप्रिंटिंग :- मनुष्य के डीएनए में पाए जाने वाले क्षार अनुक्रम लगभग 99% एक समान होते हैं, किंतु शेष डीएनए में विभिन्नताए होते हैं, इन विभिन्नताओं का तुलनात्मक अध्ययन करने के लिए जिस विधि का उपयोग किया जाता है उसे DNA फिंगरप्रिंटिंग कहते हैं। DNA फिंगरप्रिंटिंग की विधि :- 3. डीएनए को सीमा तक…
