genetics and fertilization

Meiosis Random chromosome segregation Fertilization DNA sequence Role of chromosomes in determining an individual's sex Possible combinations of alleles in a zygote from the genetic makeup of the parents Probable outcome of phenotypes in a genetic cross fr..

Meiosis Random chromosome segregation Fertilization DNA sequence Role of chromosomes in determining an individual's sex Possible combinations of alleles in a zygote from the genetic makeup of the parents Probable outcome of phenotypes in a genetic cross fr..

These are genetic variations brought about due to shuffling of parental genes into new combinations. Thus, the resulting offspring exhibits genotypic variations. Genetic recombinations occur due to: Independent assortment of chromosomes during meiosis Reciprocal recombinat..

All the cells of an organism receive the complete set of genes (total information) present in the fertilized egg through mitotic divisions. However, cells of an early embryo lose the potential for the expression of all the genes through the processes of induction and repression, perhaps b..

Crop improvement technologies improve the potentialities of higher yield and food quality in crops. New varieties and hybrids of various crops released by various crop improvement techniques are ultimately aimed to increase the yield and better quality. But, these potentialities are realisable only..

Organic chemistry is that branch of chemistry which deals with the study of compounds of carbon with hydrogen (hydrocarbons), and their derivatives. Presently about five million organic compounds are known. Since the synthesis of urea from ammonium thiocyanate, many organic compounds were prepared ..

fig. 19.2 - Bacterial Chromosome In addition to the nucleoid, a bacterial cell may show the presence of extra chromosomal DNA molecules called plasmids. Like the bacterial chromosome, plasmids are double stranded circular DNA molecules which can replicate and function independently. The plasmids ma..

The biotic component of our environment on land, i.e. plants and animals (leaving aside the oceans and other water bodies) are overwhelmingly found in forests. Forests form a buffer for the earth to protect life forms; in fact that's where all our biodiversity and including cultivated crops and ho..

Polynuclear aromatic hydrocarbons enter the body quickly and go to the fat containing tissues. There is little data available for the toxic effects of naphthalene on humans. Short-term low exposure to naphthalene may cause eye and skin irritation. At slightly higher levels (above 10 ppm), headache..

Biology - A Science of Exceptions - Physical, chemical and mathematical sciences follow a specific set of rules and regulations. They are governed by a set of laws such as the law of gravity, the laws of thermodynamics, the law of conservation of mass and so on. However, biological sciences, in the..