Biology-Today.com

1. Changes in glycosidation of lipids and proteins: The Golgi complex plays a central role in the biosynthesis of gangliosides and other glycosphingo lipids. There is evidence that in cancer cells, there are surface membrane changes that involve a loss of glycosphingo lipids and these alterations are due to the reduction of one or more [...]

1. Immortalization of cancer cell: Cancer cells are characterized by immortalization; they overcome apoptosis by altering the genes that control such death of the cell. Genetic expressions of certain genes make the malignant cells immortal. These two genes are oncogenes and tumor suppressor gene. Actually activation of protooncogene and inactivation of tumor suppressor genes both [...]

1. The tumor cells are much rounded in shape compared to normal cells. 2. Mitochondrial size is said to be smaller in cancer cells than the normal. In cancer cells, the alternation is extremely frequent mitochondrial swelling and it appears denser. Some granules are smaller than mitochondria, termed as growth granules, which are found only [...]

Cancer cells are defined by two heritable properties: they and their progeny (i) reproduce in defiance of the normal restraints on cell division and (2) invade and colonize territories normally reserved for other cells. The controlling mechanism in the cell proliferation is maintained by a chain of events. Very occasionally, this control breaks down. A [...]

The main functions of mitochondria are: Cellular respiration and production of ATP through TCA cycle. It is therefore, called as the power-house of the cell. Synthesis of Lecithin and Phosphatidyl Ethanal Amines with the aid of Fat synthesizing enzymes. Regulates Fatty Acid metabolism. Aids in Yolk formation in the developing ova. Storage of different ions.

The giant chromosome (5000-9000 µm in length) found in the Oocytes of Fishes and Amphibians are known as Lampbrush Chromosome.  It consists of a main axis, along which the extended chromonema form loops to give the structure a brush-like appearance. The loops contain RNA and Proteins.

The giant chromosomes (100-200 times large than usual) found in the Salivary glands, gut, Malpighian tubules, etc. of Dipterous insects with dark and light bands along the length are known as Polytene Chromosomes. Dark bands are rich in DNA while the light ones in RNA. Some portions of the light bands become expanded as swellings [...]

What do you mean by the ‘Power House of the Cell? What is Ultra structure? Ans. Mitochondria are known as the Power House of the cell. 1. Elongated, Rod like or elliptical in shape (3-4 µm in length and 0.5-1 µm in diameter). 2. Enclosed in Double unit membrane. 3. Inner membrane gives out numerous [...]

The part of the chromosome in the primary constriction with which the spindle fibres become connected during cell division is known as centromere. According to its position in the chromosome, the following classification can be made: i) Telocentric Chromosome: Terminal centromere. ii) Acrocentric Chromosome: Sub-terminal centromere. iii) Sub-metacentric Chromosome: Sub-median centromere. iv) Metacentric: Median Centromere

1. What is the structure of chromosomes? Ans. Chromosomes are complex fibres made of nucleoproteins with the following structure: i) Each is made of two chromatids which appear spirally coiled fibres made at least of two chromonema. ii) Dot like chromomeres remain arranged in rows on the chromonema. iii) Each chromosome bears prominent centromere, on [...]