Chromosome mutation II

Change in Number One of the major type o chromosome mutation is change in chromosome number. There are two types of numerical changes  (1) Euploidy and (2)Aneuploidy 1. Euploidy: (eu = true, ploidy = set of chromosomes) The number of …

Comparison between rhizome and corm

Rhizome Corm 1.    It is a prostrate, thickened underground stem 2.    It is usually branched and rarely unbranched. 3.    It is elongated in shape. 4.    It contains a less amount of food material. 5.    They are generally perennial and live …

Difference between spine and thorn

Comparison between thorn and spine Spine Thorn Spines are modifications of leaves or parts of leaves. Their function is protection and also prevent excessive water loss. Does not deeply seated and not connected to vascular bundle Exogenous in origin Thorns …

Attenuation

Like regulation by the trp repressor, attenuation is a mechanism for reducing expression of the trp operon when levels of tryptophan are high. However, rather than blocking initiation of transcription, attenuation prevents completion of transcription. When levels of tryptophan are high, attenuation causes RNA polymerase to stop prematurely …

Tryptophan Operon

Operon: When a single promoter controls a number of genes. If tryptophan is present in the environment, then E. coli bacteria don’t need to synthesize it, so transcription of the genes in the trp operon is switched “off.” When tryptophan availability is low, on …

Translation (Protein synthesis)

  The process of protein synthesis. Charging of tRNA: Each amino acid is attached to a tRNA molecule, specific to that amino acid by a high-energy bond derived from ATP. The process is catalyzed by a specific enzyme called a …

Genetic Code

If genes are segments of DNA and if a strand DNA is just a string of nucleotides, then the sequence of nucleotides must somehow dictate the sequence of amino acids in proteins. How does the DNA sequence dictate the protein …

RNA splicing, the removal of introns

The vast majority of eukaryotic genes contain introns, segments of unknown function that do not code for polypeptides. Introns are present not only in protein-coding genes but also in some rRNA and even tRNA genes. Introns are removed from the …