Biology Blogs For Class11th, 12th and NEET

                                     Jacob Syndrome  Jacob syndrome is due to presence of extra Y chromosome in males . This syndrome is also known as super male or criminal syndrome . Usually  in human being , there are 46 chromosomes but such a patients have extra Y chromosomes due to this the chromosome number changed from 46 to 47 . For more information click on this video .  Visit the full video for Jacob or supermale syndrome .    

                              Prokaryotes                     characteristics, cell structure , examples of prokaryotic cells                                     Prokaryotes are consist of eubacteria and arceha. The Organism that comes under  Prokaryotes are microscopic, simple organisms and the cell lacks a true nucleus.   The major characteristics of prokaryotes are as below - Features of prokaryotic Organism - True membrane-bound nucleus -   absent DNA complexed with histone - absent Number of chromosomes - One Ribosome - 70 S and 80 S Unit membrane-bound organelles - absent cell wall -  present in most of the prokaryotic cells and made up of peptidoglycan. Mitosis and meiosis - absent genetic recombination -  partial Mitochondria -  absent chloroplast - present  Sterol in Plasma membrane - Present  Cell Structure Of Prokaryotes -  The word prokaryotes comes from the Greek word where Pro means before and Karyon means nucleus. The prokaryotic organism do

                                  Phylum Platyhelminthus  Here are some important  features of phylum Platyhelminthus . Let's overview it .  Important Characters -                They are acoelomate and triploblastic . Body is leaf like or in ribbon shape forms and do not have  segmentation . They do not any circulatory system .  Digestive system absent . They follow organ level system of  organisation . They are bilaterally symmetrical organism . Hermaphrodite . Nervous system comprises of  brain and two longitudinal nerve which is connected at intervals by transverse commissures . They have internal fertilization . Asexual reproduction through fission .  Flame cells are present in the form of excretory system . Example - Taenia (Tapeworms )  , Fasciola ( Liver Fluke ) . 

                                      Chargaff's Rule  Erwin Chargaff's proposed two rules which are known as chargaff rules. This role plays a key role in double helix structure discovery. Here the rules are : - Rule 1 -  In DNA structure the total number of purines is equal to a total number of pyrimidine .,i.e., the number of guanine units is equal to the number of cytosine unit and the number of adenine units is equal to thymine units. Rule 2 -   In every species there is a unique composition of  DNA  is present in its body. Hence ,  in double stranded structure of DNA                                       A = T =  1                                       G = C =  1                 Also, the percentage of C + G does not essentially equal to the percentage of A+ T