DNA replication in eukaryotes is a complex and unique process involving many enzymes and thousands of ORI at a single time. Unlike the prokaryotic DNA, it involves a linear mode of replication. Why does linear DNA replication involve multiple origins at a time? The large linear chromosomes in eukaryotic cell …
Read More »Replication in Circular DNA: Theta Model
Following Meselson and Stahl’s work, investigators confirmed that other organisms also use semiconservative replication. There are, however, several different ways that semiconservative replication can take place, differing principally in the nature of the template DNA—whether it is linear or circular—and in the number of replication forks. Replicon and Origin of …
Read More »Translation: mRNA to Protein
Translation takes place on ribosomes; indeed, ribosomes can be thought of as moving protein-synthesizing machines. A ribosome attaches near the 5′ end of an mRNA strand and moves toward the 3′ end, translating the codons as it goes. Synthesis begins at the amino end of the protein, and the protein …
Read More »Post-transcriptional Modification
The process of transcription is very similar in prokaryotes and eukaryotes, but there are major differences in the relation between the transcript and the mRNA used for polypeptide synthesis in eukaryotes. In prokaryotes, the immediate product of transcription (the primary transcript) is mRNA; by contrast, the primary transcript (also called …
Read More »Genetic Code
The four bases in DNA – A, T, G, and C are sufficient to specify the 20 amino acids in proteins because each codon is three bases in length. Each sequence of three adjacent bases in mRNA is a codon that specifies a particular amino acid (or chain termination). The …
Read More »Transcription: The Mechanism of pre-mRNA Synthesis
Transcription is the synthesis of RNA molecule using one of the DNA strands as a template. It is the first step in the transfer of genetic information from genotype to phenotype. However, this process of transcription is a highly selective one i.e definite genes are transcribed only when their products …
Read More »Regulation of Gene Expression in Prokaryotes: General features and Significance
Every cell of an organism possesses all the structural genes or cistrons. The genes produce proteins and control the activities of the organism. But a genetic system doesn’t allow them to function all at a time in order to avoid enzymatic chaos. Many gene products are only needed occasionally by …
Read More »Induction, Repression & The Operon Models
Genes are the carriers of all the information of an organism. These information are needed for different protein synthesis at different time. So expression of gene can effect an organism’s characteristics, health and so on. As gene expression is a very important feature for any organism as well as for …
Read More »The Selfish Gene: The Mean of Existence
Part-1 This is more of a book review than just an article sharing including intuitive visualizations from the other sources related to “The Selfish Gene” (1976) on evolutionary biology by the evangelist of biological science Richard Dawkins. Unfortunately, this book wasn’t too popular from the day of it’s publications because …
Read More »Introduction to Male Sterility
Male sterility The male reproductive organs are mal-developed or aborted so that no viable pollens will be formed. This condition is known as male sterility (M.S) and may be inherited due to genetic, cytoplasmic or interaction of both genetic and cytoplasmic causes. History of Male Sterility The first documentation …
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