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Preparation and Reactions of Sulfides02:26

Preparation and Reactions of Sulfides

Sulfides are the sulfur analog of ethers, just as thiols are the sulfur analog of alcohol. Like ethers, sulfides also consist of two hydrocarbon groups bonded to the central sulfur atom. Depending upon the type of groups present, sulfides can be symmetrical or asymmetrical. Symmetrical sulfides can be prepared via an SN2 reaction between 2 equivalents of an alkyl halide and one equivalent of sodium sulfide.
Septins01:19

Septins

Septins are protein filaments forming the cytoskeleton along with the microtubules, microfilaments, intermediate filaments, and other accessory proteins. In 1971 while studying the cell division cycle in mutant Saccharomyces cerevisiae Harwell et al. first identified the septin-related genes playing a crucial role in yeast cytokinesis. Fluorescence microscopy revealed that these proteins localize at the budding neck as rings. These ring-like proteins were then named Septins by John Pringle, and...
Protein Modifications in the RER01:26

Protein Modifications in the RER

Modification of secretory and transmembrane proteins entering the rough ER begins in the ER lumen. These modifications aid in protein folding and stabilize the acquired tertiary structure. Protein modifications in the rough ER co-occur at different stages of protein folding.
Broadly, these modifications can be categorized into four main categories — glycosylation, formation of disulfide bonds, assembly of protein subunits, and specific proteolytic cleavages like removal of signal sequences.
Dehydration Synthesis01:15

Dehydration Synthesis

Dehydration synthesis (also called a condensation reaction) is the chemical process in which two molecules covalently link together to form a new molecule, along with the release of a water molecule. Many physiologically important compounds form by dehydration synthesis reactions, such as complex carbohydrates, proteins, DNA, and RNA.Synthesis of carbohydratesSugar molecules are covalently linked together by dehydration synthesis. During the reaction, the hydroxyl (-OH) group from one reactant...
Ribosomal RNA Synthesis02:53

Ribosomal RNA Synthesis

Ribosome synthesis is a highly complex and coordinated process involving more than 200 assembly factors. The synthesis and processing of ribosomal components occurs not only in the nucleolus but also in the nucleoplasm and the cytoplasm of eukaryotic cells.
Ribosome biogenesis begins with the synthesis of 5S and 45S pre-rRNAs by distinct RNA polymerases. The primary transcripts are extensively processed and modified before they are bound and folded by ribosomal proteins and assembly factors,...