Endoplasmic Reticulum By: Clea Mely & Vivian Obwogi

ER and Ribosomes The endoplasmic reticulum, or ER, plays an important role in the synthesis of proteins. The rough ER’s main function is to help, form and store proteins, while the smooth ER stores lipids, a type of fat. Ribosomes are manufactured in the cell nucleus in two types of subunits, the large and the small. The ribosomes are the site of protein synthesis. Ribosomes can either be attached to the Rough ER, or be floating freely in the cytoplasm.

Protein Manufacture Cells use genes to make proteins for critical jobs like carrying oxygen and contracting muscles. Multiple amino acids are linked together by peptide bonds, which form a long chain. Peptide bonds are formed by a biochemical reaction that extracts a water molecule as it joins the amino group of one amino acid to the carboxyl group of a neighboring amino acid which then manufactures the proteins.

Smooth/Rough ER The smooth ER has no ribosomes. It makes lipids. The rough ER is studded with ribosomes. It makes proteins. Both types are present in plants and animals. Both types consist of membrane enclosed, interconnected flattened tubes.

Why ER and Ribosomes are important The ER is the transportation system of the eukaryotic cell, and its proteins are contained within it until they are needed to move. The endoplasmic reticulum serves many general functions, including the folding of protein molecules and the transport of synthesized proteins in vesicles to the Golgi apparatus.

source http://bscb.org/learning-resources/softcell-e- learning/endoplasmic-reticulum-rough-and-smooth/ http://www.softschools.com/science/biology/the_function_of_en doplasmic_reticulum/ https://www.britannica.com/science/endoplasmic-reticulum http://bscb.org/learning-resources/softcell-e- learning/ribosome/ https://study.com/academy/lesson/protein-synthesis-in-cells- process-importance.html https://www.khanacademy.org/science/biology/structure- of.../nucleus-and-ribosomes