#24 The Role of Ribosomes, Golgi Apparatus and Endoplasmic Reticulum in the Production, Storage and Secretion of Proteins. Cell Biology Standard 1E. The learner will know the role of endoplasmic reticulum and golgi apparatus in the secretion of proteins.

The following slides list the correct order of protein processing in the cell.

Ribosomes

Ribosomes are small organelles composed of ribosomal RNA (rRNA) and 80 different proteins.The ribosomal subunits are assembled in the nucleolus. Once assembled, the subunits pass through the nuclear pores to the cytoplasm where they Decode mRNA to assemble amino acids into proteins. Protein synthesis is very important to cells, therefore large numbers of ribosomes are found in cells. Ribosomes float freely in the cytoplasm.

Rough ER

Rough Endoplasmic Reticulum Within the cytoplasm of cells is a 3-dimensional maze called the endoplasmic reticulum (ER). Ribosomes attached to the endoplasmic reticulum are called Rough ER, protein is formed within the interior to the endoplasmic reticulum. These proteins are destined for secretion, storage or incorporation into membranes.The Rough ER’s main function is to separate proteins that are leaving from those that are staying. Proteins are modified within the ER by the addition of carbohydrate and the removal of a signal sequence.

Smooth ER

Smooth ER lacks attached ribosomes and often appears more tubular than rough ER. Smooth ER gives the cell the ability to perform a variety of specialized functions. Smooth ER functions in the synthesis of lipids, carbohydrate metabolism, and the detoxification of drugs and other poisons.

Golgi Apparatus

The Golgi, a curved membrane stack resembling a stack of pancakes, concentrates and packages proteins for export or storage. It also adds directions for the destination of the protein package. Proteins made within the rough ER bud off in vesicles and are transported to the Golgi where the vesicles fuse with the membrane and the components are further modified.

Animal Cell 1. What part of the cell is the arrow pointing to? Cell Wall B. Cell Membrane C. Nucleus D. Ribosome

Animal Cell 2. What part of the cell is the arrow pointing to? Golgi B. Endoplasmic Reticulum C. Nucleus D. Ribosome

Animal Cell 3. What part of the cell is the arrow pointing to? Golgi B. Endoplasmic Reticulum C. Cell wall D. Cell membrane

4. What is the function of the golgi apparatus? Assemble amino acids into proteins. Regulate what enters & leaves cell. Concentrates & packages proteins for storage or export. Makes ribosomes

5. The golgi apparatus is primarily responsible for what cell process? Synthesizing proteins Store genetic information Translate info encoded in mRNA Processing Proteins