Question

which of the following cell organelles are required to make proteins
nucleus
smooth endoplasmic reticulum
rough endoplasmic reticulum
ribosome
mitochondria
chloroplast
golgi apparatus
cell membrane
lysosome
list them in the correct order to produce an protein for export
step 1__________
step 2__________
step 3__________
step 4__________
step 5__________

Explanation:

• Nucleus: Stores DNA which has the genetic code for proteins. Transcription (synthesis of mRNA from DNA) occurs here.
• Rough Endoplasmic Reticulum (RER): Has ribosomes attached. mRNA from the nucleus is translated into a polypeptide chain (protein synthesis) on the ribosomes of the RER. The RER also modifies (e.g., folds) the newly - made protein.
• Golgi apparatus: Receives the protein (in vesicles) from the RER. It further modifies the protein (e.g., adds sugar groups in glycosylation), sorts, and packages the protein into vesicles for export.
• Cell membrane: The vesicle containing the exported protein fuses with the cell membrane, and the protein is released outside the cell.
• Mitochondria (not in the main synthetic pathway but important): Provides ATP (energy) for all the processes (transcription, translation, modification, and transport) involved in protein synthesis and export.

Answer:

Step 1: Nucleus
Step 2: Rough Endoplasmic Reticulum
Step 3: Golgi apparatus
Step 4: Cell membrane
Step 5: Mitochondria