Question

1. what is the correct path of a protein being made and moved out of the cell?

golgi apparatus → ribosome → nucleus → cell membrane
nucleus → golgi apparatus → ribosome → mitochondria
nucleus → ribosome → golgi apparatus → cell membrane
cell membrane → golgi apparatus → ribosome → nucleus

Explanation:

To determine the correct path of a protein being made and moved out of the cell, we analyze the process of protein synthesis and secretion:

1. Nucleus: DNA in the nucleus contains the instructions for making proteins. Transcription occurs here, producing mRNA.
2. Ribosome: mRNA travels to ribosomes (either free in the cytoplasm or on the rough ER) where translation occurs, and the protein is synthesized.
3. Golgi apparatus: The newly synthesized protein is transported to the Golgi apparatus, where it is modified, sorted, and packaged into vesicles.
4. Cell membrane: The vesicles carrying the protein fuse with the cell membrane, releasing the protein outside the cell.

Now let's analyze each option:

• Option 1 (Golgi apparatus → Ribosome → Nucleus → Cell membrane): Incorrect. Protein synthesis starts in the nucleus, not the Golgi apparatus, and ribosomes are where proteins are made, not after the Golgi.
• Option 2 (Nucleus → Golgi apparatus → Ribosome → Mitochondria): Incorrect. Ribosomes are where proteins are synthesized, and mitochondria are for energy production, not part of the protein secretion pathway.
• Option 3 (Nucleus → Ribosome → Golgi apparatus → Cell membrane): Correct. This follows the order of transcription in the nucleus, translation in ribosomes, modification in the Golgi, and secretion via the cell membrane.
• Option 4 (Cell membrane → Golgi apparatus → Ribosome → Nucleus): Incorrect. The process starts in the nucleus, not the cell membrane, and the direction is reversed.

Answer:

C. Nucleus → Ribosome → Golgi apparatus → Cell membrane