AP BIOLOGY

Detailed explanation-1: -In eukaryotes, ribosomes get their orders for protein synthesis from the nucleus, where portions of DNA (genes) are transcribed to make messenger RNAs (mRNAs). An mRNA travels to the ribosome, which uses the information it contains to build a protein with a specific amino acid sequence.

Detailed explanation-2: -Although it is universally accepted that protein synthesis occurs in the cytoplasm, the possibility that translation can also take place in the nucleus has been hotly debated.

Detailed explanation-3: -If the protein is going to be targeted to the lysosome, become a component of the plasma membrane, or be secreted outside of the cell, the protein will be synthesized by a ribosome located on the rough endoplasmic reticulum (RER).

Detailed explanation-4: -Ribosomes are the sites in a cell in which protein synthesis takes place. Cells have many ribosomes, and the exact number depends on how active a particular cell is in synthesizing proteins.

Detailed explanation-5: -The many proteins that function in the nucleus-including histones, DNA and RNA polymerases, gene regulatory proteins, and RNA-processing proteins-are selectively imported into the nuclear compartment from the cytosol, where they are made.