Recall that the central dogma of molecular biology states that the information flow within a cell involves DNA replication, transcription, and translation. DNA replication involves the formation of two identical DNA molecules from a single molecule and transcription involves synthesis of mRNA from DNA. The DNA molecules can’t leave the nucleus, therefore, both of these processes occur in the nucleus

Translation involves the synthesis of proteins from mRNA molecules. The mRNA molecules exit the nucleus after transcription (through nuclear pores) and enter the cytosol. The ribosomes in the cytosol bind to mRNA and facilitate translation; therefore, translation occurs in the cytosol.

The golgi apparatus collects, packages and distributes proteins to the locations where they are used. Proteins are always synthesized on ribosomes, which can either be floating in the cytosol, or on the rough endoplasmic reticulum. The smooth endoplasmic reticulum's functions include synthesis of lipids, and detoxification of substances. Lysosomes contain hydrolytic enzymes which break down macromolecules.

Eukaryotic cells are very resourceful in every way they function. When a cell part becomes worn out or non-functional, these part is broken down and recycled by the cell via lysosomal activation. This process is known as autophagy. The biological monomers produced from the catabolic process can then be used to build new polymers and macromolecules.

Exocytosis is the process by which contents from within the cell are expelled across the membrane. This generally occurs to assist cell signaling, such as the exocytosis of neurotransmitters. Positive selection is the process by which T-lymphocytes are presented by "self" antigens. If the T-cell reacts to the "self" antigen, it is destroyed to prevent autoimmune reactions.

The tail, terminal disc, and most mitochondria are found near the rear of the sperm cell (in order to facilitate movement). The acrosome is a cap-like organelle (derived from the Golgi apparatus) that develops over the anterior half of the head in the sperm cells of many animals. The acrosome contains digestive enzymes which allows the break down of the outer membrane of the ovum (zona pellucida). In short, the acrosome is located at the head of the sperm cell and allows penetration of the egg cell.

Ribosomes are found in all cell types and in all three domains. Recall the central dogma of biology: DNA RNA protein. Thus, all cells synthesize proteins using ribosomes. Also, note that although prokaryotes have ribosomes, ribosomes are never membrane-bound. Thus it still holds true that prokaryotes do not have any membrane-bound organelles.

Glycoproteins are proteins that have been modified by the addition of chains of carbohydrates of varying length. Glycosylation of proteins happens in the endoplasmic reticulum and the Golgi apparatus. Phospholipids are not proteins and are thus not synthesized in the endoplasmic reticulum, rather, they are synthesized in the cytosol. mRNA is the nucleic acid product of transcription, which occurs in the cytosol in eukaryotes, and in the cytosol in prokaryotes. Lumen is the term which means "an opening," e.g., the lumen of a blood vessel is the space where the blood flows, the lumen of the endoplasmic reticulum is the space inside the organelle itself.

One of the functions of the liver is to detoxify certain substances such as alcohol, lactic acid, and drugs. Since the smooth endoplasmic reticulum plays an important role in detoxification, liver cells contain extensive smooth endoplasmic reticula. The process of forming glycoproteins is carried out by the rough endoplasmic reticulum, and to some extent, the Golgi apparatus.

This question requires the knowledge that several biological substrates come in enantiomer forms (think of them as your right and left hands). Effectively these molecules come in two mirror/opposite configurations. Having the right configuration or shape is crucial for enzymes to catalyze reactions due to highly shape-specific bnding sites on substrate molecules. Thus, the correct answer to this qustion is "enzymes are highly specific on shape in order to carry out a reaction." The other answer choices, except "the cell has evolved to prefer a particular enantiomer becuase it is more abundant," do not allude to this underlying concept of why cells need a particualr enantiomeritic form/shape in order to carry out a reaction and are not correct. Last, enantiomers typically appear in similar oncentrations due to equal potential energies; therefore, it is unlikely and incorrect to expect the cell to develop an evolutionary preference based upon abundance.

The endomembrane system is a collection of membranes making up a cell that are connected either physically or via transport using vesicles. One of its main functions is to package and "ship" things made in the cell to other places in the organism, such as hormones like insulin. In order to do this, different organelles with different functions are necessary, just like there are different people with different jobs who make sure a package is mailed to the proper place.

The nucleolus is a specialized region found within the nucleus. It is responsible for synthesizing ribosomal RNA (rRNA), while transcription of messenger RNA (mRNA) and transfer RNA (tRNA) occurs in parts of the nucleus other than the nucleolus.