All of the cells of the human body except sex cells are termed somatic cells. These are diploid cells, meaning that they contain two homologous copies of each chromosome. Sex cells (eggs and sperm) are haploid cells, containing just one set of chromosomes in each cell. All human cells are eukaryotic, because they contain a nucleus and organelles within a cellular membrane.

While the nucleus houses the DNA and plays an integral role in the transcription of genetic code in order to produce specific proteins, actual protein synthesis is carried out by the ribosomes. These organelles consist of two subunits and are either independent in the cytoplasm of the cell or housed in the rough endoplasmic reticulum. Note that ribosomes can be in the cytoplasm or on the endoplasmic reticulum, hence making it rough.

A hypertonic solution, or one which contains solutes in higher concentration than blood cells, would cause water to leave the red blood cell across the osmotic gradient. This causes a reversible crumpling or shriveling of the cell, termed crenation. A cell in a hypotonic solution, wherein the cell itself contained a higher level of solutes than the fluid, would take on water, potentially causing the cell to lyse (burst). 

Ribosomal subunits are manufactured by the nucleolus, which is contained within the nucleus. It's primary function is the production and assembly of ribosome subunits. The RER houses ribosomes for protein manufacture. The SER does not take part in ribosome production or functioning. Note that ribosomes are composed of rRNA and protein. Proteins are translated on ribosomes in the cytoplasm.

90% of the cell cycle is spent in interphase. This time is also termed the "resting phase" as it is absorbing nutrients and replicating cellular elements in preparation for cell division. This phase includes the stages Gap 1 and Gap 2. Mitosis and cytokinesis, the final stages in cell division, are both relatively short compared to interphase, accounting for approximately 10% of the cell cycle.

Vinblastine and similar chemotherapeutic agents function by disrupting the formation and stability of microtubules in the cell. Because cell division is dependent on microtubule function, loss of microtubule integrity targets rapidly-reproducing cells such as cancer cells.

A hypotonic solution is one that contains solutes at a lower concentration than the cell. A cell, such as a red blood cell, will swell when exposed to a hypotonic solution as water moves into the cell to balance the osmotic gradient.

Vitamin B3 and vitamin B6 are required to convert glutamic acid into glutamine. Biotin (vitamin B7) plays roles in fat and amino acid metabolism, and though there has been no conclusive evidence of its effect on the growth of hair and nails, it is commonly taken as a supplement for these purposes. Folate (vitamin B9) is required during synthesis of red blood cells, and during DNA replication. Folate cannot be synthesized de novo, and thus must be ingested from the diet. Vitamin C is a powerful antioxidant, and is a cofactor to many biological processes. Cobalmin (vitamin B12) is involved in cell metabolism, particularly in that of fatty acids and amino acids. The source of B12 is from the natural flora of the gut. Vitamin D enhances the absorption of minerals such as calcium, magnesium, and zinc from the gastrointestinal tract. Vitamin E is a fat-soluble antioxidant.

Alcoholism is associated with thiamine (vitamin B1) deficiency. This is due to multiple factors: poor nutrition, ethanol's inhibition of thiamin transport in the intestine, and reduced storage of thiamine in the liver due to fatty changes.

L-arginine is a precursor for the production of nitric oxide, essential to vasodilation. Other precursors to nitric oxide include NADPH, oxygen, and nitric oxide synthetase (NOS) enzymes. These other amino acids do not have essential roles in the nitric oxide synthesis pathway.