Carbon in structures in a human cell (in micro- and nano-scale)
Carbon exists in organic molecules such as fats, amino acids and proteins, sugars. We are built of carbon.
Structures such as inorganic and organic carbon, DNA (deoxyribonucleic acid), and parts of cell membranes contain nanotubes and fullerenes. They are subject of the inquiries made with nanotechnologies, for example molecular electronics, nanolithography, or nanorobotics.
In order to shift the concept of the scale to cell biology, we may examine a cross section of a human cell, which presents its compositional elements. The size of a human cell is between 4 μm (4 x 10-6 m) and 135 μm. Blood cells are about 2.5 μm. For comparison, the ostrich egg is the largest known cell and weights over 3 pounds (over 1360 grams). Paramecium (a single-celled freshwater animal) is about 60 μm wide and 50 to 350 μm long. The size of a skin human cell is about 30 μm. Water molecule (hydrogen oxide H2O consisting of two hydrogen atoms and one oxygen) is about 0.29 nm. A flu virus has diameter about 100 nm.
A cell is surrounded by a cell membrane. The cytoplasm lies within the plasma membrane of lipids (fat) and protein. Most cells have a single nucleus, which contains nucleoli. Nucleus embodies most of the cell’s genetic material in chromosomes containing DNA and proteins; it directs the activity of the cell. Some other organelles are: complex sets of membranes called endoplasmic reticulum (with ribosomes, numerous tiny particles consisting of RNA and proteins, which control protein synthesis), a Golgi apparatus (part of endomembrane system that processes proteins for further secretion), mitochondria (with an outer membrane and a convoluted inner membrane, a site of respiration and energy production in the cell), and centrioles near the nucleus (which play a part in cell division).
Most of the structures inside the cell belong to the nano world. For example, a molecule of the deoxyribonucleic acid, DNA is 2.5 nm wide (it is millions of atoms long). Mitochondria range from .5 to 1 μm and ribosomes are between 25 and 30 nm in diameter. Microtubules in a cytoskeleton (a scaffolding of a cell’s cytoplasm) may be 25 micrometers long, with diameter about 25 nm. Microfilaments in a cytoskeleton have individual subunits of microfilaments in the actin filaments that measure approximately 7 nm, and their bundles separate filaments by ~35 nm. In many cells one may find plasmids, which are not considered alive; they are the DNA molecules separate from the chromosomal DNA.
Scientists examine metabolism, excretion, and toxicity of fullerenes C60 and their derivatives because they have potential biological applications, such as enzyme inhibition, antiviral activity, DNA cleavage, photodynamic therapy, electron transfer, and other in vitro and in vivo biological effects. Buckyballs can act in a body as antioxidants. Antioxidant is a molecule that can add an electron and neutralize a free radical. Free radical is a molecule or atom with an unpaired electron. Free radicals may react with cells in the body and cause many types of cancer. Buckyballs may connect a drug with a molecule that reacts to changes in pH (pH is a measure of the acidity in a solution). As the harmed tissues have different pH levels than the healthy areas, buckyballs may deliver drugs directly to harmed areas of the body. Thus, by using buckyballs researchers can create drugs that are only released at the infected area (Clark, 2006).