Search results
Results from the WOW.Com Content Network
50 μm – typical length of a human liver cell, an average-sized body cell [citation needed] 50 μm – length of a silt particle; 60 μm – length of a sperm cell; 78 μm — width of a pixel on the display of the iPhone 4, marketed as Retina Display [96] 70 to 180 μm – thickness of paper
The lipid bilayer is very thin compared to its lateral dimensions. If a typical mammalian cell (diameter ~10 micrometers) were magnified to the size of a watermelon (~1 ft/30 cm), the lipid bilayer making up the plasma membrane would be about as thick as a piece of office paper. Despite being only a few nanometers thick, the bilayer is composed ...
A plant cell wall was first observed and named (simply as a "wall") by Robert Hooke in 1665. [3] However, "the dead excrusion product of the living protoplast" was forgotten, for almost three centuries, being the subject of scientific interest mainly as a resource for industrial processing or in relation to animal or human health.
Some eukaryotic cells (plant cells and fungal cells) also have a cell wall. Inside the cell is the cytoplasmic region that contains the genome (DNA), ribosomes and various sorts of inclusions. [2] The genetic material is freely found in the cytoplasm. Prokaryotes can carry extrachromosomal DNA elements called plasmids, which are usually circular.
For the average adult human, the skin has a surface area of 1.5–2.0 square metres (15–20 sq ft). The thickness of the skin varies considerably over all parts of the body, and between men and women, and young and old. An example is the skin on the forearm, which is on average 1.3 mm in males and 1.26 mm in females. [4]
A typical human red blood cell has a disk diameter of approximately 6.2–8.2 μm [19] and a maximum thickness of 2–2.5 μm and a minimum thickness in the centre of 0.8–1 μm, being much smaller than most other human cells.
The volume of the human brain has increased as humans have evolved (see Homininae), starting from about 600 cm 3 in Homo habilis up to 1680 cm 3 in Homo neanderthalensis, which was the hominid with the biggest brain size. [7] Some data suggest that the average brain size has decreased since then. [8]
The cell wall is the relatively rigid structure surrounding the plant cell. The cell wall provides lateral strength to resist osmotic turgor pressure, but it is flexible enough to allow cell growth when needed; it also serves as a medium for intercellular communication. The cell wall comprises multiple laminate layers of cellulose microfibrils ...