BIO 185 Chapter 6: Cell structure notes
Document Summary
The domains archaea and bacteria are prokaryotic: eukaryotes have a true nucleus bounded by a membranous nuclear envelope, region between nucleus and plasma membrane is called cytoplasm, within cytoplasm are membrane bound organelles specializing in, cell size. Why are cells small? importance of surface area to volume ratio? function: eukaryotes are generally bigger. Logistics of carrying out cellular metabolism sets limits on cell size. Theoretical upper limit on size that is practical for cell: as object increases in size, its volume grows proportionately more than its surface area (volume is cubed, area is squared). The smaller the object, the greater the ratio of surface area to volume: rates of chemical exchange through plasma membrane may be inadequate to maintain a cell with a very large cytoplasm. Not closed in membrane. nucleus directs protein synthesis by synthesizing mrna according to instructions provided by dna.
