Nuclear Envelope: double layered membrane (2 phosopholipid bilayers) that confines nuclear contents mRNA exits to the cytosol to convey DNA message in the synthesis of proteins. Nucleus: generally the largest organelle, houses DNA (genetic information), synthesizes messenger RNA (mRNA) according to DNA templates
This also allows multiple processes with different environmental requirements to occur simultaneously
Eukaryotic cells have membrane-bound organelles that all the cell to maintain environments within each organelle that benefit their distinct function without harming the rest of the cell's components. These extensions permit expansion of SA without significantly increasing volume. Cells that have a high exchange rate with their environments increase their surface area-to-volume ratios with extensions called microvilli Smaller cells have a better surface area-to-volume ratio The interior volume of cell expands proportionally larger (compared to surface area) as surface area increases. The plasma membrane can only pass a certain amount of a substance at a particular time, so at a certain point, excess surface area of plasma membrane is useless. How large a cell is depends on the size of the "machinery" necessary to carry out processes to sustain itself and reproduce, while still remaining practical. Prokaryotic: takes up the entirety of the cell, does not contain membrane-bound organelles, "organized" into regions Eukaryotic: region between nucleus and plasma membrane, contains membrane-bound organelles Prokaryotic: DNA is not membrane bound, but concentrated in region called the nucleoid Eukaryotic: (most) DNA located in membrane bound nucleus All cells have: a plasma membrane, cytosol, chromosomes (genes in the form of DNA), and ribosomes 6.2: Eukaryotic cells have internal membranes that compartmentalize their functionsĬomparing Prokaryotic and Eukaryotic Cells.higher speeds: pellet consists of smaller components lower speeds: pellet (precipitate at bottom of test tube) consists of larger cell components This allows researchers to separate specific organelles, etc. Cell Fractionation: technique using centrifugation that separates cellular components according to their size. 6.1: Biologists use microscopes and the tools of biochemistry to study cells.range from single celled organisms to complex organisms with higher levels of cellular organization All cells are related by their descent from earlier cells The cell is the simplest living form of matter