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20 Cards in this Set

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What are the 4 concepts of cell theory?
1. a cell is the basic structural and functional unite of living organisms.
2. The activity of an organism depends on both the individual and the collective activities of its cells.
3. According to the principle of complimentarity, teh biochemical activities of cells are dictated by the relative number and their specific subcellular structures.
4. Continuity of life has a cellular basis.
T/F A cell's shape reflects its function
True
What are the three main parts of a human cell
plasma membrane, cytoplasm, nucleus.
What is a plasma membrane?
a fragile barrier that is the outer boundary of the cell.
What is the cytoplasm?
the intracellular fluid that is packed with organelles.
What is the nucleus?
lies near the cell's center, controls cellular activities.
What does the plasma membrane separate?
The intracellular fluid from the extracellular fluid.
What is the fluid mosaic model?
depicts the plasma membrane as an exceedingly thin structure composed of a double layer, or bilayer, of lipid molecules with protein molecules dispursed in it. The proteins float in the lipid bilayer forming a constantly changing mosaic pattern.
What is the lipid bilayer constructed of?
largely of phospholipids with smaller amounts of cholesterol and glycolipids.
What do hydrophillic and hydophobic mean?
Hydrophillis is water loving, hydrophobic is water hating.
What are glycolipids?
phospholipids with attached sugar groups that are found only on the outer plasma membrane and account for about 5% of the total memebrane lipid.
What is a lipid raft?
dynamic assemblies of saturated phosphlipds associated with unique lipids called sphingolipids and lots of cholesterol. Assume to be concentrating platforms for molecules needed for cell signaling.
What are proteins in the plasma membrane?
they make up about 1/2 the membrane by mass and are responsible for most of the specialized membrane functions.
What is a feature of integral proteins that allow them to interact with the bilayer and the internal and external enviroments?
They have both hydrophillic and hydrophobic regions
What are the functions of internal proteins?
1. transporters - some cluster together in channels.
2. carriers - bind to a substance and move it through the membrane.
3. receptors - for hormones or other chemical messengers. they relay messages to the cell interior
What is a peripheral protein?
not imbedded in the lipid. attached rather loosely to integral proteins or membrane lipids and are easily removed without disturbing the membrane.
What do peripheral proteins do?
some are enzymes. some are involved in mechanical functions, some link cells together.
What is glycocalyx?
a term used to describe the fuzzy, sticky carbohydrate rich area at the cell surfact.
What is the purpose of glycocalyx?
Since every cell type has a different pattern of sugars in its glycocalyx, it provides highly specific biological markers by which approaching cells recognize each other.
Why are peripheral proteins restrcited in their movements in the plasma membrane?
They are tethered to intracellular structures that make up the cytoskeleton.