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Date Submitted: 02/28/2015 08:43 PM
The Cellular Basis of Life
1. Define cell.
- all living organisms are composed of cells, basic structure and function of life-vary widely in shape and size
- the principle of complentarity states that the biochemical activity of cells reflect the operation of organelles
- generalized cell has 3 major regions: nucleus, cytoplasm, plasma membrane
2. List the three major regions of a generalized cell and their functions.
- generalized cell has 3 major regions: nucleus, cytoplasm, plasma membrane
- plasma membrane encloses cell contents, meditates, exchanges w/ extracellular environment and plays a role in cellular communication
Cytoplasm the cellular region between the nuclear and plasma membranes, consist of the cytosol , inclusions, and cytoplasmic organelles
Nucleuscontrol center
The Plasma Membrane: Structure
3. Describe the chemical composition of the plasma membrane and relate it to membrane functions.
- plasma membrane is a fluid bilayer of lipids(phospholipids, cholesterol, and glycolipids) within which proteins are inserted
-the lipids have both hydrophilic and hydrophobic regions that organize their aggression and self-repair. The lipids form the structural part of the plasma membrane
-proteins are integral transmembrane proteins that extend entirely through membrane
-proteins are responsible for most specialized membrane functions: enzymes, receptors, and other mediate membrane transport functions
4. Compare the structure and function of tight junctions, desmosomes, and gap junctions.
- cell junctions join cells together and may aid or inhibit movement of molecules between or past cells
- tight junctions are impermeable junctions,
-desmosomes mechanically couple cells into a functional community
-gap junctions allow joined cells to communicate
The Plasma Membrane: Membrane Transport
- the plasma membrane acts as a selectively permeable barrier: substances move across the plasma membrane by...