Cellular Membrane System

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...