Summary CELL MEMBRANE, CYTOSKELETON AND ORGANELLES. Detailed Notes

CELL MEMBRANE • The cell membrane is selectively-permeable( ions and organic molecules), controls the movement of substances in and out of cells. • It consists of the phospholipid bilayer, consisting of hydrophobic tails and hydrophilic heads with embedded proteins, which are involved in a variety of cellular processes such as cell adhesion, ion conductivity and cell signaling. • The plasma membrane also serves as the attachment surface for the extracellular glycocalyx and cell wall and intracellular cytoskeleton Function • The cell membrane surrounds the protoplasm of a cell and, in animal cells, • physically separates the intracellular components from the extracellular environment. • anchoring the cytoskeleton to provide shape to the cell • attaching to the extracellular matrix and other cells to help group cells together to form tissues. • The barrier is differentially permeable and able to regulate what enters and exits the cell, • Thus facilitating the transport of materials needed for survival. • The movement of substances across the membrane can be either passive, occurring without the input of cellular energy, • active, requiring the cell to expend energy in moving it. The membrane also maintains the cell potential. A typical animal cell. Within the cytoplasm, the major organelles and cellular structures include: (1) nucleolus (9) Mitochondria (2) nucleus (10) Vacuole (3) ribosome (11) Cytosol (4) vesicle (12) Lysosome (5) rough endoplasmic reticulum (13) Centriole (6) Golgi apparatus (7) cytoskeleton (8) smooth endoplasmic reticulum • The cytoplasm has three major elements 1. cytosol 2. organelles 3. inclusions