http://www.youtube.com/watch?v=Pfu1DE9PK2w CELL MEMBRANE

https://www.youtube.com/watch?v=rABKB5aS2Zg CELL SONG

4-2 PARTS OF THE EUKARYOTIC CELL A. CELL MEMBRANE Selectively permeable 1. Membrane lipids both sides of cell surrounded by water; polar hydrophilic phosphate heads orient themselves toward the water; nonpolar, hydrophobic fatty acid tails make up the interior of the membrane and orient themselves AWAY from water phospholipids form a bilayer; cholesterol also found among fatty acid tails

2. Membrane Proteins some are attached to inner or outer surface of membrane – peripheral proteins others embedded in the membrane and span membrane – integral proteins integral proteins often have carbohydrates attached to them on the exterior face of the cell – these function as receptors, or for cellular recognition sites – form “fuzzy coat” or glycocalyx

3. Fluid Mosaic Model membrane is fluid in nature and allows for lateral movement of the lipids and proteins

NUCLEUS Control center of the cell Surrounded by a double membrane , nuclear envelope (or nuclear membrane), with small holes within (nuclear pores) Chromatin – strands of DNA and protein; when cell is dividing, chromatin coils up and compacts into chromosomes Nucleolus is where ribosomes are assembled; stains darkly

C. ORGANELLES contained in the cytosol, a gelatin like fluid containing ions, and organic molecules

1. Mitochondria site of ATP synthesis energy of ATP fuels most of the chemical reactions in a cell surrounded by a double membrane; outer membrane serves as a boundary and inner membrane is highly folded to form cristae, which increase the surface area available for chemical reactions that occur in the mito

2. Ribosomes NOT surrounded by a membrane Made up of RNA and protein, assembled in the nucleolus, shipped out through nuclear pores and are found attached to the endoplasmic reticulum (exported or become inserted into membrane) or free floating (proteins made on these remain in the cell interior for use by the cell)

3. Endoplasmic Reticulum a system of membranous tubules and sacs that function as an intracellular (within the cell) highway smooth ER synthesizes lipids and carbohydrates, breaks down toxic substances rough ER makes proteins for export or proteins to be inserted into membranes

GOLGI APPARATUS A system of flattened stacks of membranes that process, package and secrete biomolecules for export (proteins, lipids and carbohydrates)

5. Lysosomes - membrane bound organelles that contain hydrolytic enzymes that digest proteins, lipids, nucleic acids, old organelles, viruses and bacteria - rarely found in plant cells

6. Peroxisomes – oxidize toxic substances (H2O2) using various enzymes (catalase)

PROTEIN SYNTHESIS

CYTOSKELETON - internal framework of protein strands (NOT surrounded by a membrane) that support cell and help move organelles and vesicles in the cell - microfilaments – many actin molecules linked to form a chain; smallest strands in cytoskeleton - microtubules – largest – hollow tubes – compose cytoskeleton, and arranged to form centrioles (assist in cell division) and cilia and flagella (cell movement)

9. CILIA AND FLAGELLA nine pairs of microtubules arranged around a central pair Short numerous ones – cilia; in unicellular organisms, cover exterior of cell and aid in locomotion; in human respiratory tract, they trap airborne particles and propel them back into throat Longer – flagella; swiftly propel unicellular organisms and specialized cells of multicellular organisms (sperm cells)

PLANT CELLS