Cell Cytoplasm

Cell Cytoplasm

1. cytoplasm is the part of the cell located outside the nucleus

2. matrix consists of a variety of solutes

   • Na+, K+, Cl-, Ca2+
   • organic molecules (lipids, carbs etc)

3. organic molecules

   • intermediate metabolites
   • carbohydrates
   • lipids
   • proteins
   • RNAs

4. Organelles

   • Membranous (Membrane-bound)
     • Rough endoplasmic reticulum
       • ER w/ ribosomes
       • Protein synthesis and modefication
     • Smooth endoplasmic reticulum
       • lipid and steroid synthesis
       • No ribosomes
     • Golgi apparatus
       • composed of multiple flattened cisternae
       • modifying, sorting, and packaging proteins and lipids
       • intracellular or extracellular transport
     • Lysosomes
       • containing digestive enzymes
     • Transport vesicles
       • pinocytotic vesicles
       • endocytotic vesicles
       • coated vesicles
       • endocytosis and exocytosis
     • Mitochondria
       • Produce ATP via oxidative phosphorylation
     • Peroxisomes
       • production and degradation of H2O2
       • degradation of fatty acids
   • Non-membraneous
     • Microtubules
       • actin filaments
         • Flexible
       • intermediate filaments
         • confer retention and resistence
     • Filaments
     • Ribosomes
       • protein synthesis and composed of ribosomal RNA (rRNA)
     • Proteasomes
       • enzymatically degrade damaged and unnecessary proteins
     • Centrioles
       • found in the center of the microtubule-organizing center (MTOC)

5. Plasma Membrane

   • Best viewed by TEM
   • consists primarily of phospholipid, cholesterol, and protein
   • carbohydrates attached to lipids (glycolipids)
   • form the glycocalyx
     • specific functions in metabolism, cell recognition, and cell association and serve as receptor sites for hormones
   • carbohydrates attached to proteins (glycoproteins)
   • lipid rafts
     • contain high concentrations of cholesterol and glycosphingolipids
     • raft area is thicker and exhibits less fluidity
     • control the movement and distribution of proteins within the lipid bilayer
     • Two kinds
       • Planar lipid rafts
         • 47 kDa proteins (flotillins)
           • Flotillins are scaffolding proteins
       • Caveolar rafts (caveolae)
         • integral membrane proteins (caveolins)
           • Caveolins bind cholesterol and signal transduction proteins
             • participate vesicle formation in micropinocytosis
     • Lipid rafts permit movement of integral proteins (lateral migration) ---signaling pathways
   • ccontains integram proteins- visualized by a special freeze fracture (plits the vilayer)
     • P face
     • E face

6. enzymes= pumping, energy production, and digestion

7. structural proteins = include junctional proteins, scaffold proteins

8. Celll Signalling

   • respond to the external environment
   • signal transduction
     • amplificaioon and modulation
     • psysiological and bichemical regulation
     • ell and tissue specifity
   • Post-translational modifications (contribute to anplification)
     • Phosphorylation -PO4 3-
     • Glycosylation
     • Acetylation -COCH3
     • Methylation -CH3
     • Nitrosylation NO
     • Ubiquitination
     • SUMOylation (add ubiquitin modifier
   • Kinases