the (eukaryotic) cell - introduction
DESCRIPTION
A brief description of subcellular structureTRANSCRIPT
The Cell
• Cell Overview
• The Plasma Membrane
• Key Organelles
Numbers, Variety, Sizes• 50 – 106 Trillion cells in the body
• ~200 different kinds of cells in bodynerve, blood, muscle, liver, kidney
• Length: 2 microns over 1 meterPlatelets = 2 micronsnerve cells = over 3 feet long
Generalized Cell
Cellular Components
• Plasma Membrane
• Nucleus
• Organelles
• Cytosol: water, ions, nutrients, waste products
• Granules: glycogen, melanin
The Plasma Membrane
The Fluid Mosaic Model
Phospholipid bilayer structural support
Cholesterol fluidity, flexibility
Proteins (many kinds) receptors enzymes transporters ion channels specialized connections
Crossing The Plasma Membrane
Mechanisms:• Passive
NO ATP required
• Active
ATP Required
• Simple Diffusion (High -> Low concentration)
• Osmosis (water mvt)
• Facilitated Transport (transporter protein)
• Active Transport(Low -> High concentration)• Sodium/Potassium pump(Mvt of Larger molecules)• Endocytosis• Exocytosis
Key Organelles
Nucleus
Mitochondria
Ribosomes
Golgi
Endoplasmicreticulum
NucleusDouble plasma membrane with large pores
Nucleolus for ribosome synthesis
Chromatin(DNA-protein)Extended—barely visibleCondensed--visible
Ribosomes
Protein synthesis (translation of mRNA)
free or associated with endoplasmic reticulum
2 subunits made in nucleolus from nucleic acids and proteins
Endoplasmic ReticulumA continuous membrane system:
Nuclear Membrane-Rough ER-Smooth ER
Rough ER (Ribosomes, newly synthesized proteins)
Smooth ER (Lipid synthesis, transport)
MitochondriaPowerhouse of the Cell
Site of Aerobic respiration:O2 used in oxidation of glucose, fats to produce ATP
Vary in # and size within cells
Double membrane
Golgi Apparatus
Packaging & Transport