A Schwann Cell Membrane Glycoprotein - Journal of Neuroscience
Cell Architecture. CELL THEORY Mathias Schleiden and Theodore Schwann Prokaryotic cell Eukaryotic...
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Transcript of Cell Architecture. CELL THEORY Mathias Schleiden and Theodore Schwann Prokaryotic cell Eukaryotic...
Cell Architecture
CELL THEORY
• Mathias Schleiden and Theodore Schwann
• Prokaryotic cell
• Eukaryotic cell – plant cell and animal cell
• Figure 9-1
Animal cell substructures
Single and Double Membrane Substructures
• Single Membrane Structures– Plasma Membrane– Endoplasmic Reticulum– Golgi Apparatus– Lysosome– Peroxisome– Endosome
• Double membrane structures – Nucleus and Mitochondria
Plant Cell Substructures
Single and Double Membrane Substructures
• Single Membrane Structures– Plasma Membrane– Endoplasmic Reticulum– Golgi Apparatus– Lysosome– Peroxisome– Endosome
• Double membrane structures – Nucleus and Chloroplast
Plasma Membrane Chapter10 Fig.10-1
EM OF A THIN ERYTHROCYTE MEMBRANE
How do endosomes work?
Lysosomes
• Internal compartment is very different form the cytosol –more acidic pH
• Degrades substances that are obsolete• Phagocytosis and Endocytosis• All lysosmal enzymes are acid hydrolases• Tays Sach’s disease – defect in enzyme
catalyzing a step in the lysosomal breakdown of gangliosides.
Autophagy
Plant Vacuoles
• Similar to lysosomes – degradative enzymes• Concentration of solutes is larger inside the
vacuole than outside• Stores small molecules and is permeable to
water• Elongation of the plant is related to water
uptake by the vacuole
EM OF A PLANT CELL
Peroxisomes
• 0.2-1.0 micrometer in diameter• Oxidases• Catalase
2H₂O₂ -----> 2H₂O + O₂
• Main site of fatty acid peroxidation• Various toxic molecules that enter the body
are degraded here
Mitochondrial vs. Peroxisomal Oxidation
Fig. 12-12
Endoplasmic Reticulum
• Smooth ER:– Synthesis of Fatty Acids and Lipids– Metabolism of Carbohydrates– Detoxify Drugs and Poisons
• Rough ER:– Synthesis of Secretory Proteins, Membrane and
Organelle Proteins
ROUGH ER IS MADE OF RIBOSOMES
RIBOSOMES
• Composed of rRNA and protein• Site of protein synthesis• Proteins are marked for different organelles
or for secretion• Ribosomes are assembled in the nucleolus• Free Ribosomes
PROTEIN MODIFICATION IN THE ER
SECRETED PROTIENS– GLYCOSYLATION– DISULFIDE BOND FORMATION
HORMONE SECRETING CELL FROM RAT PITUITARY
Golgi Apparatus
Golgi - Function
• Flattened membrane vesicles or sacs• Cis, medial and trans -Golgi• Proteins targeted for different points in the
cell are modified differently• Secretory proteins• Plasma membrane proteins• Membrane or soluble proteins to other
organelles
HOW SECRETORY PROTEINS ARE TRANSPORTED?
ORGANELLES WITH DOUBLE MEMBRANES
• MITOCHONDRIA– Power house of the cell– Site of cellular respiration– Organic molecules are used fro ATP synthesisNUCLEUS
contains chromosomes, DNA and RNACHLOROPLAST
Site of Photosynthesis
EM OF A MITOCHONDRION
STRUCTURE OF A MITOCHONDRION
OUTER MEMBRANE AND INNER MEMBRANE
• OUTER MEMBRANE– 50% lipid and 50% protein– Porin proteins (MW of 10,000)
INNER MEMBRANE- CRISTAE
POWER HOUSE OF THE CELL
Nucleus
• Inner membrane and outer membrane• Outer membrane is continuous with rough ER• The intermembrane space is continuous with
the lumen of the ER• Nuclear pores and nucleoporins• Heterochromatin• Ribosomal RNA assembly
HETEROCHROMATIN
CHLOROPLAST
• Double membraned organelle• Length is 10µm and thickness of 0.5-2 µm• Sacs - Thylakoids• Stacks are grana• Matrix space called Stroma• Photosynthesis
MITOCHONDRIAAND CHLOROPLAST
• ATP production• Move around in the cell • Contain their own DNA• Some of their proteins are encoded in the
nucleus
EM OF A PLANT CHLOROPLAST