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Chapter 4: Cell Structure. Topics you are not responsible for: Bacterial cell walls and the Archaea Cell-to-cell interactions End of Chapter questions: Understand: all Apply: all Synthesize: 1, 3, 4 Do all mQuiz questions. Inner Life of The Cell. - PowerPoint PPT Presentation
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Cell Structure 1
Chapter 4:Cell Structure
Topics you are not responsible for:Bacterial cell walls and the ArchaeaCell-to-cell interactions
End of Chapter questions:Understand: allApply: allSynthesize: 1, 3, 4
Do all mQuiz questions
TEM of Platinum/Carbon replicas of HeLa cell cytoplasm showing clathrin-coated vesicles and microtubules
Inner Life of The Cell
Cell Structure 2
What happens to Aafter it forms?
External Amyloid plaques
Internal Neurofibrillary tangles -- Tau protein
“Trafficking” of membrane components Exportto cell surface
-- APP, secretases, etc. Import into cell
QuestionsDo plaques and/or tangles cause Alzheimer’s Dis.?
Why do neuro. tangles form?
Cells and Organs 3
Leukocyte Rolling
Leukocyte Homing
Cells of you immune system circulate continuously through your body
Circulation of cells and Interstitial fluid
-- antigens / pathogens-- immune cells
Cell extravasation-- Chemokines-- receptors-- adhesion proteins
Cell Structure 4
Light Microscopy (A-C)
A
Bright Field DIC
B
DIC Video
Confocal 3D imaging
Electron Microscopy
D E
TEM SEMFluorescence
C
Microscopy
Normal Light Microscopy
Tick and Sick-2 5
Keratocyte DanceDIC $$
Microscopy, cont
Tick and Sick-2 6
Confocal $$$$Fluorescence $$$
Electron Microscopy
SEM vs TEM $$$$$
Tick and Sick-2 7
Cell Structure 8
Examples of Electron Microscopy
D. TEM (Transmission Electron Microscopy) of neurons (cross-section) showing internal cellular structures. ttp://visualsunlimited.photoshelter. com/image/I00005SIGjGWwl9U
E. SEM (Scanning Electron Microscopy) of neurons showing external surface structures.http://www.med.nus.edu.sg/ant/histonet/txt/nervsem/nerv03.sem.html
Examples of Light Microscopy
A. Standard Bright Field Microscopy of Histological section of brain stained to show Neurofibrillary Tangles (>) and Aβ plaques (*). http://www.microscopy-uk.org.uk/mag //artsep06/mc-Alzheimer.html
B. DIC (Differential Interference Microscopy) of Neocortical neurons in primary culture. Note accentuation of edges and 3D-like appearance Adapted from http://www.ipmc.cnrs.fr/cgi-bin/standard.cgi?descriptif=mantegazza.txt&dossier1=equipes&dossier2=mantegazza&site=inter&menu=1&ssmenu=14&lang=uk
C. Fluorescence Microscopy of fibroblast cell culture stained for proteins of the nucleus, mitochondria, and peroxisomes, as well as the filamentous actin and intermediate filaments. http://learn.hamamatsu.com/galleries/ digitalimages/muntjac/muntjaclarge10.html
Growing Cells
Advantages over whole organism
•Individual cell type•Controlled conditions
•Easier analysis•Stem cell culture & tissue
regeneration
Limitations•Individual cell type•Genetic changes
Tick and Sick-2 9
Cell Structure 10
How do Eukaryotic cells differ from Prokaryotic cells?
Prokaryotes = bacteriaEukaryotes = everything else
Size
Cytoplasm organization
Structure of chromosomes
We will discuss other differences later
Eukaryotic cell cytoplasm
Cell Structure 11
How big are cells?
Why are cells so small?
Surface to volume (S/V) ratio
How Big is It?
Cell Structure 12
What are some functionalregions of cells?
Cytoplasm
Cell membrane (plasma membrane)
Extracellular structures
Cell wall
Cilia & flagella
EC matrix
Cell Structure 13
What are the components of eukaryotic cytoplasm?
Membrane bound compartments
-- Cytoplasm vs “cytosol”
Molecular building blocks
Proteins/enzymes-- Cytoskeleton
Ribosomes
Cell Structure 14
What is the structure of the nucleus?
Large nuclear pores-- two membranes
Chromosomes
Nucleolus
Cell Structure 15
How do molecules move through the cell?
1) Diffusion
2) Endomembrane transport system
What is transported?
Where to?
Endocytosis & exocytosis
MolecularDiffusion
Know this!
Cell Structure 16
What is the structure and function of the ER?
Beginning of endomembrane transport
Rough ERProtein: -- synthesis (Ribosomes)
-- folding-- modifications (glycosylation)
Smooth ERLipid synthesisCa++ storage
Transport to Golgi
Cell structure
Transportvesicles
Cell Structure 17
What is the structure & function of the Golgi?
Protein modifications-- e.g., glycosylation
Sorting & Packaging into vesicles
View these animation Virtual cell -- Protein Trafficking
Virtual cell – Protein modificationLinks on Class resource page
How are proteins transported Through the Golgi?
Intracellular Transport 18
How are proteins modified within the golgi?
How are enzymes ‘tagged’ for transport to lysosomes?
-- hydrolytic enzymes -- NAcGluAm-P transferase-- mannose-6-P-- M-6-P receptors
Cell Structure 19
What is the function of lysosomes?
Breakdown of:
Intracellular materials
Extracellular materials
How are materials transported to lysosome?
Hydrolases from Golgi
Materials from inside and outside the cells
Cell Structure 20
Mutations to transport processes underlie some genetic diseases
I-cell diseases Accumulation of lysosomesMental retardation
Metabolic abnormalitiesFatal
Mucolipidosis IINAcGluAm-P transferase deficiencyWhat is expected effect?
Tay-Sacks diseaseganglioside GM2 lipase deficiency
-- lipid recycled from cell surfaceWhat is expected effect?
Lymphocytes of Mucolipidosis II
Cell Structure 21
What are functions of chloroplasts and mitochondria?
What are distinctive properties
Double membrane
Presence of DNA
What is the origin of these organelles?
“Endosymbiosis”
70S vs 80S ribosomes
Endosymbiosis
Cell Structure 22
What proteins comprise the cell cytoskeleton?
Intermediate filaments
Microtubules
Actin filaments
How is the “cytoskeleton” differentfrom a animal skeleton?
Organization and functionof Intermediate filaments
Mechanical strength
Cell Structure 23
What are the organization and functions of microtubules?
cytoplasmic transport
chromosome movements
movements of flagella and cilia -- “9+2” structure
Cytoplasmic streaming
Closer view onmicrotubules
Flagella Cilia
Cell Structure 24
What are the organization and functions of actin filaments?
Various types of cell movements
Membrane contractions
muscle contraction
Crawling motions
Interacts with “myosin”
Heart CellMembrane ruffling
Cell Structure 25
How do plant cells differ from animal cells?
Chloroplasts
Cell Wall
Vacuole
Cell Structure 26
How are viruses different from cells?
Much smaller
Protein coat – ‘capsid’
Often no membrane
No metabolism
Why are virus infectionsVery difficult to treat?