Transcript 3-CellStructure

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
TEM of Platinum/Carbon replicas of
HeLa cell cytoplasm showing clathrincoated vesicles and microtubules
Cell Structure
1
What happens to Ab after it forms?
External Amyloid plaques
Internal Neurofibrillary tangles
-- Tau protein
“Trafficking” of membrane components
Exportto cell surface
-- APP, secretases, etc.
Import into cell
Questions
Do plaques and/or tangles
cause Alzheimer’s Dis.?
Why do neuro. tangles form?
Cell Structure
2
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
Leukocyte Rolling
Leukocyte Homing
Cells and Organs
3
Light Microscopy (A-C)
B
A
Bright Field
DIC
Electron Microscopy
C
Fluorescence
DIC Video
E
D
Confocal 3D imaging
Cell Structure
TEM
SEM
4
Microscopy
Normal Light Microscopy
DIC $$
Tick and Sick-2
Keratocyte Dance
5
Microscopy, cont
Fluorescence $$$
Confocal $$$$
Tick and Sick-2
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Electron Microscopy
SEM vs TEM $$$$$
Tick and Sick-2
7
Examples of Light Microscopy
Examples of Electron Microscopy
A. Standard Bright Field Microscopy
of Histological section of brain stained
to show Neurofibrillary Tangles (>) and
Aβ plaques (*). http://www.microscopy-
D. TEM (Transmission Electron
Microscopy) of neurons (crosssection) showing internal cellular
structures. ttp://visualsunlimited.photoshelter.
uk.org.uk/mag //artsep06/mc-Alzheimer.html
com/image/I00005SIGjGWwl9U
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/cgibin/standard.cgi?descriptif=mantegazza.txt&dossier
1=equipes&dossier2=mantegazza&site=inter&men
u=1&ssmenu=14&lang=uk
E. SEM (Scanning Electron
Microscopy) of neurons showing
external surface structures.
http://www.med.nus.edu.sg/ant/histonet/txt/nervs
em/nerv03.sem.html
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
Cell Structure
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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
How do Eukaryotic cells differ
from Prokaryotic cells?
Prokaryotes = bacteria
Eukaryotes = everything else
Size
Cytoplasm organization
Structure of chromosomes
We will discuss other
differences later
Eukaryotic cell cytoplasm
Cell Structure
10
How big are cells?
How Big is It?
Why are cells so small?
Surface to volume (S/V) ratio
Cell Structure
11
What are some functional
regions of cells?
Cytoplasm
Cell membrane (plasma membrane)
Extracellular structures
Cell wall
Cilia & flagella
EC matrix
Cell Structure
12
What are the components
of eukaryotic cytoplasm?
Membrane bound compartments
-- Cytoplasm vs “cytosol”
Molecular building blocks
Proteins/enzymes
-- Cytoskeleton
Ribosomes
Cell Structure
13
What is the structure of the
nucleus?
Large nuclear pores
-- two membranes
Chromosomes
Nucleolus
Cell Structure
14
How do molecules move through the cell?
1) Diffusion
Molecular
Diffusion
2) Endomembrane
transport system
What is transported?
Where to?
Know this!
Endocytosis & exocytosis
Cell Structure
15
What is the structure and
function of the ER?
Beginning of endomembrane transport
Rough ER
Protein: -- synthesis (Ribosomes)
-- folding
-- modifications (glycosylation)
Smooth ER
Lipid synthesis
Ca++ storage
Transport
vesicles
Transport to Golgi
Cell structure
Cell Structure
16
What is the structure &
function of the Golgi?
Protein modifications
-- e.g., glycosylation
Sorting & Packaging into vesicles
How are proteins transported
Through the Golgi?
View these animation
Virtual cell -- Protein Trafficking
Virtual cell – Protein modification
Links on Class resource page
Cell Structure
17
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
Intracellular Transport
18
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
19
Mutations to transport processes underlie
some genetic diseases
Lymphocytes of
Mucolipidosis II
I-cell diseases
Accumulation of lysosomes
Mental retardation
Metabolic abnormalities
Fatal
Mucolipidosis II
NAcGluAm-P transferase deficiency
What is expected effect?
Tay-Sacks disease
ganglioside GM2 lipase deficiency
-- lipid recycled from cell surface
What is expected effect?
Cell Structure
20
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
21
What proteins comprise the cell cytoskeleton?
Intermediate filaments
Microtubules
Actin filaments
How is the “cytoskeleton” different
from a animal skeleton?
Organization and function
of Intermediate filaments
Mechanical strength
Cell Structure
22
What are the organization and
functions of microtubules?
cytoplasmic transport
chromosome movements
movements of flagella and cilia
-- “9+2” structure
Cytoplasmic
streaming
Closer view on
microtubules
Cell Structure
Flagella
Cilia
23
What are the organization and
functions of actin filaments?
Various types of cell movements
Membrane contractions
muscle contraction
Crawling motions
Interacts with “myosin”
Membrane ruffling
Cell Structure
Heart Cell
24
How do plant cells differ from animal cells?
Chloroplasts
Cell Wall
Vacuole
Cell Structure
25
How are viruses
different from cells?
Much smaller
Protein coat – ‘capsid’
Often no membrane
No metabolism
Why are virus infections
Very difficult to treat?
Cell Structure
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