Histology Cell Cytoplasm
Terms
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- What is a cell?
- A structural and functional unit of every living organism - organization and compartmentalization
- What is the structure of the Biological Membrane.
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5-7.5nm thick
Phospholipid bilayer
asymmetric distribution of charge (resting potential)
Modified fluid mosaic
Integral membrane proteins and sugars (Glycocalyx) - What is the structure of phospholipids.
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Hydrophilic end
Hydrophobic end (fatty acid chain)
-unsaturated (bent)
-saturated (straight) - How do cholesterol and unsaturatted fatty acids affect membrane fluidity?
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cholesterol decreases fluidity
unsaturated fatty acids increase fluidity - What are some key intergral proteins of the cell membrane?
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Pumps
Channels
Receptor Proteins
Linker Proteins
Enzymes
Structural Proteins - What do membrane protein pumps do?
- Active transport of ions, amino acids, and sugars
- What are membrane protein channels? What are some types of membrane protein channels?
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Passive transport (diffusion) of small molecules
Voltage gated
Ligand gated ion channels
Mechanically gated ion channels - What are membrane receptor proteins?
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Recognition and localized binding
Antibodies - What are membrane linker proteins?
- Anchor intracellular cytoskeleton to extracellular matrix
- Membrane Enzymes
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Variety of roles
ATPase (H+ transport) - Membrane Carrier Proteins and Characteristics of Transport
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Passive transport (facilitated)
High specificity
High efficieny
Slow - Modified Fluid Mosaic
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Semifluid phospholipid bilayer
Integral membrane proteins
peripheral membrane proteins
Glycoproteins
Glycolipids -
Glycoproteins
Glycolipids -
carbohydrates on proteins
carbohydrates on lipids - Hydrophobic and Hydrophilic molecules in transport
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Hydrophobic freely diffuse
Hydrophilic must be transported - Cell Nucleus Function
- Stores and produces genetic information
- Cell Nucleus Structure
- Chromatin, Nucleolus, Nuclear Envelope
- Chromatin and types of chromatin
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DNA, Histones, and non-Histone proteins
Euchromatin - active in transciption (pale + loose)
Heterochromatin - transcriptionally inactive (dark + condensed) - Nucleoulus
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Dense, nonmembranous structure containing fibrillar and granular material
Site of ribosomal RNA synthesis (granular)
Regulation of cell cycle
Stains intensely with Hematoxylin and basic dyes - Nuclear Envelope
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Mediates transport via pores
->Nucleus structural + enzymatic proteins
<-Nucleus mRNA, tRNA, ribosomal subunits - Ribosomes Function
- Use mRNA to produce proteins in cytoplasm
- rER-bound Ribosomes
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Membrane proteins
Secretory proteins
Lysosomal proteins - sER-bound Ribosomes
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Nuclear proteins
Mitochondrial proteins
Peroxisomal proteins
Cytosolyic proteins
Cytoskeletal proteins - Rough Endoplasmic Reticulum Structure and Function
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Mainly cisternae
Ribosome attaching proteins
Protein Synthesis
Protein Modification - Smooth Endoplasmic Reticulum Structure and Function
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Mainly tubules
Flattened sheets, sacs, and tubes of membranes
non-Ribosomal
Lipid synthesis
Detoxification of xenobiotics
Storage of Ca2+
Metabolism of glycogen, lipids, + steroids - Golgi Apparatus Function
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Posttranslational modification, storing, + packing of proteins
Membrane remodeling
Glycosylation, phosphorylation, +sulfination of proteins - cis-Golgi
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Convex
5nm thick
Proteins similar to rER
Contains enzymes that cut sugar residues - trans-Golgi
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concave
7.5nm thick
Proteins similar to membrane
Contains enzymes that add sugar residues - Dictyosome and 3 types of vesicles
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Subunit of the Gogli
-Empty, new membrane fragments
-secretory granules
-hydolase vesicles become lysosomes - Exocytosis
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Vesicle discharges its contents from cell fusion with cell membrane
Constitutive
Regulated secretion
Fusion between membranes requires similarity among membranes - Constitutive Exocytosis
- Constant Process
- Regulated Secretion Exocytosis
- Dependent on external signals, hormones
- Endocytosis
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Uptake of fluid + Macromolecules
Phagocytosis
Pinocytosis
Receptor mediated - Phagocytosis
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Ingestion of large particles (debris + bactria)
>1um
cell membrane protudes outward
Receptor medicated
Specialized cells (inducible) - Pinocytosis
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Invagination
Costitutive - continuous dynamic formation of vesicles
0.1um-0.2um
Liquids
In all cells - Receptor Mediated Endocytosis
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Clathrin dependent (creates coat)
ligands dissociate from receptors at low pH in endosome
recycling and recirculation of clathrin and receptors - Clathrin
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Major protein that interacts in endocytosis
Binds with receptors, coats outside of vesicle
Eventually uncoat, recylce, and recirculate - Early Endosomes
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Derived from endocytosis
Vesiculo (tubular shape)
low acidic pH
recirculates membrane receptors - Lysosomes Structure and Function
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Late endosomes
Contains - membrane, material to be digested, + hydrolytic enzymes
Digestion by hyrdolytic enzymes (split but adding water)
ATP->ADP transporting H+, creating an acidic environment - Lysosomal Enzymes
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Acid phosphytase
B-Glucaronydase
Acid hydrolases, nucleases, proteases, glycoxidases, lipidases - Lysosomal Enzyme Incorporation
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Synthesized in rER
Labelled w/ Manose-6-Phosphate
Picked up by TGN
Transported to late endosome
Activated -
Heterolysosomes
Autolysosomes -
Digest external material (bone-osteoclasts, tumor cells, inflammation)
Digest material from within cell (ER surrounds organelle) - Mitochondria Function
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Energy creator by proton gradient (proton motive force)
Controlled release of energy by ETC (stepwise)
Citric Acid Cycle
ATP production - oxidative phosphorylation
Synthesis of Steroids - Mitochondria Structure and Composition
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Contains DNA, RNA, ATP, Ca2+
Inner and outer membranes
Aerobic bacteria ? Symbiotic relationship
Innermembrane space, matrix, matrix granules, crista, ATP synthase - Inner Mitochondrial Membrane, Folds, + Marker Enzyme
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Cristae (folds)
80% proteins
controlled passage is very specific, transport via proteins
ETC system
globular particles
Cytochrome Oxidase (marker) - Outer Mitochondrial Membrane and Marker
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Smooth contours
50% proteins
Molecular seave
Monoamioxidase (marker) -
What is the structure of a peroxisome?
How do peroxisomes appear in cells? -
Oxidative enzymes enclosed in a single membrane
Interconnected in groups
0.2-1um diameter
40+ enzymes (catylase, peroxisomal oxidase, lipid synthesising enzymes) - Peroxisomes Function
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Decomposition of H2O2
B-Oxidation of long fatty acids
Oxidation
Synthesis of lipids, bile acids, + steroids - Microtubule Structure
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Elongates polymeric structures
Equal parts alpha-Tubulin and B-Tubulin (create dimer gamma)
Create hollow cylindars 13 monomer circumference
9 Triplets
25nm Diameter - Mictotubule Function
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Intracellular transport
Cell motility
Maintinance of shape
Separation in mitosis
Dynamic instability - always changing - Microtubule Types
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Stable (cilia, flagella)
Moderately stable (cytoplasm)
Unstable (mitotic spindle) - Dyneins
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Move along microtubules towards the minus end
Move from periphery to cell center - Kinesins
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Move along microtubules towards the plus end
Move from center to periphery - Actin Filament (Microfilament) Structure
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Two stranded polymers of actin protein
5-7nm Diameter
Stable/Unstable - Actin Filament (Microfilament) Function
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Maintain cell shape
Contract when interact w/ myosin
Transport of membrane
Extracellular attachment - Intermediate Filament Structure and Location
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Ropelike fibers (levels of interwoven fibers)
10nm Diameter
In nucleus (lamins) and cytoplasm (tissue specific proteins) - Intermediate Filament Function
- Support, contact, + stabalization