Histology of Eukaryotic Cell Flashcards
Cell
Cells are the __ _ of ___ organisms. There are approximately ___ different cell types in humans.
They are basically a mass of____ containing a ____ and ____ from the environment by a selectively permeable membrane.
Two physiologically distinct compartments.
- ____
- ____
Cells are the structural units of living organisms. There are approximately 200 different cell types in humans.
They are basically a mass of protoplasm containing a nucleus and partitioned from the environment by a selectively permeable membrane.
Two physiologically distinct compartments.
- Cytoplasm
- Nucleus containing nucleoplasm
Components of the Cytoplasm
9
P
M
R
E
G
L
P
P
S
[*] Plasma membrane
[*] Mitochondria
[*] Ribosomes
[*] Endoplasmic reticulum
[*] Golgi apparatus
[*] Lysosomes
[*] Proteasomes
[*] Peroxisomes.
[*] Secretory vesicles or granules.
Which cell has no nucleus
Which cell has more than one nucleus
RBC
Muscles and Hepatocytes (liver)
Plasma Membrane (PM)
[*] A ______membrane composed of ____, ____, _____ and ____
[*] A selective barrier that maintains the intracellular environment____from the extracellular one.
[*] Functions in ____ and ____.
[*] Controls_____.
[*] Range in thickness from ____ and visible by ____
[*] Unit membrane = an ____ sandwiched between ____.
PM’s are roughly __% lipid, __% protein and __ % carbohydrate.
[*] A limiting membrane composed of phospholipids, proteins, cholesterol and oligosaccharides.
[*] A selective barrier that maintains the intracellular environment distinct from the extracellular one.
[*] Functions in recognition and regulation.
[*] Controls interactions with the extracellular environment.
[*] Range in thickness from 7.5-10 nm and visible by E.M.
[*] Unit membrane = an electron lucent layer sandwiched between two electron dense layers.
[*]
PM’s are roughly 45% lipid, 50% protein and 5 % carbohydrate.
Activities of the Plasma Membrane
____:
_____:
_____: ________ of the PM which entrap extracellular___ and __ ___. These vesicles___ ___and eventually ________.
____: “___________”. Removes ____ ____, ___, ____ ___ etc. Cytoplasmic ____ surround the object, ___ ____ enclosing object in an intracellular _____.
Endocytosis: Mass uptake of material through the PM
Exocytosis: Bulk release of material through the PM
Pinocytosis: Invaginations of the PM which entrap extracellular fluid and soluble material. These vesicles pinch off and eventually fuse with lysosomes.
Phagocytosis: “Cell eating”. Removes foreign bacteria, fungi, damaged cells etc. Cytoplasmic processes surround the object, edges fuse enclosing object in an intracellular phagosome.
Mitochondria
ØThe ___projects folds or ___ into the interior of the mito. These structures ____ the ___ of the IMM/
ØThe mitochondrial matrix is____ rich and contains __ ___ ___ and ___
ØThe IMM projects folds or cristae into the interior of the mito. These structures increase the surface area of the IMM/
ØThe mitochondrial matrix is protein rich and contains DNA, tRNA, rRNA and mRNA.
Endoplasmic Reticulum
[*] A system of_____ _____ that form a continuous membrane and enclose a ____.
[*] ___ types of ER ____with one another
1.
2.
Can also use cisterna to describe____
[*] A system of intercommunicating channels that form a continuous membrane and enclose a cisterna.
[*] Two types of ER continuous with one another
1.Rough ER (RER).
2.Smooth ER (SER).
Can also use cisterna to describe part of mitochondria
Rough ER
[*] Prominent in cells specialized for____ ____
[*] ___ and ___ stacks of ____.
[*] ___ face dotted with ribosomes.
[*] ___ proteins not ___.
[*] Prominent in cells specialized for protein secretion.
[*] Saclike and parallel stacks of cisternae.
[*] Cytoplasmic face dotted with ribosomes.
[*] Segregates proteins not destined for the cytosol.
Ribosomes
[*] ___-dense particles, ___X___ nm in size.
[*] Composed of ____ and ____.
[*] In eukaryotic cells the ____is synthesized in the nucleus and ribosomes comprise ____, ___Sand __S.
[*] Ribosomes stain ___ with ____
[*] Individual ribosomes are held together by ____ to form ____.
[*] mRNA encode for ____ and ribosomes______ into protein.
[*] Electron-dense particles, 20 X 30 nm in size.
[*] Composed of 4 types of RNA and >80 proteins.
[*] In eukaryotic cells the RNA is synthesized in the nucleus and ribosomes comprise 2 different subunits, 60S and 40S.
[*] Ribosomes stain blue with haemotoxylin.
[*] Individual ribosomes are held together by mRNA to form polyribosomes.
[*] mRNA encode for amino acids and ribosomes decode this and translate it into protein.
Smooth ER
[*] A membranous network lacking ____ so it appears smooth.
[*] SER is ___ with RER.
[*] SER has specialized functions including _______ & ____
[*] In muscle cells the SER is specialized and participates in ____. Here it is called the ____ ____ and is involved in the ____ and ___ of __ during contraction.
[*] A membranous network lacking polyribosomes so it appears smooth.
[*]
[*] SER is continuous with RER.
[*]
[*] SER has specialized functions including synthesis of steroid hormones & phospholipids.
[*]
[*] In muscle cells the SER is specialized and participates in contraction. Here it is called the sarcoplasmic reticulum and is involved in the sequestration and release of ca2+ during contraction.
Golgi Apparatus
[*] This organelle completes the _____
[*] It ___ and ___ the ____ _____ of the these proteins.
[*] RER ___ ___ ___ that shuttle _____ to the Golgi.
[*] Close to the RER the Golgi cisternae are ____ and form the -__ face
.[*] The opposite, ___ face is the____ face.
[*]____ ____ transport protein between Golgi compartments.
[*] This organelle completes the post-translational modification of proteins.
[*] It packages and directs the ultimate destination of the these proteins.
[*] RER buds off vesicles that shuttle new proteins to the Golgi.
[*] Close to the RER the Golgi cisternae are convex and form the cis face
.[*] The opposite, concave face is the trans face.
[*] Budding vesicles transport protein between Golgi compartments.
Endosomes
ØThese are a system of ___ and ___ located within the ____ near the ____ (early endosomes) and ____ within the cytoplasm (late endosomes).
ØEndosomal membranes contain _____ which _____.
ØThe acidic environment causes the _____.
ØReceptors may ____ while the ligands are then_____
Ø
ØThese are a system of vesicles and tubules located within the cytosol near the cell surface (early endosomes) and deeper within the cytoplasm (late endosomes).
ØEndosomal membranes contain ATP-driven proton pumps which acidify the interior compartment.
ØThe acidic environment causes the separation of ligand/receptor complexes.
ØReceptors may recycle back to the PM while the ligands are then contained within late endosome
Ø
Lysosomes
[*] Sites of ___ and ____
.[*] Membrane-_____, internally ___ and containing ____ enzymes.
[*] Abundant in ____ cells like ____
[*] Spherical, ____ in diameter.
[*] Lysosomal membranes and proteins are ____
[*] They are delivered separately in ____ coated vesicles to ____ forming ____ which then_____
[*] Sites of intracellular digestion and turnover
.[*] Membrane-limited, internally acidic and containing hydrolytic enzymes.
[*] Abundant in phagocytic cells like macrophages.
[*] Spherical, 0.05-0.5microm in diameter.
[*] Lysosomal membranes and proteins are packaged in the trans-Golgi network
[*] They are delivered separately in clathrin-coated vesicles to late endosomes forming endolysosomes which then mature to form lysosomes.
Primary and Secondary Lysosomes
Primary Lysosomes: Lysosomes not involved in digestion.
Secondary lysosomes: Lysosomes fused with a phagosome, heterogeneous in size and appearance.–> are involved in digestion
Residual Body
___ material remaining within ____ after ___ ___ ___ into the ____
Indigestible material remaining within vacuoles after soluble products diffuse into the cytosol.
Autophagosomes
fusion of ____ with ____
Fusion of lysosome with intracellular organelles.
Heterophagosomes
Fusion of ____ with ____ containing _____ ____
The end product of auto and hetero-phagic ___ is a___pigment which ____s with___. This is ____
Fusion of a lysosome with phagosomes containing foreign materials.
The end product of auto and hetero-phagic vacuoles is a yellow pigment which accumulates with age. This is lipofuscin
Proteasomes
Multiple ____ complexes that _____ ____ ____.
Removes ____ AND ___ _____ proteins
Multiple protease complexes that digest ubiquinated proteins. Removes excess and improperly folded proteins
Peroxisomes
____ organelles that ____ _____ ____ by___ _____ atoms to ____ ____. The product hydrogen peroxide is___and removed by___, also ____.
Peroxisomes also ___ ____ ____ chain and ____ chain ___ ____
: Spherical organelles that oxidize organic substances by tranferring hydrogen atoms to molecular oxygen. The product hydrogen peroxide is toxic and removed by catalase, also in the peroxisome. Peroxisomes also beta oxidize long chain and branched chain fatty acids.
Secretory vesicles or granules
Found in cells that ____
Vesicles are ___ bound
Vesicles containing ___ are ____ ___
Found in cells that store a product.
Vesicles are membrane bound. Vesicles containing digestive enzymes are zymogen granules
Centriole
___ ____ in a centrosome.
___ bundles of ___ microtubules
Each centriole is surrounded by ___ material (__ ____)
§Cylindrical bodies (___ X____) of short microtubules.
§Each centriole composed of ___ sets of microtubules arranged in____.
2 perpendicular in a centrosome.
9 bundles of 3 microtubules
Each centriole is surrounded by granular material (brown haze)
§Cylindrical bodies (0.15 X 0.3-0.5microm) of short microtubules.
§Each centriole composed of 9 sets of microtubules arranged in triplets.
§
Centrosome
§Close to the ___ in ___ cells is the centrosome which is composed of ____ with their long axes perpendicular to each other.
§Before cell division (s phase) centrosome ____.
§During mitosis the centrosomes ___ and ____ where they become ____________.
§Close to the nucleus in non-dividing cells is the centrosome which is composed of 2 centrioles with their long axes perpendicular to each other.
§Before cell division (s phase) centrosome duplicates.
§During mitosis the centrosomes divide in two and move to opposite poles of the cell where they become organizing centers for microtubules of the mitotic spindle.
Microtubules
- Cylindrical tubes of ____in all ____ within cytoplasm. They converge on the ____ and terminate near _____. Can be ____ in dividing cells.
- Microtubules are____ composed of___ and ____.
- α and b tubulin both have a molecular weight of ___
- Tubulin subunits can ___ and form ____.
- Microtubules form the __ for many complex cytoplasmic structures including ___, ____, ____ and ____.
•Cylindrical tubes of tubulin in all orientations within cytoplasm. They converge on the centrosome and terminate near centrioles. Can be conspicuous in dividing cells.
•Microtubules are heterodimers composed of a and b tubulin.
•α and b tubulin both have a molecular weight of ~ 50 kDa
•Tubulin subunits can polymerize and form microtubules.
•Microtubules form the basis for many complex cytoplasmic structures including centrioles, basal bodies, cilia and flagella.
•
Molecular Inclusions
Usually accumulated ____, that are ____.
____: ____ droplets of ___
_____: ___ deposits appearing as____ ___X____ particles (b) or ___ (a).
____: ____ of colored substances. May be ____ by ____ like ____ or come from ____. ____ one of the most common pigments.
Usually accumulated metabolites, transitory.
Lipids: Spherical droplets of triglyceride
Carbohydrates: Glycogen deposits appearing as single 20-30nm particles (b) or rosettes (a).
Pigments: Deposits of colored substances. May be synthesized by the cell like melanin or come from outside. Lipofuscin one of the most common pigments.
