Cell histology Flashcards
Nucleoporins
proteins inside the the nuclear pore complex arranged in rings stacked on top of each other for transport between the nucleus and cytoplasm
NLS
nuclear localization signal
examples of NLS
importins and exportins
examples of exportins
karyopherins, PTACs, Ran-binding proteins, transportins
what do exportins and importins trasnport
exportins transport macromolecules like RNA and importins transport cargo like subunits of ribosome
what regulated importin and exportin trasnport
family of GTP binding proteins called Ran which facilitates signal mediated porcesses
which is the active form, euchromatin or heterochromatin
euchromatin
what does giemsa reagent stain on chromosomes
adenine-thymine rich regions producing bands
what is the significance of giemsa staining
reveal deletions, non-disjuctions and translocations
function of telomeres
protect from degradation or fusion with other chromosomes
in what cells does telomerase prevent telomere degradation
oocytes, spermatogonia, and stem cells
what cells dont have telomerase
somatic cells
what cells do not have telomere shortening
cancer cells
only ……. of x chromosomes in …… is transcriptionally actuve
one, female. the inactive one remains that way throughout its lifetime
what is the barr body
tightly coiled clump of chromatin, inactive X chromosome
what cells can be used to study sex chromatin
epithelial cells in the cheek lining at the edge of the nuclear envelope and small drumstick-like evagination of the nuclei of the neutrophils from blood smears
what chromatin is the nucleoplasm composed of
interchromatin and perichromatin granules
give three functions of nucleoplasm
- amorphous
- maintains shape
- transport
when is nucleolus observed
during interphase
what does the nucleolus stain and why does the nucleolus stain that way.
basophilic with H&E because it is rich in rRNA and protein
nucleolus contains small amounts of inactive DNA. true or false
true
in cells actively synthesizing protein, how much does the nucleolus occupy in the nuclear volume
25%
pale staining fibrillar center in the nucleolus contains
inactive DNA
pars granulosa in the nucleolus contains
nucelolar DNA being trasncribed into rRNA
what is nucleolin (in pars fibrosa)
small nucelolar ribonuclear proteins
fibrillarin (in pars fibrosa)
ribonucleoproetin enzyme converting pre rRNA into mature RNA
nucleolar matrix contains
network of fibers for organization
what are nucleolar organizing regions (NORs)
where gene loci encode rRNA
where are NORs located
pale staining regions in at the tips of chromosomes (13, 14, 15, 21, and 22 (in humans))
what are the four basic tissues in the body
- connective tissue
- muscle tissue
- nervous tissue
- epithelial tissue
what is the protoplasm divided into
- cytoplasm
* karyoplasm (nucleus)
what is the fluid suspension in the cytoplasm called
cytosol
what do the cytoplasmic inclusions consist of
metabolic by products, storage forms of various nutrients, or inert crystals and pigments
what is the cell membrane called amphipathic
composed of a hydrophilic head and a hydrophobic tail
what are examples of amphipathic molecules
glycolipids, glycosphingo lipids, and cholesterol
what does PAS demonstrate
glycoproteins, carbohydrates and mucins
what does PAS recognized that most other techniques do not
recognizes neutral mucins
what is the PAS technique based on
upon the structure of the monosaccharide units
what is the glycocalyx
cell coat usually composed of carbohydrate chains that are covalently attached to transmembrane proteins and/or phospholipid molecules of the outer leaflet
what is the most important function of the glycocalyx
- protection of the cell from interaction with inappropriate proteins (selectively permeable)
- chemical injury
- physical injury
why does the glycocalyx stain intensely with dyes such as ruthenium red and Alcian blue
numerous negatively charged sulfate and carboxyl groups
where are the large and small ribosomal subunit manufactured
in the nucleolus
what are the
a) small subunit
b) large subunit
composed of
a) has a sedimentation value of 40S and is composed of 33 proteins and an 18S rRNA
b) sedimentation value of the large subunit is 60S, and it consists of 49 proteins and 3 rRNAs
what constitutes the SER
A system of anastomosing tubules and occasional flattened membrane-bound vesicles
which cells have an abundance of SER
synthesis of steroids, cholesterol, and triglycerides, and cells that function in detoxification of toxic materials
what is the function of the sarcoplasmic reticulum
separating calcium ions from the cytosol, assisting in the control of muscle contraction
what components of the membrane are manufactured in the RER
lipids and integral proteins
what is the Golgi apparatus composed of
one or more series of flattened, slightly curved membrane-bounded cisternae (known as faces)
what are the three faces of cisternae
The cis-face (and the cis Golgi network, closest to ER)
The medial face (intermediate face)
The trans-face (and the trans Golgi network, exit face)
what were vesicular-tubular clusters (VTC) previously known as
endoplasmic reticulum/Golgi intermediate compartment (ERGIC)
what are examples of acid hydrolases
sulfatases, proteases, nucleases, lipases, and glycosidases
what do lysosomes require
acidic pH. they possess proton pumps that actively transport H+ ions into the lysosome
what is the inner membrane of the mitochondria folded into
cristae to increase surface area for energy production
what does each mitochondrial porin form
large aqueous channel through which water-soluble molecules
what is the inner mitochondrial membrane richly edowed with
cardiolipin, a phospholipid that possesses four, rather than the usual two, fatty acyl chains
what is the mitochondrial matrix space composed of
dense fluid composed of at least 50 % protein (mostly enzymes, which accounts for its viscosity
what are the enzymes in the mitochondrial matrix responsible for
stepwise degradation of fatty acids and pyruvate to the metabolic intermediate acetyl CoA (for Krebs cycle)
where do humans get their mitochondria from
from their mothers
what is an example of cytoplasmic staining with the acid dye eosin
it is attracted to charged groups on the amino acid side chains of cytoplasmic proteins
what are examples of Eosinophilic stains
Picric acid, Indian ink, congo red, nigrosoine, eosin
what color does eosinophilic stain
pink
what are examples of Acidophilic substances in the cell
mitochondria, cytoplasm, secretory granules, ECM proteins
what does the hematoxylin-aluminum lake bind to
phosphate groups of DNA and the histone proteins bound to the phosphate groups of DNA
what are examples of Basophilic substances in the cell
nucleic acids, rRNA, rRER, glycosaminoacids, acid glycoproteins (negative structures)
what are examples of basic dyes
toluidine blue, methylene blue, hematoxylin, alcian blue
what are the names of the nuclear lamins located at the periphery of the nucleoplasm
A, B1, B2, and C
what are the functions of the nuclear lamins
- organizing and providing support to the lipid bilayer membrane
- organizing and providing support to the peri-nuclear chromatin
- playing a role in the formation of nuclear pore complexes
- assembly of vesicles to reform the nuclear envelope subsequent to cell division
what does each of the nuclear pore complexes communicate with the others with
nuclear lamina and certain pore connecting fibers
what else does the nuclear pore complex comprise of other than nucleoporins
cytoplasmic fibers, a central transporter (plug) , and a nuclear basket
where is heterochromatin normally located
periphery of the nucleus
what are autosomes
any chromosome that is not a sex chromosome
what is more gelatinous, the cytoplasm or nucleoplasm
nucleoplasm
