Flashcards in Cell Biology Deck (15):
how does hte cell regulate how many mitochondria are present in it?
levels of thyroxine or AMP/ATP ratios
Cristae can vary in arrangement and morphology
describe zellweger syndrome
rare congential, may be fatal--no enzymes are targeted to go to peroxisomes; therefore, very long fatty acids are accumulated
catalase is involved in the oxidation of long-chain FAs
where do we find cells containing peroxisomes and what are they?
liver and kidney, as they are involved in lipid metabolism and waste management;
what composes the cytoskeleton?
microfilaments (actin), intermediate filaments, microtubules
where do we find actin?
in all cells, globular actin (G actin) olymerizes into filamentous (F) actin; composes cell cortex just under the inner plasma membrane; some intercellular junctions of actin anchors; actin composes microvilli framework; has a role in pino- and phagocytosis
what is the purpose of spectrin?
to anchor actin
describe the structure of microtubules
Rigid hollow tubes made up of dimers of tubulin that can rapidly assemble and disassemble (dynamic instability)
Have a non-growing end (-end) and a growing end (+)
The – end is usually anchored in a microtubule organizing center (MTOC)
in animals MTOCs are usually associated with centrioles
Plants don’t have an MTOC
function of microtubules?
Microtubule motors move organelles along microtubule “tracks”
Major component of cilia, flagella and mitotic spindles
process of apoptosis?
In response to signals, a caspase cascade** is set up
(b) Pyknotic nucleus (nucleus shrinks and shrivels);
no cell to cell contacts; eosinophilic cytoplasm
--eosinophili– nucleus gets a little redder
(c) Breakup of nuclear material
cytoplasmic “blebs” B
(d) Cell fragments, called apoptotic bodies, (A) scavenged by macrophages (M)
in the cell, what do H&E stain?
nucleus and nucleolus--> H, hemotoxylin,
Cytoplasm, E, eosin-->pink
what is metachromatic leukodystrophy?
--deficiency of arylsulfatase A (sulfur metabolism) = accumulation of sulfatide in oligodendrocytes, Schwann cells, and some neurons
--not in every cell, but just accumulates in cells where this rxn is important—no myelin, neurodegenerative disorer
Treatment: Hematopoietic cell transplantation can stabilize the central nervous system demyelination in patients with juvenile- and adult-onset forms.
what is lipofuscin?
Brown gold pigment, accumulates with age
Found in nerve and muscle cells, liver, kidney etc
Associated with wear and tear