Biochemistry First Aid- Cellular Flashcards
what molecules regulate the cell cycle at checkpoints
cyclins, cyclin-dependent kinases (CDK’s) and tumor suppressors
what do cyclins do to CDK’s
activate them
what factors normally inhibit G1-to-S progression
p53 and hypophosphorylated Rb
name a disease associated with mutated p53 that predisposes to cancer
Li-Fraumeni (autosomal dominant)
name the phases of the cell cycle in order beginning with mitosis and ending right before the subsequent mitosis
mitosis, G1 and/or (G0), S, G2, subsequent mitosis
what is interphase
G1, S, G2
what stage of the cell cycle do permanent cells remain in
G0
what kinds of cells are permanent cells
neurons, skeletal cardiac myocytes, RBC’s
when stable cells are stimulated what do they do with respect to the cell cycle
stimulated quiescent (stable) cells move from G0 back into G1
what kinds of cells are stable (quiescent) cells
hepatocytes, lymphocytes
what kind of unique cell cycle activity do labile cells demonstrate and what are they affected by that no other cell types are affected by
do not enter G0, but rather continue from mitosis to G1 and continue dividing; most affected by chemotherapy
what kinds of cells in the body are labile cells
gastrointestinal epithelium, skin, hair follicles, germ cells and bone marrow
what are Nissl bodies
RER in neurons
which cells have a lot of smooth endoplasmic reticulum
hepatocytes and steroid hormone producing cells of the adrenal cortex and gonads
what does the golgi apparatus do to aspargine?
serine and threonine?
modifies N-oligossacharides on aspargine
adds O-oligosaccharides to serine and threonine
what kind of sugar is added to proteins so that they can be trafficked to lysosomes
mannose-6-P
what is I-cell disease
inclusion cell disease: an inherited lysosomal storage disease caused by deficiency of phosphotransferase which normally adds mannose-6P to proteins so that they can be trafficked to lysosome; instead the proteins are secreted by the cell
what clinical symptoms do patients with I-cell disease have
coarse facial features, clouded corneas, restricted joint movement, high plasma levels of lysosomal enzymes, often fatal in childhood
what is the role of signal recognition particle (SRP)
to traffic proteins from the ribosome to the RER in order to prevent them from accumulating in the cytoplasm
name three vesicular trafficking proteins
COPI (Golgi to Golgi and Golgi back to ER), COPII (Golgi to Golgi and ER to Golgi), and Clathrin (Golgi to lysosomes, plasma membrane to endosomes (endocytosis))
what do peroxisomes catabolize
long-chain fatty acids, branched-chain fatty acids, amino acids
what is a proteasome and what condition has it been implicated in
protein complex that degrades damaged or ubiquitin-tagged proteins
defects in ubiquitin-proteasome system is implicated in Parkinson’s
what are the two dimers of the microtuble
alpha-tubulin and beta-tubulin
what is bound to each dimer of microtubules
2 GTP
what role do microtubules play in the body
comprise mitotic spindles, cilia, flagella and allow for transport of neurons
what are the two molecular motor proteins that move along microtubules and what direction do they move
kinesin moves in the forward direction (- to +)
dynein moves in the backward direction (+ to -)
name 5 drugs that act on microtubules
mebendazole griseofulvin colchicine (gout treatment) vincristine/vinblastine (cancer treatment) paclitaxel (cancer treatment)
what is Kartagener syndrome (primary ciliary dyskinesia)
defect in dynein that causes immotile cilia
==> immotile sperm and dysfunctional fallopian tube cilia leads to infertility and ectopic pregnancy risk in women
can also cause bronchiectasis, recurrent sinusitis and situs inverses
what is the arrangement of microtubules in cilia
9 + 2
what does axonemal dynein do
bend the cilia
_______ are polymers and _______ are dimers (myosin vs. actin)
actin are polymers and myosin are dimers
name some intermediate filaments (they provide structure
vimentin, desmin, cytokeratin, lamin, glial fibrillary acid proteins, neurofilaments
name some common components of a plasma membrane and what particular molecules is specific to fungal membranes
cholesterol, phospholipids, sphingolipids, glycolipids and proteins (ergosterol in fungi)
what intermediate filament can you use to stain for connective tissue
vimentin
what intermediate filament can you use to stain for muscle
desmin
what intermediate filament can you use to stain for epithelial cells
cytokeratin
what intermediate filament can you use to stain for neuroglia
GFAP
what intermediate filament can you use to stain for neurons
neurofilaments
for every ATP consumed by the NaK pump how many Na and K go in/out
3 Na out, 2 K in
which drug inhibits the K binding site of the NaK pump
ouabain
what cardiac drugs works by inhibiting the NaK pump
cardiac glycosides: digoxin and digitoxin
which bone disease involves low production of type I collagen
osteogenesis imperfecta type I
what tissues of the body are made from type I collagen
bone, tendons, skin, dentin, fascia, cornea and late wound repair
what type of tissue is made from type II collagen
cartilage (“car-two-lage”
what type of tissue is made from type III collagen
reticulin: comprises skin, blood vessels, uterine tissue, fetal tissue and granulation tissue
what disease results from deficient type III cartilage
Ehler’s-Danlos
what is made from type IV collagen
basement membrane, basal lamina, lens
what disease results from defective type IV collagen
Alport syndrome (nephritis caused by thinning and splitting of GBM, also associated with lens defects and hearing deficits) Goodpasture's (autoantibodies target the defective collagen)
30% of collagen consists of what amino acid
glycine
vitamin C is important for what part of collagen synthesis
hydroxylation; specific proline and lysine residues are hydroxylated
name the six stages of collagen synthesis
- synthesis (in RER)
- hydroxylation (in RER)
- glyosylation (in RER)
- exocytosis
- proteolytic processessing (procollagen cleaved to make tropocollagen)
- cross-linking (covalent lysine-hydroxylysine cross-linkage are formed to connect tropocollagen molecules to make collagen fibrils)
besides multiple fractures and blue sclera what other symptoms do patients with osteogenesis imperfecta have
hearing loss (abnormal ossicles) and dental imperfections (deficient dentin)
what conditions may Ehler’s Danlos syndrome be associated with
berry aneurysms, joint dislocation, aortic aneurysms and organ rupture
name three different types of Ehler’s Danlos syndrome
hypermobility type (most common): flexible joints classic type: type V collagen mutation vascular type: deficient type III collagen
what is Menkes disease
connective tissue disease caused by impaired copper absportion and transport –> low lysyl oxidase activity leads to brittle, kinked hair, growth retardation and hypotonia
what molecule inhibits break down of elastin by elastase
alpha1-antitrypsin
defect in what protein causes Marfan syndrome
fibrillin (a glycoprotein that forms a sheath around elastin)
emphysema can be caused by deficiency of what molecule involved in elastin regulation
alpha1-antitrypsin deficiency ==> excess elastase activity leads to low elastin
what are the 3 major steps of PCR
- denaturation
- anealling
- elongation
