Cellular Flashcards
Shortest phase of the cell cycle
M phase
What do mutations in tumor suppressors result in
Unrestrained cell division
What tumor suppressor inhibits progression of G1 to S phase
Rb and p53
Phosphorylate other proteins to coordinate cell cycle progression
Cyclin-CDK complexes
Regulator proteins that control cell cycle events by activating CDKs
Cyclins
Cell types that enter G1 from Go when stimulated
Quiescent cells
Neurons, skeletal muscle, cardiac muscle and RBCs are what cell types
Permanent cells
Cell types that rapidly divide, never to Go, and most affected by chemotherapy
Labile cells
Classic example of quiescent cell types
Hepatocytes
Cells that remain in Go and generate from stem cells
Permanent cells
Bone marrow, gut epithelium, skin, hair follicles, and germ cells are what cell types
Labile cells
Site of steroid synthesis and detoxification of drugs and poisons
Smooth ER (SER)
Organs that have cells rich in SER
Hepatocytes and steroid-hormone producing cells of adrenal cortex and gonads
Site of N-linked oligosaccharide addition to many proteins
Rough ER (RER)
Adds mannose-6-phosphate to proteins for trafficking to lysosomes
trans-Golgi
Synthesize peptide neurotransmitters for secretion
Nissl bodies (RER in neurons)
Site of synthesis of cytosolic and organellar proteins
Free ribosomes
Site of synthesis of secretory proteins
Rough ER (RER)
Cells rich in RER
Mucus-secreting goblet cells of small intestine and antibody-secreting plasma cells
Send material to lysosomes for destruction or back to the membrane/Golgi for further use
Endosomes
Distribution center for proteins and lipids from the ER
Golgi apparatus
Sorting center for material from outside the cell or from the Golgi
Endosomes
Disorder that results in coarse facial features, clouded corneas, restricted movement and high plasma levels of lysosomal enzymes
I-cell disease
Cause of I-cell disease
Defect in N-acetylglucosaminyl-1-phosphotransferase
Failure of Golgi to phosphorylate mannose residues on glycoproteins causing proteins to be secreted extracellularly rather than delivered to lysosomes
I-cell disease
Genetic inheritance of I-cell disease
Autosomal recessive
Cytosolic ribonucleoprotein that traffics proteins from the ribosome to the RER
Signal recognition particle (SRP)
Consequence of absent or dysfunctional SRP
Proteins accumulate in the cytosol
Protein responsible for retrograde Golgi to Golgi transport
COPI
Protein responsible for trans-Golgi to lysosome transport
Clathrin
Protein responsible for cis-Golgi to ER transport
COPI
Protein responsible for anterograde ER to cis-Golgi transport
COPII
Protein involved in receptor-mediated endocytosis like LDL receptor activity
Clathrin
Responsible for modifying N- and O-oligosaccharides
Golgi
What amino acid is added to N-oligosaccharides by the Golgi
Asparagine
What amino acid is added to O-oligosaccharides by the Golgi
Serine and threonine
Barrel-shaped protein complex that degrades damaged or ubiquitin-tagged proteins
Proteosome
Deficits in proteosome-ubiquitin complex are associated with what disease
Parkinson disease
Beta-oxidation of very-long-chain fatty acids occurs in this organelle
Peroxisome
Actin and microvilli are composed of what type of filaments
Microfilaments
Mitotic spindle is composed of what type of filaments
Microtubules
Filaments that maintain cell structure
Intermediate filaments
Filaments responsible for cell movement
Microtubules
Filaments responsible for muscle contraction
Microfilaments
Filaments that make up cilia and flagella
Microtubules
Cell cytokinesis occurs through use of what filaments
Microfilaments
Filaments involved in cell division
Microtubules
GFAP positive tumors
Glioblastoma, Astrocytoma
Microtubule composition
Cylindrical arrangement of alpha and beta-tubulin
Molecular motor proteins associated with microtubules
Dynein and Kinesin
Molecular motor protein with retrograde movement
Dynein
End of microtubule that points toward nucleus
Negative end
Molecular motor protein associated with anterograde movement
Kinesin
End of microtubule that points toward periphery
Positive end
Direction of microtubule polymerization
Negative to positive end
Anthelminthic that inhibits microtubule assembly
Mebendazole
Antifungal that inhibits microtubule assembly
Griseofulvin
Antigout that inhibits microtubule assembly
Colchicine
Anticancer that inhibits microtubule assembly
Vincristine, Vinblastine, Paclitaxel
Cause of situs inversus
Dynein arm defect
Immotile cilia due to a dynein arm defect
Kartagener syndrome
Structure of cilia
9 doublet + 2 singlet arrangement of microtubules
Location of basal body of cilia
Below cell membrane
Structure of cilia basal body
9 microtubule triples with no central microtubules
ATPase that links peripheral 9 doublets and causes bending of cilium by differential sliding of doublets
Axonemal dynein
ATP side of Na-K-ATPase is located on what side of the cell membrane
Cytosolic side
Phosphorylation of Na-K-ATPase causes movement of what ions
3 Na+ out of the cell
Mechanism of ouabain on Na-K-ATPase
Binds K site
Mechanism of digoxin/digitoxin
Directly binds Na-K-ATPase indirectly inhibiting Na/Ca exchanger increasing intracellular calcium leading to increased cardiac contractility
Dephosphorylation of Na-K-ATPase causes movement of what ions
2 K+ into cell
Most abundant protein in the human body
Collagen
Most common type of collagen in the human body
Type I collagen
Tissues that contain type I collagen
Skin, Tendon, dentin, fascia, cornea, late wound repair
Type of cartilage found in skin, blood, uterus, fetal tissue, and granulation tissue
Type III
Collagen deficient in osteogenesis imperfecta
Type I
Collagen deficient in Vascular type Ehlers-Danlos
Type III
Type of collagen found in basement membrane, basal lamina and lens
Type IV
Type IV collagen is defective in what diseases
Alport syndrome and Goodpasture syndrome
Tissue that organizes and strengthens extracellular matrix
Collagen
Which step of collagen synthesis requires vitamin C
Hydroxylation
Inheritance pattern of most common form of osteogenesis imperfecta
Autosomal dominant
Most common gene defects in osteogenesis imperfecta
COL1A1 and COL1A2
Treatment for osteogenesis imperfecta
Bisphosphonates
Hydroxylation of specific proline and lysine residues in collagen synthesis occurs in what part of the cell
RER
Disease resulting in failure to form triple helix into procollagen
Osteogenesis imperfecta
Location of cleavage of procollagen C- and N- terminals in collagen synthesis
Extracellular space
Collagen synthesis defect leading to Ehlers-Danlos syndrome
Cleavage or formation of cross-linking into collagen fibers
Enzyme responsible for stabilization of cross-linking of collagen fibers
Lysyl oxidase
Formation of triple helix into procollagen occurs in what cell structure
RER
Presents with multiple fractures, blue sclerae, dental imperfections and hearing loss
Osteogenesis imperfecta
Disease that presents with faulty collagen synthesis causing hyperextensible skin, tendency to bleed and hypermobile joints
Ehler-Danlos syndrome
Most common type of Ehler-Danlos syndrome
Hypermobility type
Cause of classical type of Ehler-Danlos
Mutation in type V collagen (COL5A1, COL5A2)
Disease associated with joint dislocations, berry and aortic aneurysms, and organ rupture
Ehler-Danlos syndrome
X-linked recessive connective tissue disease caused by impaired copper absorption and transport due to defective ATP7A protein
Menkes disease
Necessary cofactor of lysyl oxidase
Copper
Disease caused by defective copper-containing lysyl oxidase
Menkes disease and/or Ehler-Danlos syndrome
Disease that presents with kinky hair, growth retardation and hypotonia
Menkes disease
Stretchy protein within skin, lungs, large arteries, elastic ligaments, vocal cords, and ligamenta flava
Elastin
Elastin is rich in what amino acids
Non-hydroxylated proline, glycine, and lysine residues
What gives elastin its elastic properties
Cross-linking of collagen fibers
Enzyme that breaks down elastin
Elastase
Disease that results in excessive elastase activity
Alpha-1 anti-trypsin deficiency
Wrinkles of aging are due to what
Decreased collagen and elastin production
Alpha-1 anti-trypsin deficiency complication
Emphysema
What inhibits elastase
Alpha-1 anti-trypsin
Autosomal dominant connective tissue disorder affecting skeleton, heart and eyes
Marfan syndrome
Cause of defective fibrillin
FBN1 gene mutation on chromosome 15
Glycoprotein that forms sheath around elastin
Fibrillin
Tall individual with hypermobile joints and long tapering fingers and toes should be evaluated for what?
Cardiovascular abnormalities like aortic incompetence, dissecting aortic aneurysm and floppy mitral valve
Eye findings in Marfan syndrome
Subluxation of lenses, typically upward and temporally