Lecture 2 Flashcards
Peroxisomes are important respiratory organelles, but differ from mito most notably because they are bound by a _____ membrane and don’t contain DNA.
Bound by a SINGLE membrane
Peroxisomes can be indentified by staining for ______, as they have a granular rich matrix abundant in _____ and oxidases.
CATALASES
Oxidases are important in carrying out _____, using molecular O2 to remove H from substrates forming _____.
RESPIRATION, forming H2O2
Catalases are important in _______ by reducing ______ to form molecular O2 and water.
DETOXIFICATION by reducing H2O2
About 1/4 to 1/2 of fatty acid breakdown occurs in peroxisomes, which are particularly important in breakdown of _____ chain fatty acids.
LONG
The life cycle of HIV and ROTA virus require that some of their proteins are sorted via _____.
PEROXISOMES
Peroxisomal matrix proteins are bound by _____ on their Peroxisomal targeting sequence (90% contain PTS 1)and this complex is recognized by docking proteins on the peroxisomal membrane. It is then internalized through transient pores into the peroxisome
PEROXINS
Zwellweger Syndrome (ZS) and Adrenoleukodystrophy (ALD) are both _____ peroxisomal biogenesis diseases.
Inherited
ZS affected infants rarely survive beyond 1 year, showing symptoms such as severe _____ system dystfunction, neuorpath changes, and developmental defects. Biochemically, this disease is characterized by loss of peroxisomal function and accumulation of ____ chain fatty acids.
NERVOUS.
LONG chain fatty acids.
ZS can result from mutations in peroxisomal _____ bigenesis, or in the ____ proteins that recognize the PTS 1/Peroxin complex. –> Peroxisomal matrix proteins are not imported into peroxisome –> loss of peroxisomal function.
Mutations in peroxisomal MEMBRANE biogen or in DOCKING proteins that recognize PTS 1/Peroxin complex.
There are 2 forms of ALD:
1. ____-linked - typically becomes symptomatic in pubertal males.
2. _____ onset
Both forms exhibit destruction of cerebral white matter and adrenal cortex
- X-linked
2. NEONATAL onset
X-linked ALD is characterized biochemically by a lack of _____ of long-chain fatty acids.
Lack of IMPORT
Neonatal-onset is characterized by diminished _____ of peroxisomes and _____ activity.
Diminished SIZE and CATALASE activity.
Smooth ER is responsible for _____ hormone synthesis, detoxification of drugs, and in muscle cells is termed _____ reticulum.
STEROID hormone synthesis, drug detoxification, and in muscle cells is termed SARCOPLASMIC reticulum
Some pathological changes of RER include cloudy swelling, which can occur following _____ infection, degranulation and _____ during times of decreased protein synth (as seen in Kwashiorkor disease) or from overexposure to alcohol.
VIRAL infection.
Degranulation and VESICULATION
The smooth ER can undergo _____ during exposure to drugs such as phenobarbitol, as they contain CytP450s which oxidize liposoluble drugs so that they may dissolve in the cytosol for metabolism
HYPERTROPHY
Hereditary Spastic Paraplegias (HSPs) are characterized by _____ limb spasticity resultant from mutations in proteins that regulate ER _____ and morphology. Defects in ER morphology lead to defects in membrane trafficking and cellular transport pathways in the corticospinal tract.
Characterized by LOWER limb spasticity resultant from mutations in proteins that regulate ER SHAPE and morphology.
Accumulation of unfolded proteins in the ER leads to build up of ER stress and triggers the _____ _____ response. If the issue is not resolved, this can lead to cell death, and in the case of neurodegenerative diseases, axonal degeneration.
UNFOLDED PROTEIN response.
The ER can also support ____ replication. Some examples include _____ C and _____ _____.
VIRAL replication. Some examples include HEPATITIS C and DENGUE virus.
