Flashcards in FunMed: PBL 2 (Peroxisomal/Mitochondrial Division Abnormality) Deck (28):
Fold between two clefts of cerebral brain surface (outer protrusion)
Indent between two clefts of cerebral brain surface
What is the sylvian fissure?
Fissure which separates the frontal and parietal lobes from the temporal lobes
What is the role of peroxisomes?
Metabolism of fatty acids and detoxification of free radicals in liver and kidney
Describe basic binary fission
Replication of circular DNA molecule inside the cell, replicated DNA then moves to poles of cell, the cell lengthens and the equatorial plate of the cell constricts and separates the plasma membrane (two daughter cells/organelles)
How do mitochondria and peroxisomes divide?
Describe mitochondrial/peroxisomal division
Replication of circular DNA inside cell, replicated DNA moves to poles of cell, cell lengthens and DRP1 protein is used to 'pinch' off the membrane stalk between the two cells, and this is activated by mitochondrial fission factor (MFF) binding to DRP1 to promote fission
How may peroxisomes be produced?
Growth by importing proteins and lipids into existing peroxisomes or binary fission
What are the 5 stages of grief?
Denial, anger, bargaining, depression and acceptance
What is the role of mitochondria?
Production of ATP by oxidative phosphorylation
What is the difference between euchromatin and heterochromatin?
Euchromatin - lightly packed and involved in transcription
Heterochromatin - responsible for gene regulation and protects chromosomal integrity
What is DRP1/DLP1?
dynamin-like protein 1 (involved in separation of mitochondria/peroxisomes in fission)
How does mitochondrial abnormality cause these symptoms?
Inability to produce sufficient ATP (too few mitochondria due to ineffective division) --> muscle hypotonia due to inability to respire --> muscle wastage
How does peroxisomal abnormality cause these symptoms?
Usually break down very long chain fatty acids (beta oxidation) to medium-chain ones, which go to mitochondria to be used in respiration, without enough, fat energy not respired --> hypotonia. First reactions to produce plasmalogen (phospholipid in myelin) occurs in peroxisomes, without --> dysmyelination and abnormal gyral patterns. Involved in bile acid production for absorption of fat and some vitamins --> malnourishment
What are the main ways in which mutations occur in cells?
Errors in replication (unrepaired), ionising radiation, UV light, mutagens, inherited mutations from germ cells
What is a frameshift mutation?
insertion/deletion of number of bases (not multiple of 3), changing reading frame of protein
What are the 3 types of point mutation?
Silent, nonsense, missense
Describe missense mutations
Change in base --> changes codon to different amino acid
Describe nonsense mutations
Change in base --> changes codon to stop codon
Describe silent mutations
Change in base --> still codes for same amino acid
What are the bases for the start codon?
AUG --> codes for methionine
What are the bases for stop codons?
UAA, UAG and UGA
What does bereavement counselling involve?
talking through emotions with counsellors, and finding incentive to distract someone from life event (sport or hobby)
What does genetic counselling involve?
Education about implicated health condition, assessment of risk of reproductive transmission, family tree to assess personal risk, genetic tests performed/recommended (risks, benefits and limitations), interpretation of results, and info about support groups
How do cells know when they have enough cell organelles prior to mitosis?
Checkpoints decipher this, at the restriction point (G1-S) number appropriation is checked, and this is repeated at G2
How could Lorenzo's oil potentially be used as a treatment?
Normalises accumulation of very long chain fatty acids in the brain so can prevent damage to white matter
Is a DLP1 mutation dominant or recessive?