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78 Cards in this Set
- Front
- Back
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How many base pairs long is the mitochondrial genome?
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16569
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What is the mutation threshold?
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The level that must be reached for a mutation to occur in the mitochondrial DNA
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What are the threshold levels of deletion mutations and tRNA mutations in the mitochondrial genome?
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Deletion mutations = 60%
tRNA mutations = 90% |
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What are the effects of somatic mutation and germ line mutation?
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Somatic mutations are common but have little effect
Germ line mutations are rare but are serious and are inherited |
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What is a DNA synonymous mutation?
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A mutation that is silent due to the degeneracy of the DNA code
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What do Splice site mutations do?
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Alter the signal for exon- intron splicing resulting in frame shift mutations
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What is southern blotting used to identify?
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Trinucleotide repeat expansion disorders
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In Duchenne muscular dystrophy is the exon deletion relevant?
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The size of the exon deletion is not relevant to the consequences of the disease however, in DMD a frame shift occurs which causes the symptoms of disease
However in Becker muscular dystrophy a frame shift does not occur resulting in milder symptoms |
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In cystic fibrosis what is the main mutation and what does this mutation cause?
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CFTR mutation
Cl secretion is vital for HCO3 secretion. HC03 is exchanged for Cl which is secreted by CFTR. In cystic fibrosis HCO3 can not be secreted |
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What does cytogenic testing test?
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Tests the whole genome however it is not very high resolution therefore can produce false negatives
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How long are cells cultured for in cytogenic testing?
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3-4 days, encourage mitosis and disrupt to prevent completion
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What occurs in a normal FISH test?
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Probe binds twice at expected regions
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How many base pairs does array CGH cover?
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50kbp
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How many RBCs are produced each day?
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2 x 10'11
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What is the mutation in hereditary hemochromatosis?
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Mutated HFE
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What does increased BCR/ABL signalling cause?
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Increased tyrosine kinase activity (this occurs in chronic myeloid leukaemia
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What binds to VWF in the activation stage of platelet plug formation?
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GP2B
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What are released from alpha granules in the release reaction of haeomostasis?
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VWF, FV and fibrinogen
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Which factors catalyse the coagulation cascade?
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FV and FVIII
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What initiates the coagulation cascade?
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Tissue factor
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What does the coagulation cascade produce?
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Thrombin
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What does FXIII do?
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Cross linking factor
Stabilises the fibrin clot |
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Where is Vit K absorbed?
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In the upper 1/3 of the small intestine in the presence of bile
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What does high INR indicate?
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Bleeding
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What prolongs the aPTT time?
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Reduced FII/FV/FVIII/FIX/FX/FXI/FXII/Fibrinogen
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What is absent in Beta thalassaemia?
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HBA
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What is the mutated gene in sickle cell anaemia?
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Sickle beta globin gene
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What is fanconi's? anaemia?
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The most commonly inherited form of aplastic anaemia (X linked recessive)
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What is dyskerin associated with?
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RNAs and is important for nuclear accumulation and stability
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What does acute leukaemia arise from?
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B cell precursors
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What does chronic leukaemia arise from?
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Mature lymphoid cells
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What is D dimer a test of?
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Degredation products of a fibrin clot
If the the test is positive it shows a fibrin clot has been formed and degraded |
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What does thrombopoietin bind to?
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c-mpl on megakaryocytes and platelets
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What are the two pathways involved in apoptosis?
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The FAS death receptor pathway (extrinsic)
The BCL 2 associated mitochondrial pathway (intrinsic) |
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What causes adaptation?
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Overwhelming the cells ability to maintain homeostasis
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What are the steps in vascular accute inflammation? (4)
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Transient vasoconstriction followed by vasodilation
Increased vascular permeability Stasis and concentration of RBCs Neutrophil margination |
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What are the stages of chemotaxis? (4)
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Margination of leukocytes- exit from central blood vessels to allow leukocyte endothelial interactions
Rolling- selectins are expressed on endothelial surfaces and slow leukocytes down Adhesion (intergrins) Transmigration |
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What causes transmigration of leukocytes across the endothelial membrane?
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PCAM-1
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What are the characteristics of chronic inflammation?
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Infiltration of mononuclear cells
Tissue destruction Angiogenesis and fibrosis |
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What cells are involved with chronic inflammation?
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Macrophages
Lymphocytes Mast cells Basophils |
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What does the liver produce in response to an increase in acute phase protein?
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C reactive protein and serum amyloid A
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Where do arterial thrombi form?
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In fast flowing blood
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What are the causes of shock?
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Pump failure
Decreased blood volume Increased vascular volume |
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What is the response to shock?
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Activation of the RAAS
Increase in sympathetic tone Redistribution of blood flow |
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What causes a true anneurysm to form?
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Any process that weakens the media - inflammatory or congenital
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Melanoma and lymphoma are ALWAYS MALIGNANT
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Melanoma and lymphoma are always MALIGNANT!!!!
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What happens when HER2 is implicated on cancer cells?`
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It activates tyrosine kinase which activates cell division
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Name the 6 steps involved in the pathogenesis of metastasis
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1. Induction of neo angiogenesis
2. Micro embolisation of blood vessels 3. Travel to new organ 4. Emigration from blood vessels 5. Induction of neo angiogenesis 6. Growth of tumour at new site |
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What results from E cadherin activation?
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Cell matrix adhesion
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What results from intergrin activation?
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cell- cell adhesion
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How do tumours escape the immune system?
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They inhibit antigen processing antigen presentation
Down regulate cytotoxic T cells and cell recognition |
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What do telomeres do?
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Add ends to chromosome in order to maintain length through successive replications
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What does RPA do in damage removal?
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Joins to the non- damaged strand and prevents cell enzymes degrading DNA
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What do ERCC1, XPG, XPF do?
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They input 2 single strand breaks
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How are double strand DNA breaks repaired?
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Through non homologous DNA end joining
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What does deficiency in double strand break repair result in?
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Immunodeficiency as this mechanism joins the variable and constant regions to the antibody
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What is the mismatch repair gene implicated in HNPCC?
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MSH2
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How many mutations are needed to result in colon cancer?
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8
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What inhibits CDK?
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INK-4 (active during and mid G1)
Cip/Kip (active throughout the cell cycle) |
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What causes a constitutive kinase reaction?
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Point mutation in the juxtamembrane region of receptor- tyrosine kinase
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What is the most common mutation in cancer?
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p53 mutation
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What does p53 regulate?
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Entry into S phase at the G1/S checkpoint
It can arrest the cell cycle and cause apoptosis |
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How does p53 trigger apoptosis?
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Via BCL 2
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What does uncapping of the telomere cause?
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Activation of p53 which causes cell cycle arrest and/ or apoptosis
If p53 is lost then senescence is bypassed |
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What is diamorphine converted to?
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6- monoacetyl morphine + morphine
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What enzyme metabolises codeine?
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CYP 2D6
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Where does Methadone act?
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At the Mu receptor
Agonist |
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What opioid antagonist is used in opioid addiction?
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Naltrexone
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What is the pain scale used for children?
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Wong- baker scale
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What can be bound to a drug to aid its absorption?
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Glucose
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What is added to a molecule to increase its lipid solubility?
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Alkyl group
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What is added to a molecule to decrease its lipid solubility?
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NH2 group
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How is sustained release of a drug ensured?
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Active drug is embedded in a soluble matrix
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What is the ECF made up of?
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Plasma + interstitial fluid = 20% of body weight
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What is the major route of glucuronide excretion?
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Biliary
Glucuronation causes a drug to increase in water solubility |
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What % of all adverse drug reactions are due to adverse drug interactions?
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15%
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Suddenly with drawing what causes increased B adrenergic responsiveness?
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LTB- blockers
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How many half lives does it take to reach oral steady state?
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10
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