ETA 1 Flashcards
What are the 3 components of the HPA axis?
- Hypothalamus
- Anterior pituitary
- Adrenal glands
What are factors (re: clotting cascade)?
Proteases or co-factors needed to activate the next step in the cascade
How does protein C halt the clotting cascade?
Breaks down factors 5a and 8a
What causes Graves’ disease?
Autoimmune stimulation of TSH receptors
Which reducing agent is necessary for glutathione (GSH) regeneration?
NADPH
What is the inactive form of fibrin?
Fibrinogen
What is fibrinolysis?
Breakdown of blood clots
Which hormone stimulates RBC production?
Erythropoietin
Which factor activates fibrin from fibrinogen?
Thrombin
What is the total number of factors in the clotting cascade?
26 (13 x 2)
What causes Hashimoto’s disease?
Autoimmune destruction of TSH receptors
What is the function of SDS-PAGE (a.k.a. protein electrophoresis)?
Separate protein fragments by size
Compare atheroma and thrombosis.
Atheroma: fatty, degenerative material narrowing artery walls by accumulating in the endothelium; may cause thrombosis by rupturing it
Thrombosis: formation of a blood clot inside a blood vessel; may result from an accumulation of atheroma rupturing the endothelium
Compare the roles of superoxide dismutase (SOD) and catalase in defence against oxidation.
SOD: converts superoxide to oxygen and hydrogen peroxide
Catalase: converts resulting hydrogen peroxide to oxygen and water
In addition to BMI, list 3 measurements a dietician might perform.
- Skin fold thickness
- Waist-to-hip ratio
- Upper arm circumference
What is the function of mass spectrometry?
Separate particles by mass-to-charge ratio
What is the role of tPA?
Convert plasminogen to plasmin
What are the 2 hormones produced by the posterior pituitary? (Hint: All Others.)
ADH (antidiuretic hormone)
Oxytocin
What is the function of the extrinsic pathway?
Regulate clotting in tissue that has undergone trauma
Define ketosis.
A state in which the body breaks down fat for food instead of glucose, producing ketone bodies
What does elevated blood creatinine indicate?
Kidney malfunction
How is metformin metabolised?
Is it NOT
Note: it is secreted in its current form
How does DNA gel electrophoresis separate DNA fragments by size?
- DNA (-ve) is placed on a charged slide
- Migrates toward cathode
- Smaller fragments migrate faster
What is the most consistent biochemical abnormality in Addison’s disease?
Low Na+ (caused by lack of aldosterone due to damaged adrenal gland)
Define atherosclerosis.
Buildup of atheroma inside an artery wall
Which factors are involved in the extrinsic pathway? (Hint: 3 X 2.)
3, 7, 10
3a, 7a, 10a
What are 2 reasons why the eye is a good site for gene therapy?
Partially protected from the immune system
Hard for viruses to travel from the eye to other parts of the body
What is the mechanism of action for rifampicin?
Binds to bacterial RNA polymerase, preventing transcription
How does glibenclamide (sulphonylurea) act on insulin?
Promotes insulin secretion
What is the function of DNA gel electrophoresis?
Separate DNA fragments by size
What does plasminogen do?
Trigger fibrinolysis
Describe the process of thrombosis.
Epithelium ruptures ->
Collagen exposed ->
Attracts platelets ->
Platelet plug forms ->
Clotting cascade triggered
How does Sanger chain termination (a.k.a. DNA sequencing) work?
- DNA is separated into 4 vials
- Different ddNTPs added to each vial (i.e., ddATP, ddTTP, ddCTP, and ddGTP)
- Terminate DNA at corresponding nucleotide
- Gel electrophoresis separates fragments by size
What is the function of FISH (fluorescence in situ hybridization)?
Use probes to dye specific DNA sequences
What is the treatment for paracetamol poisoning?
N-acetylcysteine
Define atheroma.
Fatty, degenerative material narrowing artery walls by accumulating in the endothelium
Compare the function of type 1 and type 2 ELISA.
Type 1: identify ANTIGEN
Type 2: identify ANTIBODIES
What is the function of restriction enzymes?
Cut DNA at specific points
Define foam cells.
Macrophages that have attempted to digest oxidised LDL
Which common medication might lead to thrombosis due to over-stimulation of the clotting cascade?
Oral contraceptive pill
List 5 examples of catabolic pathways.
- Glycolysis
- Glycogenolysis
- Lipolysis
- Fatty acid oxidation
- Pentose phosphate pathway
Which protein converts plasminogen to plasmin?
tPA (tissue plasminogen activator)
What is the function of PCR (a.k.a. polymerase chain reaction)?
Make it easier to examine small sections of DNA by multiplying them
How do enzyme assays determine enzyme activity?
Measure color, light diffraction, heat, etc. as a marker for enzyme presence
What are the 2 phases of drug metabolism?
Phase I: modification (add or expose a reactive group)
Phase II: conjugation (add a water soluble polar group)
What is the function of DNA chip technology (a.k.a. DNA microarray)?
Examine thousands of genes simultaneously (e.g., when comparing normal DNA to diseased DNA)
What is the role of glutathione (GSH) in RBC?
Prevent oxidative damage
How does type 1 ELISA identify ANTIGENS?
Antibody ->
Antigen ->
Antibody tagged w/ enzyme ->
Color change
What is the best technique for comparing normal DNA to diseased DNA?
DNA chip technology (a.k.a. DNA microarray)
You need a rapid burst of skeletal activity. What is the best energy source?
Creatine phosphate
How does DNA chip technology (a.k.a. DNA microarray) work?
- DNA is inserted in thousands of compartments
- Reacts with relevant probes
- Chip is inserted into a computer and read
What is the final product of the clotting cascade?
Cross-linked fibrin
What is the first line treatment for Graves’s disease (i.e., hyperthyroidism)?
Carbimazole
How does type 2 ELISA identify ANTIBODIES?
Antigen ->
Antibody ->
Antibody tagged w/ enzyme ->
Color change
What are zymogens?
Inactive precursors of enzymes
What is the function of karyotyping?
Display entire set of chromosomes
How does PCR (a.k.a. polymerase chain reaction) work?
- DENATURE: heat DNA to separate strands
- ANNEAL: decrease heat so primer can stick
- TRANSCRIBE: increase heat so polymerase can add free nucleotides
- Process is repeated to yield millions of copies
What would you use to cut DNA at specific points?
Restriction enzymes
How would you prepare a karyotype?
- Arrest chromosomes at metaphase
- Tag them with dyes
- Photograph them
- Arrange photographs in order
How would increased ACTH (e.g., in Addison’s) lead to darker skin?
Excessive ACTH exhibits MSH-like activity
Note: MSH = Melanocyte Stimulating Hormone
What is the first factor of the intrinsic pathway?
Factor 11
What are the 3 types of ketone bodies?
- Acetone
- Acetoacetate
- Beta-hydroxybutyrate
Which factors are involved in the intrinsic pathway? (Hint: 4 X 2.)
8, 9, 10, 11
8a, 9a, 10a, 11a
How does mass spectrometry separate particles by mass-to-charge ratio?
- Ionisation
- Acceleration
- Deflection (via magnet)
- Detection
What are the 2 sources of ketone bodies?
- Fat in adipose tissue
- Ketogenic amino acids
What is the best technique for determining the absence or presence of specific areas of a gene?
FISH (fluorescence in situ hybridization)
What are the 6 hormones of the anterior pituitary? (Hint: TP FLAG.)
TSH (thyroid stimulating hormone)
PRL (prolactin)
FSH (follicle stimulating hormone)
LH (luteinising hormone)
ACTH (adrenocorticotropic hormone)
GH (growth hormone)
Which factors are involved in the common pathway? (Hint: 5 X 2.)
5, 10, 13, prothrombin, fibrinogen
5a, 10a, 13a, thrombin, fibrin
How is a clot able to form from the activation of a very small amount of initial factor?
Activation of thrombin promotes further activation of factors 5, 8, 11, and 13 (i.e., positive feedback loop)
Define thrombosis.
Formation of a blood clot inside a blood vessel
How does gene therapy work?
- Add gene to a virus modified not to replicate
- Insert virus into cell
Note: can be carried out in vivo (e.g., bone marrow) or ex vivo (e.g., stem cells)
What is the function of phase I drug metabolism (i.e., modification)?
Add or expose a reactive group
Which disease do protruding eyeballs indicate?
Graves’ disease
What is the first line treatment for Hashimoto’s disease (i.e., hypothyroidism)?
Oral thyroxine
Describe the reactions of the HPA axis.
Hypothalamus
(Secretes)
Corticotrophin-releasing hormone (CRH)
(Stimulates)
Anterior pituitary
(Releases)
Adrenocorticotropic hormone (ACTH)
(Stimulates)
Adrenal glands
(Release)
Cortisol
(Negative feedback)
The presence of which protein in the bloodstream is a biomarker for myocardial infarction?
Troponin
What is the function of Sanger chain termination (a.k.a. DNA sequencing)?
Determine the sequence of nucleotides
Which activated enzyme triggers fibrinolysis?
Plasmin
What test would you use for the DDx of hypoadrenalism?
Short synacthen test
What does thrombin do?
Activates fibrin from fibrinogen
What is the best technique for identifying polyploidies, aneuploidies, or large chromosomal defects?
Karyotyping
Which pathway regulates clotting in damaged endothelial lining?
Intrinsic
What is the first factor of the extrinsic pathway?
Factor 3
What is the common point for the 2 pathways of the clotting cascade?
Factor 10
What type of glial cells produce cerebrospinal fluid?
Ependymal cells
List 5 components of atheroma.
- Oxidised LDL
- Macrophages
- Foam cells
- Calcium salts
- Fibrous tissue
How does fibrin cause clotting?
Forms a mesh which traps blood cells
What is the mechanism of action for tetracycline?
Competes with tRNA at A site of bacterial ribosomes, inhibiting protein synthesis
What are the 2 pathways of the clotting cascade?
- Intrinsic
- Extrinsic
How does SDS-PAGE (a.k.a. protein electrophoresis) separate protein fragments by size?
- Proteins (-ve or +ve) are placed on a charged slide
- Migrates towards end
- Smaller fragments migrate faster
List 3 mechanisms of halting the clotting cascade.
- DILUTION of factors by blood flow (followed by removal in the liver)
- BREAKDOWN of factors by proteases
- INHIBITION of factors by binding
Anti-coagulants reduce the risk of which progressive neurological disorder?
Dementia
What is the best technique for identifying antigens or antibodies?
ELISA (a.k.a. immunoassays)
What is the inactive form of thrombin?
Prothrombin
Which breakdown product of muscle tissue is an indicator of kidney malfunction?
Creatinine
Why can’t cellulose be broken down by the body?
- Contains beta-glyosidic bonds
- GI tract only has enzymes for breaking down alpha-glycosidic bonds
Lack of which enzyme causes lactose intolerance by making it harder to metabolize lactose into glucose and galactose?
Lactase
What is the function of phase II drug metabolism (i.e., conjugation)?
Add a water soluble group
Compare anabolic and catabolic reactions.
Anabolic: build larger molecules from smaller ones, require energy
Catabolic: break larger molecules into smaller ones, release energy
Explain how G6PD deficiency causes hemolysis.
Decreased G6PD ->
Deceased synthesis of NADPH (powerful reducing agent) in pentose phosphate pathway ->
Decreased regeneration of glutathione (powerful anti-oxidant) in RBC ->
Oxidative damage to RBC ->
Hemolysis
Define embolism.
Lodging of an embolus (blockage-causing material) inside a blood vessel
How does disulfiram treat alcoholism?
Inhibits acetaldehyde dehydrogenase, leading to acetaldehyde buildup and hangover-like side effects
How might the oral contraceptive pill lead to thrombosis?
Over-stimulation of the clotting cascade
What is the function of the intrinsic pathway?
Regulate clotting in damaged endothelial linings
List 5 examples of anabolic pathways.
- Gluconeogenesis
- Glycogenesis
- Ketogenesis
- Fatty acid synthesis
- Cholesterol synthesis
What test would you use for the DDx of hyperadrenalism?
Dexamethasone suppression test (DST)
What is the main function of the HPA axis?
Stress response
What is the toxic metabolite of alcohol?
Acetaldehyde
What is gene therapy?
Replacing a malfunctioning gene with a modified gene
What is the best technique for determining enzyme activity?
Enzyme assays
What is the mechanism of action for methotrexate?
Competitively inhibits DHFR, blocking the folate pathway Note: folate is essential for DNA synthesis
How does Antithrombin III (AT3) halt the clotting cascade?
Inhibits thrombin by binding to it
What is the mechanism of action for penicillin?
Prevents bacterial cell wall from cross-linking, causing lysis
Note: only affects gram-positive bacteria
How does metformin (biguanide) act on insulin?
Promotes insulin sensitization in liver and muscle
Which pathway regulates clotting in tissue that has undergone trauma?
Extrinsic
How does classic hemophilia cause bleeding?
Defective factor 8 hinders clotting
A toddler presents with seizures, intellectual delay, and behavioral problems. They smell musty. You suspect PKU. Which gene is mutated and which enzymatic defect results?
PAH gene
Low levels of the enzyme phenylalanine hydroxylase
