T3: Brain Metabolism Flashcards
Ketone bodies are taken into neurons by which receptor and mode of transport in the brain?
A) Glut 1, Facilitated Diffusion B) Glut 3, Active transport C) Glut 5, Simple Diffusion D) Glut 3, Facilitated Diffusion E) Glut 1, Active Transport
Answer: D - Ketone Bodies and Glucose are taken up by facilitated diffusion into NEURONS using Glut 3.
A) this is correct but this is only across the endothelial membranes question asked into neurons. there is high affinity
Describe the treatment of Parkinson’s disease. (mm)
any mcq form of this questions would have been too easy
Parkinson’s is treated with L-Dopa but once it crosses the BBB it is quickly degraded by DOPA Decarboxylase so and inhibitor of DOPA Decarboxylase must be given in combination of high enough L-DOPA levels so that is can cross the BBB
Describe what would happen to the AA Facilitative transporter in a patient with PKU. (mm)
A patient with PKU has massively high levels of PHE. PHE is a large neutral AA and it will overwhelm the AA Facilitative transporter and starve the brain from the other dietary essential AA. The same applies in MSUD.
What is the difference between PrP & PrPsc?
A. Same primary structure and different glycosylation patterns.
B. Normal PrP has B-sheet, as the secondary structure consists mostly of a B-sheet.
C. PrPsc is 33% beta-sheets and is resistant to protease digestion.
D. PrPsc is 66% beta-sheets and is resistant to protease digestion.
E. There is no difference in secondary structures, only tertiery structures.
D. PrPsc is 66% beta-sheets and is resistant to protease digestion. CORRECT
A. Same primary structure and different glycosylation patterns. FALSE
PrP & PrPsc have identical primary structure AND glycosylation patterns
B. Normal PrP has B-sheet, as the secondary structure consists mostly of a B-sheet. FALSE
Normal PrP has no beta-sheet. The secondary structure mostly consists of an alpha-helix.
C. PrPsc is 33% beta-sheets and is resistant to protease digestion. FALSE.
PrPsc is 66% beta-sheets not 33%.
E. There is no difference in secondary structures, only tertiery structures. FALSE
There is a difference in secondary AND tertiery structures. The difference between PrP and PrPsc is a conformational (shape) change.
The brain has facilitated transport for many molecules for its own functioning. Which of the Following is an example of a substance that cannot cross the blood brain barrier?
A) Linolaic Acid B) L-DOPA C) Tryptophan D) Posphotidylcholine E) Glutamine
FA
D) Posphotidylcholine is a fatty acid that is required for the synthesis of Acetylcholine. Only dietary essential FAs(a-Linoleic Acid and Linoleic Acid can cross the blood brain barrier.
Of all the essential amino acids, Which ones are primarily utilized in the formation of the Neurotransmitters Glutamate and GABA?
FA
the BCAAs Valine, Leucine, Isoleucine are the primary metabolites used in the formation of glutamate and GABA
Bob Saget was trapped on a desert island after a dog with goggles crashed a plane he was traveling on. He has been marooned for 3 days without food what is happening to his body?
A. Upregulation of monocarboxylate transporter
B. Ketones have totally replaced Glucose as energy for brain.
C. Brain is using its glycogen stores for energy
D. TAGs are being mobilized as energy for the brain.
RFA
A. Upregulation of monocarboxylate transporter- This is the transporter for ketones (shared with pyruvate,lactate and aciditate) and is upregulated during times of starvation to allow more ketone usage.
B- Glucose will still be used, Ketones will not totally replace glucose
C- Brain doesn’t have many glycogen stores
D- TAGs cant cross the BBB.
Some hydrophobic drugs can pass the blood-brain barrier quickly, but others do so very slowly. What is the reason behind this slow rate? (MG)
A. They are gasses
B. Bound to fatty acids
C. Passive diffusion is a very slow process
D. Bound to albumin
D. Bound to albumin - some hydrophobic drugs are bound to albumin and stay in the blood, so it takes a while for them to actually cross the BBB. Example: phenobarbitol.
Hydrophobic drugs that travel via passive diffusion cross the BBB at a quick rate (C) this includes gasses like O2 and CO2 (A).
What type of transporter is affected in both types of PKU? (MG) A. Fatty acid transporter B. Amino acid transporter C. Vitamin transporter D. CFTR channel
B. Amino acid transporter - large neutral amino acid facilitation transporters are overwhelmed with phenylalanine in PKU
Multifactorial diseases have a ______ concordance for monozygotic twins and _______ concordance for dizygotic twins. (MG)
A. Higher, lower
B. Lower, higher
C. The concordance is equal
D. There is no concordance with multifactorial diseases and mono or dizygotic twins
A. higher, lower
If a monozygotic twin has a multifactorial disease, it’s more likely that the other twin will have the disease as well.
Dizygotic twins should be treated like regular siblings born at different times.
A 52 year old man comes into the clinic and complains of having troubling remembering things. Looking into his history you notice he is a alcoholic. Which enzymes are most likely not active in this man ?
A. Pyruvate Decarboxylase
B. Methionine Synthase
C. BCAA DH
D. HMG CoA Reductase
RFA
C. BCAA DH- The man is suffering from Wernicke Korsakoff Syndrome due to deficiency B1 (Thiamine) Thiamine associated with DH reactions.
A. Pyruvate Decarboxylase- B6 (Pyridoxine) is need
B. Methionine Synthase- Requires B12 and Folate
D. HMG CoA Reductase- Requires B3(Niacin) and is associated with the 4 D’s (Dermatitis, Diarrhea, Dementia, Death)
A 33 year old man comes into the clinic. He is losing his vision along with lack of coordination and weakness. After test it is conclude the cause is Autoimmune what is the most probable diagnosis?
A. Creutzfeldt-Jakob
B.Guillain Barre
C. Alzheimer’s
D. Multiple Sclerosis
RFA
D. Multiple Sclerosis- MS is the autoimmune destruction of the CNS, the closest differential listed is Guillain Barre, but Guillain Barre is not associated with loss of vision since it is PNS related.
A. Creutzfeldt- Jakob- is a Prion disease
B. Guillain Bare- It is an autoimmune disease but of the PNS so lose of vision is not expected
C. Alzheimer’s- is due to a build of of Amyload plaque
