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Biochemistry Flashcards

1
Q

If a patient has opthalamoplegia, ataxia, and confusion and family believes he drinks daily, what ezymes might be defective?

A

Thiamine Deficiency

  • Pyruvate Dehydrogenase
  • Alpha-Ketoglutarate Dehydrogenase
  • Transketolase
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2
Q

Why do neurologic symptoms occur with Thiamine deficiency?

A

Unable to properly utilize glucose in the sensative tissues, hence mammilary body lesions

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3
Q

What is the best test to uncover thiamine deficiency?

A

Erythrocyte Transketolase Activity – changes sugars into different forms requiring only thiamine

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4
Q

What nutrient deficiency has dryness on the corners of the mouth and lips, thickening of the tongue, dry skin?

A

Riboflavin

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5
Q

What enzyme in the TCA cycle is most affected by Riboflavin Deficiency, if there is a decrease in fumarate production?

A

Succinate Dehydrogenase

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6
Q

What protein breaks down glycogen for use?

A

Glycogen Phosphorylase

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7
Q

How is glycogen breakdown initiated?

A

Glycogen Phosphorylase is phosphorylated/activated by Phosphorylase Kinase (which was phosphorylaed by Protein A)
– Ca+2 release from SR activated Glycogen Phosphorylase as well

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8
Q

Where does the 30S subunit of ribosome bind in prokaryotic cells?

A

Upstream of Start codon of mRNA

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9
Q

What aminoacids should be used for diet in a patient with pyruvate dehydrogenase deficiency/

A

Aminoacids ONLY used for ketogenesis

  • Lysine
  • Leucine
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10
Q

What GLUT transporter is upregulated by insulin?

A

GLUT4 - skeletal muscle / adipocytes

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11
Q

How is glycogen synthase activated in hepatocytes?

A

Protein Phosphatase-1 (activated by PO4 by Tyrosine Kinase)

  • *REMOVES PO4 from Glycogen Synthase, causes activation of it
    • REMOVES PO4 from F 1,6 Bisphosphatase (stops gluconeogenesis)
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12
Q

If a DNA base is altered by deaminase, what method would be used to repair the DNA?

A

Base Excision Repair

- Glycosylase (Removes) > Endonuclease (cleaves 5’ end) > Lyase (removes 3’ end) > DNA Polymerase > Ligase

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13
Q

What occurs first during ischemia of brain tissue?

A

Red Neurons – loss of nissl and eosinophil look

– no infiltrate yet, or necrosis

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14
Q

What happens in ischemia around 48-72 hours?

A

Necrosis and PMN Infiltration

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15
Q

What happens in ischemia 1-2 weeks post infarction?

A

Reactive Gliosis and vascular proliferation – Liquefication Necrosis

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16
Q

What occurs in the Nucleus prior to mRNA leaving into cytoplasm?

A
    • Poly A Tail
    • 5’ Cap
    • 7-methylguanosine 5-5 linkage
    • interaction with snRNP (splicing)
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17
Q

What occurs in the cytoplasm ONLY with mRNA?

A

Ribosome – Translation

Association with P-Bodies (regulation of mRNA quality)

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18
Q

Build up of GM2-Ganglioside, diffuse weakness/motor loss, and cherry red macula?

A

Tay-Sachs Disease

– Defective Hexosaminase A

19
Q

Bone pain and fractures, osteopenia, accumulation of Macrophages with accumulation of glucocerebroside?

A

Gaucher Disease

    • Defective Glucocerebrosidase
    • “Tissue Paper Macrophages”
20
Q

Early Adulthood peripheral neuropathy and motor defects – recessive genetic disorder?

A

Metachromatic Leukodystrophy

    • Defect Arysulfatase A Defect
    • accumulation of cerebroside sulfate
21
Q

What is the inheritance pattern of extremity pain, corneal changes, angiokeratomas, decreased ability to sweat?

A

Fabry Disease

    • X-linked – mostly boys
    • Defective Alpha-Galactosidase
22
Q

What disorder has a build up of glycosphingolipids?

A

Fabry Disease

– Defective Alpha-Galactosidase

23
Q

An infant is found to have a spingomyelinase deficiency, what symptoms might be expected?

A

Profound Neurodefects

    • early death
  • *Niemann Pick Disease**
  • -REGRESSION OF MOTOR FUNCTION–
24
Q

What amino acids are unable to be broken down in Maple Syrup disease?

A
  • Leucine
  • Isoleucine
  • Valine
  • *Requires Thiamine cofactor (usually)
    • Alpha-Ketoacid Decarboxylase–
25
Q

A patient is found to have a change in mentation with diffuse skin changes and was recently diagnosed with a GI mass, what is causing this syndrome?

A

Serotonin Syndrome —> Niacin Deficiency, due to over production of Serotonin from Tryptophan depleting stores.

    • Dermatitis
    • Diarrhea
    • Dementa
26
Q

What are each of the RNA Polymerases responsible for?

A

RNA Poly I – rRNA
RNA Poly II – mRNA, snRNA
RNA Poly III – tRNA

27
Q

What DNA Polymerase can remove primers from DNA?

A

DNA Polymerase I

    • 5’-3’ Polymerase
    • 5’-3’ exonuclease
    • 3-5’ proof-reading
28
Q

What is the most common problem associated with Hartnup Disease? (Impaired Neutral AA uptake)

A

Not enough Tryptophan

    • Unable to produce Serotonin / Melatonin
    • Niacin Deficiency – pellagra (Dementia, Dermatitis, Diarrhea)
29
Q

How can you tell the difference between Hartnup and Fanconi Syndrome?

A

Normal Levels of Proline, Hydroxproline, Arginine in the urine (since they are getting reabsorbed)
–Fanconi – defective proximal tubule unable to reabsorb pretty much everything across the board.

30
Q

What is the best way to reverse Warfarin?

A

Non-life threatening – Vitamin K

Life Threatening – FFP

31
Q

What are the symptoms for Riboflavin Deficiency?

A

Cheilosis
Glossitis
Keratitis
Corneal Vascularization

32
Q

If an Rb mutation is inherited, what is the most common type of cancer?

A

Osteosarcoma

33
Q

What amino acids are broken down into Propionyl-CoA?

A

Valine
Isoleucine
Threonine
Methionine

34
Q

What immune acid that is involved in Maple Syrup disease is metabolized into Acetyl-CoA?

A

Leucine

35
Q

What amino acid is cleaved to produce vasodilatory effect?

A

Arginine

– broken down into NO, due to ACh/Bradykinin/5HT/Substance P being released

36
Q

What two vitamin deficiencies can cause defunction of dorsal column and/or corticospinal tract?

A

Vitamin E Deficiency

Vitamin B12 – Elevated MMA

37
Q

What is the most common defect of urea cycle and where does it occur?

A

Ornithine Transcarbamylase
[Ornithine + Carbamoyl Phosphate –> Cirtrulline]
– Occurs inside the Mitocondria

38
Q

What is required to for Ornithine Transcarbamylase to conduct its reaction?

A

Carbamoyl Phosphate

Produced by Acetyl-Coa + Glutamate –> N-Acetyl Glutamate

39
Q

What is a missense versus nonsense mutation?

A

Missense – changes amino acid

Nonsense – changes to STOP codon (UGA, UAG, UAA)

40
Q

Where does the female ovum stop after it has been stimulated and become dominant?

A

Meiosis II – Metaphase

Before it is selected, its Prophase Meiosis I

41
Q

What is a common side effect of Verapamil?

A

Negative Inotrophy

    • gingival hyperplasia
    • constipation
42
Q

What is the consensus sequence of PolyA tail that is placed on mRNA while in nucleus?

A

“AAUAAA”

– protects from degradation

43
Q

What is a common characteristic of patients who develop Lupus-like drug reaction?

A

Slow Acetylators

    • fever
    • arthalgias
    • rash
    • pericarditis
44
Q

What is unique about tRNA sequences?

A

They have odd abnormal amino acids present

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