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Test 19 - Biochem Flashcards

0
Q

Tetrahydrobiopterin is a cofactor in the synthesis of what?

1500

A

1) Tyrosine
2) DOPA
3) Serotonin
4) N.O.

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1
Q

In the Urea cycle, which cofactor is required to activate Carbamoyl Phosphate Synthase I

A

N-acetylglutamate

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2
Q

Which enzyme converts procollagen to tropocollagen by removing the globular portions in the extracellular space?

1245

A

Procollagen peptidase

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3
Q

Which enzyme is affected in Riboflavin (B2) deficiency?

1807

A

Succinate Dehydrogenase

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4
Q

Proprionic acid is the intermediate in the catabolism of what?

1340

A

Branched chain amino acids

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5
Q

Which enzyme is responsible for the conversion of proionyl CoA to Methylmalonyl CoA and congenital deficiency can lead to proprionic acidemia?

1340

A

Proprionyl CoA Carboxylase

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6
Q

What is the function of the 16s rRNA sequence in prokaryotes? (2)

1972

A

1) 16s is found in the 30s subunit.
2) 16s rRNA contains a sequence complementary to the Shine-Delgarno sequence on mRNA. Binding of these 2 is needed for initiation of protein translation.

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7
Q

Which G protein is involved with IP3 second messenger system?

1122

A

Gq

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8
Q

Activation of Phospholipase C forms what?

1122

A

DAG and IP3

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9
Q

What bond type stabilizes the secondary structure of proteins?

2026

A

Hydrogen bonds

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10
Q

What are the very strong covalent bonds between 2 cysteine residues within the same polypeptide chain that enhance a proteins ability to withstand degradation?

2026

A

Disulfide Bonds

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11
Q

What is an immediate source of nitrogen for urea in the urea cycle?

1481

A

Aspartate

NH3

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12
Q

Deficiency of which enzyme can cause increased lactate levels in the blood?

A

Pyruvate dehydrogenase

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13
Q

Which enzyme catalyzes the first step in the B-oxidation pathway and is the most commonly deficient enzyme?

1888

A

Acyl-CoA Dehydrogenase

(pt. unable to break down fatty acids during prolonged fasting.

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14
Q

Fetal hemoglobin binds oxygen with a higher affinity due to its inability to interact with what?

1387

A

2-3, DPG.

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15
Q

Which RNA polymerase activity is restricted to the Nucleolus?

2039

A

RNA Polymerase I

16
Q

DNA synthesis only occurs in which direction?

1418

A

5’ - 3’

17
Q

Which substrates accumulate in lead poisoning?

1157

A

1) Protoporphyrin

2) Delta-ALA

18
Q

Delta-aminolevulinic acid synthase requires which cofactor?

A

B6 (Pyridoxal phosphate)

19
Q

Supplementation of what can moderately increase dTMP levels, thereby reducing erythroid precursor cell apoptosis due to deficiency of folate?

1847

20
Q

Thiamine deficiency can be diagnosed how?

A

Measure erythrocyte transketolase activity

21
Q

Thiamine (B1) is a cofactor for which enzyme reactions?

FA: 92

A

1) Pyruvate dehydrogenase
2) Alpha-ketoglutarate dehydrogenase
3) Transketolase
4) Branched-chain ketoacid dehydrogenase

22
Q

Which functions does DNA Polymerase I have? (3)

1434

A

1) 5’-3’ exonuclease
2) 3’-5’ exonuclease
3) 5’-3’ polymerase

23
Q

What is meant by bacterial mRNA can be polycistronic? Example?

1485

A
  • 1 mRNA can code for several proteins

- bacterial lac operon

24
Q

In patients with methemoglobinemia, what is normal in the blood?

1416

A

Partial pressure of oxygen because the amount of oxygen dissolved in the plasma is the same.

25
Q

What is the most abundant amino acid found in collagen?

1248

26
Q

What is a transcription factor (capable of DNA binding) that is associated with Neurofibromatosis?

2031
FA: 232

27
Q

Beta thalassemia is caused by mutations which result in what?

1940

A

Defective transcription, processing, and translation of Beta-globin mRNA.

28
Q

Which vitamin supplementation should be considered in a patient with Measles?

1045

29
Q

What is the function of ApoE 3 & 4?

2064

A

VLDL and Chylomicron remnant uptake by liver cells

30
Q

What is the function of ApoA-I

2064

A

LCAT activation

31
Q

What is function of ApoB-48?

2064

A

Chylomicron assembly and secretion by the intestines

32
Q

What is the function of ApoB-100?

2064

A

LDL particle uptake by hepatic cells

33
Q

What is the function of ApoC II?

2064

A

Lipoprotein Lipase activation

34
Q

What are the symptoms of an infant with classic galactosemia?

A

Vomiting, lethargy, and failure to thrive soon after breastfeeding is begun.

35
Q

What enzyme is deficient in classic galactosemia? What reaction does it facilitate?

1071

A

Deficiency: Galactose 1-phosphate uridyl transferase
Reaction: Galactose 1-Phosphate -> UDP- Galactose

36
Q

Which disorder can result from constitutive action of Tyrosine Kinase which results in increased STAT.

8540

A

Myeloproliferative disorders

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