Test 19 - Biochem Flashcards Preview

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Flashcards in Test 19 - Biochem Deck (37)
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0

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

N-acetylglutamate

1

Tetrahydrobiopterin is a cofactor in the synthesis of what?

1500

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

2

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

1245

Procollagen peptidase

3

Which enzyme is affected in Riboflavin (B2) deficiency?

1807

Succinate Dehydrogenase

4

Proprionic acid is the intermediate in the catabolism of what?

1340

Branched chain amino acids

5

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

1340

Proprionyl CoA Carboxylase

6

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

1972

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.

7

Which G protein is involved with IP3 second messenger system?

1122

Gq

8

Activation of Phospholipase C forms what?

1122

DAG and IP3

9

What bond type stabilizes the secondary structure of proteins?

2026

Hydrogen bonds

10

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

Disulfide Bonds

11

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

1481

Aspartate
NH3

12

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

Pyruvate dehydrogenase

13

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

1888

Acyl-CoA Dehydrogenase

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

14

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

1387

2-3, DPG.

15

Which RNA polymerase activity is restricted to the Nucleolus?

2039

RNA Polymerase I

16

DNA synthesis only occurs in which direction?

1418

5' - 3'

17

Which substrates accumulate in lead poisoning?

1157

1) Protoporphyrin
2) Delta-ALA

18

Delta-aminolevulinic acid synthase requires which cofactor?

B6 (Pyridoxal phosphate)

19

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

1847

Thymidine

20

Thiamine deficiency can be diagnosed how?

Measure erythrocyte transketolase activity

21

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

FA: 92

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

22

Which functions does DNA Polymerase I have? (3)

1434

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

23

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

1485

- 1 mRNA can code for several proteins
- bacterial lac operon

24

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

1416

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

25

What is the most abundant amino acid found in collagen?

1248

Glycine

26

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

2031
FA: 232

N-myc

27

Beta thalassemia is caused by mutations which result in what?

1940

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

28

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

1045

Vitamin A

29

What is the function of ApoE 3 & 4?

2064

VLDL and Chylomicron remnant uptake by liver cells

30

What is the function of ApoA-I

2064

LCAT activation

31

What is function of ApoB-48?

2064

Chylomicron assembly and secretion by the intestines

32

What is the function of ApoB-100?
2064

LDL particle uptake by hepatic cells

33

What is the function of ApoC II?

2064

Lipoprotein Lipase activation

34

What are the symptoms of an infant with classic galactosemia?

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

35

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

1071

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

36

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

8540

Myeloproliferative disorders