Test 19 - Biochem

Question 0

Tetrahydrobiopterin is a cofactor in the synthesis of what?

1500

Answer 0

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

Question 1

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

Answer 1

N-acetylglutamate

Question 2

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

1245

Answer 2

Procollagen peptidase

Question 3

Which enzyme is affected in Riboflavin (B2) deficiency?

1807

Answer 3

Succinate Dehydrogenase

Question 4

Proprionic acid is the intermediate in the catabolism of what?

1340

Answer 4

Branched chain amino acids

Question 5

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

1340

Answer 5

Proprionyl CoA Carboxylase

Question 6

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

1972

Answer 6

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.

Question 7

Which G protein is involved with IP3 second messenger system?

1122

Answer 7

Gq

Question 8

Activation of Phospholipase C forms what?

1122

Answer 8

DAG and IP3

Question 9

What bond type stabilizes the secondary structure of proteins?

2026

Answer 9

Hydrogen bonds

Question 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

Answer 10

Disulfide Bonds

Question 11

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

1481

Answer 11

Aspartate

NH3

Question 12

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

Answer 12

Pyruvate dehydrogenase

Question 13

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

1888

Answer 13

Acyl-CoA Dehydrogenase

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

Question 14

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

1387

Answer 14

2-3, DPG.

Question 15

Which RNA polymerase activity is restricted to the Nucleolus?

2039

Answer 15

RNA Polymerase I

Question 16

DNA synthesis only occurs in which direction?

1418

Answer 16

5’ - 3’

Question 17

Which substrates accumulate in lead poisoning?

1157

Answer 17

1) Protoporphyrin

2) Delta-ALA

Question 18

Delta-aminolevulinic acid synthase requires which cofactor?

Answer 18

B6 (Pyridoxal phosphate)

Question 19

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

1847

Answer 19

Thymidine

Question 20

Thiamine deficiency can be diagnosed how?

Answer 20

Measure erythrocyte transketolase activity

Question 21

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

FA: 92

Answer 21

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

Question 22

Which functions does DNA Polymerase I have? (3)

1434

Answer 22

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

Question 23

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

1485

Answer 23

• 1 mRNA can code for several proteins

- bacterial lac operon

Question 24

In patients with methemoglobinemia, what is normal in the blood? 1416

Answer 24

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

Question 25

What is the most abundant amino acid found in collagen? 1248

Answer 25

Glycine

Question 26

What is a transcription factor (capable of DNA binding) that is associated with Neurofibromatosis? 2031 FA: 232

Answer 26

N-myc

Question 27

Beta thalassemia is caused by mutations which result in what? 1940

Answer 27

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

Question 28

Which vitamin supplementation should be considered in a patient with Measles? 1045

Answer 28

Vitamin A

Question 29

What is the function of ApoE 3 & 4? 2064

Answer 29

VLDL and Chylomicron remnant uptake by liver cells

Question 30

What is the function of ApoA-I 2064

Answer 30

LCAT activation

Question 31

What is function of ApoB-48? 2064

Answer 31

Chylomicron assembly and secretion by the intestines

Question 32

What is the function of ApoB-100? | 2064

Answer 32

LDL particle uptake by hepatic cells

Question 33

What is the function of ApoC II? 2064

Answer 33

Lipoprotein Lipase activation

Question 34

What are the symptoms of an infant with classic galactosemia?

Answer 34

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

Question 35

What enzyme is deficient in classic galactosemia? What reaction does it facilitate? 1071

Answer 35

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

Question 36

Which disorder can result from constitutive action of Tyrosine Kinase which results in increased STAT. 8540

Answer 36

Myeloproliferative disorders