The post De-Novo Biosynthesis of Pyrimidine Nucleotides and MCQs GPAT, NEET UPSC, Pharmacist, CSIR NET and Nursing Exam appeared first on Gpatindia: Pharmacy Jobs, Admissions, Scholarships, Conference,Grants, Exam Alerts.
]]>Precursors for the De-novo synthesis of pyrimidine nucleotides:
Steps involved:
Regulation of De-novo synthesis of pyrimidine nucleotide
The first two enzymes of the process are allosteric enzymes. These are CPS-2 and aspartate transcarbamoylase.
1. Pyrimidine nucleotides are nutritionally classified as?
A. Essential
B. Non-essential
C. Semi-essential
D. None of the above
2. How many pathways are present for the biosynthesis of pyrimidine nucleotide?
A. 2
B. 3
C. 4
D. 1
3. C5 of pyrimidine ring is produced by?
A. Glycine
B. Glutamine
C. CO2
D. Aspartic acid
4. Where do mainly the de-novo biosynthesis of pyrimidine nucleotide occur?
A. Nucleus
B. Cytosol
C. Ribosomes
D. Endoplasmic reticulum
5. Glutamine provides which of the following components of pyrimidine nucleotide?
A. N3
B. N1
C. C4
D. C5
6. The ribose phosphate group attached to the pyrimidine ring is donated by which compound?
A.UMP
B. Orotate
C. Both
D. None of the above
7. Which compound is termed as the ring closure of pyrimidine ring?
A. Dihyro-orotic acid
B. OMP
C. Both
D. None
8. Match the following substrate and its product-
A. d-UMP 1. OMP
B. d-UDP 2. Dihydro-orotate
C. Carbamoyl aspartate 3. d- UMP
D. Orotate 4. D-TMP
9. Which of the following enzyme catalyzes the committed step of the de-novo biosynthesis of pyrimidine nucleotide?
A. Aspartate transcarbamoylase
B. Orotate phosphoribosyl transferase
C. Dihydro-orotate dehydrogenase
D. Both A and c
10. Which of the following is the starting compound for the de-novo biosynthesis of pyrimidine nucleotide?
A. Glutamine
B. Aspartic acid
C. CO2
D. Both A and C
11. Which of the following product in the process of de-novo biosynthesis of pyrimidine nucleotide is formed in mitochondria?
A. Orotic acid
B. Dihydro-orotic acid
C. Carbomoyl aspartate
D. All of the above
12. Which of the following statement is NOT true?
A. Ethylation of d-UMP forms d-TMP
B. CO2 provides C2 carbon of pyrimidine ring
C. Thymidylate synthase is a target enzyme in cancer chemotherapy
D. Decarboxylation of orotidylate yields UMP
13. Which of the following acts as precursors for the de-novo biosynthesis of pyrimidine nucleotide?
A. Glutamine
B. Aspartic acid
C. CO2
D. All of the above
14. Which of the following enzyme is inhibited by CTP?
A. CPS-2
B. Dihydro-orotase
C. Aspartate transcarbamoylase
D. Both A and B
15. Which of the following enzyme is activated by PRPP?
A. CPS-2
B. Dihydro-orotase
C. Aspartate transcarbamoylase
D. Both A and C
ANSWERS-
1. Non-essential
2. 1
3. Aspartic acid
4. Cytosol
5. N3
6. None of the above
7. Dihydro-orotic acid
8. A – 4 B – 3 C – 2 D – 1
9. Aspartate transcarbamoylase
10. Both A and C
11. Orotic acid
12. Ethylation of d-UMP forms d-TMP
13. all of the above
14. Aspartate transcarbamoylase
15. CPS-2
Participate in Online FREE GPAT TEST: CLICK HERE
Participate in Online FREE Pharmacist TEST: CLICK HERE
Participate in Online FREE Drug Inspector TEST: CLICK HERE
Participate in CSIR NET JRF Mock Test
REFERENCE:- 1. Pankaja Naik- Biochemistry; 4th edition; page no:- 329-331.
The post De-Novo Biosynthesis of Pyrimidine Nucleotides and MCQs GPAT, NEET UPSC, Pharmacist, CSIR NET and Nursing Exam appeared first on Gpatindia: Pharmacy Jobs, Admissions, Scholarships, Conference,Grants, Exam Alerts.
]]>