19 Questions
Which of the following are major bases in RNA?
Adenine, guanine, uracil, cytosine
What is the role of nucleotide derivatives in biosyntheses?
Activated intermediates in many biosyntheses
What is the function of ATP in biological systems?
Powers movement of macromolecules
What is the main difference between a nucleoside and a nucleotide?
Nucleoside consists of a base linked to a pentose (sugar), while a nucleotide is a phosphate diester of a nucleoside
Which nucleotide derivative is a precursor of glycogen?
UDP-glucose
What are the components of a deoxyribonucleoside?
Base, sugar, phosphate
What are the activated intermediates in many biosyntheses?
Nucleotide derivatives
Which nucleotide components link to form a nucleoside?
Base and sugar
What is the role of Cyclic AMP?
Mediator of action of many hormones
What are the components of a ribonucleotide?
Base, sugar, phosphate
What is the process of synthesizing purine and pyrimidine nucleotides from simple building blocks called?
De novo synthesis
Which of the following provides C-4, C-5, and N-7 for the synthesis of purine?
Glycine
Which enzyme catalyzes the formation of 5-phosphoribosylamine from PRPP and glutamine?
PRPP amidotransferase
What is the activated form of ribose used in de novo purine synthesis?
PRPP
Which compound is synthesized from ATP and ribose-5-phosphate to form the activated ribose used in purine and pyrimidine nucleotide synthesis?
PRPP
What provides the N-1 atom for purine synthesis?
Aspartate
Which pathway involves synthesizing nucleotides from scratch or beginning?
De novo synthesis
What is the first stage in the synthesis of IMP (Inosine monophosphate) during de novo purine synthesis?
11 steps
From which major organ is de novo purine synthesis active?
Liver
Study Notes
Nucleotides and Nucleosides
- Adenine, Guanine, Cytosine, and Uracil are major bases in RNA.
- Nucleotide derivatives play a crucial role in biosyntheses as energy carriers, signal transducers, and building blocks.
ATP and Its Function
- ATP (Adenosine Triphosphate) is a crucial energy currency in biological systems, providing energy for various cellular processes.
Nucleosides and Nucleotides
- The main difference between a nucleoside and a nucleotide is the presence of a phosphate group in a nucleotide.
- A nucleoside consists of a sugar molecule and a nitrogenous base, while a nucleotide has an additional phosphate group.
Deoxyribonucleoside and Ribonucleotide
- A deoxyribonucleoside consists of a deoxyribose sugar and a nitrogenous base.
- A ribonucleotide consists of a ribose sugar, a nitrogenous base, and a phosphate group.
Biosynthetic Pathways
- Activated intermediates in many biosyntheses are nucleotide derivatives.
- PRPP (5-Phosphoribosyl-1-Pyrophosphate) is a precursor of glycogen and is used in the synthesis of purine and pyrimidine nucleotides.
- De novo purine synthesis is the process of synthesizing purine and pyrimidine nucleotides from simple building blocks.
- Glutamine provides the N-1 atom for purine synthesis.
De Novo Purine Synthesis
- PRPP and glutamine are used to form 5-phosphoribosylamine, which is catalyzed by the enzyme PurS.
- The activated form of ribose used in de novo purine synthesis is PRPP.
- The first stage in the synthesis of IMP (Inosine monophosphate) during de novo purine synthesis is the formation of 5-phosphoribosylamine.
- De novo purine synthesis is active in the liver.
Cyclic AMP
- Cyclic AMP (Cyclic Adenosine Monophosphate) is a crucial signaling molecule in biological systems, involved in various cellular processes.
Test your knowledge of nucleotide metabolism with questions covering the synthesis, catabolic processes, regulation, and clinical significance. Explore the biosynthesis and degradation of nucleotides and understand the significance of nucleoproteins in our diet.
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