Chemistry of Nucleotides Quiz -lect-10

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Questions and Answers

Which nucleotide derivative serves as the universal currency of energy?

Guanine

NAD+

ATP (correct)

Adenine

What is formed when a nucleoside is esterified to a phosphate group?

Nucleoside diphosphate

Nucleotide (correct)

Nucleoside triphosphate

Nucleic acid

What type of nitrogenous base is adenine?

Ribose

Deoxyribose

Pyrimidine

Purine (correct)

What are the components of a nucleotide?

Purine base, pentose sugar, esterified phosphate groups Signup and view all the answers

What is the difference between a nucleoside diphosphate and a nucleoside triphosphate?

Number of phosphate groups esterified Signup and view all the answers

What is the role of NAD+ in cellular processes?

Component of co-enzymes Signup and view all the answers

Which statement about DNA and RNA is correct?

Both DNA and RNA contain the same nitrogenous bases but differ in sugar composition Signup and view all the answers

What is the function of cAMP and cGMP?

Metabolic regulation Signup and view all the answers

What type of nucleic acid is concerned with the storage and transfer of genetic information?

DNA Signup and view all the answers

What is formed when a base combines with a pentose sugar?

Nucleoside Signup and view all the answers

What are the purine bases present in RNA and DNA?

Adenine and guanine Signup and view all the answers

Which of the following best describes the function of transfer RNA (tRNA)?

It functions as an adapter, bringing a specific amino acid to the site of protein synthesis Signup and view all the answers

What is the approximate size of transfer RNA (tRNA)?

75 nucleotides Signup and view all the answers

How many tRNAs are found in humans, despite there being 20 amino acids?

32 tRNAs Signup and view all the answers

What gives transfer RNA (tRNA) its clover leaf shape?

Intrastrand hydrogen bonds Signup and view all the answers

Which sequence is present towards the 3’ end (acceptor arm) of transfer RNA (tRNA)?

CCA Signup and view all the answers

What is the role of the last nucleotide, adenine, at the 3’ end of transfer RNA (tRNA)?

It binds covalently to a specific amino acid Signup and view all the answers

What does the anticodon arm of transfer RNA (tRNA) have?

Triplet codon complementary to mRNA codon Signup and view all the answers

What is the major difference between ribosomal RNAs (rRNAs) and transfer RNA (tRNA)?

rRNAs are involved in translation, while tRNAs are associated with ribosomes Signup and view all the answers

What is the sugar component in DNA?

Deoxyribose Signup and view all the answers

Where is RNA found?

In both nucleus and cytoplasm Signup and view all the answers

Which of the following bases are found in RNA?

A, U, G and C Signup and view all the answers

What is the nature of DNA?

Double stranded Signup and view all the answers

Which of the following are purine bases in nucleic acids?

Signup and view all the answers

What is the main difference between nucleosides and nucleotides?

Nucleotides contain phosphate esters Signup and view all the answers

How are deoxyribonucleosides denoted to avoid confusion?

They are denoted with the prefix 'd-' Signup and view all the answers

What is the significance of 5'-phosphates in nucleotides?

They serve as energy currencies Signup and view all the answers

Which position of ribose or deoxyribose can be phosphorylated to form nucleotides?

3' Signup and view all the answers

What are nucleoside triphosphates, such as ATP, used for in biological processes?

Energy currencies and cofactors Signup and view all the answers

How are cyclic nucleotides, such as cAMP and cGMP, formed?

By phosphodiester linkages between the 3' and 5' positions of the ribose group Signup and view all the answers

What is the role of nucleotide triphosphates in biological processes?

They serve as energy currencies Signup and view all the answers

What is the composition of RNA?

Ribose sugar, nitrogenous bases, and phosphate Signup and view all the answers

What stabilizes mRNA and assists in its translation?

Poly(A) tail at the 3' end Signup and view all the answers

What role does transfer RNA (tRNA) play in protein synthesis?

It assists in translating the genetic code from mRNA to protein Signup and view all the answers

What holds together the structure of RNA?

Phosphodiester bonds between nucleotides Signup and view all the answers

Study Notes

The purine bases in nucleic acids are adenine and guanine, while pyrimidine bases are cytosine, thymine, and uracil
Nucleosides are formed when bases attach to pentose sugar (ribose or deoxyribose) through a beta-N-glycosidic bond
Deoxyribonucleosides are denoted with the prefix "d-" and have different carbon designations to avoid confusion
Nucleotides are phosphate esters of nucleosides, and most biologically active ones are 5'-phosphates
Nucleotides can be formed with either ribose or deoxyribose, which can be phosphorylated at the 3' or 5' positions
Nucleoside triphosphates, such as ATP, are high-energy compounds used as cofactors and energy currencies
Cyclic nucleotides, such as cAMP and cGMP, are formed by phosphodiester linkages between the 3' and 5' positions of the ribose group
Nucleotides and nucleic acids absorb ultraviolet light, and nucleotide triphosphates play essential roles in various biological processes
RNA is a single-stranded polymer of ribonucleotides, and messenger RNA (mRNA) carries genetic information from DNA for protein synthesis
RNA is composed of ribose sugar, nitrogenous bases, and phosphate, and its structure is held together by hydrogen bonds between bases and by phosphodiester bonds between nucleotides.
mRNA contains a poly(A) tail at its 3' end, which stabilizes the mRNA and helps in its translation
Transfer RNA (tRNA) plays a role in translating the genetic code from mRNA to protein
The structure of DNA, proposed by Watson and Crick, consists of two complementary strands coiled around the same axis and held together by hydrogen bonds between the bases.
RNA comes in various forms, such as messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA), and each type plays distinct roles in the cell.

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