Basics Of Nucleic Acids Part - I
Nucleic acids are biological molecules essential for life, and include DNA (deoxyribonucleic acid) and RNA (ribonucleic acid).
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Questions and Answers
- 1.
The best role of Purine and pyrimidine nucleotides is to serve as the monomeric precursors of....
- A.
RNA
- B.
DNA
- C.
Both of the above
- D.
None of the above
Correct Answer
C. Both of the aboveExplanation
Purine and pyrimidine nucleotides serve as the monomeric precursors of both RNA and DNA. This means that they are the building blocks used to construct the nucleic acids that make up these two important molecules. Nucleotides are composed of a nitrogenous base (either a purine or pyrimidine), a sugar molecule, and a phosphate group. These nucleotides are then joined together through phosphodiester bonds to form the backbone of RNA and DNA. Therefore, both RNA and DNA rely on purine and pyrimidine nucleotides for their synthesis.Rate this question:
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- 2.
The purine nucleotides act as the components of ……
- A.
FAD
- B.
NAD
- C.
NADP+
- D.
All of the above
Correct Answer
D. All of the aboveExplanation
The purine nucleotides, which include adenine and guanine, act as components of FAD, NAD, and NADP+. FAD (flavin adenine dinucleotide), NAD (nicotinamide adenine dinucleotide), and NADP+ (nicotinamide adenine dinucleotide phosphate) are all important coenzymes involved in various metabolic reactions in the cell. They participate in electron transfer reactions and play a crucial role in energy production and metabolism. Therefore, all of the above options are correct.Rate this question:
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- 3.
The pyrimidine nucleotides act as the high energy intermediates…
- A.
UDPG
- B.
ATP
- C.
ADP
- D.
AMP
Correct Answer
A. UDPGExplanation
Pyrimidine nucleotides, such as UDPG, are known to act as high energy intermediates. This means that they play a crucial role in transferring and storing energy within cells. These nucleotides are involved in various metabolic processes, including the synthesis of DNA and RNA, as well as the production of energy-rich molecules like ATP. Therefore, UDPG is the correct answer as it is one of the pyrimidine nucleotides that function as high energy intermediates.Rate this question:
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- 4.
The chemical name of Thymine….
- A.
2-oxy-4-4-aminopyrimidine
- B.
2,4-dioxy-5-dipyrimidine
- C.
2,4-dioxypyrimidine
- D.
None of the above
Correct Answer
B. 2,4-dioxy-5-dipyrimidineExplanation
Thymine is a chemical compound that belongs to the pyrimidine group. Its chemical name is 2,4-dioxy-5-dipyrimidine.Rate this question:
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- 5.
The chemical name of 2-amino-6-oxypurine is said to be….
- A.
Adenine
- B.
Xanthine
- C.
Guanine
- D.
Hypoxanthine
Correct Answer
C. GuanineExplanation
Guanine is the correct answer because the chemical name of 2-amino-6-oxypurine is guanine. Guanine is one of the four nucleobases found in DNA and RNA, along with adenine, cytosine, and thymine (or uracil in RNA). It is a purine derivative and plays a crucial role in the structure and function of nucleic acids.Rate this question:
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- 6.
The lactum form is the predominant tautomer of ….
- A.
Uracil
- B.
Cytosine
- C.
Adenine
- D.
Xanthine
Correct Answer
A. UracilExplanation
Uracil is the correct answer because it is known to exist in two tautomeric forms: lactam and lactim. However, the lactam form is more stable and therefore the predominant tautomer of uracil.Rate this question:
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- 7.
N7-methylguanine has been found more recently in the nucleic acids of the cells of ….
- A.
Bacteria
- B.
Yeast
- C.
Plant
- D.
Mammals
Correct Answer
A. BacteriaExplanation
N7-methylguanine has been found more recently in the nucleic acids of the cells of bacteria.Rate this question:
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- 8.
Hypoxanthine and ribose constitute ….
- A.
Adenosine
- B.
Inosine
- C.
Guanosine
- D.
Cytidine
Correct Answer
B. InosineExplanation
Hypoxanthine and ribose constitute Inosine. Inosine is a nucleoside formed by the combination of hypoxanthine, a purine base, and ribose, a sugar molecule. Nucleosides are the building blocks of nucleotides, which are essential for the synthesis of DNA and RNA. Inosine can be found in RNA molecules and also plays a role in cellular processes such as signaling and regulation of gene expression.Rate this question:
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- 9.
Thymine and deoxyriboxe form….
- A.
Deoxycytidine
- B.
Deoxyadenosine
- C.
Deoxythymidine
- D.
Deoxyuridine
Correct Answer
C. DeoxythymidineExplanation
Thymine and deoxyribose form deoxythymidine. Thymine is one of the four nucleobases found in DNA, and deoxyribose is the sugar molecule that makes up the backbone of DNA. When thymine and deoxyribose combine, they form deoxythymidine, which is a nucleoside.Rate this question:
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- 10.
The most abundant intracellular free nucleotides….
- A.
ATP
- B.
FAD+
- C.
NAD+
- D.
NADP+
Correct Answer
A. ATPExplanation
ATP is the correct answer because it is the most abundant intracellular free nucleotide. ATP is an important molecule in cells as it serves as the primary energy currency, providing energy for cellular processes. It is involved in various metabolic reactions and is essential for cellular functions such as muscle contraction, active transport, and synthesis of macromolecules. FAD+, NAD+, and NADP+ are also important nucleotides, but they are not as abundant as ATP in the cell.Rate this question:
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- 11.
The concentration of ATP in living mammalian cells in mM is near
- A.
0.2
- B.
0.4
- C.
0.6
- D.
1.0
Correct Answer
B. 0.4Explanation
The correct answer is 0.4. This is because the concentration of ATP in living mammalian cells is typically around 0.4 millimolar (mM). ATP is the primary energy currency of cells and is involved in various cellular processes. This concentration allows for efficient energy transfer and utilization within the cell.Rate this question:
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- 12.
The biosynthesis of Phosphoglycerides in animal tissue requires.
- A.
UTP
- B.
CTP
- C.
GTP
- D.
ATP
Correct Answer
B. CTPExplanation
The biosynthesis of phosphoglycerides in animal tissue requires CTP. CTP, or cytidine triphosphate, is a nucleotide that plays a crucial role in the synthesis of phospholipids, which are the main components of phosphoglycerides. CTP is specifically involved in the formation of CDP-diacylglycerol, an intermediate in the biosynthesis of phosphoglycerides. Without CTP, the synthesis of phosphoglycerides would be impaired, leading to a disruption in cellular membrane structure and function.Rate this question:
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- 13.
“Transforming factor” is used for the name of ….
- A.
RNA
- B.
DNA
- C.
TRNS
- D.
None of the above
Correct Answer
B. DNAExplanation
The term "transforming factor" is commonly used to refer to DNA. This is because DNA is known to carry genetic information and has the ability to transfer genetic material from one organism to another through a process called transformation. RNA and tRNS are not typically referred to as "transforming factors" as they do not have the same role in genetic transfer. Therefore, the correct answer is DNA.Rate this question:
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- 14.
Guanosine nucleotide is held by the cytosine nucleotide by the number of hydrogen bonds….
- A.
1
- B.
2
- C.
3
- D.
4
Correct Answer
C. 3Explanation
Guanosine nucleotide is held by the cytosine nucleotide by three hydrogen bonds.Rate this question:
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- 15.
Within the single turn of DNA the number of base pair exits…
- A.
4
- B.
6
- C.
8
- D.
10
Correct Answer
D. 10Explanation
In a single turn of DNA, the number of base pairs that exist is 10. This means that there are 10 base pairs, which consist of adenine (A) paired with thymine (T), and cytosine (C) paired with guanine (G), that are present within one complete rotation of the DNA double helix. Each base pair is held together by hydrogen bonds, forming the characteristic double helical structure of DNA.Rate this question:
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- 16.
Each turn of DNA structure has a pitch in nm of ….
- A.
1.4
- B.
2.4
- C.
3.4
- D.
4.4
Correct Answer
C. 3.4Explanation
The pitch of a DNA structure refers to the distance between two consecutive turns of the DNA helix. In this case, the pitch is 3.4 nm, indicating that each turn of the DNA helix is separated by a distance of 3.4 nanometers.Rate this question:
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- 17.
The double stranded DNA molecules loses its viscosity upon….
- A.
Denaturation
- B.
Filtration
- C.
Sedimentation
- D.
Concentration
Correct Answer
A. DenaturationExplanation
Denaturation refers to the process in which the double stranded DNA molecules lose their structure and become single stranded. This can occur due to various factors such as high temperature, extreme pH, or exposure to certain chemicals. When denaturation occurs, the DNA molecules lose their ability to maintain their shape and viscosity, resulting in a loss of viscosity. Therefore, the correct answer is denaturation.Rate this question:
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- 18.
A nucleoside consists of
- A.
Nitrogenous base
- B.
Purine or pyrimidine base + sugar
- C.
Purine or pyrimidine base + phosphorous
- D.
Purine + pyrimidine base + sugar + phosphorous
Correct Answer
B. Purine or pyrimidine base + sugarExplanation
A nucleoside consists of a nitrogenous base (either a purine or pyrimidine base) and a sugar molecule. The nitrogenous base and sugar are bonded together to form the nucleoside. The presence of a phosphorous molecule is not necessary for a nucleoside.Rate this question:
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- 19.
Nucleotides and nucleic acids concentration are often also expressed in terms of
- A.
Ng
- B.
Mg
- C.
Meq
- D.
OD at 260nm
Correct Answer
D. OD at 260nmExplanation
The concentration of nucleotides and nucleic acids can be expressed in terms of OD at 260nm. OD (optical density) at 260nm is a measure of the absorbance of light at a specific wavelength, which is used to quantify the concentration of nucleic acids in a sample. This method is commonly used because nucleic acids have a characteristic absorbance at 260nm due to the presence of aromatic bases. By measuring the OD at 260nm, the concentration of nucleotides and nucleic acids can be determined.Rate this question:
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- 20.
The carbon of the pentose in ester linkage with the phosphate in a nucleotide structure is...
- A.
C1
- B.
C3
- C.
C4
- D.
C5
Correct Answer
D. C5Explanation
In a nucleotide structure, the carbon of the pentose (a type of sugar) that is in ester linkage with the phosphate group is C5. This means that the phosphate group is attached to the fifth carbon atom of the pentose sugar.Rate this question:
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Mar 21, 2023Quiz Edited by
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Sep 20, 2011Quiz Created by
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