s-nucleic acids chemistry tutorial.doc

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Nucleic acids chemistry tutorialY1, 2009

Prof. Iman Elshabrawy

Purines, pyrimidines, nucleosides & nucleotides

MCQ

1- Nucleotides contain

A. nitrogenous bases.

B. fucose.

C. no phosphate.

D. deoxy pentose.

E. glycosidic bonds.

2- Purine bases includeA. adenine.

B. cytosine.

C. uracil.

D. guanine.

E. hypoxanthine.

3- Nitrogenous bases present in both DNA and RNA are:

A. uracil.

B. cytosine.

C. thymine.

D. adenine.E. guanine.

OBA

1- The order of bases from left-to right is

A. U A G C T

B. T G A C U

C. A T C G U

D. C U G A T

E. T A G C U

2- Adjacent nucleotides are joined by

A. a purine base.

B. a 3'- 5' phosphodiester bond.

C. a glycosidic bond .

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D. a deoxyribose.

E. a pyrimidine base.

3- Nucleoside nitrogenous base is attached to a pentose via

A. a purine base.

B. a 3'- 5' phosphodiester bond .C. a glycosidic bond.

D. a deoxyribose.

E. a pyrimidine base.

Relational

1- Aspartate and glutamine are essential for nucleotides synthesis.

BECAUSE

Aspartate and glutamine are precursors for the synthesis of both purines and

pyrimidines.

2- The abbreviation dTMP, indicates the presence of deoxy ribose in this nucleotide.

BECAUSE

The abbreviation dTMP has the fourth letter P.

3- Nucleotides with multiple phosphate groups are called nucleosides.

BECAUSE

Nucleotides with multiple phosphate groups lakes the pentose.

MEQ

1- Purine and pyrimidine bases are components of nucleosides and nucleotides.Nucleotides are the basic units of nucleic acids.

A. Illustrate with structure the common purine bases, and mention the enumeration

of each atom of the base. Mention the bases in DNA and RNA.

B. Illustrate with structure the common pyrimidine bases, and mention the

enumeration of each atom of the base. Mention the bases in DNA and RNA.

C. Explain the difference between nucleosides and nucleotides. Illustrate with

diagram.

D. Explain the nomenclature of nucleosides and nucleotides with examples forpurines and pyrimidenes.

E. Explain how to write the sequence of a polynucleotide chain with abbreviation.

Illustrate with diagram.

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Nucleic acids, DNA and RNA

MCQ

1- Double helix of DNA

A. is formed of 2 long polypeptide chains.B. involves bonding of A-G and C-T.

C. has 2 identical chains.

D. is right handed in B form.

E. denatures by temperature but unable to anneal by cooling.

2- Histones are

A. components of nucleosomes.

B. only one class in DNA core.

C. present with B form of DNA but not with A and Z forms.

D. the only protein type present in nucleosomes.

E. acting as a core to coil DNA.

3- mRNA

A. is formed in cytoplasm and transferred to the nucleus.

B. recognizes by its anticodon a specific amino acid.

C. sequence of bases directs the synthesis of a specific protein.

D. is in the form of heterogeneous nuclear RNA (hnRNA) primarily.

E. bonds amino acids by peptidyl transferase.

OBA

1- RNA with unusual modified nucleotides isA. hnRNA .

B. mRNA .

C. rRNA.

D. snRNA.

E. tRNA.

2- RNA with the largest weight of cytoplasmic RNA is

A. hnRNA .

B. mRNA.

C. rRNA .

D. snRNA.E. tRNA.

3- Which one of the following double-stranded DNA molecules has the highest

melting temperature (Tm)?

A. GCGCGCGC

CGCGCGC G

B. GCCATGGC

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CGGTACCG

C. GGAATTCC

CCTTAAGG

D. GAAATTTC

CTTTAAAG

E. ATATATATTATATATA

Relational

1- mRNA poly A tail don't have complementary sequences in nuclear DNA.

BECAUSE

mRNA poly A tail isadded posttranscriptionally.2- DNA carries the genetic information.

BECAUSE

DNA contains histones in nucleosomes.

3- Temperature of melting (Tm) of melting curve indicates DNA base composition.

BECAUSE

Temperature of melting (Tm) of melting curve indicates DNA sequences located on

chromosomes, as multigene families and clusters.

MEQ

1- Nucleic acids are deoxy ribonucleic acids and ribonucleic (DNA and RNA).

A. Explain the structure of DNA. Illustrate with diagrams.

B. Describe properties and forms of DNA.

C. Describe the structure of different major types of RNA.

D. Describe the function of different major types of RNA.

E. Describe the differences between DNA and RNA.

Free Nucleotides of Biological Importance

MCQ

1- Free nucleotides with biological importance include:

A. adenine triphosphate (ATP).

B. transfer ribonucleic acid (tRNA).

C. cyclic adenosine monophosphate (cAMP).

D. uridine diphosphate (UDP).

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E. Z form of deoxy ribonucleic acid (Z form of DNA).

2- Free nucleotides that act as 2nd messenger are

A. 3- phosphoadenosine-phosphosulfate (PAPS).

B. S- adenosyle methionine (SAM).

C.cyclic adenosine monophosphate (cAMP).D. uridine diphosphate (UDP).

E.cyclic guanosine mono phosphate (cGMP).3- Coenzyme nucleotides are

A. uridine diphosphate (UDP).

B. coenzyme A.

C. flavine adenine dinucleotide (FAD).

D.coenzyme B12.E. fatty acyl-adenylates.

OBA

1- A free nucleotide that act as a methyl donor in transmethylation reactions is


B. uridine diphosphate (UDP).

C. adenine triphosphate (ATP).

D. S- adenosyle methionine (SAM).

E. cytidine diphosphate (CDP).

2- A free nucleotide that act as an active donor of sulfate is


B. S- adenosyle methionine (SAM).C. adenine triphosphate (ATP).

D. uridine diphosphate (UDP).


3- A free nucleotide that act asthe carrier of glucose in metabolic reactions isA. 3- phosphoadenosine-phosphosulfate (PAPS).

B. uridine diphosphate (UDP).

C. adenine triphosphate (ATP).

D. S- adenosyle methionine (SAM).


Relational

1- Nucleotides are not only components of nucleic acids.

BECAUSE

Nucleotides of great biological importance exist in the free state in living cells.

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2- Free energy is collected in the form of adenosine triphosphate (ATP).

BECAUSE

Free energy of ATP produces ADP which is critical for platelet aggregation.

3- Gyanosine triphosphate (GTP ) is required for mRNA capping.

BECAUSEGTP is required for signal transduction through GTP- binding proteins.

MEQ

1- In addition to importance of nucleotides as components of nucleic acids, a

number of nucleotides of great biological importance exist in the free state in living

cells.

A. List the functions of adenosine derivatives free nucleotides.

B. List the functions of guanosine derivatives free nucleotides.

C. List the functions of hypoxanthine (Inosine), uridine and cytosine derivatives free

nucleotides.

D. Give 3 examples of vitamin nucleotides.

E. Give 2 examples of coenzyme nucleotides.

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s-nucleic acids chemistry tutorial.doc

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