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Subjective Questions

1- What are Okazaki fragments? Explain their significance in replication.

 2-Briefly describe the events happening at the replication fork.

 3- Describe the initiation of DNA synthesis at the origin of replication.

 4-What is semi-conservative replication? Briefly describe the steps and regulation of replication in prokaryotes.

 5- Differentiate between mechanism of action of Helicase and Telomerases in the process of replication.

 6- Outline the salient features of replication and differentiate between prokaryotic and eukaryotic replication processes.

7-Elaborate on proof reading process occurring during  DNA replication; differentiate between, 3’-5’ and 5’-3’ exonuclease activities. Show by means of diagrams the error correction by DNA editing mechanism.


8- Describe the mechanisms by which high accuracy is achieved in DNA replication

 9-Give a brief account of mechanism of action of Telomerase and elaborate on its clinical and biological significance.


 Explain the importance of telomerase in human biology.

 10-Give an account of DNA synthesis by RNA dependent DNA polymerase, mention the clinical significance if any of this process.


 Give an account of DNA synthesis by Revere Transcriptase; discuss the significance of this process in relation to HIV cycle.

 11- Outline the causes of DNA damage and give a brief account of DNA repair system.

 12- What is Xeroderma pigmentosum? Describe the biochemical basis for this condition.

 13- Describe the initiation of transcription in prokaryotes.

 14- Describe briefly about RNA polymerase of prokaryotes.

 15-The DNA sequence given below contains information for termination of RNA synthesis in bacteria.



 (a)    Write down the base sequence of the transcript based on the DNA sequence.

(b)    Indicate and explain how the transcript contributes to the termination of transcription.


 Give an account of the process of termination of transcription in prokaryotes.


Differentiate between Rho dependent and Rho independent modes of termination of transcription.


What is meant by a palindrome sequence, what is the significance of palindrome sequence in termination of transcription in prokaryotes?

 16- Discuss the important points of differences between Replication and Transcription in relation to prokaryotes.

 17- What is the mechanism of action of (a) Actinomycin D (b) Rifampicin and (c) Cycloheximide (Actidione)?

 18- Elaborate on the processes involved in the conversion of a primary transcript to mature m RNA.


What is meant by splicing? Give an account of the process involved and discuss the significance if any of this process. Highlight the role of small nuclear RNA in this process.

 19- Enlist the important inhibitors of transcription used commercially as drugs.

 20- What is genetic code? Discuss the characteristics of genetic code.

 21-What are the  different components required for the process of translation, enlist and explain the function of each of them.

 22-By means of a diagram, briefly describe the elongation cycle of protein synthesis in eukaryotes.

 22- Briefly describe initiation and termination of protein synthesis in prokarotes.

 23- Describe three differences between prokaryotic and eukaryotic protein synthesis.

 24- What is Post-translational processing? Give suitable examples and explain the function of Vit K in post- translational protein modification.


 Using specific examples, explain the functional significance of posttranslational modifications.

 25- Explain how Puromycin blocks protein synthesis. Enlist the important inhibitors of translation and state the mechanism of each of them.

 26- Explain how lactose causes E coli in culture to synthesize B-galactosidase.

 27- Briefly describe concept of lac operon model of control of protein synthesis.

 28- What is meant by repression and derepression of gene expression? Give examples in support of your answer.


 Describe the catabolite repression of the lac operon.

 29-Give a brief description of the processes involved in the regulation of gene expression in eukaryotes.

 30- What is meant by gene rearrangement, explain your answer giving a suitable example?

 31-A mutation is often recognized by a change of loss of function of the protein product of a gene. Despite this, explain how it is also possible for single base mutations to occur without any consequent change in protein function?

 32-The expansion of triplet repeats is responsible for diseases distinct from those caused by missense or nonsense mutations. Briefly explain the molecular basis of this statement.

 33- Give a detailed account of the causes, types and effects of mutations.

 34- What distinguishes a frame shift mutation from a missense and a nonsense mutation?

 35- How is cDNA made from mRNA?

 36- Compare and contrast cDNA and genomic libraries.

 37- The discovery of repetitive DNA sequences scattered throughout the human genome has led to the development of useful clinical tests. Describe an example of such a test.


 What is restriction fragment length polymorphism (RFLP)?

Explain and describe DNA fingerprinting. List some of its application in human genetics.


Explain how restriction fragment length polymorphism (RFLP) may be used in forensic medicine.


Explain and discuss the applications of restriction fragment length polymorphism (RFLPs).

 39- What are vectors of cloning? Enlist the essential requirements for a DNA molecule to be a considered a vector of cloning? Give details of vectors used in the recombinant DNA technology.

 40- Give a brief account of the principle, procedure and applications of Polymerase chain reaction.


 Compare and contrast gene cloning and polymerase chain reaction.

 41- Differentiate between c DNA and genomic libraries. Outline the steps of synthesis of each of them.

 42- Give a brief account of DNA probes. Show by means of a diagram the process of identification of gene of interest by a DNA probe.

 43- Discuss the principle, procedure and significance of Southern hybridization.

 44- Discuss the roles of genetic engineering in the practice of medicine.

 45-What is the significance of the Tm (melting temperature) of DNA? How will the Tm value be affected by (a) presence of urea? (b) an increase in the GC content of the DNA?

 46- Give three structural features of the B-form of the DNA double helix.

 47-Explain the following terms in the context of RNA structure: (a) poly A tail (b) cap.

 48-Describe two features that characterize the B-form of DNA. What does it mean if a sample of DNA does not obey Chargaff’s rules?

 49-Compare and contrast the structure of A, B-DNA with that of Z-DNA.

 50- Give a diagrammatic representation of secondary structure of t RNA, Discuss  its role in  the process of translation.

51- Give an account of Restriction endonucleases  and  highlight their role in recombinant DNA technology.







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Q.1- Give a brief description of functions of c- AMP ? Justify its role as a second messenger in hormonal action.

Q.2- Distinguish between:

a) Nucleoside and Nucleotide

b) Denaturation and Renaturation

c) Ribonucleotide and Deoxyribonucleotide

d) Uridine and Pseudouridine

e) Nucleotides in RNA and DNA

Q.3- Name the components of a nucleotide and show the order in which they are linked together,

Q.4-Why ATP is called the “energy currency of a cell”? Support your answer giving suitable examples.

Q.5- Name base and nucleoside analogs used as anticancer drugs.

Q,6- What is meant by hyperchromicity of denaturation?

Q.7- a) “Uracil is not present in DNA”, suggest the possible reason?

 b) ‘Thymine nucleotides are not present in RNA but exception to the rule is there’, give example in support of the statement.

Q.8- Discuss the biological significance of nucleotides?

Q.9- Compare and contrast the B and Z forms of DNA.

Q.10- Explain the extent to which the Watson-Crick structure of DNA is compatible with Chargaff’s rule.

Q-11- Explain how base-paired segments may occur in a single strand of RNA.

Q.12- Explain the following terms in the context of RNA structure: (a) poly A tail (b) cap.

Q.13- The following base sequence represents part of the transcribing strand of DNA     5’TACCATGGGCCC.3’

 (a) Give the orientation and base sequence of the complementary strand.

(b) Give the orientation and base sequence of the RNA that is  synthesized from it.

Q.14-Enlist the important differences between DNA and RNA

Q.15-Draw a well labeled diagram of secondary structure of t RNA and describe the significance of each of its arm. Why is t RNA called an adapter molecule?

Q.16- Discuss the functions of different types of RNAs present in a cell?

Q.17- Discuss the role played by Histones in DNA packaging?

Q.18- Draw a well labeled diagram showing the secondary structure of DNA. Discuss the salient features of Watson and Crick model of double stranded structure of DNA.

Q.19-Give a brief account of the small RNA s present in a cell. Discuss the significance of each of them.

Q.20-What is meant by polarity of DNA? What is its significance in replication or transcription mechanisms?

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