Nootan solutions for Biology [English] Class 12 ISC chapter 6 - Molecular Basis of Inheritance [Latest edition]

The experiment which shows that DNA is the genetic material in bacteriophages is the ______.

Genetic information in a DNA molecule is coded in the ______.

Which enzyme catalyses the synthesis of a new strand for a DNA molecule by linking nucleotides to the developing strand?

In DNA replication, the Okazaki fragments on the lagging strand are joined together by ______.

Transcription is the transfer of genetic code from a DNA molecule to ______.

Translation is the ______.

The signal to start translation is the initiator codon, usually AUG, the codon for ______.

If a DNA strand has a nitrogenous base sequence T, A, C, G, A, the sequence of bases on the corresponding mRNA would be ______.

Transcription involves ______.

When DNA replication begins ______.

Which is not a nucleotide base in DNA?

What are the base-pairing rules for DNA?

A DNA strand having the sequence C-G-A-T-T-G would be complementary to the sequence ______.

‘One species’ DNA differs from others in its ______.

A RNA molecule is ______.

A mRNA molecule is produced by ______.

Each codon calls for a specific ______.

Anticodons pair with ______.

In translation, an initiation complex consists of ______.

A polysome is ______.

If 30% of an organism’s DNA is thymine, then ______.

The double-helix model of DNA resembles a twisted ladder in which the rungs of the ladder are:

In a DNA molecule ______.

Which of the following is not a chemical component of deoxyribonucleic acid?

Which of the following regarding DNA is not true?

In his work with pneumonia-causing bacteria and mice, Griffith found that ______.

E. coli cell grown on ¹⁵N medium are transferred to ¹⁴N medium and allowed to grow for two generations. DNA extracted from these cells is ultracentrifuged in a cesium chloride density gradient. What density distribution of DNA would you expect in this experiment?

The elongation of the leading strand during DNA synthesis ______.

What is the basis for the difference in the synthesis of the leading and lagging strand of DNA molecules?

In an analysis of the number of different bases in a DNA sample, which result would be consistent with the base pairing rules?

The ‘primer’ required to initiate synthesis of a new DNA strand consists of ______.

A particular gene measures about 1 µm in length along a double-stranded DNA molecule. What is the approximate number of base pairs in this gene?

Extranuclear chromosomes occur within various organelles, including ______.

Which of the following is the correct sequence of event with reference to the central dogma?

The base sequence known as the anti-codon is a part of a ______.

If the DNA codons are CAT CAT CAT, and a guanine base is added at the beginning, then which would result?

The central dogma of molecular biology ______.

If the sequence of bases in DNA is TAGC, then the sequence of bases in RNA would be ______.

RNA processing is ______.

During protein synthesis, an anticodon on transfer RNA (tRNA) pairs with ______.

The creation of a RNA molecule from a section of DNA is known as ______.

Which of the following is not true of a codon?

RNA polymerase ______.

The bonds between the anticodon of a tRNA molecule and the complementary codon of mRNA are ______.

The phenomenon known as wobble refers to ______.

Which of the following is not true of RNA processing?

Which of the following mutations would be most likely to have a harmful effect on an organism?

Which component is not directly involved in the process known as translation?

DNA was first proven to be the transforming factor in bacterial cells by ______.

Hershey and Chase experimented with radioactively labelled phosphorus and sulfur to determine that DNA and not protein is the genetic material. Which of the following was essential to this confirming experiment?

Which statement is not correct about the results of the Hershey - Chase experiment with T₂ bacteriophage?

Which is not a major function of the genetic material?

Nucleic acid was first discovered in pus cells in ______.

One of Chargaff’s rules states that:

If a species contains 23% adenine in its DNA, what is the percentage of guanine it would contain?

The amount of adenine is always equal to the amount of ______ in DNA.

Information from X-ray crystallographic data collected by ______ was used by Watson and Crick in their development of the model of DNA.

The X-ray diffraction photography of Rosalind Franklin and Maurice Wilkins was critical evidence of DNA:

In the Watson and Crick model of DNA, the ‘steps’ of the ladder are composed of ______.

Which of the following statements about DNA replication is not correct?

Because the original strand of the double-stranded helix is found in each daughter cell, the replication process is called:

Which does not describe a function of the DNA polymerase molecule?

Which statement is not true about DNA replication?

Which statement is not true about DNA replication in prokaryotes?

Which statement is ·not true about DNA replication in eukaryotes?

Before the DNA repair enzyme complex has completed its function, approximately how many base pairs are still improperly matched?

The evidence that the transformation as described by Griffith’s experiments was due to DNA:

If a species contains 40% guanine in its DNA, what is the percentage of cytosine that is would contain?

The DNA model proposed by Watson and Crick:

Replication of DNA is:

Genetic mutations are:

The idea that a single gene coded for a polypeptide rather than an enzyme was evident from the ______.

Today, it is most appropriate to state that a gene controls:

The concept of an ‘inborn error of metabolism’ was the first recognition of the relationship between gene activity and metabolic disease, made by ______.

Studies by Beadle and Tatum that produced the ‘one-gene one-enzyme hypothesis’ were conducted using the ______.

Which of the classes of RNA molecules is found in almost no prokaryotes?

Which of the classes of RNA molecules is linked with proteins in forming the large and small subunits of a cytoplasmic structure?

Prior to protein synthesis, DNA ______.

Which of the classes of RNA molecules carries the genetic information as it is needed for the construction of a protein?

Which of the classes of RNA molecules carries the amino acids that are added to the growing polypeptide chain?

Which of the classes of RNA molecules is never found in the cytosol?

The first codon to be deciphered was ______ which codes for ______.

Transcription of a part of a DNA molecule with a nucleotide sequence of A-A-A-C-A-A-C-T-T results in a mRNA molecule with the complementary sequence of ______.

If one strand of DNA has the base sequence AAGCAA, the complementary strand has which of the following sequences?

Which is the process that synthesises mRNA, tRNA, or rRNA?

Which of the following nucleotide bases is found only in RNA, not in DNA?

Which of the following nucleotide bases is found only in DNA, not in RNA?

An intervening sequence in a eukaryotic gene that is not an active part of the gene is called a ______.

A ribozyme is ______.

For translation to take place, which of the following would not be required to be present?

Which of the following processes does not take place during translation?

The correct sequence of events in the production of a polypeptide is ______.

All of the following are associated with the role of ribosomes except:

What part of haemoglobin is affected in sickle cell anaemia?

An unknown chemical is analysed and found to contain the bases thymine and guanine. The chemical is most likely ______.

Which is the process by which a protein is constructed?

In order to produce many copies of a protein fast, the cell uses ______.

Which is most directly responsible for the sequence of amino acids in a protein?

Which is not true about the genetic code?

Codons are:

The portion of the tRNA that permits proper sequencing of amino acids to occur on the mRNA strand ______.

Which statement regarding translation is out of order first?

If you grew bacteria in heavy nitrogen and then switched them to light nitrogen, how many generations after switching would you have some light/light DNA?

Frederick Griffith has discovered ______.

To initiate translation, the mRNA first binds to ______.

Which of the following steps in transcription is catalysed by RNA polymerse?

Both deoxyribose and ribose belong to a class of sugars called ______.

In a DNA strand the nucleotides are linked together by ______.

In some viruses, DNA is synthesised by using RNA as template. Such a DNA is called ______.

Which of the following are the functions of RNA?

In a nucleosome, the DNA is wrapped around ______.

Which is not true about the chromosomes of a multicellular organism?

The diploid (2n) number of chromosomes for humans is ______.

Eukaryotic chromosomes:

Meselson and Stahl’s experiment proved ______.

Initiation codon of protein synthesis in Eukaryotes is ______.

A nucleoside differs from a nucleotide in the absence of ______.

Which of the following is true with respect to AUG?

The first genetic material could be ______.

The amino acid attaches to the tRNA at its ______.

Length of DNA with 23 base pairs is ______.

Which of the following groups of codons are used for the termination of polypeptide chain synthesis?

Similarity in DNA and RNA is ______.

Messenger RNA is produced in ______.

Hargbvind Khorana is known for ______.

An operon is a ______.

The lac operon is transcribed when ______.

Using recombinant DNA technology, genes from a donor cell can be implanted into a bacterium for DNA replication and protein synthesis. The kind of cells that can be used as gene donors are ______.

A restriction enzyme breaks bonds between the ______.

An eukaryotic chromosome differs from a bacterial chromosome in having ______.

Each restriction enzyme cleaves a molecule only at ______.

In recombinant DNA technology a plasmid vector must be cleaved by ______.

About how much of the DNA in a eukaryotic cell is expressed at any one time:

Viral genes are made up of ______.

Some RNA viruses carry a gene for an enzyme that uses viral RNA as a template in the synthesis of DNA. This enzyme is:

When lactose is present:

When tryptophan is present:

Which of these is mismatched?

A scientist adds radioactive uridine to a culture of cells and examines an autoradiograph. Which type of chromatin is apt to· be labelled?

In prokaryotic but not eukaryotic cells, a ______ precedes the genes of an operon.

A base sequence signalling the start of a gene is a ______.

DNA fragments result when ______ cut DNA molecules at specific sites.

A bacterial gene that is perpetually active is said to be ______.

Which of the following information transfers is catalyzed the reverse transcriptase?

A mutation that renders the regulatory gene of a repressible operon non-functional would result in:

Inducible operons differ from repressible operons in that ______.

In E.coli, the lac operon gets switched on when ______.

Control of gene expression in prokaryotes takes place at the level of ______.

If the sequence of nitrogen bases of the coding strand of DNA in a transcription unit is 5’ - ATGAATG - 3’ the sequence of bases in its RNA transcript would be ______.

DNA segments are recognised by ______.

The genetic code is a sequence of ______ along a sugar-phosphate strand of a DNA molecule.

After RNA processing, an mRNA molecule travels from the ______ to the ______, where it joins with a ______.

Each functioning ribosome is composed of two subunits; the smaller subunit of a ribosome has a binding site for ______, and the larger subunit has two binding sites for two ______ molecules.

After a mRNA has been translated and leaves the ribosome or polysome, it is ______.

In the Meselson-Stahl experiment, it was confirmed that DNA replication is ______, as was predicted by the Watson and Crick double-helix model.

The genes that code for polypeptides are called ______ genes, whereas the genes that activate or inactivate other genes are called ______ genes.

In general, bacterial genes are regulated at the time of ______.

When an end product of a metabolic pathway activates the repressor of the operon that produces enzymes for the pathway, it is called ______.

Most RNA viruses carry a gene for an enzyme that uses viral RNA as a template in the synthesis of more viral RNA. This enzyme is ______.

State whether the following statement is true or false.

In 1964, Marshall Nirenberg broke the genetic code by showing that UUU is the mRNA codon for the amino acid glycine.

State whether the following statement is true or false.

Meselson and Stahl showed clearly that DNA replication was semiconservative.

State whether the following statement is true or false.

Translation of the genetic code takes place on the ribosome.

State whether the following statement is true or false.

All DNA polymerases can only extend polynucleotide chains; they cannot initiate new chains.

State whether the following statement is true or false.

The 5’ end of the coding segment in mRNA corresponds to the amino terminus of its nascent polypeptide chain.

State whether the following statement is true or false.

The eukaryotic chromosome contains nucleosome spools.

State whether the following statement is true or false.

The primary transcript is much longer than mature mRNA because of the presence of introns in the former.

State whether the following statement is true or false.

Introns are found in the circular chromosomes of prokaryotes.

State whether the following statement is true or false.

All the structural genes of the operon are transcribed on a single long mRNA.

State whether the following statement is true or false.

In repressible operons, an inactive repressor is normally produced that is activated by the metabolic product (corepressor) of the reaction controlled by the operon enzymes.

Name the scientists who were awarded the Nobel Prize for deciphering the DNA structure.

Who proposed the theory of semi-conservative replication of DNA?

Name an organism in which RNA acts as a genetic material.

If the base sequence of one strand of DNA is CAT TAG TAC GAC, what will be the base sequence of the complementary DNA strand?

If the base sequence of one strand of DNA is CAT TAG TAC GAC, what will be the base sequence of the complementary RNA strand?

Name the anticodon required to recognize the following codon: AAU.

Name the anticodon required to recognize the following codon: CGA

Name the anticodon required to recognize the following codon: UAU

Name the anticodon required to recognize the following codon: GCA.

How many triplet codons can be made from the four ribonucleotides A, U, G, and C containing no uracils?

Where are the genes located in a cell?

Name the scientist who performed transformation experiments on Diplococcus pneumoniae and in which year.

What is transformation?

Name the organism on which Hershey and Chase conducted their genetic experiments.

Name the scientists who first demonstrated that RNA is the genetic material.

Name the scientists who provided evidence in support of the semi-conservative model of DNA replication.

What is a genetic code?

Name the chain initiation codons.

Name the chain termination codons.

Mention two functions of the codon AUG.

Give reasons:

Genetic code is ‘universal’.

Which one out of the Rho factor and the sigma factor acts as the initiation factor during transcription in a prokaryote?

Which of the two subunits of the ribosome encounters an mRNA?

Name the enzyme that joins the small fragments of DNA of a lagging strand during DNA replication.

Which property of the DNA double helix led Watson and Crick to hypothesise a semi-conservative mode of DNA replication?

Name the scientist who postulated the presence of an adapter molecule that can assist in protein synthesis.

Why tRNA is called an adapter molecule?

1. Name the scientist who suggested that the genetic code should be made of a combination of three nucleotides.
2. Explain the basis on which he arrived at this conclusion.

Name the specific components and the linkage between them that form deoxyadenosine.

If a double stranded DNA has 20 per cent of cytosine, calculate the per cent of adenine in the DNA.

Who coined the term ‘nucleosomes’?

Who coined the term cistron, recon and muton?

Name the scientist who first regarded tRNA as an adapter molecule.

What is a cistron?

Why is hnRNA required to undergo splicing?

Name the positively charged proteins around which the negatively charged DNA is wrapped.

How do histones acquire a positive charge?

Name the two basic amino acids that provide positive charges to histone proteins.

Name the transcriptionally active region of chromatin in a nucleus.

What is the central dogma?

Give the scientific term for the following:

The smallest unit of DNA can mutate.

Give an example of a codon having a dual function.

Who discovered the phenomenon of RNA splicing?

Who coined the term ‘gene’?

State the difference between the structural genes in a Transcription Unit of Prokaryotes and Eukaryotes.

Mention the two additional processing which hnRNA needs to undergo after splicing so as to become functional.

The amino acids become attached to which end of the RNA?

Which scientist gave the nucleosome concept?

Define the term ‘house-keeping genes.’

Name the scientists who proposed the operon model.

Who discovered bacteriophages?

In which condition does the phenomenon of feedback repression operate in E. coli?

Name the scientists who first discovered the phenomenon of reverse transcription.

Who proposed the gene battery model to explain gene expression in eukaryotes?

Retroviruses have no DNA. However, the DNA of the infected host cell does possess viral DNA. How is it possible?

State the best-known contribution of Alec Jeffrey.

Write the scientific importance of the single-nucleotide polymorphism identified. in the human genome.

State any three goals of the human genome project.

Which human chromosome has the maximum number of genes?

Which human chromosome has the fewest genes?

Expand the following abbreviation: BAC

Expand ‘YAC’.

What is the general idea behind the following expression?

DNA → RNA → Protein.

In which direction, 5’-3’ or 3’-5’, are the new strands of DNA formed during replication?

In 1928, the bacteriologist Frederick Griffith conducted transformation experiments. How did these experiments contribute to the history of molecular genetics?

A segment of DNA, GCCAGGGGATG, was translated into the oligopeptide arginine-serine- praline-tyrosine.

1. What was the base sequence in the mRNA transcribed from the DNA segment?
2. What are the codons for the 4 amino acids?
3. If the first adenine in the DNA segment gets substituted by guanine, what will be the:
   1. mRNA transcript?
   2. sequence of amino acids in the new oligopeptide?
   3. anticodons on tRNA for the amino acids?

A hypothetical mRNA, AUG CGC CUA AAG AGG, codes for five amino acids. What will happen if you delete the first ‘C’? Will five amino acids still be coded for? Give reasons.

The genetic code is said to be a triplet code. What does this mean and why is it important?

What properties of the bacteriophages made them ideal material for solving the controversy that which is the genetic material, protein or DNA?

How did the Meselson-Stahl experiment confirm that DNA replication is semi-conservative?

How are errors that occur during DNA replication repaired?

How do a code, codon, and anticodon differ?

A tRNA molecule has four active sites. Where are these sites and what does each do?

What is the difference between the P-site and A-site of a ribosome?

Why are there 64 different codons for 20 different amino acids?

What is the evidence that indicates DNA is the primary genetic material?

What is a codon?

How many codons serve as stop (nonsense) codons?

How many codons serve as initiating codons?

In genetics, a reference is made to an abbreviated expression ‘AUG’. Write any three points of scientific information embodied in this combination of three letters.

Write about the transfer RNAs as follows:

Any two characteristics in their structure.

Write about the transfer RNAs as follows:

Part of the cell where they are located.

Write about the transfer RNAs as follows:

The technical name for the set of bases that are complementary to the triplet code on the mRNA.

Write the transcribed mRNA of a DNA strand with the base sequence GAT CAT ACT. What is the name and the specific role of the last codon of the transcribed mRNA in this case?

The base sequence on one of the strands of DNA is TAC TAG GAT.

1. Give the base sequence of its complementary strand.
2. What is the distance maintained between the two consecutive paired bases in the DNA molecule?
3. Who contributed the base complementarity rule?
4. Categorise these bases using their full names.
5. What holds these base pairs together?

How is the wrong base removed before proceeding to add new bases in the 5’ - 3’ direction during DNA replication?

A U G G A C C U G A U A U U U U G A is the base sequence in a strand of mRNA.

1. Write the base sequence of the DNA strand from which it has been transcribed.
2. Upon translation, how many amino acids will the resulting peptide have?

An mRNA strand has a series of codons out of which three are mentioned below:

1. AUG
2. UUU
3. UAG

1. What will these codons be translated into?
2. What are the DNA codons that would have transcribed these RNA codons?

A tRNA is charged with the amino acid phenylalanine.

1. At what end of tRNA is this amino acid attached?
2. What is the mRNA codon that codes for phenylalanine?
3. What is its anticodon?
4. Name the enzyme responsible for this attachment.

The DNA is contained within the nucleus of a eukaryotic cell; the proteins for which it codes are needed within the cytoplasm. Explain the roles of the following in the translation of the genetic code into an active enzyme in the cytoplasm:

DNA, mRNA, tRNA, rRNA, and polysomes.

What is the central dogma in molecular biology?

Name the two processes represented in the central dogma in molecular biology.

How has the central dogma in molecular biology been modified with the discovery of retroviruses?

Give an account of the Hershey-Chase experiment proving that DNA and not the protein coat of the virus is the infecting agent.

How is transformation different from transduction?

Give a brief account of the different steps involved in the translation of mRNA into a polypeptide in prokaryotes.

Explain the experiment performed by Griffith on Streptococcus pneumoniae. What did he conclude from this experiment?

Name the three scientists who followed up on Griffith’s experiments. What did they conclude and how?

What are introns?

What are exons?

What ensures a linear arrangement of amino acids, although the genes are discontinuous?

In E. coli, three enzymes, β-galactosidase, permease, and transacetylase, began to be produced as soon as lactose was added. Explain why the enzymes were not forming in the absence of lactose.

What is meant by an operon?

How does an excess of tryptophan cause a ‘switching-off’ of the tryptophan operon?

How is the functioning of the lac operon different from that of the try operon?

All the cells in a multicellular organism have the same genetic constitution, yet they function differently. How would you account for this?

Explain the following term in connection with the concept of the lac operon in E.coli:

Structural genes

Explain the following term in connection with the concept of the lac operon in E.coli:

Operon

Explain the following term in connection with the concept of the lac operon in E.coli:

Cistron

Explain the following term in connection with the concept of the lac operon in E.coli:

Polycistron

Explain the following term in connection with the concept of the lac operon in E.coli:

Repressor

What is ‘reverse transcription’?

Mention the term used for the group of viruses which show reverse kind of transcription.

Distinguish between structural gene, regulatory gene and operator gene.

Explain how the structural genes of the lac operon start transcription on the addition of lactose.

Differentiate between induction and repression.

When and in what system do the phenomena of induction operate in a cell system?

When and in what system do the phenomena of feedback repression operate in a cell system?

What is ‘reverse transcription’?

Explain how the single-stranded RNA of viruses give rise to double-stranded DNA.

What is ‘feedback inhibition’?

Compare feedback inhibition with the mechanism of regulation based on the operon model.

Mention the differences between the mechanisms of the regulation of gene activity in the lac operon and the try operon in E. coli.

How has the sequencing of the human genome opened new windows for the treatment of various genetic disorders?

A low level of expression of the lac operon occurs at all times. Can you explain the logic behind this phenomenon?

What is a genetic code?

Mention the essential qualities for a universal genetic code.

How did Hershey and Chase prove that DNA is the genetic material?

Describe the experiment performed by Griffith. What conclusions did he infer from his observations?

Explain the mechanism of transcription in a prokaryotic cell.

Describe Avery, McLeod and McCarty’s experiment. State its significance.

Describe the structure of a nucleosome.

Which one of the following is NOT a structural part of a transcription unit in DNA?

The final proof for DNA as the genetic material came from the experiments conducted by ______.

The codons used in chain termination are ______.

The abbreviation hnRNA stands for ______.

The human genome contains more than ______ nucleotide pairs.

Assertion: Nucleosome consists of a strand of DNA coiled around a core of histone proteins.

Reason: The histone proteins forming the core of nucleosome are of four major types, viz, H1, H2, H3 and H4.

Study the diagram given below and answer the questions that follow:

1. Identify the part labelled as ‘A’:
   1. Leading strand
   2. Lagging strand
   3. DNA template
   4. RNA template
2. The enzyme which joins the small fragments of newly synthesised DNA on the 5’ → 3’ template strand is:
   1. Helicase
   2. Topoisomerase
   3. DNA ligase
   4. RNA polymerase
3. The overall process of DNA replication is:
   1. Continuous
   2. Lagging
   3. Discontinuous
   4. Semi-discontinuous
4. The alphabet ‘B’ and ‘C’ represent:
   1. mRNA
   2. mRNA
   3. Okazaki fragments
   4. Single-strand binding protein
5. The role of the enzyme DNA polymerase is to:
   1. unwind the DNA helix
   2. synthesis mRNA
   3. cause the polymerisation of the complementary daughter strand
   4. synthesise RNA primer

If the following is the sequence of nucleotides in mRNA, predict the sequence of amino acids coded by it:

AUG UUU UUC UUC UUU UUU UUC.

Can you now correlate which two properties of the genetic code you have learnt?

Correlate the codons of the mRNA strand with the amino acids of the polypeptide translated.

5’ AUG ACC UUU CACU UCG UGU AA3’ → mRNA

Met - Thr - Phe - His - Phe - Val → Translated polypeptide

Infer any three properties of the genetic code with examples from the above information.

Depending upon the chemical nature of the template (DNA or RNA) and the nature of nucleic acids synthesised from it (DNA or RNA), list the types of nucleic acid polymerases.

List two essential roles of ribosomes during translation.

Name the parts ‘A’ and ‘B’ of the transcription unit shown below.

Draw a schematic representation of the structure of a transcription unit and show the following in it.

1. Direction in which the transcription occurs.
2. Polarity of the two strands involved.
3. Template strand.
4. Terminator gene.

Mention the function of the promoter gene in transcription.

Look at the given figure and answer the questions:

1. What is this diagram representing?
2. Name the parts a, b, c, and d.
3. In the eukaryotes, the DNA molecules are organised within the nucleus. How is the DNA molecule organised in a bacterial cell in the absence of a nucleus?

Explain the processing the hnRNA needs to undergo before becoming functional mRNA in eukaryotes.

Describe post-transcriptional processing of RNA in eukaryotes.

Write the dual purpose served by deoxyribonucleoside triphosphates in the polymerisation.

Although a prokaryotic cell has no defined nucleus, yet DNA is not scattered throughout the cell. Explain.

State the ‘Central dogma’ as proposed by Francis Crick. Are there any exceptions to it? Support your answer with a reason and an example.

Study the given figure and answer the following:

1. Name the molecule ‘X’ synthesised by the ‘i’ gene. How does this molecule get inactivated?
2. Which one of the structural genes codes for β-galactosidase?
3. When will the transcription of this gene stop?

Study the given figure and answer the questions:

1. How does the repressor molecule get inactivated?
2. When does the transcription of lac mRNA stop?
3. Name the enzyme transcribed by the gene ‘z’.

Retroviruses have no DNA. However, the DNA of the infected host cell does possess viral DNA. How is it possible?

Group the following as nitrogenous bases and nucleosides:

Adenine, Cytidine, Thymine, Guanosine, Uracil and Cytosine.

If a double stranded DNA has 20 per cent of cytosine, calculate the per cent of adenine in the DNA.

If the sequence of one strand of DNA is written as follows:

5’- ATG CATG CATG CATG CATG CATGC - 3’

Write down the sequence of the complementary strand in 5’ → 3’ direction.

If the sequence of the coding strand in a transcription unit is written as follows:

5’ - ATGC ATGC ATGC ATGC ATGC ATGC ATGC - 3’

Write down the sequence of mRNA.

Which property of DNA double helix led Watson and Crick to hypothesise semi-conservative mode of DNA replication? Explain.

Depending upon the chemical nature of the template (DNA or RNA) and the nature of nucleic acids synthesised from it (DNA or RNA), list the types of nucleic acid polymerases.

Differentiate between the following:

mRNA and tRNA

Differentiate between the following:

Template strand and Coding strand

List two essential roles of ribosomes during translation.

Explain (in one or two lines) the function of the following:

tRNA

Briefly describe the following:

Transcription 

Briefly describe the following:

Translation

In the medium where E. coli was growing, lactose was added, which induced the lac operon. Then, why does lac operon shut down some time after addition of lactose in the medium?

Explain (in one or two lines) the function of the following:

Promoter

Explain (in one or two lines) the function of the following:

Exons

Why is the Human Genome project called a mega project?

What is DNA fingerprinting?

Give the applications of DNA fingerprinting technique.

Briefly describe the following:

Bioinformatics

Differentiate between the following:

Repetitive DNA and Satellite DNA

Study the flow chart given below and answer the questions that follow:

1. S-strain → into mice → mice die
2. R-strain → into mice → mice live
3. Heat-killed S-strain + live R-strain → into mice → ‘A’
4. Heat-killed S-strain + DNAase + live R-strain → into mice → ‘B’

1. Name the organism and differentiate between its two strains, R and S, respectively.
2. Write the results ‘A’ and ‘B’ obtained in steps (c) and (d), respectively.
3. Name the scientist who performed the steps (a), (b) and (c).
4. Write the specific conclusion drawn from step (d).

“A very small sample of tissue or even a drop of blood can help determine paternity”. Provide a scientific explanation to substantiate the statement.

Name and describe the technique that will help in solving a case of paternity dispute over the custody of a child by two different families.

Following a severe accident, many charred, disfigured bodies are recovered from the site, making the identification of the dead very difficult. Name and explain the technique that would help the authorities establish the identity of the dead to be able to hand over the dead to their respective relatives.

In a hospital, two babies one boy and the other girl are borne simultaneously and somehow got exchanged. Both the women claimed to be the mother of baby boy and ultimately the matter went to the court. The judge asked to conduct certain tests to settle the issue of the paternity. Answer the following:

1. Name the test that the judge ordered to conduct.
2. How is it helpful in deciding paternity issues?

What do ‘Y’ and ‘B’ stand for in ‘YAC’ and ‘BAC’ used in the Human Genome Project (HGP)? Mention their role in the project.

Write the percentage of the total human genome that codes for proteins and the percentage of discovered genes whose functions are known as observed during HGP.

Expand the ‘SNPs’ identified by scientists in HGP.

Differentiate between Cistron, muton and recon.

Differentiate between Conservative and dispersive replication of DNA.

Differentiate between Euchromatin and Heterochromatin.

Differentiate between Exons and introns.

Differentiate between Leading stand and lagging strand.

Differentiate between the following:

mRNA and tRNA

Differentiate between the one gene-one enzyme hypothesis and the one gene-one polypeptide hypothesis.

Differentiate between prokaryotic and eukaryotic replication.

Differentiate between promoter and terminator in a transcription unit.

Differentiate between RNA polymerase I, RNA polymerase II and RNA polymerase III.

Differentiate between sense and anti-sense DNA strands.

Differentiate between the following:

Template strand and Coding strand

Distinguish between the following.

Transcription and Translation

Differentiate between unambiguous and degenerate codons.